Association Between Quadriceps Myosteatosis and Muscle Strength and Physical Function in Patients With Knee Osteoarthritis- A Systematic Review

OBJECTIVE: To synthesize the available evidence on the association between quadriceps myosteatosis and muscle strength and physical function in individuals with knee osteoarthritis. DESIGN: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Joanna Briggs Institute (JBI) guidelines and was prospectively registered with PROSPERO. PubMed, EMBASE, Web of Science, Scopus, and CINAHL were searched from inception to February 2026. Studies quantifying quadriceps myosteatosis using objective imaging and reporting muscle strength or physical function were eligible. Methodological quality was assessed using the JBI critical appraisal tools. Due to clinical and methodological heterogeneity, findings were synthesized narratively following the Synthesis Without Meta-analysis (SWiM) framework. RESULTS: Seven studies were included. Most demonstrated low to moderate risk of bias. Quadriceps myosteatosis may be associated with reduced muscle strength and poorer physical function, with the association varying by muscle region, fat compartment, and imaging modality. The most consistent associations were observed for vastus medialis and intermuscular fat, and in MRI-based studies with multivariable adjustment. CONCLUSION: Quadriceps myosteatosis may be associated with poorer muscle function in knee osteoarthritis, most consistently for vastus medialis. Findings should be interpreted cautiously, given the limited evidence base and methodological heterogeneity.