Thigh Muscle health vs. Movement patterns of Hip-OA Subjects

Intramuscular fat fraction has been shown to have a stronger association with knee osteoarthritis (KOA), than muscle size. Longitudinal increase of fat infiltration in muscles, i.e., decrease in lean muscle mass, is demonstrated to be correlated with KOA and contribute as potential risk-factors for worsening symptoms and eventual total knee replacement (TKR). Individuals with radiographic hip-OA (HOA) on the other hand, are known to have volume deficits in thigh muscles. However, the underlying relationships between thigh muscle biomarkers and normal behaving knee joint health in individuals with radiographic HOA, is not well understood. This preliminary study investigates the associations between knee functional (biomechanics) and morphological (imaging) parameters with normalized-lean-muscle-volumes (NLMV) of major thigh muscles and fat volumes (FV) in HOA patients. Muscular cross-sectional-area (CSA) differences between HOA patients and healthy controls are additionally explored. The results reiterate the conceptual understanding that the stronger the lean muscles in the HOA patients, the greater the knee strengths and knee cartilage thickness. HOA patients having significantly lower muscle CSA than healthy controls, which might be indicative of eventual KOA development in the future. Additionally, increased intra-MAT fat was tied to lower femoral and patellar CT, which might be of interest to understand whether these associations are a result of worsening the knee longitudinally with simultaneous progression of HOA. Although performed on a small cohort, the preliminary results are promising. Further muscle modifying and OA prevention strategies such as interventional studies decreasing FF and increasing NLMV could be investigated for HOA-KOA correlations in additional patients.