Is the degree of osteophyte formation associated with the symptoms and functions in the patellofemoral joint in patients undergoing total knee arthroplasty?

Osteophyte formation and loss of articular cartilage are the main pathologic features of osteoarthritis in the patellofemoral joint. The goal of this study was to determine whether the degree of osteophyte formation was associated with the degree of cartilage loss and the patellofemoral symptoms and functions in osteoarthritic patients undergoing total knee arthroplasty (TKA). We evaluated 71 knees in 54 consecutive patients who underwent TKA under the diagnosis of osteoarthritis. The degree of patellofemoral osteophyte formation was assessed by proportional diameter and proportional rim involvement. The cartilage status was assessed by depth and size of the cartilage lesion. The patellofemoral symptoms and functions included anterior knee pain, abilities of chair-rising and stair-climbing and quadriceps muscle power. No significant association was found between the degrees of patellar or trochlear osteophyte formation with anterior knee pain or any of the patellofemoral functional parameters (P>0.05). The degree of osteophyte formation in the patella and the trochlea had a significant but weak correlation with the status of patellar cartilage and the status of the trochlear cartilage, respectively (correlation coefficient = 0.22-0.41 and P<0.05). This study indicates that physicians need to be cautious not to easily reach the conclusion that the patellofemoral symptoms and functional disabilities can be attributed to the presence of osteophyte in the patellofemoral joint in consulting patients with the patellofemoral radiographs or deciding on patellar resurfacing in TKA.