On a Trajectory for Success-9 in Every 10 People With a Degenerative Meniscus Tear Have Improved Knee Function Within 2 Years After Treatment: A Secondary Exploratory Analysis of a Randomized Controlled Trial

OBJECTIVE: To identify trajectories of patient-reported knee function over 5 years in patients with degenerative meniscal tears, and to explore whether baseline characteristics were associated with trajectories of sport and recreational function. DESIGN: Prospective cohort study. METHODS: We conducted a secondary exploratory analysis of the Odense-Oslo Meniscectomy Versus Exercise randomized controlled trial. Patient-reported knee function was assessed with the Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline, 3 months, 1 year, 2 years, and 5 years. We used group-based trajectory modeling to identify subgroups of patients who followed distinctive patterns of change. Multinomial logistic regression was used to examine the associations of patient demographics, knee function, and disease-related factors with KOOS sport and recreational function subscale trajectories. RESULTS: The analysis of data from a sample of 140 participants identified 3 trajectories for all KOOS subscales: (1) low, minimal improvement (10%-12% of the participants), (2) moderate, gradual improvement (20%-36%), and (3) high. early improvement (53%-70%). Baseline prognostic factors for deteriorating function in sport and recreational activities were higher body mass index, poorer mental health, greater knee pain, lower perceived knee function, poorer quadriceps and hamstrings muscle strength, poorer functional performance, more meniscal extrusion, and radiographic signs of knee osteoarthritis. CONCLUSION: We found 3 distinct trajectories of patient-reported knee function over 5 years: (1) low, minimal improvement. (2) moderate, gradual improvement, and (3) high, early improvement. Nine in every 10 participants improved at least gradually over 2 years after diagnosis of a degenerative meniscal tear.