umu.sePublikationer
Ändra sökning
Avgränsa sökresultatet
1 - 37 av 37
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Bjerke, Joakim
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Öhberg, Fredrik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Foss, Olav A
    Orthopaedic Research Centre, Trondheim University Hospital, Trondheim, Norway.
    Stensdotter, Ann-Katrin
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Peak knee flexion angles during stair descent in TKA patients2014Ingår i: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 29, nr 4, s. 707-711Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reduced peak knee flexion during stair descent (PKSD) is demonstrated in subjects with total knee arthroplasty (TKA), but the underlying factors are not well studied. 3D gait patterns during stair descent, peak passive knee flexion (PPKF), quadriceps strength, pain, proprioception, demographics, and anthropometrics were assessed in 23 unilateral TKA-subjects ~ 19 months post-operatively, and in 23 controls. PKSD, PPKF and quadriceps strength were reduced in the TKA-side, but also in the contralateral side. A multiple regression analysis identified PPKF as the only predictor (57%) to explain the relationship with PKSD. PPKF was, however sufficient for normal PKSD. Deficits in quadriceps strength in TKA-group suggest that strength is also contributing to smaller PKSD. Increased hip adduction at PKSD may indicate both compensatory strategy and reduced hip strength.

  • 2.
    Bjerke, Joakim
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Öhberg, Fredrik
    Department of Biomedical Engineering & Informatics, Umeå University Hospital, Umeå, Sweden.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Stensdotter, Ann-Katrin
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Compensatory strategies for muscle weakness during stair ascent in subjects with total knee arthroplasty2014Ingår i: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 29, nr 7, s. 1499-1502Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Subjects with total knee arthroplasty (TKA) exhibit decreased quadriceps and hamstring strength. This may bring about greater relative effort or compensatory strategies to reduce knee joint moments in daily activities. To study gait and map out the resource capacity, knee muscle strength was assessed by maximal voluntary concentric contractions, and whole body kinematics and root mean square (RMS) electromyography (EMG) of vastus lateralis and semitendinosus were recorded during stair ascent in 23 unilateral TKA-subjects ~19months post-operation, and in 23 healthy controls. Muscle strength and gait velocity were lower in the TKA group, but no significant group differences were found in RMS EMG or forward trunk lean. The results suggest that reduced walking velocity sufficiently compensated for reduced knee muscle strength.

  • 3.
    Bjerke, Joakim
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Öhberg, Fredrik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Stensdotter, Ann-Katrin
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi. Department of Physiotherapy, School of Health Education & Social Work, Sør-Trøndelag University College, Trondheim, Norway.
    Gait on soft versus hard surface after total knee arthroplastyManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Asymmetric gait patterns are common following total knee arthroplasty (TKA). Gait on even and hard surface is primarily characterized by reduced peak knee flexion in the prosthetic knee, increased contralateral knee adduction angle, and decreased walking speed compared to controls. Natural conditions may however lead to different strategies. Therefore, the objective of the present study was to explore how gait patterns may differ when walking on a soft surface. Methods: 3D kinematics during gait on hard and soft surface were assessed in 23 unilateral TKA-subjects ~19 months post-operative, and in 23 controls. Results: Gait characteristics in TKA-subjects that differed from controls observed on hard surface were amplified on soft surface. Flexion in the prosthetic knee was further decreased and a tendency towards reduced flexion in the contralateral knee was observed. Knee and hip adduction were not affected by surface conditions nevertheless there was a difference between groups, in particular with regard to the prosthetic side. In addition, step width increased on soft surface in TKA-subjects. Conclusion: Gait on an even and soft surface did not amplify asymmetries in TKA-subjects, but decreased knee flexion and increased step-width, albeit with similar gait speed as the control group suggests that the soft surface provided a small but significant challenge making the TKA-subjects precautious.

  • 4.
    Bjerke, Joakim
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi. Department of Physiotherapy, Faculty of Health and Social Sciences, Norwegian University of Science and Technology, Trondheim, Norway.
    Öhberg, Fredrik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Stensdotter, Ann-Katrin
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering. epartment of Physiotherapy, Faculty of Health and Social Sciences, Norwegian University of Science and Technology, Trondheim, Norway .
    Walking on a compliant surface does not enhance kinematic gait asymmetries after unilateral total knee arthroplasty2016Ingår i: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 24, nr 8, s. 2606-2613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    PURPOSE: To investigate gait asymmetries and the effect of walking on compliant surfaces in individuals with unilateral total knee arthroplasty (TKA), hypothesizing that asymmetries would increase as an effect of the compliant surface.

    METHODS: Individuals with unilateral TKA ~19 months post-operative (n = 23, median age 59 years) recruited from one orthopaedic clinic and age- and gender-matched healthy individuals without knee complaints (n = 23, median age 56 years) walked at comfortable speed on a hard surface and on a compliant surface. 3D kinematic analyses were made for knee and hip angles in sagittal and frontal planes, stance time, step length, and gait velocity.

    RESULTS: Shorter stance time (p < 0.01) and less peak knee flexion (p < 0.001) at weight bearing acceptance was found in the prosthetic side compared with the contralateral side. Larger knee (p < 0.01) and hip (p < 0.001) adduction was found compared with healthy controls. Neither asymmetries between the prosthetic and the contralateral side nor differences compared with healthy controls were enhanced when walking on compliant surfaces compared with hard surfaces.

