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  • 1.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Bjur, Dennis
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Thorsen, Kim
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Sandström, Patrick
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    High intratendinous lactate levels in painful chronic Achilles tendinosis. An investigation using microdialysis technique.2002In: Journal of Orthopaedic Research, ISSN 0736-0266, E-ISSN 1554-527X, Vol. 20, no 5, p. 934-938Article in journal (Refereed)
    Abstract [en]

    In this investigation the microdialysis technique was used to study the concentrations of lactate in Achilles tendons with painful chronic tendinosis and in normal pain-free tendons. In four patients (mean age 40.7 years) with a painful thickening localized at the 2-6 cm level in the Achilles tendon (chronic Achilles tendinosis) and in five controls (mean age 37.2 years) with normal Achilles tendons the local concentrations of lactate were registered under resting conditions. All tendons were examined using ultrasonography. In the tendons with tendinosis the painful thickening corresponded to a widened tendon and structural tendinosis changes. Normal tendons showed no widening and a normal structure. A standard microdialysis catheter was inserted into the Achilles tendon under local anesthesia. Samplings were done every 15 min during a 4 h period. The results showed significantly higher mean concentrations of lactate in tendons with tendinosis compared to normal tendons (2.15 mmol/l vs. 1.14 mmol/l). The lactate concentrations in the tendons with tendinosis were stable, and approximately twofold higher than in the normal tendons during the whole 4 h investigation period. In conclusion, the higher concentrations of lactate in Achilles tendons with painful tendinosis indicate that there are anaerobic conditions in the area with tendinosis. The importance of this finding for the pathogenesis and pain mechanisms in this chronic condition needs to be further investigated.

  • 2.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Anatomy.
    Thorsen, Kim
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Fahlström, Martin
    Umeå University, Faculty of Medicine, Community Medicine and Rehabilitation, Rehabilitation Medicine. Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Johansson, Håkan
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Glutamate NMDAR1 receptors localised to nerves in human Achilles tendons. Implications for treatment?2001In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 9, no 2, p. 123-126Article in journal (Refereed)
    Abstract [en]

    In this investigation, we show the presence of both free glutamate (microdialysis) and glutamate NMDAR1 receptors (immunohistochemical analyses of tendon biopsies), in tendons from patients with chronic Achilles tendon pain (Achilles tendinosis) and in controls (pain-free tendons). The NMDAR1 immunoreaction was usually confined to acetylcholinesterase-positive structures, implying that the reaction is present in nerves. Glutamate is a potent pain mediator in the human central nervous system, and in animals it has been shown that peripherally administered glutamate NMDA receptor antagonists diminish the response to formalin-induced nociception. Our present finding of glutamate NMDA receptors in human Achilles tendons might have implications for pain treatment.

  • 3.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Anatomy.
    Thorsen, Kim
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    In vivo microdialysis and immunohistochemical analyses of tendon tissue demonstrated high amounts of free glutamate and glutamate NMDAR1 receptors, but no signs of inflammation, in Jumper's knee.2001In: Journal of Orthopaedic Research, ISSN 0736-0266, E-ISSN 1554-527X, Vol. 19, no 5, p. 881-886Article in journal (Refereed)
    Abstract [en]

    This investigation describes, to our knowledge, the first experiment where the microdialysis technique was used to study certain metabolic events in human patellar tendons in combination with immunohistochemical analyses of tendon biopsies. In five patients (four men and one woman) with a long duration (range 12-36 months) of pain symptoms from Jumper's knee (localized tenderness in the patellar tendon verified as tendon changes with ultrasonography or MRI), and in five controls (four men and one woman) with normal patellar tendons, a standard microdialysis catheter was inserted into the patellar tendon under local anestesia. The local concentrations of glutamate (excitatory neurotransmitter) and prostaglandin E2 (PGE2) were registered under resting conditions. Samplings were done every 15 min during a 2 h period. In all individuals (patients and controls) biopsies were taken for immunohistochemical analyses. The results showed that it was possible to detect and measure the concentrations of glutamate and PGE2 in the patellar tendon with the use of microdialysis technique. There were significantly higher concentrations of free glutamate, but not PGE2, in tendons with tendinosis compared to normal tendons. In the biopsies, there were no inflammatory cell infiltrates, but, for the first time, it was shown that there was immunoreaction for the glutamate receptor NMDAR1 in association with nerve structures in human patellar tendons. These findings altogether indicate that glutamate might be involved in painful Jumper's knee, and further emphasizes that there is no chemical inflammation (normal PGE2 levels) in this chronic condition.

  • 4.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Hedberg, G
    Bergström, E
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    High thigh muscle strength but not bone mass in young horseback-riding females1998In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 62, no 6, p. 497-501Article in journal (Refereed)
    Abstract [en]

    To evaluate whether the type of weight-bearing loading subjected to the skeleton during horseback-riding was associated with differences in bone mass and muscle strength of the thigh, we investigated bone mass and isokinetic muscle strength in 20 female horse riders (age 17.9 +/- 0.6 years) who were riding 7.0 +/- 3.4 hours/week, and 20 nonactive females (age 17.8 +/- 1.1 years). The groups were matched according to age, weight, and height. Areal bone mineral density was measured in total body, head, lumbar spine, right femoral neck, Ward's triangle, and trochanter, the whole dominant and nondominant humerus, and in specific sites in the right femur diaphysis, distal femur, proximal tibia, and tibia diaphysis using dual X-ray absorptiometry. Isokinetic concentric and eccentric peak torque of the quadricep and hamstring muscles were measured using an isokinetic dynamometer. There were no significant differences in bone mass between the horseback riders and nonactives at any site measured. The horse riders were significantly (P < 0.05-0.01) stronger in concentric hamstrings strength at 90 degrees/second and 225 degrees/second and in eccentric quadricep and hamstring strength at 90 degrees/second. Horseback riding in young females is associated with a high muscle strength of the thigh, but not with a high bone mass.

  • 5.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Ljung, B O
    Thorsen, Kim
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    In vivo investigation of ECRB tendons with microdialysis technique--no signs of inflammation but high amounts of glutamate in tennis elbow.2000In: Acta Orthopaedica Scandinavica, ISSN 0001-6470, Vol. 71, no 5, p. 475-479Article in journal (Refereed)
    Abstract [en]

    We used the microdialysis technique to study concentrations of substances in the extensor carpi radialis brevis (ECRB) tendon in patients with tennis elbow. In 4 patients (mean age 41 years, 3 men) with a long duration of localized pain at the ECRB muscle origin, and in 4 controls (mean age 36 years, 2 men) with no history of elbow pain, a standard microdialysis catheter was inserted into the ECRB tendon under local anesthesia. The local concentrations of the neurotransmitter glutamate and prostaglandin E2 (PGE2) were recorded under resting conditions. Samplings were done every 15 minutes during a 2-hour period. We found higher mean concentrations of glutamate in ECRB tendons from patients with tennis elbow than in tendons from controls (215 vs. 69 micromoL/L, p < 0.001). There were no significant differences in the mean concentrations of PGE2 (74 vs. 86 pg/mL). In conclusion, in situ microdialysis can be used to study certain metabolic events in the ECRB tendon of the elbow. Our findings indicate involvement of the excitatory neurotransmitter glutamate, but no biochemical signs of inflammation (normal PGE2 levels) in ECRB tendons from patients with tennis elbow.

  • 6.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, R
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Autologous periosteum transplantation for the treatment of full thickness patellar cartilage defects.2001In: Ortopedia, traumatologia, rehabilitacja, ISSN 1509-3492, Vol. 3, no 2, p. 216-223Article in journal (Refereed)
    Abstract [en]

    Full-thickness patellar cartilage defects are often, but not always, associated with disabling anterior knee-pain and inability to take part in regular daily activities. There is no treatment of choice for this condition. It is well known that the cells in the cambium layer of the periosteum are pluripotent and can differentiate into hyaline (or hyaline-like) cartilage, especially if in a joint environment and under the influence of continous passive motion. In a few clinical studies autologous periosteum transplants alone have been used in the treatment of full thickness patellar cartilage defects. The results are varying. At our clinic, autologous periosteum transplantation alone, followed by continous passive motion (CPM) in the immediate postoperative period and non-weight bearing loading for 3 months, has shown promising clinical results. The best clinical results have been achieved on traumatic (fracture, contusion, dislocation) cartilage defects, where 83% of patients have been clinically graded as excellent or good at follow-up (> 2 years postoperatively). For non-traumatic patellar cartilage defects (chondromalacia NUD) the results are poor, with only 35% of patients being graded as excellent or good. Therefore, we believe that no-traumatic patellar cartilage defects (chondromalacia NUD) are less suitable for treatment with autologous periosteum transplants, and are at our clinic not any longer included for this type of treatment.

