Background: The infrapatellar fat pad can obstruct exposure during minimally invasive total knee arthroplasty (MIS TKA). Many surgeons often remove the fat pad for better knee visibility. There remains debate regarding the impact of fat pad excision on patella baja, pain, and functionality. This randomized controlled trial aimed to assess whether infrapatellar fat pad removal during MIS TKA affects patellar tendon shortening (indicated by patella baja), Knee Society Score or functional subscore reductions, anterior knee pain, or patella-related complications.
Subjects and Methods: One hundred forty patients undergoing MIS TKA at one institution were randomized into two groups. One group, consisting of 70 patients, had complete infrapatellar fat pad excision, while the other group of 45 patients underwent surgery without fat pad removal. Patellar resurfacing was selectively performed, with no difference between groups regarding the percentage of resurfaced patellae. We evaluated patellar tendon shortening, knee flexion, anterior knee pain, Knee Society Score (KSS), functional subscore, and patellar complications preoperatively and postoperatively at intervals of 6 weeks, 3 months, 6 months, and 1 year. Complete follow-up data were available for 81% of patients (113 out of 140).
Results: There were no significant differences between the groups in terms of patellar tendon shortening, KSS scores, functional subscores, or knee flexion at the final follow-up. However, patients who underwent infrapatellar fat pad excision experienced more anterior knee pain (9.1% compared to 1.2%; p = 0.00). Neither group reported any patellar complications.
Conclusions: In minimally invasive total knee arthroplasty, removing the infrapatellar fat pad slightly increases the likelihood of patients experiencing anterior knee pain after surgery. Surgeons are advised to preserve the fat pad if sufficient exposure can be achieved, but may opt for its removal if it is essential to improve surgical visibility during the procedure.