Quadriceps strength and the risk of cartilage loss and symptom progression in knee osteoarthritis

Abstract

Objective To determine the effect of quadriceps strength in individuals with knee osteoarthritis (OA) on loss of cartilage at the tibiofemoral and patellofemoral joints (assessed by magnetic resonance imaging [MRI]) and on knee pain and function. Methods We studied 265 subjects (154 men and 111 women, mean ± SD age 67 ± 9 years) who met the American College of Rheumatology criteria for symptomatic knee OA and who were participating in a prospective, 30-month natural history study of knee OA. Quadriceps strength was measured at baseline, isokinetically, during concentric knee extension. MRI of the knee at baseline and at 15 and 30 months was used to assess cartilage loss at the tibiofemoral and patellofemoral joints, with medial and lateral compartments assessed separately. At baseline and at followup visits, knee pain was assessed using a visual analog scale, and physical function was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index. Results There was no association between quadriceps strength and cartilage loss at the tibiofemoral joint. Results were similar in malaligned knees. However, greater quadriceps strength was protective against cartilage loss at the lateral compartment of the patellofemoral joint (for highest versus lowest tertile of strength, odds ratio 0.4 [95% confidence interval 0.2, 0.9]). Those with greater quadriceps strength had less knee pain and better physical function over followup (P < 0.001). Conclusion Greater quadriceps strength had no influence on cartilage loss at the tibiofemoral joint, including in malaligned knees. We report for the first time that greater quadriceps strength protected against cartilage loss at the lateral compartment of the patellofemoral joint, a finding that requires confirmation. Subjects with greater quadriceps strength also had less knee pain and better physical function over followup.

Association of lower muscle strength with self‐reported knee instability in osteoarthritis of the knee: Results from the Amsterdam Osteoarthritis Cohort

“…Some longitudinal studies have demonstrated a role of lower muscle strength in the onset (16,22,39) and progression (40,41) of radiographic knee OA, while one other longitudinal study showed that in malaligned or lax knees, progression of radiographic knee OA was associated with higher muscle strength (42). We showed an association between lower muscle strength and self-reported knee instability.…”

Association of Thigh Muscle Strength With Knee Symptoms and Radiographic Disease Stage of Osteoarthritis: Data From the Osteoarthritis Initiative

“…The finding of lower isometric muscle strength in symptomatic versus asymptomatic legs is supported by previous studies reporting a protective effect of muscle strength on knee pain (12,37). O'Reilly et al observed lower quadriceps strength in symptomatic versus asymptomatic legs, but did not match case and control knees for radiographic disease stage (38).…”

“…Muscle weakness is considered a potentially modifiable (9) risk factor of KOA and quadriceps muscle strengthening is recommended by the current Osteoarthritis Research Society International KOA treatment guidelines (10). Previous studies reported a reduction of knee pain (11)(12)(13) following quadriceps strengthening exercise but no significant modification of structural (i.e., radiographic) disease progression (11) with training intervention.…”

Targeting Care

“…Limited evidence exists to support muscle strength as a predictor of knee OA progression (13). Yet, over time, people with knee OA who have greater quadriceps strength report less pain and superior functional ability compared to their weaker counterparts (37). Quadriceps strength has been studied widely in relation to knee OA, however muscles around the hip stabilising the pelvis also have an effect on adduction forces around the knee that may result in increased compression of the medial compartment (38) and influence the pathogenesis and progression of OA.…”