Background/Purpose: Traumatic meniscus injury is associated with increased risk of developing knee osteoarthritis (OA). The purpose of meniscus repair, beyond short time symptom relief and restoration of knee biomechanics, is to reduce the risk of later knee OA. However, the long-term consequences of meniscus repair have not been sufficiently investigated. Thus, our objective was to compare the consultation rate for symptomatic knee OA in patients after meniscus repair, arthroscopic partial meniscectomy (APM), and in the general population.

Methods: We identified patients aged 16-45 years having had meniscus surgery due to acute meniscus tear in 1998-2009 in southern Sweden by a healthcare register. All patients were followed from the time of first meniscus surgery until a diagnosis of knee OA, relocation outside the Skåne region, death, or December 31^st, 2014. We studied the consultation rate for knee OA compared to the general population as well as calculated the age- and sex-adjusted hazard ratio (HR) for knee OA consultation after meniscus repair vs. APM.

Results: We identified 2409 patients with an acute meniscus tear (mean [SD] age 30.5 [8.6] years); 211 (8.8%) of them had had meniscus repair. The absolute risk of having consulted for knee OA during the study period was 16.4% after APM, 10.0% after meniscus repair, and 2.1% in the general population (Figure). The age- and sex-standardized incidence of knee OA was 110/10 000 person-years after meniscus repair, 165/10 000 person-years after APM, and 19/10 000 person-years in the general population. The HR for knee OA after repair vs APM was: 0.79 (95% confidence interval [CI] 0.51, 1.24). A sensitivity analysis, excluding cases with OA within the first 2 years post-surgery, yielded the HR of 0.53 (95% CI 0.27, 1.04).

Figure. The survival estimates for doctor-diagnosed knee osteoarthritis among persons aged 16 to 45 years in patients having had arthroscopic partial meniscectomy (APM), meniscal repair or in the general population.

Conclusion: The point estimates suggests about 20-50% lower risk of knee OA in patients after meniscus repair as compared to patients with APM. However, the consultation rate for OA after repair was still at least 2.5 times higher as compared to the general population.