    CONCLUSION: The TKA group adapted their gait to compliant surfaces similarly to healthy controls. Gait asymmetries in the TKA group observed on hard surface were not enhanced, and adduction in hip and knee joints did not increase further as an effect of walking on compliant surfaces. Thus, unfavourable knee joint loading did not increase when walking on a compliant surface. This implies that recommendations for walking on soft surfaces to reduce knee joint loading are not counteracted by increased gait asymmetries and unfavourable joint loading configurations.

    LEVEL OF EVIDENCE: III.

  • 5. Callary, Stuart A
    et al.
    Campbell, David G
    Mercer, Graham E
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Field, John R
    The 6-Year Migration Characteristics of a Hydroxyapatite-Coated Femoral Stem A Radiostereometric Analysis Study2012Ingår i: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 27, nr 7, s. 1344-1348Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A prospective cohort of 30 patients undergoing primary total hip arthroplasty for treatment of osteoarthritis was enrolled in a study to characterize the migration behavior of a clinically successful cementless stem. At 6 years, the mean subsidence of the stem was 0.63 mm (range, -0.33 to 3.68 mm); the mean rotation into retroversion was 1.41° (range, -1.33° to 7.48°). No stems had additional subsidence of more than 0.25 mm between 6 months and 6 years. The resultant mean subsidence between 2 and 6 years was 0.03 mm, which is below the limit measurable by radiostereometric analysis. The data demonstrate that subsidence of this cementless stem occurs within the first 6 months, after which there is persistent stabilization.

  • 6. Callary, Stuart A.
    et al.
    Campbell, David G.
    Mercer, Graham
    Nilsson, Kjell G.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Field, John R.
    Wear of a 5 Megarad Cross-linked Polyethylene Liner: A 6-year RSA Study2013Ingår i: Clinical Orthopaedics and Related Research, ISSN 0009-921X, E-ISSN 1528-1132, Vol. 471, nr 7, s. 2238-2244Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One cross-linked polyethylene (XLPE) liner is manufactured using a lower dose of radiation, 5 Mrad, which may result in less cross-linking. The reported in vivo wear rate of this XLPE liner in patients undergoing THA has varied, and has included some patients in each reported cohort who had greater than 0.1 mm/year of wear, which is an historical threshold for osteolysis. Previous studies have measured wear on plain radiographs, an approach that has limited sensitivity. We therefore measured the amount and direction of wear at 6 years using Radiostereometric analysis (RSA) in patients who had THAs that included a cross-linked polyethylene liner manufactured using 5 Mrad radiation. We prospectively reviewed wear in 30 patients who underwent primary THAs with the same design of cross-linked acetabular liner and a 28-mm articulation. Tantalum markers were inserted during surgery and all patients had RSA radiographic examinations at 1 week, 6 months, 1, 2, and 6 years postoperatively. The mean proximal, two-dimensional (2-D) and three-dimensional (3-D) wear rates calculated between 1 year and 6 years were 0.014, 0.014, and 0.018 mm/per year, respectively. The direction of the head penetration recorded between 1 week and 6 years was in a proximal direction for all patients, proximolateral for 16 of 24 patients, and proximomedial for eight of 24 patients. The proximal, 2-D and 3-D wear of a XLPE liner produced using 5 Mrad of radiation was low but measurable by RSA after 6 years. No patients had proximal 2-D or 3-D wear rates exceeding 0.1 mm/year. Further followup is needed to evaluate the effect of XLPE wear particles on the development of long-term osteolysis.

  • 7. Campbell, David
    et al.
    Callary, Stuart
    Field, John
    Nilsson, Kjell G.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    All-polyethylene tibial components in young patients have stable fixation; a comparison RSA study2019Ingår i: Knee (Oxford), ISSN 0968-0160, E-ISSN 1873-5800, Vol. 26, nr 2, s. 392-399Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: All-polyethylene (AP) tibial components in patients aged greater than 60 years have stable tibial migration patterns and favorable survival rates when compared to identical Metal-backed (MB) designs. Tibial component migration in younger patients has not been reported. The aim of this study was to examine the migration characteristics of patients aged less than 60 years compared to a previous cohort of AP and MB tibial components of identical design in older patients.

    METHODS: A prospective consecutive study examined tibial component migration in 21 patients aged less than 60 years undergoing a cemented total knee arthroplasty with an AP tibial component by radiostereometric analysis (RSA) to 24 months. Results were compared to the authors' previous series of 21 patients aged greater than 60 years that were randomized to either an AP or MB tibial component.

    RESULTS: Both age groups of patients implanted with an AP component had stable migration patterns with no patient having greater than 0.2° rotation or 0.2 mm maximum total point motion. Five of 11 MB tibial components displayed continued migration between one and two years. Subsidence was similar in all groups, whilst maximum total point motion was greater for the MB cohort (0.34 mm, 0.33 mm, 0.61 mm; AP <60, AP >60, MB).

    CONCLUSIONS: Young patients implanted with an AP tibial component had stable tibial migration patterns comparable to older patients with the same AP implant. Regardless of age, AP tibial components were at least as stable as MB tibial components.

    LEVEL OF EVIDENCE: Level II, Prospective comparative study.

