The Knee
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Alterations in lower extremity kinetics have been shown to exist in persons with knee osteoarthritis (OA), however few investigations have examined how the intersegmental coordination of the lower extremity kinetic chain varies in the presence of knee joint pathology. The objective of this study was to evaluate how knee OA and walking speed affect total support moment and individual joint contributions to the total support moment. Fifteen healthy subjects and 30 persons with knee OA participated in 3D walking analysis at constrained (1.0 m/s), self-selected and fastest tolerable walking speeds. ⋯ There was a significant increase in the ankle contribution and a significant decrease in the hip contribution when walking speed was increased (p < 0.004), however individual walking speeds were not significantly related to joint contributions. This suggests that the relationship between walking speed and joint contribution is dependent on the individual's control strategy and we cannot estimate the joint contribution solely based on walking speed. The slower gait speed observed in persons with knee OA is not responsible for the reduction in knee joint moments, rather this change is likely due to alterations in the neuromuscular strategy of the lower extremity kinetic chain in response to joint pain or muscle weakness.
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Comparative Study
The relationship between trochlear dysplasia and medial patellofemoral ligament rupture location after patellar dislocation: an MRI evaluation.
The medial patellofemoral ligament (MPFL) and the native trochlear geometry represent two of the most critical components of patellofemoral stability. We sought to define the relationship between trochlear dysplasia and MPFL rupture location in patients with documented patellar dislocations. We hypothesized that patients with lower grades of trochlear dysplasia would have patellar based MPFL ruptures, while patients with higher grade dysplasia would have femoral-sided ruptures. ⋯ In contrast to our original hypothesis, the type of trochlear dysplasia does not appear to be related to the rupture location of the MPFL after patellar dislocation. According to our results, it is not possible to presume the location of the MPFL rupture based on assessment of the trochlear morphology. Therefore, a MRI is mandatory for final indication of any surgery.
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Comparative Study
Unicompartmental knee replacement for patients with partial thickness cartilage loss in the affected compartment.
It is recommended that in medial compartment osteoarthritis (OA) unicompartmental knee replacement (UKR) should not be undertaken unless there is bone on bone. This recommendation is not evidence based and it is important to know if it is correct as there are many patients with pain and partial thickness cartilage loss (PTCL) who could potentially benefit from UKR. The aim of this study was to determine if the recommendation is valid. ⋯ At a mean follow up of 2 years (range 1-6) the Oxford Knee Score (OKS) of the PTCL group (mean 36 SD 10) was significantly (p < 0.001) worse than the OKS of either the bone exposed group (mean 43 SD 4) or the bone loss group (mean 43 SD 5). 21% of those with PTCL did not benefit substantially from the operation (increase in OKS ≤ 6), whereas all patients in the other groups did. We conclude that the results of UKR for PTCL are unpredictable and therefore that UKR should only be done for medial compartment OA if there is bone on bone. There is a need to develop a method to identify which patients with PTCL will do well so that this subgroup could be treated with UKR.