Associations of Joint Line Tenderness and Patellofemoral Grind With Long‐Term Knee Joint Outcomes: Data From the Osteoarthritis Initiative

Abstract

Objective To examine whether joint line tenderness and patellofemoral grind from physical examination were associated with cartilage volume loss, worsening of radiographic osteoarthritis, and risk of total knee replacement. Methods This study examined 4353 Osteoarthritis Initiative participants. For each of joint line tenderness and patellofemoral grind, the patterns were defined as no (none at baseline and 1‐year), fluctuating (present at either time‐point), and persistent (present at both time‐points). Cartilage volume loss and worsening of radiographic osteoarthritis over 4 years were assessed using magnetic resonance imaging and x‐ray, and total knee replacement over 6 years was assessed. Results 35.0% participants had joint line tenderness, and 15.8% had patellofemoral grind. Baseline patellofemoral grind, but not joint line tenderness, was associated with increased cartilage volume loss (1.08%/year vs. 0.96%/year, p=0.02) and increased risk of total knee replacement [odds ratio (OR) 1.55, 95%CI 1.11‐2.17, p=0.01]. While the patterns of joint line tenderness were not significantly associated with joint outcomes, participants with persistent patellofemoral grind had increased rate of cartilage volume loss (1.30%/year vs. 0.90%/year, p<0.001) and increased risk of total knee replacement (OR 2.10, 95%CI 1.30‐3.38, p=0.002) compared with those without patellofemoral grind. Conclusions Patellofemoral grind, but not joint line tenderness, may represent a clinical marker associated with accelerated cartilage volume loss over 4 years and increased risk of total knee replacement over 6 years. This simple clinical examination may provide clinicians with an inexpensive way to identify those at higher risk of disease progression who should be targeted for surveillance and management.