  • 8. Campbell, David
    et al.
    Mercer, Graham
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Wells, Vanessa
    Field, John R
    Callary, Stuart A
    Early migration characteristics of a hydroxyapatite-coated femoral stem: an RSA study.2011Ingår i: International Orthopaedics, ISSN 0341-2695, E-ISSN 1432-5195, Vol. 35, nr 4, s. 483-488Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurement of early stem subsidence can be used to predict the likelihood of long-term femoral component loosening and clinical failure. Data that examines the early migration pattern of clinically proven stems will provide clinicians with useful baseline data with which to compare new stem designs. This study was performed to evaluate the early migration pattern of a hydroxyapatite-coated press-fit femoral component that has been in use for over ten years. We enrolled 30 patients who underwent THA for osteoarthritis. The median age was 70 years (range, 55-80 years). Patients were clinically assessed using the Harris hip score. Radiostereometric analysis was used to evaluate stem migration at three to four days, six months, one year and two years. We observed a mean subsidence of 0.73 mm at six months, 0.62 mm at one year and 0.58 mm at two years and a mean retroversion of 1.82° at six months, 1.90° at one year and 1.59° at two years. This data suggests that subsidence is confined to the first six months after which there was no further subsidence. The results from this study can be compared with those from novel cementless stem designs to help predict the long-term outcome one may expect from new cementless stem designs.

  • 9. Cronskär, Marie
    et al.
    Rännar, Lars-Erik
    Bäckström, Mikael
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Samuelsson, Börje
    Patient-Specific Clavicle Reconstruction Using Digital Design and Additive Manufacturing2015Ingår i: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 137, nr 11, artikel-id 111418Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a trend toward operative treatment for certain types of clavicle fractures and these are usually treated with plate osteosynthesis. The subcutaneous location of the clavicle makes the plate fit important, but the clavicle has a complex shape, which varies greatly between individuals and hence standard plates often have a poor fit. Using computed tomography (CT) based design, the plate contour and screw positioning can be optimized to the actual case. A method for patient-specific plating using design based on CT-data, additive manufacturing (AM), and postprocessing was initially evaluated through three case studies, and the plate fit on the reduced fracture was tested during surgery (then replaced by commercial plates). In all three cases, the plates had an adequate fit on the reduced fracture. The time span from CT scan of the fracture to final implant was two days. An approach to achieve functional design and screw-hole positioning was initiated. These initial trials of patient-specific clavicle plating using AM indicate the potential for a smoother plate with optimized screw positioning. Further, the approach facilitates the surgeon's work and operating time can be saved.

  • 10.
    Dalen, Tore
    et al.
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Ortopedi.
    Nilsson, Kjell G
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Ortopedi.
    VersaBond bone cement prospective randomized study of the clinical properties of a new bone cement in total knee replacement.2005Ingår i: The Knee, ISSN 0968-0160, Vol. 12, nr 4, s. 311-7Artikel i tidskrift (Refereegranskat)
  • 11.
    Fredrik, Öhberg
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Grip, Helena
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Edström, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Gustavsson, Ola
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Häger, Charlotte
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Lundström, Ronnie
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin.
    Gait analysis using a portable motion sensor system: measurements in subjects with hip implant as compared with healthy controls2013Ingår i: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 38, nr suppl 1, s. 99-100Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: There is an increase of age related diseases such as hip joint arthritis, something that is often treated with hip replacement surgery. The aim of this study was to quantify movement function and its effect on quality of life in persons treated with hip implant, in comparison to matched asymptomatic controls.

    Patients/Materials and Methods: This is an ongoing study, and so far, 2 asymptomatic subjects (CTRL, age 50 ± 13 years, BMI 23 ± 2), and 4 subjects with hip implant (HIP, age 51 ± 15 years, BMI 25 ± 3), have been analyzed. The HIP group received their implant 2.6 ± 1.1 years ago and finished their rehabilitation 1.6 ± 1.1 years ago. Hip dysfunction and Osteoarthritis Outcome Score (HOOS) was used to assess the subject's hip function and its associated problems. A functional calibration (flexion/abduction movements) was done and each subject then performed 5 repetitions of gait (approx. 25 left/right gait cycles). Movement was registered with a custom-developed portable motion sensor system, where each sensor consisted of a tri-axial accelerometer and gyroscope. Sensors were placed on pelvis and each thigh and shank. Further calculations were done in MATLAB (v7.12 R2011a, Mathworks). Cosine rotation matrices were extracted by functional sensor-to- segment-calibration and sensor fusion [1], and hip and knee angles were obtained as Euler angles.

    Results: Preliminary results indicated larger range in hip rotation and smaller range of knee flexion during gait in HIP group than in the CTRL group (Fig. 1). HOOS profile (Fig. 2) indicated that hip function during sports (SP) and the general quality of life (QOL) were lower in the HIP group.

    Fig. 1. 

    Mean and SD of hip and knee angle over 15 gait cycles in one HIP subject (blue) as compared with the CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

    Figure optionsFig. 2. 

    HOOS profiles in HIP (blue square) and CTRL group (black). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

    Figure options

    Discussion and conclusions: Motion patterns during gait seemed to be negatively affected in subjects with hip implant, even after the rehabilitation program was completed and even though the HOOS profiles indicated a relative good hip function.