  • 7.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Chronic Achilles tendinosis: recommendations for treatment and prevention.2000In: Sports Medicine, ISSN 0112-1642, E-ISSN 1179-2035, Vol. 29, no 2, p. 135-146Article in journal (Refereed)
    Abstract [en]

    Chronic Achilles tendinosis is a condition with an unknown aetiology and pathogenesis that is often, but not always, associated with pain during loading of the Achilles tendon. Histologically, there are no inflammatory cells, but increased amounts of interfibrillar glycosaminoglycans and changes in the collagen fibre structure and arrangement are seen. In situ microdialysis has confirmed the absence of inflammation. It is a condition that is most often seen among recreational male runners aged between 35 and 45 years, and it is most often considered to be associated with overuse. However, this condition is also seen in patients with a sedentary lifestyle. Chronic Achilles tendinosis is considered a troublesome injury to treat. Nonsurgical treatment most often includes a combination of rest, NSAIDs, correction of malalignments, and stretching and strengthening exercises, but there is sparse scientific evidence supporting the use of most proposed treatment regimens. It has been stated that, in general, nonsurgical treatment is not successful and surgical treatment is required in about 25% of patients. However, in a recent prospective study, treatment with heavy load eccentric calf muscle training showed very promising results and may possibly reduce the need for surgical treatment of tendinosis located in the midportion of the Achilles tendon. The short term results after surgical treatment are frequently very good, but in the few studies with long term follow-up there are signs of a possible deterioration with time. Calf muscle strength takes a long time to recover and, furthermore, a prolonged progressive calcaneal bone loss has been shown on the operated side up to 1 year after surgical treatment.

  • 8.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Intratendinous glutamate levels and eccentric training in chronic Achilles tendinosis: a prospective study using microdialysis technique.2003In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 11, no 3, p. 196-199Article in journal (Refereed)
    Abstract [en]

    Microdialysis has shown intratendinous glutamate levels to be significantly higher in Achilles tendons with painful tendinosis than in normal pain-free tendons, and treatment with eccentric training has shown good clinical results with diminished tendon pain during activity. In six patients with chronic painful Achilles tendinosis we performed microdialysis for 2 h, before and after the 12-week eccentric training program. The treatment was successful in all six patients, and the mean VAS score (amount of pain during Achilles tendon loading) decreased from 69 before treatment to 17 after treatment. There was no significant difference between the intratendinous glutamate levels before and after treatment. Our results offer no obvious neurophysiological explanation but showed that successful treatment with eccentric training was not associated with lowered intratendinous glutamate levels.

  • 9.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Sclerosing polidocanol injections of small vessels to treat the chronic painful tendon.2007In: Cardiovascular & hematological agents in medicinal chemistry, ISSN 1871-5257, Vol. 5, no 2, p. 97-100Article, review/survey (Refereed)
    Abstract [en]

    The chronic painful tendon (tendinopathy, tendinosis) is generally considered difficult to treat, not seldom causing long-term disability and sometimes ending the sports or work carreér. Most common sites for tendinopathy are the Achilles-, patellar-, extensor carpi radialis brevis (ERCB)-, and supraspinatus tendons. The origin of pain has for many years been unknown, but recently, by using ultrasound (US) + colour Doppler (CD), immunohistochemical analyses of tendon biopsies, and diagnostic injections of local anaestesia, we found a close relationship between areas with vasculo-neural ingrowth and tendon pain. Sensory nerves (Substance-P-SP and Calcitonin Gene Related Peptide-CGRP) were found inside and outside the vascular wall. In following clinical studies we have demonstrated good short-and mid-term clinical results using treatment with US+CD-guided sclerosing polidocanol injections, targeting the area with neovessels outside the tendon. Two-year follow ups have showed remaining good clinical results, and sonographically signs of remodelling with a significantly thinner tendon with a more normal structure. Whether the effects of polidocanol are mediated through destruction of neovessels, activity on nerves or a combination, is under evaluation.

  • 10.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Superior results with continuous passive motion compared to active motion after periosteal transplantation: A retrospective study of human patella cartilage defect treatment1999In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 7, no 4, p. 232-238Article in journal (Refereed)
    Abstract [en]

    Fifty-seven consecutive patients (33 men and 24 women), with a mean age of 32 years (range 16-53 years), who suffered from an isolated full-thickness cartilage defect of the patella and disabling knee pain of long duration, were treated by autologous periosteal transplantation to the cartilage defect. The first 38 consecutive patients (group A) were postoperatively treated with continuous passive motion (CPM), and the next 19 consecutive patients (group B) were treated with active motion for the first 5 days postoperatively. In both groups, the initial regimens were followed by active motion, slowly progressive strength training, and slowly progressive weight bearing. In group A, after a mean follow-up of 51 months (range 33-92 months), 29 patients (76%) were graded as excellent or good, 7 patients (19%) were graded as fair, and 2 patients (5%) were graded as poor. In group B, after a mean follow-up of 21 months (range 14-28 months), 10 patients (53%) were graded as excellent or good, 6 patients (32%) were graded as fair, and 3 patients (15%) were graded as poor. Altogether, nine of the fair or poor cases (50%) were diagnosed with chondromalacia of the patella. Our results, after performing autologous periosteal transplantation in patients with full-thickness cartilage defects of the patella and disabling knee pain, are good if CPM is used postoperatively. The clinical results using active motion postoperatively are not acceptable, especially not in patients with chondromalacia of the patella.

  • 11.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Aerobic workout and bone mass in females1997In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 7, no 6, p. 336-341Article in journal (Refereed)
    Abstract [en]

    This cross-sectional study aimed to investigate bone mass in females participating in aerobic workout. Twenty-three females (age 24.1 +/- 2.7 years), participating in aerobic workout for about 3 hours/week, were compared with 23 age-, weight- and height-matched non-active females. Areal bone mineral density (BMD) was measured in total body, head, whole dominant humerus, lumbar spine, right femoral neck, Ward's triangle, trochanter femoris, in specific sites in right femur diaphysis, distal femur, proximal tibia and tibial diaphysis, and bone mineral content (BMC) was measured in the whole dominant arm and right leg, using dual energy X-ray absorptiometry. The aerobic workout group had significantly (P < 0.05-0.01) higher BMD in total body (3.7%), lumbar spine (7.8%), femoral neck (11.6%), Ward's triangle (11.7%), trochanter femoris (9.6%), proximal tibia (6.8%) and tibia diaphysis (5.9%) compared to the non-active controls. There were no differences between the groups concerning BMD of the whole dominant humerus, femoral diaphysis, distal femur and BMC and lean mass of the whole dominant arm and right leg. Leaness of the whole dominant arm and leg was correlated to BMC of the whole dominant arm and right leg in both groups. In young females, aerobic workout containing alternating high and low impact movements for the lower body is associated with a higher bone mass in clinically important sites like the lumbar spine and hip, but muscle strengthening exercises like push-ups and soft-glove boxing are not associated with a higher bone mass in the dominant humerus. It appears that there is a skeletal adaptation to the loads of the activity.

  • 12.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Bone mass in female volleyball players: a comparison of total and regional bone mass in female volleyball players and nonactive females1997In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 60, no 4, p. 338-342Article in journal (Refereed)
    Abstract [en]

    The purpose of this cross-sectional study was to evaluate bone mass in female athletes participating in an impact loading sport (volleyball), and especially to investigate whether any changes in bone mass might be related to the type and magnitude of weightbearing loading and muscle strength. The volleyball group consisted of 13 first division players (age 20.9 +/- 3.7 years) training for about 8 hours/week, and the reference group consisted of 13 nonactive females (age 25.0 +/- 2.4 years) not participating in any kind of regular or organized sport activity. The groups were matched according to weight and height. Areal bone mineral density (BMD) was measured in total body, head, lumbar spine, femoral neck, Ward's triangle, trochanter, the whole femur, and humerus using dual-energy-X-ray absorptiometry. Isokinetic concentric peak torque of the quadricep and hamstring muscles was measured using an isokinetic dynamometer. Compared with the controls, the volleyball players had a significantly (P < 0.05-0.01) higher BMD of the total body (6.1%), lumbar spine (13.2%), femoral neck (15.8%), Ward's triangle (17.9%), trochanter (18.8%), nondominant femur (8.2%), and humerus (dominant 9.5%, nondominant 10.0%), but not of the head and the dominant whole femur. The dominant humerus showed significantly higher BMD than the nondominant humerus in both the volleyball and nonactive group (P < 0.05). There was no significant difference in muscle strength of the thigh between the two groups. In the nonactive group, muscle strength in the quadriceps, and especially hamstrings, was correlated to BMD of the adjacent bones (whole femur, hip sites) and also to distant sites (humerus). However, in the volleyball group there were no correlations between muscle strength and BMD of the adjacent bones, but quadricep strength correlated to BMD of the humerus. These results clearly show that young female volleyball players have a high bone mass. The demonstrated high bone mass seems to be related to the type of loading subjected to each BMD site. Muscle strength of the thigh seems to have little impact on BMD in female volleyball players.

  • 13.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Prolonged progressive calcaneal bone loss despite early weightbearing rehabilitation in patients surgically treated for Achilles tendinosis1998In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 62, no 2, p. 166-171Article in journal (Refereed)
    Abstract [en]

    We prospectively evaluated areal bone mineral density (BMD) of the calcaneus and calf-muscle strength (concentric and eccentric plantar flexion peak torque in Nm) in 10 recreational athletes (5 males and 5 females), mean age 40.9 years (range 26-55), who were selected to undergo surgical treatment for chronic Achilles tendinosis localized at the 2-6 cm level. Surgery was followed by immobilization in a plaster cast for 2 weeks, followed by flexibility training and slowly progressing strength training and weight-bearing activity. One patient was excluded after week 0 because of a new injury. Seven patients were back to their preinjury activity at the 26-week control, and eight patients at the 52-week control postoperatively. BMD in the calcaneus and calf-muscle strength on the injured and noninjured side was measured preoperatively (week 0) and postoperatively (weeks 2, 6, 16, 26, and 52). There were no significant differences in BMD between the injured and noninjured side at weeks 0, 2, and 6, but at weeks 16, 26, and 52, BMD was significantly (P < 0.05) lower (11.5%, 18.4%, and 16.4%, respectively) in the calcaneus of the injured side. Concentric and eccentric plantar flexion strength were significantly lower on the injured side preoperatively. Eccentric, but not concentric plantar flexion strength had recovered compared with the noninjured side 1 year postoperatively. Calf-muscle strength was not related to bone mass in the calcaneus. As a comparison, we used a group of 11 recreational athletes (10 males and 1 female), with a mean age of 46.1 years (range 28.9-58.5) who had been surgically treated for chronic Achilles tendinosis at the 2-6 cm level 39.5 +/- 11.8 months ago. In this group, there was no significant difference in BMD of the calcaneus between the injured and noninjured side. It seems that there was a delayed and prolonged calcaneal bone loss despite early weightbearing loading in patients surgically treated for chronic Achilles tendinosis at the 2-6 cm level. Around that time, when the Achilles tendon had healed (4-6 months) and the athletes returned to their sports, the calcaneal bone had a relatively low BMD and might possibly be vulnerable to heavy loadings. There were no signs of recovery 1 year postoperatively, but in a comparison group there were no significant side-to-side differences 39.5 months postoperatively.

