Patellofemoral arthroplasty is cheaper and more effective in the short term than total knee arthroplasty for isolated patellofemoral osteoarthritis: cost-effectiveness analysis based on a randomized trial.

AIMS: The aim is to assess the cost-effectiveness of patellofemoral arthroplasty (PFA) in comparison with total knee arthroplasty (TKA) for the treatment of isolated patellofemoral osteoarthritis (OA) based on prospectively collected data on health outcomes and resource use from a blinded, randomized, clinical trial. METHODS: A total of 100 patients with isolated patellofemoral osteoarthritis were randomized to receive either PFA or TKA by experienced knee surgeons trained in using both implants. Patients completed patient-reported outcomes including EuroQol five-dimension questionnaire (EQ-5D) and 6-Item Short-Form Health Survey questionnaire (SF-6D) before the procedure. The scores were completed again after six weeks, three, six, and nine months, and again after one- and two-year post-surgery and yearly henceforth. Time-weighted outcome measures were constructed. Cost data were obtained from clinical registrations and patient-reported questionnaires. Incremental gain in health outcomes (quality-adjusted life-years (QALYs)) and incremental costs were compared for the two groups of patients. Net monetary benefit was calculated assuming a threshold value of €10,000, €35,000, and €50,000 per QALY and used to test the statistical uncertainty and central assumptions about outcomes and costs. RESULTS: The PFA group had an incremental 12 month EQ-5D gain of 0.056 (95% confidence interval (CI) 0.01 to 0.10) and an incremental 12 month cost of minus €328 (95% CI 836 to 180). PFA therefore dominates TKA by providing better and cheaper outcomes than TKA. The net monetary benefit of PFA was €887 (95% CI 324 to 1450) with the €10,000 threshold, and it was consistently positive when different measures of outcomes and different cost assumptions were used. CONCLUSION: This study provides robust evidence that PFA from a one-year hospital management perspective is cheaper and provides better outcomes than TKA when applied to patients with isolated patellofemoral osteoarthritis and performed by experienced knee surgeons. Cite this article: Bone Joint J 2020;102-B(4):449-457.

Reliability of stress radiography in the assessment of coronal laxity following total knee arthroplasty.

BACKGROUND: Stress radiography is used in the valuation of soft tissue laxity following total knee arthroplasty (TKA). However, reliability and agreement is largely unknown. METHODS: In this prospective reliability study, we included 15 participants with prior TKA. Standardized coronal stress radiographs were obtained in both extension and flexion and with both varus and valgus stress. All radiographs were repeated (test-retest). In extension the Telos stress device was used, and flexion radiographs were obtained using the epicondylar-view. Three independent raters measured angulation between femoral and tibial component from all radiographs. Reliability was assessed by intra-class correlation coefficient (ICC) and agreement visualized with Bland-Altman plots and by mean difference and limits of agreement (LOA). RESULTS: Stress radiography in extension showed excellent reliability with ICC = 0.96 (0.95-0.98) and LOA of ±1.2°. Stress radiography at 80-90° of flexion showed good to excellent reliability when measuring medial laxity with ICC = 0.94 (0.89-0.97) and LOA of ±1.7°; however, when measuring lateral laxity the reliability was only moderate to good with ICC = 0.70 (0.51-0.84) and LOA of ±6.3°. CONCLUSION: Stress radiography is clinically applicable and the methods described in this study provide excellent reliability for measurement of laxity in extension. The reliability of measurements in flexion is good to excellent when measuring medial laxity but only moderate to good when measuring lateral laxity.

[Knee osteoarthritis from the point of view of the orthopaedic surgeon].

Arthroplasty for knee osteoarthritis is efficient - both from a patient and a cost-benefit point of view. Surgery should not await debilitating symptoms or progressive age and is expected to result in pain reduction, increased function and health-related quality of life and satisfaction. Patient information should modulate expectations by emphasizing the expected positive outcome with a low risk of complications. Mortality and morbidity is low although specific patients present a challenge regarding co-morbidities and surgery - necessitating individual planning.