Kneeling as a risk factor of patellofemoral joint cartilage damage worsening: an exploratory analysis on the Osteoarthritis Initiative.

• 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).