    Reference

    • [1]
    • J. Favre, B.M. Jolles, O. Siegrist, K. Aminian
    • Quaternion-based fusion of gyroscopes and accelerometers to improve 3D angle measurement

  • 12.
    Gao, Feng
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Henricson, Anders
    Falu General Hospital, Falun, Sweden.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Cemented versus uncemented fixation of the femoral component of the NexGeb CR total knee replacement in patients younger than 60 years: A Prospective Randomised Controlled RSA Study2009Ingår i: The Knee, ISSN 0968-0160, Vol. 16, nr 3, s. 200-206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optimal mode of femoral fixation in total knee arthroplasty (TKA) remains controversial, especially for the young patient. In a prospective randomised study we compared the magnitude and pattern of the fixation of cemented versus uncemented femoral components during 2 years in patients younger than 60 years. Forty-one knees in 41 patients were randomised to receive a NexGen (Zimmer, Warsaw, USA) cruciate-retaining TKA with either a cemented or an uncemented non HA-coated femoral component. The patients were examined by radiostereometric analysis (RSA), as well as clinical and radiological evaluation. The magnitude and pattern of migration as measured by RSA did not differ significantly between the cemented and uncemented fixation during the 2-year follow-up, nor were there any differences between the groups in clinical parameters. These findings suggest that an uncemented and non HA-coated femoral component may behave equally as well as a cemented one in the long-term.

  • 13.
    Grip, Helena
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Häger, Charlotte G.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Avdelningen för fysioterapi.
    Lundström, Ronnie
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Öhberg, Fredrik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Does the Femoral Head Size in Hip Arthroplasty Influence Lower Body Movements during Squats, Gait and Stair Walking?: A Clinical Pilot Study Based on Wearable Motion Sensors2019Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, nr 14, artikel-id 3240Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A hip prosthesis design with larger femoral head size may improve functional outcomes compared to the conventional total hip arthroplasty (THA) design. Our aim was to compare the range of motion (RoM) in lower body joints during squats, gait and stair walking using a wearable movement analysis system based on inertial measurement units (IMUs) in three age-matched male groups: 6 males with a conventional THA (THAC), 9 with a large femoral head (LFH) design, and 8 hip- and knee-asymptomatic controls (CTRL). We hypothesized that the LFH design would allow a greater hip RoM, providing movement patterns more like CTRL, and a larger side difference in hip RoM in THAC when compared to LFH and controls. IMUs were attached to the pelvis, thighs and shanks during five trials of squats, gait, and stair ascending/descending performed at self-selected speed. THAC and LFH participants completed the Hip dysfunction and Osteoarthritis Outcome Score (HOOS). The results showed a larger hip RoM during squats in LFH compared to THAC. Side differences in LFH and THAC groups (operated vs. non-operated side) indicated that movement function was not fully recovered in either group, further corroborated by non-maximal mean HOOS scores (LFH: 83 +/- 13, THAC: 84 +/- 19 groups, vs. normal function 100). The IMU system may have the potential to enhance clinical movement evaluations as an adjunct to clinical scales.

  • 14. Gudnason, Asgeir
    et al.
    Adalberth, Gunnar
    Nilsson, Kjell-Gunnar
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    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 years2017Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 88, nr 3, s. 282-287Artikel i tidskrift (Refereegranskat)
    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.

  • 15. Henricson, Anders
    et al.
    Nilsson, Kjell G.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Trabecular metal tibial knee component still stable at 10 years: An RSA study of 33 patients less than 60 years of age2016Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 87, nr 5, s. 504-510Artikel i tidskrift (Refereegranskat)
    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

  • 16.
    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 universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Trabecular metal tibia still stable at 5 years: an RSA study of 36 patients aged less than 60 years2013Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 84, nr 4, s. 398-405Artikel i tidskrift (Refereegranskat)
    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.

  • 17. Henricson, Anders
    et al.
    Wojtowicz, Radek
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Uncemented or cemented femoral components work equally well in total knee arthroplasty2019Ingår i: Knee Surgery, Sports Traumatology, Arthroscopy, ISSN 0942-2056, E-ISSN 1433-7347, Vol. 27, nr 4, s. 1251-1258Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    PURPOSE: To study the pattern of migration and clinical results up to 10 years of uncemented versus cemented fixation of the femoral component in total knee arthroplasty.

    METHODS: Randomized controlled trial was conducted of 41 patients (23 women, 18 men) under the age of 60 years using radiostereometric analysis.

    RESULTS: About two-thirds of the cemented implants and half of the uncemented implants stabilized between 2 and 10 years, while the remainder displayed a small annual increase of maximum total point motion of 0.09-0.10 mm/year. At 10 years there were no statistically significant differences in migration or clinical results between the groups.

    CONCLUSION: Uncemented fixation with titanium fiber mesh coating of the femoral component in total knee arthroplasty works equally as well as cemented fixation up to 10 years. An annual migration of 0.1 mm seems compatible with excellent long-term performance.

    LEVEL OF EVIDENCE: I.

