QUADRICEPS WEAKNESS AND ITS RELATIONSHIP TO TIBIOFEMORAL AND PATELLOFEMORAL KNEE OSTEOARTHRITIS IN CHINESE

Background: Muscle weakness has been associated with tibiofemoral knee osteoarthritis (OA) and may cause OA due to reduced shock absorption during impulse loading at heel strike, when the patellofemoral joint is not engaged.

Research question/s: Is muscle weakness associated with compartment-specific knee OA, are there gender differences, and are symptoms associated with weakness?

Methodology:subjects: 2472 subjects (female = 1475, male = 997) (>60 yrs).

Experimental procedure: All subjects underwent radiography to defined subjects with (1) tibiofemoral (TF) OA when the Kellgren/Lawrence (K/L) grade >2 on AP/PA view; (2) patellofemoral (PF) OA (skyline view with osteophyte score >2 or when the JSN score was >2 and the osteophyte score was >1); and (3) mixed (MX) OA when the knee had both patellofemoral and tibiofemoral radiographic OA. Muscle strength was measured isometrically for each leg separately, and knee pain was evaluated.

Measures of outcome: Weakness related to presence of OA.

Main finding/s:

• Females: Quadriceps weakness was associated with tibiofemoral OA and mixed OA (OR 0.4, 95% CI 0.3 to 0.6)

• Males: Quadriceps weakness was associated with mixed OA (isolated tibiofemoral disease was not associated with weakness but sample size in this group was small)

• Once subjects with knee symptoms were excluded, the relationship of quadriceps weakness of OA was attenuated, with only the relationship between muscle weakness and …