  • 14.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Total and regional bone mass in female soccer players1996In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 59, no 6, p. 438-442Article in journal (Refereed)
    Abstract [en]

    This cross-sectional study investigated bone mass in female athletes participating in an impact-loading sport (soccer), and evaluated whether any changes in bone mass could be related to the type of weight-bearing loading and muscle strength. The group of soccer players consisted of 16 second-division female players (age 20.9 +/- 2.2 years) training for about 6 hours/week. The reference group consisted of 13 nonactive females (age 25.0 +/- 2.4 years) not participating in any kind of regular or organized sport activity. The groups were matched according to weight and height. Areal bone mineral density (BMD) was measured in total body, head, lumbar spine, femoral neck, Ward's triangle, trochanter, the whole femur and humerus, and in specific sites in femur diaphysis, distal femur, proximal tibia, and tibia diaphysis using dual X-ray absorptiometry. Isokinetic concentric peak torque of the quadriceps and hamstring muscles was measured using an isokinetic dynamometer. The soccer players had significantly (P < 0.05-0.01) higher BMD in the lumbar spine (10.7%), femoral neck (13.7%), Ward's triangle (19.6%), nondominant femur and humerus (8.2 and 8.0%, respectively), distal femur (12.6%), and proximal tibia (12.0%) compared with the nonactive women. There was no significant difference in muscle strength of the thigh between the two groups. In the nonactive group, muscle strength in the quadriceps and especially hamstrings, was correlated to BMD of the adjacent bones (whole femur, hip sites) and also to distant sites (humerus). In the soccer group, there were no correlations between muscle strength and BMD of the adjacent and distant bones. Soccer playing and training appears to have a beneficial effect on bone mass in young females, and it seems that there is a site-specific skeletal response to the type of loading subjected to each BMD site. Muscle strength in the thigh is not related to bone mass in female soccer players.

  • 15.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Bone mass in the calcaneus after heavy loaded eccentric calf-muscle training in recreational athletes with chronic achilles tendinosis1999In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 64, no 5, p. 450-455Article in journal (Refereed)
    Abstract [en]

    In an ongoing prospective study of 14 recreational athletes (12 males and 2 females, mean age 44.2 +/- 7.1 years) with unilateral chronic Achilles tendinosis, we investigated the effect of treatment with heavy-loaded eccentric calf-muscle training. Pain during activity (recorded on a VAS scale) and isokinetic concentric and eccentric calf-muscle strength (peak torque at 90 degrees /second and 225 degrees /second) on the injured and noninjured side were evaluated. In this group of patients, we examined areal bone mineral density (BMD) of the calcaneus after 9 months (range 6-14 months) of training. BMD of the injured side (subjected to heavy-loaded eccentric training) was compared with BMD of the noninjured side. Before onset of heavy-loaded eccentric training, all patients had Achilles tendon pain which prohibited running activity, and significantly lower concentric and eccentric plantar flexion peak torque on the injured compared with the noninjured side. The training program consisted of 12 weeks of daily, heavy-loaded, eccentric calf-muscle training; thereafter the training was continued for 2-3 days/week. The clinical results were excellent-all 14 patients were back at their preinjury level with full running activity at the 3 month follow-up. The concentric and eccentric plantar flexion peak torque had increased significantly and did not significantly differ from the noninjured side at the 3 and 9 month follow-up. There were no significant side-to-side differences in BMD of the calcaneus. There was no significant relationship between BMD of the calcaneus and calf-muscle strength. As a comparison group, we used 10 recreational athletes (5 males and 5 females) mean age 40.9 years (range 26-55 years), who were selected for surgical treatment of chronic Achilles tendinosis localized at the 2-6 cm level. Their duration of symptoms and severity of disease were the same as in the experimental group. There were no significant side-to-side differences in BMD of the calcaneus preoperatively, but 12 months postoperatively BMD of the calcaneus was 16.4% lower at the injured side compared with the noninjured side. Heavy-loaded eccentric calf-muscle training resulted in a fast recovery in all patients, equaled the side-to-side differences in muscle strength, and was not associated with side-to-side differences in BMD of the calcaneus. In this group of middle-aged recreational athletes, BMD of the calcaneus was not related to calf-muscle strength.

  • 16.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Long-term loading and regional bone mass of the arm in female volleyball players1998In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 62, no 4, p. 303-308Article in journal (Refereed)
    Abstract [en]

    In the present study, we compared the bone mineral content (BMC) and bone mineral density (BMD) in the arms of 11 female volleyball players (mean age 22.0 +/- 2.6 years) training for about 8 hours/week, and 11 nonactive females aged 24.6 +/- 3.1 years (mean +/- SD) not participating in regular or organized sport activity. Using dual X-ray absorptiometry (DXA), BMC was measured in the proximal and distal humerus, and BMD in the distal radius. Isokinetic concentric peak torque (highest value attained during 5 or 10 repetitions) of the rotator muscles of the shoulder and flexor and extensor muscles of the elbow were measured using an isokinetic dynamometer. The volleyball players had significantly higher BMC (P < 0.05) at the proximal humerus of the dominant arm compared with the nonactive group, but there were no differences between the groups in BMC of the distal humerus and BMD of the distal radius. In the volleyball players, BMC was significantly higher at the proximal humerus, at the distal humerus, and at the distal radius in the dominant compared with the nondominant arm. In the nonactive group, there were no significant differences in BMC and BMD between the dominant and nondominant arm at any site measured. Except for shoulder internal rotation strength and elbow flexion strength at 90 degrees/second that was higher in the dominant arm in the volleyball players, there were no significant differences in muscle strength of the rotator muscles of the shoulder and flexor and extensor muscles of the elbow between the dominant and nondominant arm in the volleyball players and nonactive controls. In the volleyball players, but not in the nonactive controls, there were several significant relationships between shoulder and elbow strength and BMC at the distal humerus of the dominant and especially the nondominant arm. These results show that young female volleyball players have a higher bone mass in the proximal humerus, distal humerus, and distal radius in the dominant compared with the nondominant arm, and a higher bone mass in the proximal humerus compared with nonactive controls. Muscle strength of the rotator muscles of the shoulder is not related to the higher bone mass in the proximal humerus of the dominant arm. Theoretically, the observed differences in bone mass can be related to the type of loading the skeleton undergoes when playing volleyball.

  • 17.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis1998In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 26, no 3, p. 360-366Article in journal (Refereed)
    Abstract [en]

    We prospectively studied the effect of heavy-load eccentric calf muscle training in 15 recreational athletes (12 men and 3 women; mean age, 44.3 +/- 7.0 years) who had the diagnosis of chronic Achilles tendinosis (degenerative changes) with a long duration of symptoms despite conventional nonsurgical treatment. Calf muscle strength and the amount of pain during activity (recorded on a visual analog scale) were measured before onset of training and after 12 weeks of eccentric training. At week 0, all patients had Achilles tendon pain not allowing running activity, and there was significantly lower eccentric and concentric calf muscle strength on the injured compared with the noninjured side. After the 12-week training period, all 15 patients were back at their preinjury levels with full running activity. There was a significant decrease in pain during activity, and the calf muscle strength on the injured side had increased significantly and did not differ significantly from that of the noninjured side. A comparison group of 15 recreational athletes with the same diagnosis and a long duration of symptoms had been treated conventionally, i.e., rest, nonsteroidal antiinflammatory drugs, changes of shoes or orthoses, physical therapy, and in all cases also with ordinary training programs. In no case was the conventional treatment successful, and all patients were ultimately treated surgically. Our treatment model with heavy-load eccentric calf muscle training has a very good short-term effect on athletes in their early forties.

  • 18.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Chronic Achilles tendinitis and calf muscle strength1996In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 24, no 6, p. 829-833Article in journal (Refereed)
    Abstract [en]

    We evaluated 10 men and 3 women (mean age, 44 +/- 8.5 years) with chronic Achilles tendinitis who underwent surgical treatment. Surgery was followed by immobilization in a weightbearing below-the-knee plaster cast for 6 weeks and a stepwise increasing strength training program. We prospectively studied calf muscle strength on the injured and noninjured sides preoperatively and at 16, 26, and 52 weeks postoperatively. Preoperatively, concentric peak torque in dorsiflexion at 90 deg/sec and plantar flexion at 225 deg/sec was significantly lower on the injured side. Postoperatively, concentric plantar flexion peak torque on the injured side increased significantly between Weeks 16 and 26 at 90 deg/sec but was significantly lower than the noninjured side from Weeks 16 to 52 at 90 and 225 deg/sec. Dorsiflexion peak torque at 90 and 225 deg/sec increased between Weeks 0 and 26 and was significantly higher on the injured side at Week 26. Eccentric plantar flexion peak torque was significantly lower on the injured side at Week 26 but not at 1 year. This prospective study demonstrates that 6 months of postoperative rehabilitation for chronic Achilles tendinitis is not enough to recover concentric and eccentric plantar flexion muscle strength compared with the noninjured side.