  • 18.
    Li, Ming G
    et al.
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Ortopedi.
    Nilsson, Kjell G
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Ortopedi.
    Nivbrant, Bo
    Decreased precision for BMD measurements in the prosthetic knee using a non-knee-specific software.2004Ingår i: Journal of Clinical Densitometry, ISSN 1094-6950, Vol. 7, nr 3, s. 319-25Artikel i tidskrift (Refereegranskat)
  • 19.
    Nilsson, Kjell G.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Kinematics and fixation of total knee arthroplasties: a clinical, radiographic, scintimetric, and roentgen stereophotogrammetric evaluation1992Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Aseptic loosening of the tibial component is an important cause of failure after total knee arthroplasty. Bone destruction often claimed to be caused by the cement makes the revision difficult. In order to treat younger patients, uncemented fixation has been introduced, but the etiology to loosening is multifactorial and only partly known. Early detection of implant migration facilitates research in this field but is difficult using conventional techniques. In this study modified versions of roentgen stereophotogrammetric analysis (RSA) were developed to obtain accurate and standardized evaluations facilitating comparison between prosthetic designs. The method was used to record the efficacy of cemented and uncemented fixation of different designs of the tibial component, to determine the accuracy of scintimetry in the detection of early aseptic loosening, and to analyse the in vivo kinematics of knee arthroplasties with different design and stability between the joint surfaces.

    Forty-three arthroplasties with comparatively high inherent stability of the joint surfaces were randomized to cemented or uncemented fixation of the tibial component. In all groups micromovements were rather large, but with no differences between the cemented and uncemented components. The preoperative diagnosis (arthrosis OA, n=25; rheumatoid arthritis RA, n=18) did not influence the magnitude of micromotion.

    20 arthroplasties with the same design as above but equipped with an intramedullary stem, were randomized to cemented or uncemented fixation in patients with RA. Cement improved the fixation. Uncemented stemmed components displayed micromovements seemingly larger than unstemmed ones.

    34 arthroplasties with an unconstrained design of the joint area and fixed to the tibia with four pegs were randomized to cemented or uncemented fixation in patients with OA. When used uncemented 4 screws were added. Compared with previously investigated designs small micromotions were recorded, and especially in the cemented cases. Uncemented components with thin polyethylene inserts displayed larger initial micromotions. The preoperative deformity influenced the direction of the micromotion.

    33 knees were followed prospectively with RSA and scintimetry to evaluate any correlation between these methods. Low activity under the tibial component at 2 years implied prosthetic stability, whereas high activity indicated instability or high bone remodelling caused by the preoperative malalignment.

    The in vivo kinematics in three different designs of knee arthroplasties were analyzed during active flexion and extension without weight-bearing. Each type of prosthesis displayed design-specific abnormalities when compared with a normal material. Pronounced posterior tibial translations were recorded during flexion regardless whether the posterior cruciate ligament had been sacrificed or not. Data from the kinematic and the fixation studies suggest that movements restricted by the design of the joint area are transmitted to the bony interface with design-specific micromotions as the result.

    Analysis of knee joint kinematics during extension and weight-bearing revealed small alterations compared with non-weight-bearing. Evaluation of the three-dimensional movements in terms of helical axis rotations and translations confirmed the constrained or unconstrained in vivo behaviour of the designs under study. This analysis also facilitated the interpretation of the kinematic behaviour of the prosthetic knees and may be of value in the evaluation of new designs.

  • 20.
    Nilsson, Kjell G
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Henricson, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Norgren, Bo
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Dalén, Tore
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Uncemented HA-coated implant is the optimum for the TKA in the young patient2006Ingår i: Clinical Orthopaedics and Related Research, ISSN 0009-921X, E-ISSN 1528-1132, Vol. 448, s. 129-139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fixation of the tibial component in total knee arthroplasty in younger patients remains controversial. We evaluate the results of three different types of fixation of the Profix total knee arthroplasty in a randomized controlled trial of 97 consecutive knees (85 patients) with osteoarthrosis or inflammatory arthritis with 2-year followup of all patients. We randomized patients to three different types of fixation of the tibial component: cemented, uncemented (HA coated) with screws, or uncemented (HA coated) without screws. We performed clinical evaluations and radiostereometric analysis at 6 weeks, and 3, 6, 12 and 24 months postoperatively. The knees in the uncemented groups migrated more than those in the cemented group during the first 3 months, but at 2 years we observed no differences. The uncemented implants displayed all migration within the first 3 months. The cemented implants did not stabilize but had continuously increasing migration during the followup. Cementless implants without screws did not migrate more than implants with screws and displayed similar pattern of migration, indicating screws do not improve fixation. Uncemented fixation using hydroxyapatite-coated implants without screws seems to be the best solution for the younger patient.

  • 21.
    Nilsson, Kjell G
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Lundholm, Rolf
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk mikrobiologi.
    Friberg, Sven
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Assessment of horizontal laminar air flow instrument table for additional ultraclean space during surgery2010Ingår i: Journal of Hospital Infection, ISSN 0195-6701, E-ISSN 1532-2939, Vol. 76, nr 3, s. 243-246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The area in a vertical ultraclean laminar air flow (LAF) theatre is usually too small to accommodate all the equipment needed for major surgery. We investigated the addition of an instrument table supplied with fixed ultraclean LAF and placed alongside the existing main LAF unit, to determine its physical and bacteriological effect on the main unit. In phase 1, with two investigators but without a patient, smoke tests showed no intrusion of air from the table into the main unit and particle counts did not show any adverse effect on the main LAF unit. In phase 2, during patients undergoing two total knee replacements, the LAF table and a table without LAF were placed alongside the main LAF unit. The tables were subjected to the activity of an extra operating room (OR) nurse working from inside the main LAF vigorously simulating handling of instruments. During this activity, the >5 μm particle counts were 275/m3 at the instrument table with LAF and 8550/m3 at the table without LAF (P < 0.0001). Also, without the OR nurse activity, the particle counts, just inside the main unit and adjacent to the LAF table, were significantly reduced (P < 0.03–0.003). Sedimentation plates on the LAF table and in the main unit registered 22 and 25 cfu/m2/h respectively compared with 45 cfu/m2/h at the instrument table without LAF. In conclusion, the results from the smoke tests, particle counts and bacteriological evaluation showed that the additional instrument table supplied with LAF is efficient and can be safely used as an extension additional to a main OR LAF unit.

