| 1. |
- Bjerke, Joakim, et al.
(author)
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Compensatory strategies for muscle weakness during stair ascent in subjects with total knee arthroplasty
- 2014
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In: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 29:7, s. 1499-1502
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Journal article (peer-reviewed)abstract
- 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.
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| 2. |
- Bjerke, Joakim, et al.
(author)
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Peak knee flexion angles during stair descent in TKA patients
- 2014
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In: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 29:4, s. 707-711
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Journal article (peer-reviewed)abstract
- 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.
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| 3. |
- Callary, Stuart A, et al.
(author)
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The 6-Year Migration Characteristics of a Hydroxyapatite-Coated Femoral Stem A Radiostereometric Analysis Study
- 2012
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In: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 27:7, s. 1344-1348
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Journal article (peer-reviewed)abstract
- 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.
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| 4. |
- Chen, Antonia, et al.
(author)
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Prevention of Late PJI
- 2014
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In: The Journal of Arthroplasty. - : Elsevier BV. - 0883-5403 .- 1532-8406. ; 29:2, s. 119-128
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Journal article (peer-reviewed)
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| 5. |
- Goldvasser, Dov, et al.
(author)
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A New Technique for Measuring Wear in Total Hip Arthroplasty Using Computed Tomography
- 2012
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In: The Journal of Arthroplasty. - : Elsevier. - 0883-5403 .- 1532-8406. ; 27:9, s. 1636-1640
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Journal article (peer-reviewed)abstract
- Accurately estimating polyethylene wear in 3 dimensions, without the need for additional procedures or equipment, is of significant interest. We investigated the use of a high-resolution clinical computed tomographic (CT) scanner to estimate femoral head displacement relative to the cup as an indirect method of estimating polyethylene wear. A hip phantom was used to simulate the 3-dimensional displacement of a femoral head. The phantom was imaged in a high-resolution CT scanner. The mean difference between the true phantom displacement as positioned by micrometers and the calculated displacement based on the CT images was as follows: for the x-axis, 0 mm (SD, 0.213; SE, 0.058); y-axis, 0.039 mm (SD, 0.035; SE, 0.026); and z-axis, 0.039 mm (SD, 0.051; SE, 0.020).
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| 6. |
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| 7. |
- Malchau, Henrik, 1951, et al.
(author)
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The stepwise introduction of innovation into orthopedic surgery: the next level of dilemmas.
- 2011
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In: The Journal of arthroplasty. - : Elsevier BV. - 1532-8406 .- 0883-5403. ; 26:6, s. 825-31
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Journal article (peer-reviewed)abstract
- The optimum method for the appropriate introduction of innovative technologies into orthopedics is a vital but vexing issue. Compromises in the introduction process are driven by (a) the magnitude of the problem addressed (incidence and severity), (b) the advantages and risks of the proposed solution, and (c) the "universal dilemma," meaning the inherent "gap" between all the nonhuman supporting data and the unknowns of both efficacy and long-term safety in large human usage over many years. Drawing on the data generated and the actual decision tree used in the introduction of a new highly cross-linked polyethylene as a case study, this article illustrates these "subsequent dilemmas."
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| 8. |
- Rolfson, Ola, 1973, et al.
(author)
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Costs Related to Hip Disease in Patients Eligible for Total Hip Arthroplasty.
- 2012
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In: The Journal of Arthroplasty. - : Elsevier BV. - 1532-8406 .- 0883-5403. ; 27:7, s. 1261-1266
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Journal article (peer-reviewed)abstract
- This study was designed to estimate direct and indirect costs incurred by hip disease in patients eligible for total hip arthroplasty (THA). Before THA, 2635 patients completed a questionnaire regarding the use of resources because of their hip disease. Costs were assigned using official statistical sources or market prices. Annual costs amounted to US$ 7666 per patient. In a regression analysis, higher annual costs were associated with working age, female gender, comorbidity, and operation waiting time more than 90 days (P < .005). The burden of disease for THA candidates is extensive, where loss of productivity is the principal cost. Long wait for surgery is associated with increased costs. This study provides baseline cost data, which will be useful for further health economic analyses and could provide guidance for health care decision makers.
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| 9. |
- Sandgren, Buster, et al.
(author)
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Computed Tomography vs. Digital Radiography Assessment for Detection of Osteolysis in Asymptomatic Patients With Uncemented Cups: A Proposal for a New Classification System Based on Computer Tomography.
- 2013
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In: The Journal of arthroplasty. - : Elsevier BV. - 1532-8406 .- 0883-5403. ; 28:9, s. 1608-1613
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Journal article (peer-reviewed)abstract
- Digital radiographic images in the anterior-posterior and lateral view have been gold standard for evaluation of peri-acetabular osteolysis for patients with an uncemented hip replacement. We compared digital radiographic images and computer tomography in detection of peri-acetabular osteolysis and devised a classification system based on computer tomography. Digital radiographs were compared with computer tomography on 206 hips, with a mean follow up 10years after surgery. The patients had no clinical signs of osteolysis and none were planned for revision surgery. On digital radiographs, 192 cases had no osteolysis and only 14 cases had osteolysis. When using computer tomography there were 184 cases showing small or large osteolysis and only 22 patients had no osteolysis. A classification system for peri-acetabular osteolysis is proposed based on computer tomography that is easy to use on standard follow up evaluation.
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| 10. |
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