  • 19.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Concentric and eccentric shoulder and elbow muscle strength in female volleyball players and non-active females1998In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 8, no 5 Pt 1, p. 265-270Article in journal (Refereed)
    Abstract [en]

    Maximal isokinetic concentric (60 degrees/s and 180 degrees/s) and eccentric (60 degrees/s) muscle strength of the external and internal rotator muscles of the shoulder and the flexor and extensor muscles of the elbow was measured in a position resembling spiking and serving in volleyball, on 11 non-injured female volleyball players (first division) and 11 non-active females. In the dominant arm, the volleyball players had significantly higher concentric peak torque of the internal and external rotators and elbow extensors at both velocities, and significantly higher eccentric peak torque of the shoulder internal and external rotators and elbow flexors and extensors, than the controls. In the volleyball group, the concentric internal rotation peak torque at 60 degrees/s was significantly higher in the dominant than in the non-dominant arm. The external/internal strength ratio was significantly lower at 60 degrees/s, but not at 180 degrees/s, in the dominant arm. CONCLUSION: The female volleyball players had a higher concentric and eccentric strength in the rotator muscles of the shoulder and in the extensor muscles of the elbow compared to untrained controls in this special test position. There were signs of rotator muscle imbalance at the low test speed, but no signs of weakness of the external rotators, in the dominant arm of the volleyball players.

  • 20.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Öhberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Achilles tendinosis and calf muscle strength: the effect of short-term immobilization after surgical treatment1998In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 26, no 2, p. 166-71Article in journal (Refereed)
    Abstract [en]

    We prospectively studied calf muscle strength in 7 men and 4 women (mean age, 40.9 +/- 10.1 years) who had surgical treatment for chronic Achilles tendinosis. Surgery was followed by immobilization in a weightbearing below-the-knee plaster cast for 2 weeks followed by a stepwise increasing strength training program. Strength measurements (peak torque and total work) were done preoperatively (Week 0) and at 16, 26, and 52 weeks postoperatively. We measured isokinetic concentric plantar flexion strength at 90 and 225 deg/sec and eccentric flexion strength at 90 deg/sec on both the injured and noninjured sides. Preoperatively, concentric and eccentric strength were significantly lower on the injured side at 90 and 225 deg/sec. Postoperatively, concentric peak torque on the injured side decreased significantly between Weeks 0 and 16 and increased significantly between Weeks 26 and 52 at 90 deg/sec but was significantly lower than that on the noninjured side at all periods and at both velocities. The eccentric strength was significantly lower on the injured side at Week 26 but increased significantly until at Week 52 no significant differences between the sides could be demonstrated. It seems, therefore, that the recovery in concentric and eccentric calf muscle strength after surgery for Achilles tendinosis is slow. We saw no obvious advantages in recovery of muscle strength with a short immobilization time (2 weeks) versus a longer (6 weeks) period used in a previous study.

  • 21.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Thorsen, Kim
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    In situ microdialysis in tendon tissue: high levels of glutamate, but not prostaglandin E2 in chronic Achilles tendon pain1999In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 7, no 6, p. 378-381Article in journal (Refereed)
    Abstract [en]

    This investigation was to our knowledge the first to use the microdialysis technique to study concentrations of substances in a human tendon. In four patients (mean age 40.7 years) with a painful nodule in the Achilles tendon (chronic Achilles tendinosis) and in five controls (mean age 37.2 years) with normal Achilles tendons (confirmed by ultrasonography) the local concentrations of glutamate and prostaglandin E2 were measured under resting conditions. A standard microdialysis catheter was inserted into the Achilles tendon under local anesthesia. Sampling was performed every 15 min over a 4-h period. The results showed significantly higher concentrations of glutamate in tendons with tendinosis than in normal tendons (196 +/- 59 vs. 48 +/- 27 mumol/l, P < 0.05), and there were no significant changes in glutamate concentration over the period of investigation. There were no significant differences in the mean concentrations of prostaglandin E2 (83 +/- 22 vs. 54 +/- 24 pg/ml) between tendons with tendinosis and normal tendons. In conclusion, in situ microdialysis appears a useful method to study certain metabolic events in tendon tissue. The higher concentrations of the excitatory neurotransmitter glutamate in Achilles tendons with a painful nodule may possibly be involved in the pain mechanism in this chronic condition. Furthermore, there were no signs of inflammation in the tendons with painful nodules, as indicated by the normal prostaglandin E2 levels.

  • 22.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Thorsen, Kim
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Treatment of tear of the anterior cruciate ligament combined with localised deep cartilage defects in the knee with ligament reconstruction and autologous periosteum transplantation.1999In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 7, no 2, p. 69-74Article in journal (Refereed)
    Abstract [en]

    An acute tear of the anterior cruciate ligament (ACL) is frequently associated with injuries to the joint cartilage and subchondral bone. These injuries may progress to deep cartilage defects, causing disabling pain, and represent a therapeutic challenge in patients with the combination instability and pain. At our clinic we treat patients with the combined injury with simultaneous ACL reconstruction and autologous periosteum transplantation of the cartilage defect. This report describes the technique for periosteum transplantation of full-thickness cartilage defects in the medial femoral condyle. Our clinical report includes the first 7 patients (6 men and 1 woman, mean age 29.1 years at operation) who have been followed for 2 years or longer of 14 consecutive patients (12 men and 2 women). All patients had suffered a total tear of the ACL and a full-thickness defect of the cartilage at the medial femoral condyle. The cartilage defects had a mean area of 7.3 cm2 (range 1.0-13.5 cm2). All patients had disabling instability and medial knee pain when walking. The anterior cruciate ligament was reconstructed with a bone-tendon-bone graft of the central third of the patellar ligament. After preparation of the cartilage lesion, the periosteum transplant was anchored to the underlying bone with suture anchors and fibrin glue. Postoperatively, these patients (n = 7) were initially treated with continuous passive motion, followed by active flexibility training and slowly progressing strength training and weight-bearing activities. At follow-up a mean of 31.3 months (range 24-38 months) later, 6 patients evidenced subjectively stable knees, no pain during rest or when walking, and had returned to not too heavy knee-loading work. One patient had a subjectively stable knee, but felt medial knee pain. Meticulous surgical technique and rigorous postoperative rehabilitation are probably of the greatest importance in this procedure. With the use of suture anchors and fibrin glue, the periosteum transplant can be well adapted to the condylar subchondral bone bed.

  • 23.
    Alfredson, Håkan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Öhberg, Lars
    Umeå University, Faculty of Medicine, Radiation Sciences, Diagnostic Radiology.
    Zeisig, Ewa
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Treatment of midportion Achilles tendinosis: similar clinical results with US and CD-guided surgery outside the tendon and sclerosing polidocanol injections.2007In: Knee Surg Sports Traumatol Arthrosc, ISSN 0942-2056, Vol. 15, no 12, p. 1504-1509Article in journal (Refereed)
  • 24.
    Andersson, Gustav
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Backman, Ludvig
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Scott, Alexander
    Department of Physical Therapy, University of British Columbia, Vancouver, British Columbia, Canada; Centre for Hip Health and Mobility, Vancouver Coastal Health and Research Institute, Vancouver, British Columbia, Canada.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Danielson, Patrik
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Substance P accelerates hypercellularity and angiogenesis in tendon tissue and enhances paratendinitis in response to Achilles tendon overuse in a tendinopathy model2011In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 45, no 13, p. 1017-1022Article in journal (Refereed)
    Abstract [en]

    Background Tenocytes produce substance P (SP) and its receptor (neurokinin-1 receptor (NK-1R) is expressed throughout the tendon tissue, expecially in patients with tendinopathy and tissue changes (tendinosis) including hypercellularity and vascular proliferation. Considering the known effects of SP, one might ask whether SP contributes to these canges.

    Objectives To test whether development of tendinosislike changes (hypercellularity and angiogenesis) is accelerated during a 1-week course of ecercise with local administration of SP in an establish Achilles tendinopathy model.

    Methods Rabbits were subjected to a protocol of Achilles tendon overuse for 1 week, in conjunction with SP injections in the paratenon. Exercised control animals received NaCl injections or no injections, and unexercised, uninjected controls were also used. Tenocyte number and vascular density, as well as paratendinous inflammation, were evaluated. Immunohistochemistry and in sity hybridisation to detect NK-1R were conducted.

    Results There was a significant increase in tenocyte number in the SP-injected and NaCl-injected groups compared with both unexercised and exercised, uninjected controls. Tendon blood vessels increased in number in the SP-injected group compared with unexercised controls, a finding not seen in NaCl-injected controls or in uninjected, exercised animals. Paratendinous inflammation was more pronounced in the SP-injected group than in the NaCl controls. NK-1R was detected in blood vessel walls, nerves, inflammatory cells and tenocytes.

    Conclusions SP accelerated the development of tendinosis-like changes in the rabbit. Achilles tendon, which supports theories of a potential role of SP in tendinosis development; a fact of clinical interest since SP effects can be effectively blocked. The angiogenic response to SP injections seems related to parateninitis.

