Effect of Extensor Muscle Strength on Meniscus Damage Progression in Subjects Without Radiologic Knee Osteoarthritis

Background It has been demonstrated that high extensor strength decreases knee osteoarthritis symptomatic progression. However, few studies have detected a significant association between extensor strength and structural progression. Methods Participants in the Osteoarthritis Initiative with both muscle strength and meniscus assessment, Kellgren-Lawrence grade 1 or less, and body mass index less than 30 were enrolled. In a separate-sex analysis, participants were divided into the high and low strength groups, referring to the median value. Meniscus progression according to the Magnetic Resonance Imaging Osteoarthritis Knee Score was compared between the two groups at 12 mos (393 females and 229 males) and 24 mos (340 females and 208 males). Results In females, less overall medial meniscus progression (11.1% [17/153] vs. 23.2% [32/138], P = 0.04), less medial meniscal medial extrusion (5.2% [8/155] vs. 12.5% [18/144], P = 0.04), and less medial meniscal anterior extrusion progression (0% [0/108] vs. 5.3% [6/113], P = 0.03) were present in the high strength group at 24 mos. In males, no significant difference was detected between the high strength group and the low strength group. Conclusions In females, higher extensor muscle strength was associated with a decreased risk of medial meniscus progression in medial and anterior extrusion.