The purpose of this study is to research the effect of lateral patellar facetectomy to clinical results on patients who have undergone patellar resurfacing total knee arthroplasty operations. Between June 2018 and May 2020, 59 patients with a diagnosis of advanced gonarthrosis who underwent total knee replacement and patella resurfacing were included in the study. Patients were divided into 2 groups according to lateral patellar facetectomy. Clinical assessments of the patients were made pre-surgical and post-surgical (6th and 12th months) with WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) and Kujala scores. VAS was used for pain assessment. Although there was no statistical difference between the two groups in terms of preoperative Kujala test, a statistically significant difference was found in favor of the facetectomy group in the comparison of both groups at the 6th and 12th months after surgery. The preoperative Womac test score was statistically significantly lower in the group scheduled for facetectomy. In the comparison at the 6th and 12th months after surgery, it was observed that the womac score improved significantly in the facetectomy group and there was a statistically significant difference between the two groups in favor of the facetectomy group. The excision of lateral patellar facet during patellar resurfacing total knee prosthesis surgery affects the clinical results positively.