  • 25.
    Andersson, Gustav
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Backman, Ludvig
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Scott, Alexander
    Department of Physical Therapy, University of British Columbia, Vancouver, BC, Canada.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Danielson, Patrik
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Substance P induces tendinosis-like changes in a rabbit model of Achilles tendon overuseManuscript (preprint) (Other academic)
    Abstract [en]

    BACKGROUND: In previous studies we found evidence favouring that human Achilles tendon cells (tenocytes) are capable of producing the neuropeptide substance P (SP). Furthermore, the preferred receptor for SP (the neurokinin-1 receptor, NK-1 R) was widely expressed throughout the tendon, especially in patients suffering from chronic tendon pain (tendinopathy) with tissue changes (tendinosis) including hypercellularity and vascular proliferation. Considering known effects of SP, one might ask whether SP contributes to tendon cell proliferation and neovascularisation in tendinosis. We have an established animal (rabbit) model of Achilles tendinopathy based on overuse in the form of repetitive exercise. Recent studies with this model have shown that tendinosis-like changes are present after 3 weeks of exercise, but not after only 1 week. The current study aimed to test whether the development of tendinosis-like changes would be accelerated during a 1 week course of exercise with repetitive local administration of SP.

    MATERIAL AND METHODS: Four groups of animals (5-6 New Zealand white rabbits per group) were used. Three groups were subjected to the previously established protocol of Achilles tendon overuse for 1 week. One of these groups was given repetitive SP injections in the paratendinous tissue of the Achilles tendon, whereas one group (‘NaCl controls’) was given an equivalent schedule of saline injections. Two additional control groups existed: One in which the animals were neither subjected to the overuse protocol nor to any injections (‘untrained controls’), and one in which the animals trained for 1 week but were not given any injections (‘1 week controls’). Tenocyte number, vascular density, and the possible occurrence of paratendinous inflammation were evaluated. Immunohistochemistry and in situ hybridisation to detect NK-1 R were also conducted.

    RESULTS: There was a significant increase in tenocyte number in the SP-injected group compared to both untrained controls and 1 week controls. However, the same phenomenon was noticed for NaCl controls, i.e. tenocyte number was significantly increased in response to NaCl injections compared to untrained controls. There was an increase in the number of tendon blood vessels in the SP-injected group as compared to untrained controls, and this increase in vascularity was not seen for the NaCl controls or the 1 week controls. Paratendinous inflammation, as evidenced by invasion of inflammatory cells in the paratenon, was clearly more pronounced in the SP-injected group than in the NaCl controls. NK-1 R was detected in blood vessel walls, on nerves, on inflammatory cells, and on tenocytes.

    DISCUSSION AND CONCLUSIONS: The observations suggest that SP induces tenocyte proliferation and angiogenesis in the rabbit Achilles tendon, thus supporting a potential role of this neuropeptide in the processes that occur in tendinosis. The study corroborates findings on the human Achilles tendon in that NK-1 R was expressed on tenocytes and tendon blood vessel walls, thereby providing a potential anatomic basis for the observed effects of SP on the development of tendinosis. The hypercellularity observed in response to NaCl injections might be due increased tissue pressure or to stimulation of endogenous SPproduction, a phenomenon not unheard of. The angiogenic effect of SP injections, on the other hand, appeared to be more specifically related to an induction of inflammation in the paratendon.

  • 26.
    Andersson, Gustav
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Scott, Alexander
    University of British Columbia, Vancouver, Vancouver Coastal Health and Research Institute.
    Gaida, James Edmund
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Stjernfeldt, Johanna Elgestad
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Backman, Clas
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Danielson, Patrik
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Tenocyte hypercellularity and vascular proliferation in a rabbit model of tendinopathy: contralateral effects suggest the involvement of central neuronal mechanisms2011In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 45, no 5, p. 399-406Article in journal (Refereed)
    Abstract [en]

    Objective To determine whether there are objective findings of tendinosis in a rabbit tendinopathy model on exercised and contralateral (non-exercised) Achilles tendons. Design Four groups of six New Zealand white rabbits per group were used. The animals of one (control) group were not subjected to exercise/stimulation. Interventions Animals were subjected to a protocol of electrical stimulation and passive flexion-extension of the right triceps surae muscle every second day for 1, 3 or 6 weeks. Main Outcome Measures Tenocyte number and vascular density were calculated. Morphological evaluations were also performed as well as in-situ hybridisation for vascular endothelial growth factor (VEGF) messenger RNA. Results There was a significant increase in the tenocyte number after 3 and 6 weeks of exercise, but not after 1 week, in comparison with the control group. This was seen in the Achilles tendons of both legs in experimental animals, including the unexercised limb. The pattern of vascularity showed an increase in the number of tendon blood vessels in rabbits that had exercised for 3 weeks or more, compared with those who had exercised for 1 week or not at all. VEGF-mRNA was detected in the investigated tissue, with the reactions being more clearly detected in the tendon tissue with tendinosis-like changes (6-week rabbits) than in the normal tendon tissue (control rabbits). Conclusions There were bilateral tendinosis-like changes in the Achilles tendons of rabbits in the current model after 3 weeks of training, suggesting that central neuronal mechanisms may be involved and that the contralateral side is not appropriate as a control.

  • 27.
    Bagge, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Unexpected presence of the neurotrophins NGF and BDNF and the neurotrophin receptor p75 in the tendon cells of the human Achilles tendon2009In: Histology and Histopathology, ISSN 0213-3911, E-ISSN 1699-5848, Vol. 24, no 7, p. 839-848Article in journal (Refereed)
    Abstract [en]

    Neurotrophins are substances that have been shown to be important in growth and remodelling phases in different types of tissue. There is no information concerning the possible occurrences of neurotrophins and their receptors in tendons. In this study, sections of both chronic painful (tendinosis) and pain-free (non-tendinosis) human Achilles tendons were immunohistochemically stained with antibodies against the neurotrophins NGF and BDNF, and their receptors TrkA, TrkB and p75. There were marked immunoreactions for NGF and BDNF in the tendon cells (tenocytes) of both tendinosis and non-tendinosis specimens. The tenocytes were also reactive for the receptor p75, but not for the receptors TrkA and TrkB. In addition, p75 immunoreactions were seen in nerve fascicles and in the walls of arterioles. This is the first study to identify neurotrophins in the tenocytes of human tendon. It is clear from this study that the local cells of tendons are sources of neurotrophins. The neurotrophins may play an important role in the tendon through their interaction with the receptor p75 in the tenocytes. These interactions may regulate tropic modulatory, and apoptotic effects. In conclusion, the observations show a new concept concerning production and function of neurotrophins, namely in the tenocytes of tendons.

  • 28. Barnekow-Bergkvist, M
    et al.
    Hedberg, G
    Pettersson, U
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, R
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Relationships between physical activity and physical capacity in adolescent females and bone mass in adulthood.2006In: Scand J Med Sci Sports, ISSN 0905-7188, Vol. 16, no 6, p. 447-55Article in journal (Refereed)
  • 29.
    Berglin, Eva
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Reumatology.
    Lorentzon, Ronnie
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordmark, L
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Nilsson-Sojka, Birgitta
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Immunology.
    Rantapää Dahlqvist, Solbritt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Reumatology.
    Predictors of radiological progression and changes in hand bone density in early rheumatoid arthritis2003In: Rheumatology, ISSN 1462-0324, E-ISSN 1462-0332, Vol. 42, no 2, p. 268-275Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To identify predictors for radiological and functional outcome and bone loss in the hands in early rheumatoid arthritis (RA) during the first 2 yr of disease and to study the relationship between these variables.

    METHODS: An inception cohort of consecutively recruited patients was examined at baseline and after 12 and 24 months using X-rays of hands and feet, clinical [28-joint count, Health Assessment Questionnaire (HAQ), global visual analogue scale (VAS), grip strength] and laboratory (erythrocyte sedimentation rate, C-reactive protein, markers of bone formation and resorption) measurements and dual-energy X-ray absorptiometry measurements of the hands.

    RESULTS: Joint destruction increased significantly during the study, with the Larsen score at baseline as the strongest predictor. Radiological progression and bone loss over 24 months were significantly retarded in patients responding to therapy. The effects of the shared epitope and initial high inflammatory activity on radiological progression were overridden by the therapeutic response. Radiological progression correlated significantly with bone loss. Global VAS, Larsen score and HAQ at inclusion significantly predicted change in HAQ over time.

    CONCLUSIONS: Radiological progression and bone loss were retarded by early therapeutic response. Bone loss was related to radiological progression.

  • 30.
    Brax-Olofsson, Lisbeth
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lindström, Inger
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Periosteal transplantation to the rabbit patella.2007In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 15, no 5, p. 560-563Article in journal (Refereed)
    Abstract [en]

    Autologous periosteal transplantation (without chondrocyte cell transplantation) for treating traumatic articular cartilage defects of the patella gives pain relief in uncontrolled clinical studies. To study the whole transplanted area macroscopically and microscopically, animal studies are motivated. In this pilot study, we reproduce the surgical technique for periosteum transplantation on human patella to a rabbit model. A full-thickness cartilage defect of the whole patella was created in eight adult female rabbits. The defect was treated with autologous periosteal transplantation. After surgery, the rabbits were allowed free activity. This is the difference compared to the treatment in humans, where our group uses CPM for 5 days and non-weight-bearing for 12 weeks. After 21 weeks, there was a diffuse synovitis in all transplanted knees, and in five of eight knees there were signs of osteoarthritis in the patello-femoral joint. Histologically, in three animals, small islands of hyaline cartilage surrounded by fibrocartilage were seen in the transplanted area. In the other five animals, fibrocartilage was the predominant tissue. In contrast to previous experimental studies using a rabbit model, we did not achieve hyaline cartilage resurfacing.

