Increased Joint Space Narrowing After Arthroscopic Partial Meniscectomy: Data From the Osteoarthritis Initiative

Background: Arthroscopic partial meniscectomy (APM) is widely performed and remains an important therapeutic option for patients with a meniscal tear. However, it is debated whether or not APM accelerates the progression of osteoarthritis (OA) in the long term. Purpose/Hypothesis: The purpose was to compare the progression of OA measured by the change in tibiofemoral joint space width (JSW)-a quantitative measure of OA radiographic severity-across 3 groups with a midterm follow-up: (1) patients undergoing APM; (2) those with a meniscal tear treated nonoperatively; and (3) those without a tear. We hypothesized that the reduction in JSW would be greatest in patients undergoing APM and least in those patients without a tear. Study Design: Cohort study; Level of evidence, 3. Methods: Using the Osteoarthritis Initiative cohort, a total of 144 patients were identified that underwent APM with at least 12 months of follow up and without previous knee surgery. Those with a meniscal tear who did not have APM (n = 144) and those without a tear (n = 144) were matched to patients who had APM by sex, age, Kellgren-Lawrence (KL) grade, and follow up time. Participants underwent magnetic resonance imaging at baseline. Knee radiographs to assess JSW were collected annually or biannually. The change in minimum medial compartment JSW was calculated using a validated automated method. A piecewise linear mixed effects model was constructed to examine the relationship between JSW decline over time and treatment group-adjusting for age, body mass index, smoking status, KL grade, and baseline JSW. Results: All groups had comparable baseline JSW-ranging from 4.33 mm to 4.38 mm. The APM group had a rate of JSW decline of -0.083 mm/mo in the first 12 months and -0.014 mm/mo between 12 and 72 months. The rate of JSW decline in the APM group was approximately 27 times greater in the first 12 months than that in the nonsurgical group (-0.003 mm/mo) and 5 times greater than that in the no tear group (-0.015 mm/mo); however, there was no significant difference between groups for 12 to 72 months (nonsurgical group: -0.009 mm/mo; no tear group: -0.010 mm/mo). The adjusted JSW in the APM group was 4.38 mm at baseline and decreased to 2.57 mm at 72 months; the JSW in the nonsurgical group declined from 4.31 mm to 3.73 mm, and in the no tear group it declined from 4.33 mm to 3.54 mm. There was a statistically significant difference in JSW change between baseline and 72 months for the APM group compared with the other groups (P < .001), but not between the nonsurgical and no tear groups (P = .12). Conclusion: In the first postoperative year, APM results in a faster rate of joint space narrowing compared with knees undergoing nonsurgical management of meniscal tears. Thereafter, there are comparable rates of OA progression regardless of the chosen management. APM results in a persistent decrease in JSW over at least 72 months. An untreated meniscal tear does not contribute to radiographic progression-assessed by JSW-as compared with an intact meniscus.