Clinical and Radiologic Outcomes of Partial Lateral Patellar Facetectomy in Total Knee Arthroplasty.

Recently, some authors have performed partial lateral patellar facetectomy in total knee arthroplasty (TKA) and reported good results. However, research on partial lateral patellar facetectomy in TKA is still lacking. The aim of this study was to evaluate the clinical and radiologic results of partial lateral patellar facetectomies in patellar non-resurfacing and resurfacing TKAs. Total 251 TKAs (patellar non-resurfacing: 131; resurfacing: 120) that were followed up for at least 24 months to evaluate the clinical and radiologic results of partial lateral patellar facetectomies in patellar non-resurfacing and resurfacing TKAs were retrospectively reviewed. The radiologic evaluations involved assessments of the patellar tilt angle and the lateral patellar displacement, and the clinical evaluations involved assessments of the Knee Society knee score, Knee Society function score, Feller patellar score, and Kujala score. In patellar non-resurfacing TKA, the average postoperative patellar tilt angle and lateral patellar displacement of the group that did not undergo facetectomy were 7.0 ± 4.8 degrees and 2.4 ± 3.6 mm, respectively, and the average postoperative patellar tilt angle and lateral patellar displacement of the group that did undergo facetectomy were 4.0 ± 3.8 degrees and 0.7 ± 2.5 mm, respectively. Significant differences were observed in the postoperative patellar tilt angle and lateral patellar displacement (< 0.001 and  = 0.004, respectively). In patellar resurfacing TKA, while the patellar tilt angle showed a significant difference between the group that underwent facetectomy (6.7 ± 3.1 degrees) and the group that did not (8.3 ± 4.4 degrees) ( = 0.023), it exhibited no difference in the lateral patellar displacement between the two groups. In both patellar non-resurfacing TKA and resurfacing TKA, the postoperative clinical results did not show any difference between no-facetectomy group and facetectomy group. Partial lateral patellar facetectomies in patellar non-resurfacing and resurfacing TKAs improved the patellar tilt angles and patellar lateral displacements but were not related to improvements in the clinical outcomes in the minimum 2-year follow-up.