Introduction Mechanical symptoms are considered an important indication for meniscal surgery. We investigated if young (≤40 years) and older (>40 years) patients, respectively, with preoperative mechanical symptoms improved more in patient-reported outcomes after meniscal surgery than those without mechanical symptoms.

Materials and methods Patients from Knee Arthroscopy Cohort Southern Denmark (KACS) undergoing arthroscopic meniscal surgery between February 2013 and January 2015 completed online questionnaires pre-surgery, and at 12 and 52 weeks follow-up. Questionnaires included self-reported presence of mechanical symptoms (i.e. sensation of catching and/or locking) and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Between-group differences in change in 4 of 5 KOOS subscales (KOOS₄) from baseline to 52 weeks were analysed using an adjusted mixed linear model.

Results 150 young patients (mean age 31 (SD 7), 67% men) and 491 older patients (mean age 54 (SD 9), 53% men) constituted the baseline cohorts. In general, patients with mechanical symptoms had worse self-reported outcomes before surgery. At 52 weeks follow-up, young patients with preoperative mechanical symptoms had improved more in KOOS₄ scores than young patients without preoperative mechanical symptoms (adjusted mean difference 10.5, 95% CI: 4.3 to 16.6), but did not exceed their absolute KOOS₄ scores. No essential difference in improvement was observed between older patients with or without mechanical symptoms (adjusted mean difference 0.7, 95% CI: −2.6 to 3.9).

Conclusion Young patients (≤40 years) with preoperative mechanical symptoms experienced greater improvements after arthroscopic meniscal surgery compared to young patients without mechanical symptoms. Randomised controlled trials are needed to confirm this potential subgroup benefit.