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  • 1.
    Aspenberg, Per
    et al.
    Department of Orthopaedics, IKE, Faculty of Health Sciences, Linköping.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Fixed or loose?: Dichotomy in RSA data for cemented cups.2008In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 79, no 4, p. 467-473Article in journal (Refereed)
    Abstract [en]

    Background and purpose: Roentgen stereometric analysis (RSA) cannot discern whether a single prosthesis is fixed or migrating below the detection level. Samples of patients usually show migration values that appear to be continuously distributed. Is there such continuity, or is there a dichotomy between stable and migrating prostheses? The hypothesis of a dichotomy has, to our knowledge, not been tested. We present an exploratory evaluation of such a dichotomy using a mixture distribution algorithm.

    Methods: We analyzed the migration (as determined by RSA) of 147 cemented acetabular cups of 7 different designs by using a new set of algorithms for frequency distribution analysis called Rmix.

    Results: We first analyzed a migration vector, regardless of direction. After 2 years there was a significant dichotomy between 2 lognormal subgroups within the sample. Although some types of cups were over‐represented in one of the subgroups, neither cup design, sex, nor operating department could explain the dichotomy into two groups, which appears to reflect the existence of two basically different types of behavior of the cups. We next analyzed the migration along the 3 axes in space, and found a similar dichotomy. During the second year, around 80% of the patients belonged to a distinct, normally distributed subgroup with a mean not different from 0 mm and a small variation. The remainder differed significantly from this subgroup and showed migration.

    Interpretation: There is a dichotomy in migration pattern. During the second postoperative year, most cups belonged to a subpopulation that appeared stable. The remainder is probably at risk of loosening. For a single type of prosthesis, the relative size of the stable subgroup may be a good index of the expected performance. The possibility of detecting subgroups within a seemingly continuous sample might be useful in many fields of medicine.

  • 2.
    Bergström, Ulrica
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Jonsson, Håkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Gustafson, Yngve
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Pettersson, Ulrika
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Pharmacology.
    Stenlund, Hans
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    The hip fracture incidence curve is shifting to the right: a forecast of the age-quake2009In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 80, no 5, p. 520-524Article in journal (Refereed)
    Abstract [en]

    Background The number of hip fractures has doubled in the last 30–40 years in many countries. Age-adjusted incidence has been reported to be decreasing in Europe and North America, but is there a decreasing trend in all age groups? Patients and methods This population-based study included all hip-fracture patients over 50 years of age (a total of 2,919 individuals, 31% of whom were men) admitted to Umeå University Hospital, Sweden, from 1993 through 2005. Results The incidence of hip fracture declined between the periods 1993–1996 and 2001–2005: from 706 to 625 hip fractures per 105 women and from 390 to 317 hip fractures per 105 men. However, there was a 114% increase in the number of fractures in women aged 90 or older (12 and 25 hip fractures/year, respectively, in the two time periods). For the period 2001–05, women ≥ 90 years of age accounted for almost the same numbers of hip fractures as women aged 75–79 (27 fractures/year). The rate increased during this period, from 2,700 per 105 women to 3,900 per 105 women > 90 years. In men there were declining trends for both relative and absolute numbers. Interpretation Although age-adjusted incidence declined in the population > 50 years of age, absolute fracture rate and incidence increased in the very old. Women over 90 now have the same absolute number of hip fractures every year as women aged 75–79 years. There was a right-shift in hip fracture distribution towards the oldest old, probably due to an increased number of octo/nonagenarians, a new population of particularly frail old people that hardly existed earlier. Better health among septuagenarians may also have delayed the age at which fractures occurred. This changing pattern will strain orthopedic and geriatric resources even more.

  • 3.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Orthopedic surgery in ancient Egypt2014In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 85, no 6, p. 670-676Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Ancient Egypt might be considered the cradle of medicine. The modern literature is, however, sometimes rather too enthusiastic regarding the procedures that are attributed an Egyptian origin. I briefly present and analyze the claims regarding orthopedic surgery in Egypt, what was actually done by the Egyptians, and what may have been incorrectly ascribed to them.

    METHODS: I reviewed the original sources and also the modern literature regarding surgery in ancient Egypt, concentrating especially on orthopedic surgery.

    RESULTS: As is well known, both literary sources and the archaeological/osteological material bear witness to treatment of various fractures. The Egyptian painting, often claimed to depict the reduction of a dislocated shoulder according to Kocher's method, is, however, open to interpretation. Therapeutic amputations are never depicted or mentioned in the literary sources, while the specimens suggested to demonstrate such amputations are not convincing.

    INTERPRETATION: The ancient Egyptians certainly treated fractures of various kinds, and with varying degrees of success. Concerning the reductions of dislocated joints and therapeutic amputations, there is no clear evidence for the existence of such procedures. It would, however, be surprising if dislocations were not treated, even though they have not left traces in the surviving sources. Concerning amputations, the general level of Egyptian surgery makes it unlikely that limb amputations were done, even if they may possibly have been performed under extraordinary circumstances.

  • 4. Brodén, Cyrus
    et al.
    Mukka, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics. Department of Orthopedics, Sundsvall Hospital, Sundsvall.
    Muren, Olle
    Eisler, Thomas
    Boden, Henrik
    Stark, André
    Sköldenberg, Olof
    High risk of early periprosthetic fractures after primary hip arthroplasty in elderly patients using a cemented, tapered, polished stem: an observational, prospective cohort study on 1,403 hips with 47 fractures after mean follow-up time of 4 years2015In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 86, no 2, p. 169-174Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Postoperative periprosthetic femoral fracture (PPF) after hip arthroplasty is associated with considerable morbidity and mortality. We assessed the incidence and characteristics of periprosthetic fractures in a consecutive cohort of elderly patients treated with a cemented, collarless, polished and tapered femoral stem (CPT). Patients and methods - In this single-center prospective cohort study, we included 1,403 hips in 1,357 patients (mean age 82 (range 52-102) years, 72% women) with primary osteoarthritis (OA) or a femoral neck fracture (FNF) as indication for surgery (367 hips and 1,036 hips, respectively). 64% of patients were ASA class 3 or 4. Hip-related complications and need for repeat surgery were assessed at a mean follow-up time of 4 (1-7) years. A Cox regression analysis was used to evaluate risk factors associated with PPF. Results - 47 hips (3.3%) sustained a periprosthetic fracture at median 7 (2-79) months postoperatively; 41 were comminute Vancouver B2 or complex C-type fractures. The fracture rate was 3.8% for FNF patients and 2.2% for OA patients (hazard ratio (HR) = 4; 95% CI: 1.3-12). Patients > 80 years of age also had a higher risk of fracture (HR = 2; 95% CI: 1.1-4.5). Interpretation - We found a high incidence of early PPF associated with the CPT stem in this old and frail patient group. A possible explanation may be that the polished tapered stem acts as a wedge, splitting the femur after a direct hip contusion. Our results should be confirmed in larger, registry-based studies, but we advise caution when using this stem for this particular patient group.