  • 31.
    Fahlström, M
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Fahlström, P G
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Positive short-term subjective effect of sports drink supplementation during recovery.2006In: J Sports Med Phys Fitness, ISSN 0022-4707, Vol. 46, no 4, p. 578-84Article in journal (Refereed)
  • 32.
    Fahlström, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Björnstig, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Acute Achilles tendon rupture in badminton players1998In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 26, no 3, p. 467-470Article in journal (Refereed)
    Abstract [en]

    All patients with badminton-related acute Achilles tendon ruptures registered during 1990 to 1994 at the University Hospital of Umeå were retrospectively followed up using a questionnaire. Thirty-one patients (mean age, 36.0 years), 27 men and 4 women, were included. Thirty patients (97%) described themselves as recreational players or beginners. The majority of the injuries (29 of 31, 94%) happened at the middle or end of the planned game. Previous local symptoms had been noticed by five patients (16%). Long-term results showed that patients treated with surgery had a significantly shorter sick leave absence than patients treated without surgery (50 versus 75 days). There was no obvious selection favoring any treatment modality. None of the surgically treated patients had reruptures, but two reruptures occurred in the nonsurgically treated group. There seemed to be fewer remaining symptoms and a higher sports activity level after the injury in the surgically treated group. Our results indicate that local muscle fatigue may interfere with strength and coordination. Preventive measures such as specific treatment of minor injuries and adequate training of strength, endurance, and coordination are important. Our findings also indicate that surgical treatment and careful postoperative rehabilitation is of great importance among badminton players of any age or sports level with Achilles tendon rupture.

  • 33.
    Fahlström, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Björnstig, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Acute badminton injuries1998In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 8, no 3, p. 145-148Article in journal (Refereed)
    Abstract [en]

    During 1990-1994, 1.2% of all sports injuries that required emergency care at the University Hospital of Umeå were caused by badminton. In 90.7% of the cases the patients described themselves as recreational players or beginners. There were 51.3% minor injuries (AIS 1) and 48.7% moderate injuries (AIS 2). The lower extremities were affected in 92.3% of the cases. Achilles tendon ruptures (34.6%) and ankle sprains and fractures (29.5%) were the most frequent. By the time of the follow-up (10-69 months), 52.6% of the players still had symptoms from the injuries and 39.5% had not been able to return to playing badminton. Our data indicate the importance of adequate treatment and rehabilitation after acute badminton injuries.

  • 34.
    Fahlström, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Chronic Achilles tendon pain treated with eccentric calf-muscle training2003In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 11, no 5, p. 327-333Article in journal (Refereed)
    Abstract [en]

    Injuries involving the Achilles tendon and manifested as chronic tendon pain are common, especially among recreational athletes. In a pilot study on a small group of patients with chronic painful midportion Achilles tendinosis, eccentric calf-muscle training was shown to give good clinical results. The aim of this prospective study was to investigate if the previously achieved good clinical results could be reproduced in a larger group of patients, and also to investigate the effects of eccentric calf-muscle training in patients with chronic insertional Achilles tendon pain. Seventy-eight consecutive patients, having chronic painful Achilles tendinosis at the mid-portion (2–6 cm level) in a total of 101 tendons (55 unilateral and 23 bilateral), and thirty consecutive patients with chronic insertional Achilles tendon pain in 31 tendons (29 unilateral and one bilateral) were treated with eccentric calf-muscle training for 12 weeks. Most patients were recreational athletes. Evaluation of the amount of tendon pain during activity was recorded on a visual analogue scale (VAS), before and after treatment. In 90 of the 101 Achilles tendons (89%) with chronic painful mid-portion Achilles tendinosis, treatment was satisfactory and the patients were back on their reinjury activity level after the 12-week training regimen. In these patients, the amount of pain during activity, registered on the VAS-scale (mean±SD), decreased ignificantly from 66.8±19.4 to 10.2±13.7. On the contrary, in only ten of the tendons (32%) with chronic insertional Achilles tendon pain was treatment satisfactory, with a significant decrease on the VAS-scale (mean±SD), from 68.3±7.0 to 13.3±13.2. Our conclusion is that treatment with eccentric calf-muscle training produced good clinical results in patients with chronic painful mid-portion Achilles tendinosis, but not in patients withchronic insertional Achilles tendon pain.

  • 35.
    Fahlström, Martin
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Sports Medicine.
    Painful conditions in the Achilles tendon region: a common problem in middle-aged competitive badminton players.2002In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 10, no 1, p. 57-60Article in journal (Refereed)
    Abstract [en]

    Overuse injuries are the most frequent type in badminton, generally localized in the legs. An earlier study found 32% of young Swedish elite badminton players to have experienced disabling pain in the Achilles tendon region during the previous 5 years. The present investigation examined the prevalence and characteristics of painful conditions in the Achilles tendon region in 32 middle-aged competitive badminton players by means of questionnaire and physiotherapist's examination. Pain in the Achilles tendon region was reported by 44%, either presently or during the past 5 years, generally localized in the middle portion of the tendon. Symptoms had lasted 2 weeks-1 year (96 days). On the competition days 22% of the reported pain currently in the region. Age was found to be correlated to Achilles tendon pain, but there was no relationship between symptoms of pain and body mass index, gender, training quantity, or years of playing badminton. In conclusion, Achilles tendon pain seems to be relatively common among Swedish middle-aged competitive badminton players, particularly in the older ones.

  • 36.
    Fahlström, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Painful conditions in the Achilles tendon region in elite badminton players.2002In: American Journal of Sports Medicine, ISSN 0363-5465, E-ISSN 1552-3365, Vol. 30, no 1, p. 51-54Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the prevalence and characteristics of painful conditions in the Achilles tendon region in elite badminton players. The study group consisted of 66 players in the Swedish elite division (highest level) in badminton, 41 men (mean age, 24.4 years) and 25 women (mean age, 21.9 years). Twenty-one players (32%) reported the occurrence of a disabling painful condition in the Achilles tendon region during the previous 5 years, and 11 players (17%) had an ongoing painful condition. A majority of the painful conditions (12 of 21, or 57%) were described as involving the midportion of the Achilles tendon. The players who had a painful condition reported a significantly higher weekly training load as measured by the number of hours spent in total training, badminton training, and endurance and strength training. There were no differences in age, sex, and body mass index between the players with and without painful conditions in the Achilles tendon region.

  • 37.
    Ferry, Tomas
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Bergström, Ulrica
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Hedström, Erik M
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Zeisig, Eva
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Epidemiology of acute knee injuries seen at the Emergency Department at Umeå University Hospital, Sweden, during 15 years2014In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 22, no 5, p. 1149-1155Article in journal (Refereed)
    Abstract [en]

    PURPOSE: To describe the incidence and injury distribution of knee injuries in the general population of a European setting. METHODS: Retrospective study of all knee injuries registered at the Emergency Department at Umeå University Hospital, Sweden, during 1995-2009 in relation to age, sex, diagnosis, location and activity at the time of injury, mechanism of injury, and treatment and/or follow-up plan. RESULTS: During 1995-2009, 12,663 knee injuries were registered, 8 % of all injuries. The incidence of knee injuries resulting in a visit to the Emergency Department was six cases per 1,000 person years. One-third of all injuries occurred during sports. And 30 % were 15-24 years. More men than women were injured during sporting activities and women were mostly injured during transportation. CONCLUSION: Knee injuries in a general population are common and the injury distribution varies with age and sex. Sports activities and young age were prominent features of the injured population. LEVEL OF EVIDENCE: IV.

  • 38.
    Högström, M
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, H
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, R
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Thorsen, K
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, P
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Current physical activity is related to bone mineral density in males but not in females.2007In: International Journal of Sports Medicine, ISSN 0172-4622, E-ISSN 1439-3964, Vol. 28, no 5, p. 431-436Article in journal (Refereed)
  • 39.
    Lorentzon, Ronny
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Hildingsson, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Treatment of deep cartilage defects of the patella with periosteal transplantation1998In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 6, no 4, p. 202-208Article in journal (Refereed)
    Abstract [en]

    Twenty-six consecutive patients (19 men and 7 women) with a mean age of 31.5 years (range 19-52 years) who suffered from an isolated full-thickness cartilage defect of the patella (area ranged from 0.75 to 20.0 cm2) and disabling knee pain were treated with autologous periosteal transplantation (without any chondrocytes). The duration of symptoms was 59 months (range 11-144 months). During the first 5 postoperative days all patients were treated with continuous passive motion (CPM). This was followed by active motion, slowly progressive strength training, and slowly progressive weight-bearing. After a mean follow-up of 42 months (range 24-76 months), 17 patients (65%) were graded as excellent (were painfree), 8 patients (31%) as good (had pain with strenuous knee-loading activities), and 1 patient as poor (had pain at rest). Twenty-two patients (85%) had returned to their previous occupation. Twelve patients (46%) had resumed sports or recreational activities at their former level. Repeated magnetic resonance imaging (MRI) investigations showed progressive, and finally complete, filling of the articular defects. Biopsies taken in five randomly selected cases showed hyaline-like cartilage. Patients with full-thickness cartilage defects of the patella and disabling knee pain can be treated with autologous periosteal transplantation (without any chondrocytes), followed by CPM, and slowly progressive strength training and weight-bearing. We believe this is a good method to accomplish regeneration of articular cartilage and satisfactory clinical results.

