Arthroscopic partial meniscectomy outcomes are comparable in patients with synovitis treated by synovectomy and those without synovitis

Abstract

Purpose: To determine whether patients undergoing arthroscopic partial meniscectomy (APM) with synovitis treated by synovectomy exhibit similar outcomes to those without synovitis after 24-month follow-up.

Methods: A total of 181 patients who underwent primary APM at a single institution between 2018 and 2022 were included: 87 without synovitis and 94 with synovitis treated via synovectomy involving at least two compartments. Synovitis extent was assessed intraoperatively by the surgeon. Nine Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, including three derived from the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), were collected preoperatively and at 24 months postoperatively. Patient demographics, surgical details, preoperative Kellgren-Lawrence (KL) osteoarthritis (OA) grade and intraoperative outerbridge chondral scores were compared between cohorts. 'Failures' underwent subsequent ipsilateral knee surgery during follow-up. 'Responders' reached the minimal clinically important difference (MCID) by 24 months. Time-to-response analysis using Cox regression compared the time to achieve MCID between groups.

Results: There were no significant differences in demographics between the cohorts including age, body mass index, sex, smoking status and number of comorbidities. The treated synovitis group demonstrated greater preoperative OA severity (median KL: 2 vs. 1.5; p = 0.013) and intraoperative chondral degeneration (median global outerbridge: 2 vs. 1; p < 0.001). All nine KOOS subscales improved between baseline and 24-month follow-up (all p < 0.001). At 24 months, all KOOS subscales were similar between groups (all p > 0.05), except WOMAC Stiffness, which was higher in the treated snifters group (24.9 vs. 17.9; p = 0.025). Time-to-response analysis showed no difference in time to MCID achievement (374 vs. 362 days; p = 0.727), and failure rates were also similar (7.4% vs. 11.5%; p = 0.498).

Conclusions: Despite greater OA severity and chondral degeneration, snifters treated with synovectomy in patients undergoing APM did not result in worse KOOS scores, delayed clinical response or increased risk of subsequent ipsilateral knee surgery compared to APM without synovitis.

Level of evidence: Level III.

Keywords: Knee injury and Osteoarthritis Outcome Score (KOOS); arthroscopy; partial meniscectomy; patient‐reported outcome measures; synovectomy.