To determine whether kneeling activity is associated with the MRI measures of patellofemoral (PF) joint cartilage damage worsening in subjects with/without patella alta (PA).
Baseline and 24-month 3-T MR images and semi-quantitative MRI Osteoarthritis Knee Score (MOAKS) of PF joint of 600 subjects from the FNIH study, a nested study within the Osteoarthritis Initiative (OAI), were extracted. At baseline visit, subjects were asked how many days per week they participated in kneeling activities lasted ≥ 30 min. Insall-Salvati ratio (ISR) (patellar tendon/patellar height) was measured on baseline MRIs by a musculoskeletal radiologist; ISR ≥ 1.3 was considered PA. Regression analysis adjusted for confounding variables was used to assess the impact of kneeling on worsening of MOAKS cartilage over 24 months. The potential moderating effect of PA was evaluated using adjusted regression analysis.
Six hundred subjects (58.8% female, years, BMI = 30.7 ± 4.8 kg/m
• Frequent daily kneeling activity is associated with a higher risk of patellofemoral cartilage damage resulting in patellofemoral osteoarthritis. • The cartilage damage associated with extensive kneeling activity may be worse in subjects with an underlying patella alta (i.e., high-riding patella).
Extensive kneeling activity (≥ 6 days/week) may be associated with the MRI-based worsening of PF cartilage damage, specifically in subjects with an underlying patella alta.