  • 40.
    Mafi, Nader
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Superior short-term results with eccentric calf muscle training compared to concentric training in a randomized prospective multicenter study on patients with chronic Achilles tendinosis.2001In: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 9, no 1, p. 42-47Article in journal (Refereed)
    Abstract [en]

    In a previous uncontrolled pilot study we demonstrated very good clinical results with eccentric calf muscle training on patients with painful chronic Achilles tendinosis located at the 2-6 cm level in the tendon. In the present prospective multicenter study (Sundsvall and Umeå) patients with painful chronic Achilles tendinosis at the 2-6 cm level in the tendon were randomized to treatment with either an eccentric or a concentric training regimen for the calf muscles. The study included 44 patients, with 22 patients (12 men, 10 women; mean age 48 years) in each treatment group. The amount of pain during activity (jogging or walking) was recorded by the patients on a visual analogue scale, and patient satisfaction was assessed before and after treatment. The patients were instructed to perform their eccentric or concentric training regimen on a daily basis for 12 weeks. In both types of treatment regimen the patients were told to do their exercises despite experiencing pain or discomfort in the tendon during exercise. The results showed that after the eccentric training regimen 82% of the patients (18/22) were satisfied and had resumed their previous activity level (before injury), compared to 36% of the patients (8/22) who were treated with the concentric training regimen. The results after treatment with eccentric training was significantly better (P<0.002) than after concentric training. The good clinical results previously demonstrated in the pilot study with eccentric calf muscle training on patients with chronic Achilles tendinosis, were thus reproduced in this multicenter, showing superior results to treatment with concentric training.

  • 41.
    Martin, Fahlström
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine. Umeå University, Faculty of Medicine, Department of Clinical Sciences, Professionell Development.
    Fahlström, P G
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Positive short-term subjective effect of sports drink supplementation during recovery.2006In: J Sports Med Phys Fitness, ISSN 0022-4707, Vol. 46, no 4, p. 578-84Article in journal (Refereed)
  • 42.
    Nordström, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Eklund, Fredrik
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Björnstig, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Sievänen, Harri
    Gustafson, Yngve
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Do both areal BMD and injurious falls explain the higher incidence of fractures in women than in men?2011In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 89, no 3, p. 203-210Article in journal (Refereed)
    Abstract [en]

    The higher incidence of fractures in women than in men is generally attributed to the lower areal bone mineral density (areal BMD, g/cm(2)) of the former. The purpose of the present study was to investigate both areal BMD and injurious falls as risk factors for fractures. In a first cohort, areal BMD was measured in 5,131 men and women (age range 40-95 years). In a second cohort, consisting of 26,565 men and women (age range 40-69 years), a health survey was conducted including questions about lifestyle and medication. Main outcome measures included validated prospective injurious falls and fractures in both cohorts. The higher areal BMD and femoral neck BMD in men compared to women (P < 0.001) were explained by a higher diameter of the femoral neck. Importantly, the diameter of the femoral neck was not associated with fractures in either sex (hazard ratio [HR] 0.94-1.04, P > 0.05 for all), suggesting that a higher areal BMD and lower incidence of osteoporosis in men do not explain their lower incidence of fractures. In contrast, women were more prone to sustain injurious falls than men in both cohorts investigated (HR for women = 1.61 and 1.84, P < 0.001 for both), resulting in a higher incidence of fractures (HR for women = 2.24 and 2.36, P < 0.001 for both). The number of injurious falls and fractures occurring each month during the study period showed a very strong correlation in both women (r = 0.95, P < 0.00001) and men (r = 0.97, P < 0.00001). In summary, low areal BMD, and thus osteoporosis, may not explain the higher fracture incidence in women than in men. Instead, a higher incidence of injurious falls in women was strongly associated with the higher fracture risk.

  • 43.
    Pettersson, Ulrika
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Bone mass in female cross-country skiers: relationship between muscle strength and different BMD sites.2000In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 67, no 3, p. 199-206Article in journal (Refereed)
    Abstract [en]

    In this cross-sectional study, bone mass and muscle strength of the thigh were investigated in 16 Caucasian female cross-country skiers, age 16.2 +/- 0.3 years, that had been ski-training for 6.4 +/- 1.8 years (range 3-9 years) and were now training for 6.3 +/- 2.4 hours/week (range 3-12 hours). They were compared with 16 nonactive females, age 16.4 +/- 0.7 years. The groups were matched according to age, weight, height, and pubertal status. Areal bone mineral density (BMD) was measured using dual energy X-ray absorptiometry, in the total body, head, both total humerus and humerus diaphyses, spine, and in the right femoral neck, greater trochanter, femoral diaphysis, distal femur, proximal tibia, and tibia diaphysis. Bone mineral apparent density (BMAD) was also calculated for the femoral neck and humerus diaphyses. Isokinetic muscle strength of the quadricep and hamstring muscles was measured in an isokinetic dynamometer. Compared with the controls, the cross-country skiing group had significantly higher BMD in the right whole humerus (6.9%), left whole humerus (9.2%), left humerus diaphysis (8.1%), femoral neck (8.9%), greater trochanter (9.3%), femur diaphysis (7.6%), and BMAD of the femoral neck (+19.4%). In the nonactive group there were significant side-to-side differences in BMD of the whole humeri, humerus diaphyses, and BMAD of the humerus diaphyses (3.1%, 5.4%, and 8.8% higher in the right arm, respectively). No such differences were found in the cross-country skiing group. Lean body mass was significantly higher in the cross-country skiers (21.7%), and fat mass (-25.5%) and body fat percent (-28.0%) were significantly lower compared with the nonactive group. There were, however, no significant differences in concentric peak torque of the thigh muscles between the two groups. Stepwise regression analyses revealed that BMI was the best predictor of several sites in the nonactive group. In the cross-country group, on the other hand, muscle strength was a strong predictor of BMD, both at adjacent and more distant BMD sites. In conclusion, it seems that this type of endurance training is associated with a site-specific higher bone mass that may be associated with the type and magnitude of loading during off-season and during the main sports activity, cross-country skiing.

  • 44.
    Pettersson, Ulrika
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsen, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Effect of high impact activity on bone mass and size in adolescent females: A comparative study between two different types of sports.2000In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 67, no 3, p. 207-214Article in journal (Refereed)
    Abstract [en]

    The purpose of this cross-sectional study was to investigate the influence of two different types of weight-bearing activity, muscle strength, and body composition on bone mineral density (BMD), bone mineral content (BMC), and bone area in three different groups of late adolescent girls. The first group consisted of 10 females participating in competitive rope-skipping (age 17.8 +/- 0.8 years) training for 6.7 +/- 3.1 hours/week; the second group consisted of 15 soccer players (age 17.4 +/- 0.8 years) training for 6.1 +/- 2.0 hours/week; and the third group consisted of 25 controls (age 17.6 +/- 0.8 years) with physical activity of 0.9 +/- 1.1 hours/week. The groups were matched for age, height, and weight. BMD (g/cm(2)), BMC (g), and bone area (cm(2)) of the total body, lumbar spine, hip, total femur, distal femur, diaphyses of femur and tibia, proximal tibia, and humerus were measured using dual-energy X-ray absorptiometry (DXA). Bone density was also assessed in the radial forearm site of the dominant limb in the rope skippers and in 10 matched controls. The rope skippers had 22% higher BMD at the ultradistal site (P < 0.01). Both high-activity groups had significantly higher BMD (P < 0.05) at most loaded sites compared with the control group. When adjusting for differences in lean mass and starting age of sport-specific training between the activity groups, the rope-skipping group had a higher BMD of the total body, lumbar spine, and right humerus compared with the soccer group. They also had a significantly higher bone area of the total body, total femur, and the proximal femur than both other groups, and a significantly higher bone area of the tibia diaphysis, compared with the soccer group. In a multivariate analysis among all subjects (n = 50), all BMD sites, except the femur diaphysis, distal femur, and proximal tibia, were significantly related to type of physical activity (beta = 0.25-0.43, P < 0.05). The bone area values at different sites were strongly related to muscle strength and parameters related to body size [height, weight, lean mass, fat mass, and body mass index (BMI)]. In conclusion, it appears that in late adolescent women, weight-bearing activities are an important determinant for bone density, and high impact activities such as jumping also seem to be associated with a modification of the bone geometry (hence, the bone width) at the loaded sites.

