Objective
To evaluate whether knee pain location can influence symptoms, functional status and knee-related quality of life in older adults with chronic knee pain.
Methods
A total of 2959 painful knees from the Osteoarthritis Initiative database were analyzed. Trained interviewers recorded patient-reported location of knee pain. Painful knees were divided into three groups of patellofemoral only pain, tibiofemoral only pain, and combined pain. Self-reported knee-specific symptoms, functional status and knee-related quality of life were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS).
Results
The most common knee pain pattern was tibiofemoral only pain (62%), followed by patellofemoral only pain (23%) and combined pain (15%). The combined pain pattern was associated with greater odds of reporting pain, symptoms, sports or recreational activity limitations and lower knee-related quality of life compared to either isolated knee pain patterns, after adjusting for demographics and radiographic disease severity. Individual item analysis further revealed that patients with combined pain had greater odds of reporting difficulty with daily weightbearing activities that required knee bending compared to tibiofemoral or patellofemoral only pain patterns. Furthermore, symptoms, functional status, and knee-related quality of life were comparable between patients with patellofemoral and tibiofemoral only pain patterns, after adjusting for demographics and radiographic disease severity.
Discussion
Combined patellofemoral and tibiofemoral pain is associated with poorer clinical presentation compared to isolated knee pain from either location. Additionally, patellofemoral pain in isolation may be as important as tibiofemoral pain in causing symptoms and functional limitation in older adults with chronic knee pain.