The Influence of Infrapatellar Fat Pad Resection on Outcomes Following Total Knee Arthroplasty

Abstract

Introduction: During a total knee arthroplasty, resection of the infrapatellar fat pad is usually performed to widen the surgical exposure. However, infrapatellar fat pad resection is known to produce shortening of the patellar tendon which leads to poor clinical outcomes following a total knee arthroplasty. Otherwise, recent studies suggested that the infrapatellar fat pad secretes proinflammatory cytokines. Thus, preservation of the infrapatellar fat pad may cause anterior knee pain after a knee replacement surgery. The purpose of the present study is to compare the patellar tendon length and clinical outcomes in the knees receiving either fat pad resection or fat pad retention during a total knee arthroplasty.

Methods: One hundred and twenty patients (mean age, 70.2 years), undergoing sequential simultaneous bilateral total knee arthroplasty for late-stage osteoarthritis, were randomized to have infrapatellar fat pad resected in one knee and preserved in the contralateral knee. Seven patients were men, and 113 were women. At the mean of 2.4 years postoperatively, patients were evaluated, clinically, with the knee-rating systems of the Knee Society and the Hospital for Special Surgery and with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. In addition, patellar tendon length and component position were measured, radiographically, and were compared between the two groups.

Results: At 3 months, 12 months, or 24 months after the surgery, there were no significant differences between the fat pad resection and retention group in terms of the knee-scoring systems, range of motion, anterior knee pain and patient preference. With regard to the patellar tendon length, tibio-femoral anlge, femoral component position, tibial component position, joint line level and patellar tilt, no significant differences were found between the two groups at any follow-up interval. However, lateral overhang or underhang of the tibial component of more than 3 mm was observed in seven knees in the retention group, as compared with one knee in the resection group.

Conclusions: After a minimum duration of follow-up of two years, no significant differences were identified between the fat pad resection and retention groups, with respect to the clinical outcomes and patellar tendon length. However, the incidence of size mismatch between the lateral aspect of the tibial component and the lateral surface of the proximal tibia was observed more often in the fat pad retention groups. Therefore, routine resection of the infrapatellar fat pad for enhanced surgical exposure was recommended during a total knee arthroplasty.