  • 5.
    Crnalic, Sead
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Hildingsson, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Wikström, Pernilla
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Löfvenberg, Richard
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Widmark, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Outcome after surgery for metastatic spinal cord compression in 54 patients with prostate cancer2012In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 83, no 1, p. 80-86Article in journal (Refereed)
    Abstract [en]

    Background and purpose The criteria for selecting patients who may benefit from surgery of spinal cord compression in metastatic prostate cancer are poorly defined. We therefore studied patients operated for metastatic spinal cord compression in order to evaluate outcome of surgery and to find predictors of survival. Patients and methods We reviewed the records of 54 consecutive patients with metastatic prostate cancer who were operated for spinal cord compression at Umeå University Hospital. The indication for surgery was neurological deficit due to spinal cord compression. 41 patients had hormone-refractory cancer and 13 patients had previously untreated, hormone-naïve prostate cancer. 29 patients were operated with posterior decompression only, and in 25 patients posterior decompression and stabilization was performed. Results Preoperatively, 6/54 of patients were able to walk. 1 month after surgery, 33 patients were walking, 15 were non-ambulatory, and 6 had died. Mortality rate was 11% at 1 month, 41% at 6 months, and 59% at 1 year. In the hormone-naïve group, 8/13 patients were still alive with a median postoperative follow-up of 26 months. In the hormone-refractory group, median survival was 5 months. Patients with hormone-refractory disease and Karnofsky performance status (KPS) of ≤ 60% had median survival of 2.5 months, whereas those with KPS of 70% and KPS of ≥ 80% had a median survival of 7 months and 18 months, respectively (p < 0.001). Visceral metastases were present in 12/41 patients with hormone-refractory tumor at the time of spinal surgery, and their median survival was 4 months-as compared to 10 months in patients without visceral metastases (p = 0.003). Complications within 30 days of surgery occurred in 19/54 patients. Interpretation Our results indicate that patients with hormone-naive disease, and those with hormone-refractory disease with good performance status and lacking visceral metastases, may be helped by surgery for metastatic spinal cord compression.

  • 6.
    Edmundsson, David
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Chronic compartment syndrome also affects nonathletic subjects: a prospective study of 63 cases with exercise-induced lower leg pain2007In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 78, no 1, p. 136-142Article in journal (Refereed)
    Abstract [en]

    Background Chronic exertional compartment syndrome is most often reported in young and physically active people.

    Patients and methods We studied 73 consecutive patients (mean age 39 (16–77) years, 45 women) with a history of exercise-induced pain and suspicion of chronic exertional compartment syndrome (CECS) of the lower leg—clinically, radiographically and with intramuscular pressure measurements.

    Results Intramuscular pressure increased with reproduction of symptoms and fulfilled the criteria for diagnosis of CECS in 36 patients (mean age 36 (16–65) years, 22 women), with engagement of 66 anterior, 2 lateral and 7 posterior muscle compartments in 72 legs. The patients with CECS of the lower leg were divided into 4 etiological groups: 18 with overuse, 10 with earlier trauma, 4 insulin-treated diabetics, and 4 others. Two-thirds of the patients had pain during walking. The outcome after fasciotomy was excellent or good in 41/57 of the legs.

    Interpretation CECS of the lower leg probably has a multifactorial etiology and is more common in sedentary individuals than has been recognized previously. Fasciotomy appears to be beneficial in these cases also.

  • 7.
    Edmundsson, David
    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.
    Toolanen, Göran
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Intermittent claudication in diabetes mellitus due to chronic exertinal compartment syndrome of the leg: an observation study of 17 patients2008In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 79, no 4, p. 534-539Article in journal (Refereed)
    Abstract [en]

    Background and purpose: Intermittent claudication in diabetes mellitus is commonly associated with arterial disease but may occur without obvious signs of peripheral circulatory impairment. We investigated whether this could be due to chronic exertional compartment syndrome (CECS).

    Patients and methods: We report on 17 patients (3 men), mean age 39 (18–72) years, with diabetes mellitus—12 of which were type 1—and leg pain during walking (which was relieved at rest), without clinical signs of peripheral arterial disease. The duration of diabetes was 22 (1–41) years and 12 patients had peripheral neuropathy, retinopathy, or nephropathy. The leg muscles were tender and firm on palpation. Radiography, scintigraphy, and intramuscular pressure measurements were done during exercises to reproduce their symptoms.

    Results: 16 of the 17 patients were diagnosed as having CECS. The intramuscular pressures in leg compartments were statistically significantly higher in diabetics than in physically active non‐diabetics with CECS (p < 0.05). 15 of the 16 diabetics with CECS were treated with fasciotomy. At surgery, the fascia was whitish, thickened, and had a rubber‐like consistency. After 1 year, 9 patients rated themselves as excellent or good in 15 of the 18 treated compartments. The walking time until stop due to leg pain increased after surgery from less than 10 min to unlimited time in 8 of 9 patients who were followed up.

    Interpretation: Intermittent claudication in diabetics may be caused by CECS of the leg. The intramuscular pressures were considerably elevated in diabetics. One pathomechanism may be fascial thickening. The results after fasciotomy are good, and the increased pain‐free walking time is especially beneficial for diabetics.

  • 8. Gudnason, Asgeir
    et al.
    Adalberth, Gunnar
    Nilsson, Kjell-Gunnar
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Hailer, Nils P.
    Tibial component rotation around the transverse axis measured by radiostereometry predicts aseptic loosening better than maximal total point motion A follow-up of 116 total knee arthroplasties after at least 15 years2017In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 88, no 3, p. 282-287Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Maximal total point motion (MTPM) measured by radiostereometry (RSA) is widely used as a predictor of total knee arthroplasty (TKA) loosening. We compared the ability of different RSA measurements at different time points to predict loosening of tibial TKA components in the long term. Patients and methods - 116 TKAs in 116 patients were included in our analysis. 16 (14.8-17.4) years after surgery, 5 tibial components had been revised due to aseptic loosening. Receiver operating characteristic curves were calculated in order to investigate the specificity and sensitivity of different RSA parameters at different thresholds. Results - Rotation around the transverse (x-) axis measured 2 years postoperatively had the best predictive value of all parameters, with an area under the curve (AUC) of 80%. Using a threshold of 0.8 degrees, a specificity of 85% and a sensitivity of 50% were reached. The AUC for tibial component distal translation was 79% and it was 77% for proximal translation, whereas it was only 68% for MTPM. Interpretation - Rotation of the cemented tibial component around the transverse axis, proximal translation, and distal translation are slightly better at predicting aseptic loosening than MTPM, and tibial component migration measured after 2 years gives a good prediction of aseptic loosening up to 15 years.

