Partial or total resection of the infrapatellar fat pad (IPFP) helps surgeon improve access to lateral tibial plateau for better placement of the knee prosthesis. We aimed to investigate the effect of IPFP excision on clinical and radiologic outcomes including patellar tendon length (PTL), range of motion, and functional scores after total knee arthroplasty (TKA) at 5-year follow-up. We retrospectively evaluated postoperative first X-rays (day 0) and postoperative final 5-year control views of 228 knees in patients with primary osteoarthritis who underwent TKA between September 2006 and December 2009 in our hospital. Exclusion criteria were patients who had lateral release, patellar resurfacing, septic or aseptic loosening, fracture around the replaced knee, any other prior knee surgery, or any systemic inflammatory disease. IPFP was completely resected in all knees to enhance surgical exposure and patellar mobilization. Radiologic evaluation of PTL was performed in early postoperative and 5-year control X-rays comparatively. The mean early postoperative PTL was 47.4 ± 6 (range: 35-72), the mean final postoperative PTL was 47 ± 6.3 (range: 33-68) (p = 0.1). The average preoperative flexion was 115 ± 11 degrees, whereas it was 111 ± 4 degrees, postoperatively (p = 0.73). Both the clinical and functional outcome scores improved in all patients. IPFP excision during TKA did not alter PTL at 5-year follow-up. A focus on other surgical and/or host-related factors may help clarify contradictory patellar tendon shortening reported in the literature.