Effect of arthroscopic partial meniscectomy on structural degeneration of the knee: A 5-year MRI-based follow-up of the placebo-surgery controlled FIDELITY (Finnish Degenerative Meniscus Lesion Study) trial

Objective: To assess the 5-year effects of arthroscopic partial meniscectomy (APM) vs. placebo surgery on the development of the structural changes of the knee by magnetic resonance imaging (MRI). Design: This multicentre, randomized, participant- and outcome-assessor-blinded, placebo-surgery-controlled trial was carried out in Finland. We randomized 146 adults, mean age 52 years (range 35 to 65) to undergo either APM or placebo surgery. The subjects had symptoms of degenerative medial meniscus tear, a tear verified in MRI and arthroscopy, and no advanced osteoarthritis at baseline. We compared the baseline and 5-year follow-up MRIs using MRI Osteoarthritis Knee Score scoring to derive subregional data on cartilage damage, osteophytes and bone marrow lesions (BMLs). Progression of structural cartilage changes analyzed per subregion was the main outcome, that of osteophytes and BMLs secondary outcomes. We analyzed the progression with multilevel logistic regression model on subregion-level data, adjusted for randomization stratification factors, and using robust standard errors. Results: Sixty-three (90%) subjects in the APM and 73 (96%) in the placebo-surgery group had MRI at both time points. The adjusted odds ratio (APM vs. placebo-surgery) was 1.31 (95% confidence interval 0.81, 1.94) for progression of cartilage damage, 2.86 (1.16, 6.21) for osteophytes, and 1.43 (0.84, 2.43) for BMLs. Conclusions: We found a slightly greater risk for progression of osteophytes in the APM group compared to the placebo-surgery group at 5 years after surgery. Trial registration: ClinicalTrials.gov (NCT01052233 and NCT00549172).