The effect of infrapatellar fat pad excision on complications after minimally invasive TKA: a randomized controlled trial

Clin Orthop Relat Res. 2014 Feb;472(2):695-701. doi: 10.1007/s11999-013-3321-z. Epub 2013 Oct 18.


Background: The infrapatellar fat pad is one of the structures that obscures exposure in minimally invasive total knee arthroplasty (MIS TKA). Most MIS TKA surgeons (and many surgeons who use other approaches as well) excise the fat pad for better exposure of the knee. There is still controversy about the result of fat pad excision on patella baja, pain, and function.

Questions/purposes: In the setting of a randomized controlled trial, we sought to determine whether infrapatellar fat pad excision during MIS TKA causes (1) patellar tendon shortening (as measured by patella baja); (2) increased anterior knee pain; (3) decreases in the Knee Society Score or functional subscore; or (4) more patella-related complications.

Methods: We randomized 90 patients undergoing MIS TKA at one institution into two groups. In one group, 45 patients underwent MIS TKA with complete infrapatellar fat pad excision and in the other group, 45 patients received MIS TKA without infrapatellar fat pad excision. The patella was selectively resurfaced in these patients; there was no difference between the groups in terms of the percentage of patients whose patellae were resurfaced. We measured patellar tendon shortening, knee flexion, anterior knee pain, Knee Society Score (KSS), functional subscore, and patellar complications at preoperative and postoperative periods of 6 weeks, 3 months, 6 months, and 1 year; complete followup data were available on 86% of patients (77 of 90) who were enrolled.

Results: At the final followup, no significant differences were observed in patellar tendon shortening, KSS, functional subscore, or knee flexion in either group. However, patients with their infrapatellar fat pad excised experienced more anterior knee pain (8.3% versus 0%; p = 0.03; 95% confidence interval, -0.007 to 0.174) at the end of the study. No patellar complications were found in either group.

Conclusions: Infrapatellar fat pad excision in MIS TKA resulted in an increasing small percentage of patients with anterior knee pain after surgery. Surgeons should keep the fat pad if excellent exposure can be achieved but resect it if needed to improve exposure during TKA.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adipose Tissue / surgery*
  • Aged
  • Arthralgia / etiology
  • Arthralgia / surgery
  • Arthroplasty, Replacement, Knee / adverse effects
  • Arthroplasty, Replacement, Knee / methods*
  • Biomechanical Phenomena
  • Female
  • Humans
  • Knee Joint / diagnostic imaging
  • Knee Joint / physiopathology
  • Knee Joint / surgery*
  • Lipectomy* / adverse effects
  • Male
  • Middle Aged
  • Minimally Invasive Surgical Procedures
  • Osteoarthritis, Knee / complications
  • Osteoarthritis, Knee / diagnosis
  • Osteoarthritis, Knee / physiopathology
  • Osteoarthritis, Knee / surgery
  • Pain, Postoperative / etiology
  • Patella / diagnostic imaging
  • Patella / physiopathology
  • Patella / surgery*
  • Radiography
  • Recovery of Function
  • Thailand
  • Time Factors
  • Treatment Outcome