  • 22.
    Nilsson, Kjell G.
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi. Umeå University Hospital, S-901 85 Umeå, Sweden.
    Theodoulou, Annika
    Mercer, Graham
    Quinn, Stephen J.
    Krishnan, Jeganath
    Mid-term migration of a cementless, porous acetabular cup: A 5 year Radiostereometric analysis2017Ingår i: Journal of Orthopaedics, ISSN 0972-978X, E-ISSN 0972-978X, Vol. 14, nr 4, s. 454-460Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: The aim of the study was to determine the 5 year migratory and wear patterns, adverse events and clinical outcomes of a cementless, porous acetabular cup. Methods: RSA imaging of a cohort of 11 patients was retrospective analysed at 5 years post Total Hip Arthroplasty (THA). Changes in pain, function and symptoms of the hip at 5 years post-THA were compared to preoperative and 2 year postoperative assessments on the Harris Hip Score (HHS) and Hip dysfunction and Osteoarthritis Outcome Score (HOOS). Results: The majority of cup migration occurred up to 6 months and stabilised thereafter (6 months to 5 years, p = 0.091-0.866, Wilcoxon Signed Rank test). The direction of rotation around the 3 axes was evenly distributed among the cups between anterior-posterior rotation, internal-external rotation and increased-decreased inclination. The majority of the cups translated proximally, at an average migration of 0.36 mm (+/- 95% CI 0.17) at 5-years post-THA. Following initial bedding in, up to 6 months, there was no detectable polyethylene wear between 6 months and 5 years. At 5 years postoperatively, a statistically significant difference was observed across all HOOS subscales in comparison to preoperative values, with higher means reported at 5 years (p < 0.001). The total mean HHS displayed a statistically significant improvement, increasing from 'poor' preoperatively to 'good' at 5 years post-THA. Conclusion: Following initial migration between discharge and 6 months, the cementless porous acetabular cup demonstrated a tendency for stabilisation from 6 months up to 5 years post-THA, suggesting good mid-term fixation. Additionally, improvements in clinical outcome measures of pain, function and quality-of-life remained high following THA at 5 years post-surgery. 

  • 23. Norgren, B0
    et al.
    Dalen, Tore
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Ortopedi.
    Nilsson, Kjell G
    Umeå universitet, Medicinsk fakultet, Kirurgisk och perioperativ vetenskap, Ortopedi.
    All-poly tibial component better than metal-backed: a randomized RSA study.2004Ingår i: Knee (Oxford), ISSN 0968-0160, E-ISSN 1873-5800, The Knee, Vol. 11, nr 3, s. 189-196Artikel i tidskrift (Refereegranskat)
  • 24.
    Otten, Volker
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Maguire, Gerald Q. Jr.
    Noz, Marilyn E.
    Zeleznik, Michael P.
    Nilsson, Kjell G.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Olivecrona, Henrik
    Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups?: A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties2017Ingår i: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, Vol. 2017, artikel-id 3681458Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36 degrees, 1.36 degrees, and 0.60 degrees for X-, Y-, and Z-rotation and 0.40, 0.17, and 0.37mm for X-, Y-, and Z-translation. The limit of agreement between CT and RSA was 1.51 degrees, 2.17 degrees, and 1.05 degrees for rotation and 0.59, 0.56, and 0.74mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3 degrees to 2 degrees for rotation and 0.15 to 0.6mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers.

  • 25.
    Otten, Volker T C
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Röhrl, Stephan M
    Nivbrant, Bo
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Stability of Uncemented Cups - Long-Term Effect of Screws, Pegs and HA Coating: A 14-Year RSA Follow-Up of Total Hip Arthroplasty2016Ingår i: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 31, nr 1, s. 156-161Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Screws, pegs and hydroxyapatite-coating are used to enhance the primary stability of uncemented cups. We present a 14-year follow-up of 48 hips randomized to four groups: press-fit only, press-fit plus screws, press-fit plus pegs and hydroxyapatite-coated cups. Radiostereometric migration measurements showed equally good stability regardless cup augmentation. The mean wear rate was high, 0.21mm/year, with no differences between the groups. Seven hips had radiographical osteolysis but only in hips with augmented cups. Cups without screw-holes compared with cups with screw-holes resulted in better clinical outcome at the 14-year follow-up. Thus, augmentation of uncemented cups with screws, pegs, or hydroxyapatite did not appear to improve the long-term stability compared with press-fit only.