  • 45.
    Pettersson, Ulrika
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Stålnacke, Britt-Marie
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Ahlénius, Gerd-Marie
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Henriksson-Larsén, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Low bone mass density at multiple skeletal sites, including the appendicular skeleton in amenorrheic runners1999In: Calcified Tissue International, ISSN 0171-967X, E-ISSN 1432-0827, Vol. 64, no 2, p. 117-125Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate any difference in bone mass at different sites between female long-distance runners with amenorrhea and those with eumenorrhea. We compared 10 amenorrheic and 10 eumenorrheic athletes to determine whether athletes with amenorrhea have lower BMD in multiple skeletal regions, including weight-bearing lower limbs. The amenorrheic group had experienced menstrual dysfunction ranging from 3 to 43 months. As a further control group, 16 eumenorrheic soccer players were compared with the former two running groups regarding their BMD measurements. The two groups were matched for age, height, and amount of training. Areal bone mineral density (BMD) was measured and was found to be significantly lower in the total body, humerus, spine, lumbar spine, pelvis, femoral neck, trochanter, total femur, femur diaphysis, tibia diaphysis and in the nonweight-bearing head of the femur in the amenorrheic group. Body weight, BMI, fat mass, and body fat percent were significantly lower in the amenorrheic group. The differences in the BMD of the head, humerus, femoral neck, total femur, femur diaphysis, and tibia diaphysis disappeared when adjusted for body weight. Compared with the soccer group, the amenorrheic subjects had significantly lower BMD values at all sites except for the head, Ward's triangle, and femur diaphysis. Blood samples were obtained in the two running groups for analysis of osteocalcin, carboxy terminal telopeptide (ICTP), procollagen I (PICP), and estradiol. There were no significant differences between the groups but there was a strong tendency towards a lower estradiol level and a higher osteocalcin level in the amenorrheic group. A free estradiol index (FE2) was derived as the ratio of estradiol to sex hormone binding globulin (SHBG) and was significantly lower in the amenorrheic group. No difference in their daily intake of total energy, protein, carbohydrates, fiber, calcium, and vitamin D was observed. However, both groups showed a surprisingly low energy intake in relation to their training regimens. Stepwise regression analyses revealed that weight was the best predictor of spine BMD in both groups. Estradiol and FE2 were significant predictors of the BMD of the proximal femur in the eumenorrheic group, but did not predict any BMD site in the amenorrheic group. In conclusion, amenorrhea in athletic women affects trabecular and cortical bone in both axial and appendicular skeleton. However, some of the discrepancy can be explained by a lower body weight. Physical weight-bearing activity does not seem to completely compensate for the side effects of reduced estrogen levels even in weight-bearing bones in the lower extremity and spine.

  • 46.
    Purdam, C R
    et al.
    Department of Physical Therapies, Australian Institute of Sport, Belconnen, Australia.
    Jonsson, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Alfredson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Cook, J L
    La Trobe University Musculoskeletal Research Centre, Victoria, Australia.
    Khan, K M
    Department of Family Practice and School of Human Kinetics, University of British Columbia, Canada.
    A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy2004In: British Journal of Sports Medicine, ISSN 0306-3674, E-ISSN 1473-0480, Vol. 38, no 4, p. 395-397Article in journal (Refereed)
    Abstract [en]

    Objectives: This non-randomised pilot study investigated the effect of eccentric quadriceps training on 17 patients (22 tendons) with painful chronic patellar tendinopathy.

    Methods: Two different eccentric exercise regimens were used by subjects with a long duration of pain with activity (more than six months). (a) Nine consecutive patients (10 tendons; eight men, one woman; mean age 22 years) performed eccentric exercise with the ankle joint in a standard (foot flat) position. (b) Eight patients (12 tendons; five men, three women; mean age 28 years) performed eccentric training standing on a 25° decline board, designed to increase load on the knee extensor mechanism. The eccentric training was performed twice daily, with three sets of 15 repetitions, for 12 weeks. Primary outcome measures were (a) 100 mm visual analogue scale (VAS), where the subject recorded the amount of pain during activity, and (b) return to previous activity. Follow up was at 12 weeks, with a further limited follow up at 15 months.

    Results: Good clinical results were obtained in the group who trained on the decline board, with six patients (nine tendons) returning to sport and showing a significantly reduced amount of pain over the 12 week period. Mean VAS scores fell from 74.2 to 28.5 (p  =  0.004). At 15 months, four patients (five tendons) reported satisfactory results (mean VAS 26.2). In the standard squat group the results were poor, with only one athlete returning to previous activity. Mean VAS scores in this group were 79.0 at baseline and 72.3 at 12 weeks (p  =  0.144).

    Conclusion: In a small group of patients with patellar tendinopathy, eccentric squats on a decline board produced encouraging results in terms of pain reduction and return to function in the short term. Eccentric exercise using standard single leg squats in a similar sized group appeared to be a less effective form of rehabilitation in reducing pain and returning subjects to previous levels of activity.

     

  • 47.
    Song, Yafeng
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Yu, Jiguo
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Stål, Per
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Effects on contralateral muscles after unilateral electrical muscle stimulation and exercise2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 12, p. e52230-Article in journal (Refereed)
    Abstract [en]

    It is well established that unilateral exercise can produce contralateral effects. However, it is unclear whether unilateral exercise that leads to muscle injury and inflammation also affects the homologous contralateral muscles. To test the hypothesis that unilateral muscle injury causes contralateral muscle changes, an experimental rabbit model with unilateral muscle overuse caused by a combination of electrical muscle stimulation and exercise (EMS/E) was used. The soleus and gastrocnemius muscles of both exercised and non-exercised legs were analyzed with enzyme-and immunohistochemical methods after 1, 3 and 6 weeks of repeated EMS/E. After 1 w of unilateral EMS/E there were structural muscle changes such as increased variability in fiber size, fiber splitting, internal myonuclei, necrotic fibers, expression of developmental MyHCs, fibrosis and inflammation in the exercised soleus muscle. Only limited changes were found in the exercised gastrocnemius muscle and in both non-exercised contralateral muscles. After 3 w of EMS/E, muscle fiber changes, presence of developmental MyHCs, inflammation, fibrosis and affections of nerve axons and AChE production were observed bilaterally in both the soleus and gastrocnemius muscles. At 6 w of EMS/E, the severity of these changes significantly increased in the soleus muscles and infiltration of fat was observed bilaterally in both the soleus and the gastrocnemius muscles. The affections of the muscles were in all three experimental groups restricted to focal regions of the muscle samples. We conclude that repetitive unilateral muscle overuse caused by EMS/E overtime leads to both degenerative and regenerative tissue changes and myositis not only in the exercised muscles, but also in the homologous non-exercised muscles of the contralateral leg. Although the mechanism behind the contralateral changes is unclear, we suggest that the nervous system is involved in the cross-transfer effects.

  • 48.
    Song, Yafeng
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Stål, Per
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Backman, C
    Yu, Jiguo
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Experimental studies favour that tachykinins are involved in the process of myositis and muscle derangement in an overuse animal modelManuscript (preprint) (Other academic)
  • 49.
    Song, Yafeng
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Stål, Per S
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Yu, Ji-Guo
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Backman, Clas
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Inhibitors of endopeptidase and angiotensin-converting enzyme lead to an amplification of the morphological changes and an upregulation of the substance P system in a muscle overuse model2014In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 15, p. 126-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: We have previously observed, in studies on an experimental overuse model, that the tachykinin system may be involved in the processes of muscle inflammation (myositis) and other muscle tissue alterations. To further evaluate the significance of tachykinins in these processes, we have used inhibitors of neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE), substances which are known to terminate the activity of various endogenously produced substances, including tachykinins.

    METHODS: Injections of inhibitors of NEP and ACE, as well as the tachykinin substance P (SP), were given locally outside the tendon of the triceps surae muscle of rabbits subjected to marked overuse of this muscle. A control group was given NaCl injections. Evaluations were made at 1 week, a timepoint of overuse when only mild inflammation and limited changes in the muscle structure are noted in animals not treated with inhibitors. Both the soleus and gastrocnemius muscles were examined morphologically and with immunohistochemistry and enzyme immunoassay (EIA).

    RESULTS: A pronounced inflammation (myositis) and changes in the muscle fiber morphology, including muscle fiber necrosis, occurred in the overused muscles of animals given NEP and ACE inhibitors. The morphological changes were clearly more prominent than for animals subjected to overuse and NaCl injections (NaCl group). A marked SP-like expression, as well as a marked expression of the neurokinin-1 receptor (NK-1R) was found in the affected muscle tissue in response to injections of NEP and ACE inhibitors. The concentration of SP in the muscles was also higher than that for the NaCl group.

    CONCLUSIONS: The observations show that the local injections of NEP and ACE inhibitors led to marked SP-like and NK-1R immunoreactions, increased SP concentrations, and an amplification of the morphological changes in the tissue. The injections of the inhibitors thus led to a more marked myositis process and an upregulation of the SP system. Endogenously produced substances, out of which the tachykinins conform to one substance family, may play a role in mediating effects in the tissue in a muscle that is subjected to pronounced overuse.

  • 50.
    Spang, Christoph
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Scott, Alexander
    University of British Columbia, Vancouver Coastal Health and Research Institute.
    Danielson, Patrik
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    Lorentzon, Ronny
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Forsgren, Sture
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Anatomy.
    VGluT2 and NMDAR1 expression in cells in the inflammatory infiltrates in experimentally induced myositis: evidence of local glutamate signaling suggests autocrine/paracrine effects in an overuse injury model2012In: Inflammation, ISSN 0360-3997, E-ISSN 1573-2576, Vol. 35, no 1, p. 39-48Article in journal (Refereed)
    Abstract [en]

    It is not known whether a glutamate signaling system is involved in muscle inflammation (myositis). In the present study, we examined this question in the soleus muscle in a laboratory model of myositis resulting from repetitive overuse induced by electrical stimulation and injection of pro-inflammatory substances. Sections of rabbit soleus muscle with an induced myositis, i.e., exhibiting infiltration of inflammatory cells, were examined immunohistochemically using antibodies against vesicular glutamate transporter VGluT2 and the glutamate receptor NMDAR1. In situ hybridization for demonstration of VGluT2 mRNA was also performed. Specific reactions for both VGluT2 and NMDAR1 could be observed immunohistochemically in the same cells. In situ hybridization demonstrated the occurrence of VGluT2 mRNA in the cells. Double staining showed that the VGluT2 reactions were detectable in cells marked with T cell/neutrophil marker and in cells expressing eosinophil peroxidase. These data suggest the occurrence of previously unknown glutamate-mediated autocrine/paracrine effects within the inflammatory infiltrates during the development of muscle inflammation.

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