People with meniscal tears are at high risk to develop or progress to knee osteoarthritis. Knee extensor weakness is considered a risk factor for osteoarthritis and is often reported in these individuals. The purpose of this systematic review and meta-analysis was to investigate knee extensor strength in people undergoing an arthroscopic partial meniscectomy (APM).
Six databases (Medline, CINAHL, SPORTDiscus, Embase, PEDro, and AMED) were searched up to June 22, 2014. Studies that measured knee extensor muscle strength in people age ≥30 years undergoing APM for a meniscal tear and used either a healthy control group or the contralateral leg to compare knee extensor muscle strength were included. Methodological quality was assessed using guidelines from the Centre for Reviews and Dissemination.
Eleven studies, in which participants were predominantly male, were included (n = 596). A moderate reduction in muscle strength was observed prior to APM compared to controls (standardized mean difference [SMD] 0.58, 95% confidence interval [95% CI] 0.04, 1.13) and continued up to 6 months postsurgery (SMD range -2.42 to -0.47). There was no difference in muscle strength at 2 years post-APM (SMD -0.01 [95% CI -0.36, 0.35]), while a moderate reduction was again apparent at 4 years post-APM (SMD -0.56, [95% CI -1.20, 0.08]) compared to controls.
Our findings suggest that middle-aged and older individuals undergoing APM have reduced knee extensor muscle strength in the operated leg compared to control data. As meniscus pathology and knee extensor muscle weakness are risk factors for osteoarthritis, these results highlight the clinical importance of addressing muscle weakness in these individuals.