Effect of total knee prosthesis design on patellar tracking and need for lateral retinacular release

Intraoperative lateral retinacular release (LRR) during primary total knee arthroplasty (TKA) is discouraged, except when LRR is necessary to centralize patellofemoral tracking. This study compares the LRR rates in four designs of total knee implants and correlates how changes in prosthesis design affect LRR rates. 2881 primary TKAs performed by one surgeon using a single surgical technique were reviewed. After controlling for all variables, LRR rates dropped from 71.6% to 19.5% to 9.7% to 2.7% with each design change (P<.0001). Differences in varus/valgus alignment and male/female proportions were compared in each group and the differences did not correlate with LRR rates. This study concludes that changes and improvements in knee implant designs play a significant role in decreasing lateral retinacular release rates in TKA.