  • 9.
    Guez, Michel
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Hildingsson, Christer
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Nasic, Salmir
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Medicine.
    Toolanen, Göran
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Chronic low back pain in individuals with chronic neck pain of traumatic and non-traumatic origin: a population-based study.2006In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 77, no 1, p. 132-137Article in journal (Refereed)
  • 10. Hagsten, B
    et al.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Health-related quality of life and self-reported ability concerning ADL and IADL after hip facture: a randomized trial2006In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 77, no 1, p. 114-119Article in journal (Refereed)
  • 11.
    Hedström, Erik M
    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.
    Bergström, Ulrica
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Michno, Piotr
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Epidemiology of fractures in children and adolescents2010In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 81, no 1, p. 148-153Article in journal (Refereed)
    Abstract [en]

    Background and purpose Fractures are most common in youth and in the elderly, with differences in incidence over time and between regions. We present the fracture pattern in a population of youths 19 years of age, who were seen at Umeå University Hospital, Sweden.

    Material and methods All injuries seen at the hospital have been recorded in a database since 1993. The data include variables such as age, sex, date, type of injury, mechanism of injury, and treatment. For the period 1993–2007, there were 10,203 injury events that had resulted in at least 1 fracture.

    Results The incidence for the whole period was 201/104 person years. The incidence increased by 13% during the period 1998–2007, when we were able to control for registration errors. The most common fracture site was the distal forearm. The most common type of injury mechanism was falling. The peak incidence occurred at 11–12 years in girls and at 13–14 years in boys, with a male-to-female incidence ratio of 1.5. We found variations in mechanisms and activities at injury with age, and over time.

    Interpretation Fractures are caused by a combination of intrinsic and extrinsic factors that vary with age. We believe the increase in incidence is partly explained by changes in children's activity patterns over time. Further research may help to identify preventive measures to reduce the number of fractures, in particular those involving hospital care, surgical treatment, and—most importantly—long-term impairment.

    Read More: http://informahealthcare.com/doi/abs/10.3109/17453671003628780

  • 12.
    Hedström, Erik M
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Bergström, Ulrica
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Michno, Piotr
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Epidemiology of fractures in children and adolescents: Increased incidence over the past decade: a population-based study from northrn Sweden2010In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 81, no 1, p. 148-153Article in journal (Refereed)
    Abstract [en]

    Background and purpose Fractures are most common in youth and in the elderly, with differences in incidence over time and between regions. We present the fracture pattern in a population of youths <= 19 years of age, who were seen at Umeå University Hospital, Sweden. Material and methods All injuries seen at the hospital have been recorded in a database since 1993. The data include variables such as age, sex, date, type of injury, mechanism of injury, and treatment. For the period 1993-2007, there were 10,203 injury events that had resulted in at least 1 fracture. Results The incidence for the whole period was 201/10<sup>4</sup> person years. The incidence increased by 13% during the period 1998-2007, when we were able to control for registration errors. The most common fracture site was the distal forearm. The most common type of injury mechanism was falling. The peak incidence occurred at 11-12 years in girls and at 13-14 years in boys, with a male-to-female incidence ratio of 1.5. We found variations in mechanisms and activities at injury with age, and over time. Interpretation Fractures are caused by a combination of intrinsic and extrinsic factors that vary with age. We believe the increase in incidence is partly explained by changes in children's activity patterns over time. Further research may help to identify preventive measures to reduce the number of fractures, in particular those involving hospital care, surgical treatment, and-most importantly-long-term impairment.

  • 13. Henricson, Anders
    et al.
    Nilsson, Kjell G.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Trabecular metal tibial knee component still stable at 10 years: An RSA study of 33 patients less than 60 years of age2016In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 87, no 5, p. 504-510Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Total knee replacement (TKR) in younger patients using cemented components has shown inferior results, mainly due to aseptic loosening. Excellent clinical results have been reported with components made of trabecular metal (TM). In a previous report, we have shown stabilization of the TM tibial implants for up to 5 years. In this study, we compared the clinical and RSA results of these uncemented implants with those of cemented implants. Patients and methods - 41 patients (47 knees) aged 60 years underwent TKR. 22 patients (26 knees) received an uncemented monoblock cruciate-retaining (CR) tibial component (TM) and 19 patients (21 knees) received a cemented NexGen Option CR tibial component. Follow-up examination was done at 10 years, and 16 patients (19 knees) with TM tibial components and 17 patients (18 knees) with cemented tibial components remained for analysis. Results - 1 of 19 TM implants was revised for infection, 2 of 18 cemented components were revised for knee instability, and no revisions were done for loosening. Both types of tibial components migrated in the first 3 months, the TM group to a greater extent than the cemented group. After 3 months, both groups were stable during the next 10 years. Interpretation - The patterns of migration for uncemented TM implants and cemented tibial implants over the first 10 years indicate that they have a good long-term prognosis regarding fixation

  • 14.
    Henricson, Anders
    et al.
    Department of Orthopaedics and Center for Clinical Research, Falu General Hospital , Falun.
    Rösmark, Dan
    Department of Orthopaedics and Center for Clinical Research, Falu General Hospital , Falun.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Trabecular metal tibia still stable at 5 years: an RSA study of 36 patients aged less than 60 years2013In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 84, no 4, p. 398-405Article in journal (Refereed)
    Abstract [en]

    Background and purpose Clinical results of total knee replacement (TKR) are inferior in younger patients, mainly due to aseptic loosening. Coating of components with trabecular metal (TM) is a new way of enhancing fixation to bone. We have previously reported stabilization of TM tibial components at 2 years. We now report the 5-year follow-up of these patients, including RSA of their TM tibial components. Patients and methods 22 patients (26 knees) received an uncemented TM cruciate-retaining tibial component and 19 patients (21 knees) a cemented NexGen Option cruciate-retaining tibial component. Follow-up with RSA, and clinical and radiographic examinations were done at 5 years. In bilaterally operated patients, the statistical analyses included only the first-operated knee. Results Both groups had most migration within the first 3 months, the TM implants to a greater extent than the cemented implants. After 3 months, both groups stabilized and remained stable up to the 5-year follow-up. Interpretation After a high initial degree of migration, the TM tibia stabilized. This stabilization lasted for at least 5 years, which suggests a good long-term performance regarding fixation. The cemented NexGen CR tibial components showed some migration in the first 3 months and then stabilized up to the 5-year follow-up. This has not been reported previously.

  • 15.
    Jonsson , Håkan
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences. Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    A review of the TLICS system: a novel, user friendly thoracolumbar trauma classification system2008In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 79, no 4, p. 461-466Article in journal (Refereed)
  • 16.
    Lysholm, Jack
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Yelverton, Tegner
    Department of Health Sciences, University of Technology, Luleå.
    Knee injury rating scales2008In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 78, no 4, p. 445-453Article in journal (Refereed)
  • 17.
    Mahmood, Sarwar S.
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Mukka, Sebastian S.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics. Sundsvall and Norrland University Hospitals.
    Crnalic, Sead
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Wretenberg, Per
    Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden.
    Sayed-Noor, Arkan S.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics. Sundsvall and Norrland University Hospitals.
    Association between changes in global femoral offset after total hip arthroplasty and function, quality of life, and abductor muscle strength: A prospective cohort study of 222 patients2016In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 87, no 1, p. 36-41Article in journal (Refereed)
    Abstract [en]

    Background and purpose - There is no consensus on the association between global femoral offset (FO) and outcome after total hip arthroplasty (THA). We assessed the association between FO and patients? reported hip function, quality of life, and abductor muscle strength.

    Patients and methods - We included 250 patients with unilateral hip osteoarthritis who underwent a THA. Before the operation, the patient?s reported hip function was evaluated with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and quality of life was evaluated with EQ-5D. At 1-year follow-up, the same scores and also hip abductor muscle strength were measured. 222 patients were available for follow-up. These patients were divided into 3 groups according to the postoperative global FO of the operated hip compared to the contralateral hip, as measured on plain radiographs: the decreased FO group (more than 5 mm reduction), the restored FO group (within 5 mm restoration), and the increased FO group (more than 5 mm increment).

    Results - All 3 groups improved (p < 0.001). The crude results showed that the decreased FO group had a worse WOMAC index, less abductor muscle strength, and more use of walking aids. When we adjusted these results with possible confounding factors, only global FO reduction was statistically significantly associated with reduced abductor muscle strength. The incidence of residual hip pain and analgesics use was similar in the 3 groups.

    Interpretation - A reduction in global FO of more than 5 mm after THA appears to have a negative association with abductor muscle strength of the operated hip, and should therefore be avoided.

  • 18.
    Mellner, Carl
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Hand Surgery.
    Eisler, Thomas
    Börsbo, Johannes
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Brodén, Cyrus
    Morberg, Per
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Mukka, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    The Sernbo score predicts 1-year mortality after displaced femoral neck fractures treated with a hip arthroplasty2017In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 88, no 4, p. 402-406Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Displaced femoral neck fractures (FNFs) are associated with high rates of mortality during the first postoperative year. The Sernbo score (based on age, habitat, mobility, and mental state) can be used to stratify patients into groups with different 1-year mortality. We assessed this predictive ability in patients with a displaced FNF treated with a hemiarthroplasty or a total hip arthroplasty. Patients and methods - 292 patients (median age 83 (65-99) years, 68% female) with a displaced FNF were included in this prospective cohort study. To predict 1-year mortality, we used a multivariate logistic regression analysis including comorbidities and perioperative management. A receiver operating characteristic (ROC) analysis was used to evaluate the predictive ability of the Sernbo score, which was subsequently divided in a new manner into a low, intermediate, or high risk of death during the first year. Results - At 1-year follow-up, the overall mortality rate was 24%, and in Sernbo's low-, intermediate-, and high-risk groups it was 5%, 22%, and 51%, respectively. The Sernbo score was the only statistically significant predictor of 1-year mortality: odds ratio for the intermediate-risk group was 4.2 (95% Cl: 1.5-12) and for the high-risk group it was 15 (95% CI: 5-40). The ROC analysis showed a fair predictive ability of the Sernbo score, with an area under the curve (AUC) of 0.79 (95% CI: 0.73-0.83). Using a cutoff of less than 11 points on the score gave a sensitivity of 61% and a specificity of 83%. Interpretation - The Sernbo score identifies patients who are at high risk of dying in the first postoperative year. This scoring system could be used to better tailor perioperative care and treatment in patients with displaced FNF.

  • 19.
    Minde, Jan
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Holmberg, Monica
    Umeå University, Faculty of Medicine, Medical Biosciences, Medical and Clinical Genetics.
    Solders, Göran
    Toolanen, Göran
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Orthopedic aspects of familial insensitivity to pain due to a novel nerve growth factor beta mutation.2006In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 77, no 2, p. 198-202Article in journal (Refereed)
  • 20.
    Mohammed, Jabbar
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Mukka, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Hedbeck, Carl-Johan
    Chammout, Ghazi
    Gordon, Max
    Sköldenberg, Olof
    Reduced periprosthetic fracture rate when changing from a tapered polished stem to an anatomical stem for cemented hip arthroplasty: an observational prospective cohort study with a follow-up of 2 years2019In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 90, no 5, p. 427-432Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Straight collarless polished tapered stems have been linked to an increased risk for periprosthetic femur fractures in comparison with anatomically shaped stems, especially in elderly patients. Therefore, we evaluated the effect of an orthopedic department's full transition from the use of a cemented collarless, polished, tapered stem to a cemented anatomic stem on the cumulative incidence of postoperative periprosthetic fracture (PPF). Patients and methods - This prospective single-center cohort study comprises a consecutive series of 1,077 patients who underwent a cemented hip arthroplasty using either a collarless polished tapered stem (PTS group, n = 543) or an anatomic stem (AS group, n = 534). We assessed the incidence of PPF 2 years postoperatively and used a Cox regression model adjusted for age, sex, ASA class, cognitive impairment, BMI, diagnosis, and surgical approach for outcome analysis. Results - Mean age at primary surgery was 82 years (49-102), 73% of the patients were female, and 75% underwent surgery for a femoral neck fracture. The PPF rate was lowered from 3.3% (n = 18) in the PTS group to 0.4% (n = 2) in the AS group. The overall complication rate was also lowered from 8.8% in the PTS group to 4.5% in the AS group. In the regression model only cognitive dysfunction (HR 3.8, 95% CI 1.4-10) and the type of stem (PTS vs AS, HR 0.1, CI 0.0-0.5) were correlated with outcome. Interpretation - For elderly patients with poor bone quality use of cemented anatomic stems leads to a substantial reduction in periprosthetic fracture rate without increasing other complications.

  • 21.
    Mukka, Sebastian
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Knutsson, Björn
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Majeed, Ammar
    Sayed-Noor, Arkan S
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Reduced revision rate and maintained function after hip arthroplasty for femoral neck fractures after transition from posterolateral to direct lateral approach2017In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 88, no 6, p. 627-633Article in journal (Refereed)
    Abstract [en]

    Background and purpose The direct lateral (DL) approach to the hip for femoral neck fractures (FNF) has been shown to reduce the rate of dislocation and reoperations. We evaluate the effect of transition from the posterolateral (PL) to DL approach on reoperation and dislocation rates and patients' reported outcome.

    Patients and methods In a prospective cohort study between 2012 and 2015, we enrolled 362 patients (median age 83 years, 70% women, mean follow-up 25 months) with a displaced FNF. The first group of 146 patients were operated using the PL and the second group of 216 patients with a DL approach, after change of our routines. A multivariable Cox regression analysis was used to evaluate factors associated with dislocation and reoperation. A generalized linear model was used to evaluate the functional outcome by comparing WOMAC and Harris hip scores between the 2 groups.

    Results The reoperation rate was reduced from 13% in the PL to 6% in the DL group and the dislocation rate from 13% to 4%. Cox proportional hazard analysis identified the PL approach as the only factor associated with an increased risk of reoperation (hazard ratio =2.5, 95% CI 1.2-5.2). Age, sex, ASA classification, type of arthroplasty, cognitive dysfunction, or the experience of the surgeon had no effect on the risk of reoperation. Patient-reported outcome was similar between the 2 groups.

    Interpretation In patients with FNF we have reduced the reoperation and dislocation rates by changing the surgical approach used for hip arthroplasty without affecting the patient-reported functional outcome.

  • 22.
    Mukka, Sebastian
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Mellner, Carl
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Knutsson, Bjorn
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Sayed-Noor, Arkan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Skoldenberg, Olof
    Substantially higher prevalence of postoperative periprosthetic fractures in octogenarians with hip fractures operated with a cemented, polished tapered stem rather than an anatomic stem A prospective cohort study involving 979 hips2016In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 87, no 3, p. 257-261Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Recent studies have demonstrated a high incidence of postoperative periprosthetic femoral fracture (PPF) in elderly patients treated with 2 commonly used cemented, polished tapered stems. We compared the prevalence and incidence rate of PPF in a consecutive cohort of octagenerians with femoral neck fractures (FNFs) treated with either a collarless, polished tapered (CPT) stem or an anatomic matte stem (Lubinus SP2). Patients and methods - In a multicenter, prospective cohort study, we included 979 hips in patients aged 80 years and above (72% females, median age 86 (80-102) years) with a femoral neck fracture as indication for surgery. 69% of the patients were classified as ASA class 3 or 4. Hip-related complications and repeat surgery were assessed at a median follow-up of 20 (0-24) months postoperatively. Results - 22 hips (2.2%) sustained a PPF at a median of 7 (0-22) months postoperatively; 14 (64%) were Vancouver B2 fractures. 7 of the 22 surgically treated fractures required revision surgery, mainly due to deep infection. The cumulative incidence of PPFs was 3.8% in the CPT group, as compared with 0.2% in the SP2 group (p < 0.001). The risk ratio (RR) was 16 (95% CI: 2-120) using the SP2 group as denominator. Interpretation - The CPT stem was associated with a higher risk of PPF than the SP2 stem. We suggest that the tapered CPT stem should not be used for the treatment of femoral neck fractures in patients over 80 years.

  • 23.
    Nordvall, Helena
    et al.
    Department of Physiotherapy, Sunderby Hospital, Department of Orthopaedics, Sunderby Hospital, Luleå.
    Glanberg-Persson, Gunhild
    Department of Orthopaedics, Sunderby Hospital, Luleå.
    Lysholm, Jack
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Are distal radius fractures due to fragility or to falls?: a consecutive case-control study of bone mineral density, tendency to fall, risk factors for osteoporosis, and health-related quality of life2007In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 78, no 2, p. 271-277Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: A fracture of the distal radius is considered to indicate an increased risk of future fractures, especially a hip fracture. The main causes may be osteoporosis or a tendency to fall, separately or in combination.

    METHODS: 93 women and 5 men with a recent radius fracture and the same number of controls were measured with a heel-DXL and asked to complete one questionnaire on their quality of life (SF-36), and one on risk factors.

    RESULTS: The mean T-score of the patients was -2.1, and for the controls it was -1.9 (p = 0.3). The patients aged over 64 years had a history of falling more often than the corresponding controls (p = 0.01), but there was no difference in T-score. By contrast, patients 45-64 years of age showed a non-significant, lower T-score (p = 0.09), but there was no difference concerning their history of falling. For all other risk factors, no differences were found between the patients and the controls. There were significant differences between the patients and the controls in some of the functions in the SF-36, due to the radius fracture.

    INTERPRETATION: This study indicates that the underlying cause of a distal radius fracture may be different in patients aged 45-64 years and those who are more than 64 years old.

  • 24.
    Otten, Volker T C
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Mukka, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Crnalic, Sead
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Kärrholm, Johan
    Uncemented cups with and without screw holes in primary THA: a Swedish Hip Arthroplasty Register study with 22,725 hips2019In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 90, no 3, p. 258-263Article in journal (Refereed)
    Abstract [en]

    Background and purpose — Uncemented cups in total hip arthroplasty (THA) are often augmented with additional screws to enhance their primary stability. We investigated whether there is a difference in the risk for revision between cups with screw holes and cups without screw holes.

    Patients and methods — We analyzed the risk for cup revision of uncemented cups registered in the Swedish Hip Arthroplasty Register (SHAR) between 2000 and 2017 with respe ct to the presence of screw holes. Only patients with primary osteoarthritis (OA) were included. 22,725 cups, including 12,354 without screw holes and 10,371 with screw holes, were evaluated. Revision rates at 2 and 10 years after the primary operation were analyzed.

    Results — At a median follow-up time of 3.4 years (0–18), 459 cup revisions were reported. The main reasons for cup revision during the whole observation time were infection, 52% of all cup revisions, and dislocation, 26% of all cup revisions. The survival rate with cup revision due to aseptic loosening as endpoint was 99.9% (95% CI 99.8–99.9) at 2 years for both cups with and cups without screw holes, and the survival rates at 10 years were 99.5% (CI 99.3–99.7) and 99.1% (CI 98.6–99.5), respectively. Cups without screw holes showed a decreased risk of revision due to any reason at both 2 years (adjusted hazard ratio [HR] 0.6, CI 0.5–0.8) and 10 years (HR 0.7, CI 0.5–0.9).

    Interpretation — We found a very low revision rate for aseptic loosening with modern, uncemented cup designs. Cups with screw holes had an increased risk of revision due to any reason in patients with primary OA

  • 25. Petursson, Gunnar
    et al.
    Fenstad, Anne Marie
    Gøthesen, Øystein
    Haugan, Kristin
    Dyrhovden, Gro Sævik
    Hallan, Geir
    Röhrl, Stephan M
    Aamodt, Arild
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Furnes, Ove
    Similar migration in computer-assisted and conventional total knee arthroplasty.2017In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 88, no 2, p. 166-172Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Computer-assisted surgery (CAS) in total knee arthroplasty (TKA) has been used in recent years in the hope of improving the alignment and positioning of the implant, thereby achieving a better functional outcome and durability. However, the role of computer navigation in TKA is still under debate. We used radiostereometric analysis (RSA) in a randomized controlled trial (RCT) to determine whether there are any differences in migration of the tibial component between CAS- and conventionally (CONV-) operated TKA. Patients and methods - 54 patients (CAS, n = 26; CONV, n = 28) with a mean age of 67 (56-78) years and with osteoarthritis or arthritic disease of the knee were recruited from 4 hospitals during the period 2009-2011. To estimate the mechanical stability of the tibial component, the patients were examined with RSA up to 24 months after operation. The following parameters representing tibial component micromotion were measured: 3-D vector of the prosthetic marker that moved the most, representing the magnitude of migration (maximum total point motion, MTPM); the largest negative value for y-translation (subsidence); the largest positive y-translation (lift-off); and prosthetic rotations. The precision of the RSA measurements was evaluated and migration in the 2 groups was compared. Results - Both groups had most migration within the first 3 months, but there was no statistically significant difference in the magnitude of the migration between the CAS group and the CONV group. From 3 to 24 months, the MTPM (in mm) was 0.058 and 0.103 (p = 0.1) for the CAS and CON groups, respectively, and the subsidence (in mm) was 0.005 and 0.011 (p = 0.3). Interpretation - Mean MTPM, subsidence, lift-off, and rotational movement of tibial trays were similar in CAS- and CONV-operated knees.

  • 26. Rydholm, Anders
    et al.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Happy birthday, Acta!2010In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 81, no 1, p. 1-2Article in journal (Other (popular science, discussion, etc.))
  • 27.
    Röhrl, Stephan M
    et al.
    Department of Orthopaedics, Oslo University Hospital, Oslo.
    Nivbrant, Bo
    Perth Orthopaedic Institute, University of Western Australia, Perth, Australia.
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    No adverse effects of submelt-annealed highly crosslinked polyethylene in cemented cups: an RSA study of 8 patients 10 years after surgery2012In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 83, no 2, p. 148-152Article in journal (Refereed)
    Abstract [en]

    Background and purpose Highly crosslinked polyethylene (PE) is in standard use worldwide. Differences in the crosslinking procedure may affect the clinical performance. Experimenatal data from retrieved cups have shown free radicals and excessive wear of annealed highly crosslinked PE. We have previously reported low wear and good clinical performance after 6 years with this implant, and now report on the 10-year results. Patients and methods In 8 patients, we measured wear of annealed highly crosslinked PE prospectively with radiostereometry after 10 years. Activity was assessed by UCLA activity score and a specifically designed activity score. Conventional radiographs were evaluated for osteolysis and clinical outcome by the Harris hip score (HHS). Results The mean (95% CI) proximal head penetration for highly crosslinked PE after 10 years was 0.07 (-0.015 to 0.153) mm, and the 3D wear was 0.2 (0.026 to 0.36) mm. Without creep, proximal head penetration was 0.02 (-0.026 to 0.066) mm and for 3D penetration was 0.016 (-0.47 to 0.08) mm. This represents an annual proximal wear of less than 2 mu m. All cups were clinically and radiographically stable but showed a tendency of increased rotation after 5 years. Interpretation Wear for annealed highly crosslinked PE is extremely low up to 10 years. Free radicals do not affect mechanical performance or lead to clinically adverse effects. Creep stops after the first 6 months after implantation. Highly crosslinked PE is a true competitor of hard-on-hard bearings.

  • 28.
    Röhrl, Stephan M
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Nivbrant, Bo
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Snorrason, Finnur
    Kärrholm, Johan
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Porous-coated cups fixed with screws.: A 12-year clinical and radiostereometric follow-up study of 50 hips.2006In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 77, no 3, p. 393-401Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Excellent mid-term results have stimulated the use of hemispherical porous-coated cups in hip replacement. With longer follow-up, there have been problems related to polyethylene wear and liner fixation, and osteolysis has been documented in reports of selected cases. We evaluated the clinical and radiographic results of 50 patients followed for 12 years. PATIENTS AND METHODS: 58 consecutive patients (58 hips), mean age 55 years, were operated with Harris-Galante (HG) I or II cups using line-to-line fit and additional screw fixation. Polyethylene linersgamma-sterilized in air and 32-mm ceramic heads were used. 8 patients died within 12 years, leaving 50 patients with a complete 12 year follow-up. 23 of the cups were also evaluated with radiostereometry (RSA) for migration, liner stability, and wear. RESULTS: All metal shells were still in situ after 12 years. 4 hips had been revised due to femoral loosening. In these revisions, the liner had been exchanged due to wear and/or instability, resulting in a cup survival rate of 89%. 28 cups displayed osteolytic lesions, mainly in relation to screws. RSA revealed minimum translations, but in many cases there were pronounced liner rotations suggesting unstable liners within the metal shell. The annual proximal wear was 0.09 mm and the three-dimensional wear was 0.16 mm. INTERPRETATION: RSA can predict the long-term performance of cup fixation. Low migration during the initial years after implantation indicates excellent long-term results regarding fixation of the metal shell. The main problem with this design appears to be liner instability and osteolysis, factors that are probably interrelated. Because these phenomena are clinically silent, we recommend regular follow-up of patients with HG cups to avoid sudden loosening and complicated revisions.

  • 29.
    Rörhrl, Stephan M
    et al.
    Department of Orthopaedics, Ullevål University Hospital, Division of Neuroscience, Orthopaedics and Rehabilitation, Oslo, Norway.
    Ming, Guo Li
    Perth Orthopaedic Institute, University of Western Australia, Perth, Australia.
    Nilsson, Kjell-Gunnar
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Nivbrant, Bo
    Perth Orthopaedic Institute, University of Western Australia, Perth, Australia.
    Very low wear of non-remelted highly cross-linked polyethylene cups: an RSA study lasting up to 6 years.2007In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 78, no 6, p. 739-745Article in journal (Refereed)
    Abstract [en]

    Background and purpose: Highly cross-linked polyethylenes (PEs) all appear to reduce wear dramatically in laboratory studies, although there is substantial variation in this respect between manufacturers. Nonremelted cross-linked PE is almost as tough as unirradiated PE, but is not completely stable and can oxidize in vivo, as has been shown in recent retrievals studies.

    We had reported low wear and good clinical performance after 2 years for 10 non-remelted highly crosslinked PE cups compared to 16 conventional PE cups sterilized by gamma-in-air.

    Method: Because of possible degradation by free radicals, we followed up both cohorts for 5 years (conventional PE) and 6 years (highly cross-linked PE).

    Result: Mean (CI) proximal head penetration over the observation time was linear and measured 0.08 (0.02–0.13) mm for cross-linked PE and 0.42 (0.23–0.62) mm for conventional PE, and total penetration was 0.23 (0.1–0.35) mm and 0.75 (0.05–1.4) mm respectively. After subtracting creep, the annual wear for non-remelted highly cross-linked PE was below 6 µm. The cups had equally low migration and few radiolucencies.

    Interpretation: The theoretical possibility of oxidation in non-remelted highly cross-linked PE may not show clinically. However, it may be that cemented cups with their thicker PE are more forgiving than metal-backed cups with thin PE moving in the locking mechanism. So far, we can conclude that the Crossfire highly crosslinked polyethylene cups performed very well clinically, with extremely low wear even after almost 6 years. This is reassuring, but care should be taken in extrapolating these results to other cross-linked PEs or uncemented cups where toughness of PE is more of an issue.

  • 30.
    Sayed-Noor, Arkan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Mukka, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Mohaddes, Maziar
    Kärrholm, Johan
    Rolfson, Ola
    Body mass index is associated with risk of reoperation and revision after primary total hip arthroplasty: a study of the Swedish Hip Arthroplasty Register including 83,146 patients2019In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 90, no 3, p. 220-225Article in journal (Refereed)
    Abstract [en]

    Background and purpose: The prevalence of obesity is on the rise, becoming a worldwide epidemic. The main purpose of this register-based observational study was to investigate whether different BMI classes are associated with increased risk of reoperation within 2 years, risk of revision within 5 years, and the risk of dying within 90 days after primary total hip arthroplasty (THA). We hypothesized that increasing BMI would increase these risks.

    Patients and methods: We analyzed a cohort of 83,146 patients who had undergone an elective THA for primary osteoarthritis between 2008 and 2015 from the Swedish Hip Arthroplasty Register (SHAR). BMI was classified according to the World Health Organization (WHO) into 6 classes: < 18.5 as underweight, 18.5-24.9 as normal weight, 25-29.9 as overweight, 30-34.9 as class I obesity, 35-39.9 as class II obesity, and ≥ 40 as class III obesity.

    Results: Both unadjusted and adjusted parameter estimates showed increasing risk of reoperation at 2 years and revision at 5 years with each overweight and obesity class, mainly due to increased risk of infection. Uncemented and reversed hybrid fixations and surgical approaches other than the posterior were all associated with increased risk. Obesity class III (≥ 40), male sex, and increasing ASA class were associated with increased 90-day mortality.

    Interpretation: Increasing BMI was associated with 2-year reoperation and 5-year revision risks after primary THA where obese patients have a higher risk than overweight or normal weight patients. As infection seems to be the main cause, customizing preoperative optimization and prophylactic measures for obese patients may help reduce risk.

  • 31.
    Sjöholm, Pontus
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Otten, Volker T C
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Wolf, Olof
    Gordon, Max
    Karsten, Gustav
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Sköldenberg, Olof
    Mukka, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Posterior and anterior tilt increases the risk of failure after internal fixation of Garden I and II femoral neck fracture2019In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Preoperative posterior tilt of the femoral head as seen on lateral radiographs has been reported to affect the risk of fixation failure in cases of minimally displaced femoral neck fractures (Garden I-II). We investigated radiological risk factors of treatment failure.

    Patients and methods - We included 417 patients (68% women, median age: 78 years (50-108) with a minimally displaced femoral neck fracture (Garden I-II) treated with internal fixation in a retrospective cohort study. The patients were followed for 3.4 years (2-14). Data on age, sex, housing, cognitive impairment, implant angulation, pre- and postoperative tilt, hip complications, and reoperations were recorded. The risk of fixation failure was assessed using Cox proportional hazards regression analysis.

    Results - The overall reoperation rate was 17%, and the rate of treatment failure (fixation failure, nonunion, avascular necrosis, or posttraumatic osteoarthritis) was 13%. Cox proportional hazard analysis revealed an increased risk of treatment failure with a preoperative posterior tilt of at least 20° and a preoperative anterior tilt greater than 10°. A failure occurred in 13 of the 65 patients with a posterior tilt of at least 20° and in 5 of the 9 patients with an anterior tilt greater than 10°.

    Interpretation - A preoperative posterior tilt of 20° and an anterior tilt greater than 10° in cases of Garden I and II femoral neck fractures increase the risk of fixation failure necessitating additional surgery. In this group of patients, there is a need for future interventional studies regarding the feasibility of primary hip arthroplasty.

  • 32.
    Strömqvist, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Ahmad, Murad
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Hildingsson, Christer
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Strömqvist, Björn
    Universitetssjukhuset i Lund.
    Gender differences in lumbar disc herniation surgery2008In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 79, no 5, p. 643-649Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Although there have been numerous publications on lumbar disc herniation (LDH) treated surgically, there has been little interest in sex differences. It has been shown in many studies that sex differences may be important in certain diseases. We therefore reviewed consecutive register material from one institution for possible gender differences in pre- and postoperative parameters in patients operated for lumbar disc herniation.

    PATIENTS AND METHODS: Pre- and postoperative parameters for all patients operated on at the Department of Orthopedics, Lund University Hospital over 6 years (2000-2005 inclusive) (301 patients, 165 males) were analyzed regarding sex differences.

    RESULTS: Statistically significant and clinically relevant sex differences were found. Preoperatively, females had more pronounced back pain and disability, and also lower quality of life in some respects. At 1-year followup, females reported a higher rate of consumption of analgesics, a higher degree of postoperative back and leg pain, and less improvement regarding disability and some aspects of quality of life. Relative improvement, rate of return to work, and satisfaction with the outcome of surgery were not, however, statistically significantly different between females and males.

    INTERPRETATION: There are statistically significant differences between the sexes in lumbar disc herniation surgery regarding basic demographic status and postoperative status, whereas the surgical effect is similar. Further investigations should focus on whether there is a true sex difference or whether these differences are due to selection for surgery, differences in proneness to seek medical advice or to accept/choose surgery, or other unknown factors.

     

  • 33.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences. Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Orthopaedics.
    Long-term cost and effect on quality of life of osteoporosis-related fractures in Sweden2008In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 79, no 2, p. 269-280Article in journal (Refereed)
  • 34.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    The classic: Walldius, Börje: “Arthroplasty of the Knee Using an Endoprosthesis: 8 Years’ Experience”, Acta Orthopaedica Scandinavica, 1960; 30: 1, 137–1482010In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 81, no 1, p. 21-33Article in journal (Other (popular science, discussion, etc.))
  • 35.
    Söderlund, Per
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Dahl, Jon
    Rohrl, Stephan
    Nivbrant, Bo
    Nilsson, Kjell G.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    10-year results of a new low-monomer cement Follow-up of a randomized RSA study2012In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 83, no 6, p. 604-608Article in journal (Refereed)
    Abstract [en]

    Background and purpose The properties and performance of a new low-monomer cement were examined in this prospective randomized, controlled RSA study. 5-year data have already been published, showing no statistically significant differences compared to controls. In the present paper we present the 10-year results. Methods 44 patients were originally randomized to receive total hip replacement with a Lubinus SPII titanium-aluminum-vanadium stem cemented either with the new Cemex Rx bone cement or with control bone cement, Palacos R. Patients were examined using RSA, Harris hip score, and conventional radiographs. Results At 10 years, 33 hips could be evaluated clinically and 30 hips could be evaluated with RSA (16 Cemex and 14 Palacos). 9 patients had died and 4 patients were too old or infirm to be investigated. Except for 1 hip that was revised for infection after less than 5 years, no further hips were revised before the 10-year follow-up. There were no statistically significant clinical differences between the groups. The Cemex cement had magnitudes of migration similar to or sometimes lower than those of Palacos cement. In both groups, most hips showed extensive radiolucent lines, probably due to the use of titanium alloy stems. Interpretation At 10 years, the Cemex bone cement tested performed just as well as the control (Palacos bone cement).

  • 36.
    Wojtowicz, Radoslaw
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Henricson, Anders
    Nilsson, Kjell G
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Crnalic, Sead
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Uncemented monoblock trabecular metal posterior stabilized high-flex total knee arthroplasty: similar pattern of migration to the cruciate-retaining design - a prospective radiostereometric analysis (RSA) and clinical evaluation of 40 patients (49 knees) 60 years or younger with 9 years' follow-up2019In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682Article in journal (Refereed)
    Abstract [en]

    Background and purpose — Uncemented monoblock cruciate retaining (CR) trabecular metal (TM) tibial components in total knee arthroplasty (TKA) work well in the long-term perspective in patients ≤ 60 years. Younger persons expect nearly normal knee flexion after TKA, but CR implants generally achieve less knee flexion compared with posterior stabilized (PS) implants. Cemented PS implants have higher revision rate than CR implants. Can an uncemented monoblock PS TM implant be used safely in younger patients?

    Patients and methods — 40 patients (49 knees) age ≤ 60 years with primary (20 knees) or posttraumatic osteoarthritis (OA) were operated with a high-flex TKA using an uncemented monoblock PS TM tibial component. Knees were evaluated with radiostereometric analysis (RSA) a mean 3 days (1–5) postoperatively, and thereafter at 6 weeks, 3 months, 1, 2, 5, and 9 years. Clinical outcome was measured with patient-related outcome measures (PROMs).

    Results — The implants showed a pattern of migration with initial large migration followed by early stabilization lasting up to 9 years, a pattern known to be compatible with good long-term results. Clinical and radiological outcome was excellent with 38 of the 40 patients being satisfied or very satisfied with the procedure and bone apposition to the entire implant surface in 46 of 49 knees. Mean knee flexion was 130°. 1 knee was revised at 3 months due to medial tibial condyle collapse.

    Interpretation — The uncemented monoblock PS TM implant works well in younger persons operated with TKA due to primary or secondary OA.

  • 37.
    Wänman, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Grabowski, Pawel
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Nyström, Helena
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Gustafsson, Patrik
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Widmark, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Crnalic, Sead
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Metastatic spinal cord compression as the first sign of malignancy: Outcome after surgery in 69 patients2017In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 88, no 4, p. 457-462Article in journal (Refereed)
    Abstract [en]

    Background and purpose - Metastatic spinal cord compression (MSCC) as the initial manifestation of malignancy (IMM) limits the time for diagnostic workup; most often, treatment is required before the final primary tumor diagnosis. We evaluated neurological outcome, complications, survival, and the manner of diagnosing the primary tumor in patients who were operated for MSCC as the IMM.

    Patients and methods - Records of 69 consecutive patients (51 men) who underwent surgery for MSCC as the IMM were reviewed. The patients had no history of cancer when they presented with pain (n = 2) and/or neurological symptoms (n = 67).

    Results - The primary tumor was identified in 59 patients. In 10 patients, no specific diagnosis could be established, and they were therefore defined as having cancer of unknown primary tumor (CUP). At the end of the study, 16 patients were still alive (median follow-up 2.5 years). The overall survival time was 20 months. Patients with CUP had the shortest survival (3.5 months) whereas patients with prostate cancer (6 years) and myeloma (5 years) had the longest survival. 20 of the 39 patients who were non-ambulatory preoperatively regained walking ability, and 29 of the 30 ambulatory patients preoperatively retained their walking ability 1 month postoperatively. 15 of the 69 patients suffered from a total of 20 complications within 1 month postoperatively.

    Interpretation - Postoperative survival with MSCC as the IMM depends on the type of primary tumor. Surgery in these patients maintains and improves ambulatory function.

1 - 37 of 37
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