  • 26.
    Otten, Volker T C
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Mukka, Sebastian
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Kärrholm, Johan
    Uncemented cups with and without screw holes in primary THA: a Swedish Hip Arthroplasty Register study with 22725 hipsManuskript (preprint) (Övrigt vetenskapligt)
    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 respect to the presence of screw holes. Only patients with primary osteoarthritis (OA) were included. 22725 cups, including 12354 without screw holes and 10371 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 (0-18) years, 459 cup revisions were reported. The main reasons for cup revision during the whole observations 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 for revision due to any reason in patients with primary OA.

  • 27.
    Otten, Volker T C
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Mukka, Sebastian
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Kärrholm, Johan
    Uncemented cups with and without screw holes in primary THA: a Swedish Hip Arthroplasty Register study with 22,725 hips2019Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 90, nr 3, s. 258-263Artikel i tidskrift (Refereegranskat)
    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

  • 28.
    Otten, Volker T C
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Stamenkov, Roumen
    Callary, Stuart A.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Howie, Donald W.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Osteolysis around uncemented cups withand without screw holes: Analysis of osteolytic lesions on CT images in 48 hips at a 14-year follow-upManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Osteolysis around uncemented cups is a major complication for THA. We present a 14-year follow-up of 48 hips previously randomized to four groups of cup fixation – sealed cups with press-fit only, cups with hydroxyapatite coating, cups with screws, and cups with pegs. CT scans revealed three types of osteolytic lesions – Type 1A (absence of trabecular bone and a sclerotic border), Type 1B (absence of trabecular bone without a sclerotic border), and Type 2 (reductions in radiodensity and trabeculae). Cups with screw-holes were surrounded with larger osteolytic lesions that were predominantly Type 1A. Unsealed screw holes in uncemented cups appeared to be a risk factor for osteolysis development. Modern CT scans reveal three types of osteolytic lesions. Distinction between types is important for comparability between studies.

  • 29. 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 universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Furnes, Ove
    Similar migration in computer-assisted and conventional total knee arthroplasty.2017Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 88, nr 2, s. 166-172Artikel i tidskrift (Refereegranskat)
    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.

  • 30.
    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 universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    No adverse effects of submelt-annealed highly crosslinked polyethylene in cemented cups: an RSA study of 8 patients 10 years after surgery2012Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 83, nr 2, s. 148-152Artikel i tidskrift (Refereegranskat)
    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.

  • 31.
    Röhrl, Stephan M
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Nivbrant, Bo
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Snorrason, Finnur
    Kärrholm, Johan
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Porous-coated cups fixed with screws.: A 12-year clinical and radiostereometric follow-up study of 50 hips.2006Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 77, nr 3, s. 393-401Artikel i tidskrift (Refereegranskat)
    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.

  • 32.
    Röhrl, Stephan M
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Nivbrant, Bosse
    Ström, Håkan
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Effect of augmented cup fixation on stability, wear and osteolysis: a 5-year follow-up of total hip arthroplasty with RSA2004Ingår i: The Journal of Arthroplasty, ISSN 0883-5403, E-ISSN 1532-8406, Vol. 19, nr 8, s. 962-971Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To evaluate different modes of cementless fixation of hemispherical cups, we operated on 87 hips in 81 patients using 4 different means of cup fixation. The hips were randomly assigned to fixation with press-fit technique only (PF), or with augmentation with screws (S), pegs (P), or hydroxyapatite (HA) coating. The patients were evaluated with radiostereometric analysis (RSA) for cup migration and wear, conventional radiography for osteolysis, and Harris Hip Score for clinical outcome over 5 years. The fixation of the cups did not differ between the groups, but HA showed a tendency to decrease proximal migration. HA-coated cups displayed the best interface with hardly any signs of radiolucent lines, indicating a superior sealing effect of the HA coating. Cups with screws or pegs had more radiolucent lines and osteolytic lesions than the other groups. Radiolucent lines were correlated to higher proximal migration, young age, and female gender (r2=.2). The wear rate of the ethylene oxide-sterilized polyethylene liner was high (0.2 mm/y) but did not differ between the groups. Two cups with a perioperative fracture of the acetabular rim showed large initial migration but stabilized thereafter.

  • 33. Suijkerbuijk, Mathijs A. M.
    et al.
    Ponzetti, Marco
    Rahim, Masouda
    Posthumus, Michael
    Häger, Charlotte
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Avdelningen för fysioterapi.
    Stattin, Evalena
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Teti, Anna
    Meuffels, Duncan E.
    van der Eerden, Bram J. C.
    Collins, Malcolm
    September, Alison V.
    Functional polymorphisms within the inflammatory pathway regulate expression of extracellular matrix components in a genetic risk dependent model for anterior cruciate ligament injuries.2019Ingår i: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 22, nr 11, s. 1219-1225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVES: To investigate the functional effect of genetic polymorphisms of the inflammatory pathway on structural extracellular matrix components (ECM) and the susceptibility to an anterior cruciate ligament (ACL) injury.

    DESIGN: Laboratory study, case-control study.

    METHODS: Eight healthy participants were genotyped for interleukin (IL)1B rs16944 C>T and IL6 rs1800795 G>C and classified into genetic risk profile groups. Differences in type I collagen (COL1A1), type V collagen (COL5A1), biglycan (BGN) and decorin (DCN) gene expression were measured in fibroblasts either unstimulated or following IL-1β, IL-6 or tumor necrosis factor (TNF)-α treatment. Moreover, a genetic association study was conducted in: (i) a Swedish cohort comprised of 116 asymptomatic controls (CON) and 79 ACL ruptures and (ii) a South African cohort of 100 CONs and 98 ACLs. Participants were genotyped for COL5A1 rs12722 C>T, IL1B rs16944 C>T, IL6 rs1800795 G>C and IL6R rs2228145 G>C.

    RESULTS: IL1B high-risk fibroblasts had decreased BGN (p=0.020) and COL5A1 (p=0.012) levels after IL-1β stimulation and expressed less COL5A1 (p=0.042) following TNF-α treatment. Similarly, unstimulated IL6 high-risk fibroblasts had lower COL5A1 (p=0.012) levels than IL6 low-risk fibroblasts. In the genetic association study, the COL5A1-IL1B-IL6 T-C-G (p=0.034, Haplo-score 2.1) and the COL5A1-IL1B-IL6R T-C-A (p=0.044, Haplo-score: 2.0) combinations were associated with an increased susceptibility to ACL injury in the Swedish cohort when only male participants were evaluated.

    CONCLUSIONS: This study shows that polymorphisms within genes of the inflammatory pathway modulate the expression of structural and fibril-associated ECM components in a genetic risk depended manner, contributing to an increased susceptibility to ACL injuries.

  • 34.
    Söderlund, Per
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Dahl, Jon
    Rohrl, Stephan
    Nivbrant, Bo
    Nilsson, Kjell G.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    10-year results of a new low-monomer cement Follow-up of a randomized RSA study2012Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 83, nr 6, s. 604-608Artikel i tidskrift (Refereegranskat)
    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).

  • 35.
    Tengman, Eva
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Brax Olofsson, Lisbeth
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Tegner, Yelverton
    Luleå tekniska universitet .
    Lundgren, Lars
    Luleå tekniska universitet.
    Häger, Charlotte
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Anterior cruciate ligament injury after more than 20 years: I. Physical activity level and knee function2014Ingår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, nr 6, s. e491-e500Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Little is known about physical activity level and knee function including jump capacity and fear of movement/reinjury more than 20 years after injury of the anterior cruciate ligament (ACL). Seventy persons with unilateral ACL injury participated (23 ± 2 years post-injury): 33 treated with physiotherapy in combination with surgical reconstruction (ACLR), and 37 treated with physiotherapy alone (ACLPT). These were compared with 33 age- and gender-matched controls. Assessment included knee-specific and general physical activity level [Tegner activity scale, International Physical Activity Questionnaire (IPAQ)], knee function [Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS)], jump capacity (one-leg hop, vertical jump, side hops), and fear of movement/reinjury [Tampa Scale for Kinesiophobia (TSK)]. Outcomes were related to degree of osteoarthritis (OA). ACL-injured had lower Lysholm, KOOS, and Tegner scores than controls (P < 0.001), while IPAQ score was similar. ACL-injured demonstrated inferior jump capacity in injured compared with noninjured leg (6–25%,P < 0.001–P = 0.010 in the different jumps), while noninjured leg had equal jump capacity as controls. ACL groups scored 33 ± 7 and 32 ± 7 of 68 on TSK. Lower scores on Lysholm and KOOS symptom were seen for persons with moderate-to-high OA than for no-or-low OA, while there were no differences for physical activity and jump capacity. Regardless of treatment, there are still negative knee-related effects of ACL injury more than 20 years later.

  • 36.
    Tengman, Eva
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Brax Olofsson, Lisbeth
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Stensdotter, Ann-Katrin
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik. Sor-Trondelag University College, Trondheim, Norge.
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Ortopedi.
    Häger, Charlotte
    Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Sjukgymnastik.
    Anterior cruciate ligament injury after more than 20 years: II. Concentric and eccentric knee muscle strength2014Ingår i: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 24, nr 6, s. e501-e509Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The long-term consequences on knee muscle strength some decades after rupture of the anterior cruciate ligament (ACL) are not established. The aims of our study were to examine peak torque more than 20 years after ACL injury and to compare their knee muscle strength to that of healthy controls. We tested 70 individuals with unilateral ACL injury 23 ± 2 years after injury, whereof 33 (21 men) were treated with physiotherapy in combination with ACL reconstruction (ACLR) and 37 (23 men) with physiotherapy alone (ACLPT). These were compared with 33 age- and gender-matched controls (21 men). A Kin-Com® dynamometer (90°/s) was used to measure peak torque in knee flexion and extension in both concentric and eccentric contractions. Knee extension peak torque, concentric and eccentric, was ∼10% lower for the injured leg compared with the non-injured leg for both ACLR (P < 0.001; P < 0.001) and ACLPT (P = 0.007; P = 0.002). The ACLPT group also showed reduced eccentric knee flexion torque of the injured leg (P = 0.008). The strength of the non-injured leg in both ACL groups was equal to that of controls. No difference was seen for those with no-or-low degree of knee osteoarthritis compared to those with moderate-to-high degree of osteoarthritis. ACL injury may lead to a persistent reduction of peak torque in the injured leg, which needs to be considered across the lifespan.

  • 37.
    Wojtowicz, Radoslaw
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Henricson, Anders
    Nilsson, Kjell G
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    Crnalic, Sead
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap.
    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-up2019Ingår i: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682Artikel i tidskrift (Refereegranskat)
    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.

1 - 37 av 37
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf