Patella position is not a determinant for anterior knee XXXX 10  years after balanced gap total knee arthroplasty.

@entity1 @entity626 @entity158
PURPOSE: Incidence of anterior knee @entity158 after total knee arthroplasty (TKA) is reported to be between 4 and 49  %. The incidence of AKP at long-term follow-up and possible determinants after cruciate cruciate-retaining TKA were investigated. METHODS: A 10-year follow-up of a cohort of 55 @entity1 (63 TKAs), who received the balanSys    cruciate-retaining total knee system (Mathys Ltd, Bettlach, Switzerland) between 1999 and 2002, was performed. @entity1 had undergone the balanced gap technique, with either a fixed bearing or an AP-glide bearing. Standardised diagnostic questions regarding AKP were collected and categorised into two groups: those with and without AKP. The lateral patellar tilt, patellar displacement measurement and modified Insall-Salvati ratio were used for patella position evaluation on skyline radiographs. The Knee Society Score (KSS), the @entity626 Outcome Score (KOOS) and Numerical Rating Scales (NRS) for @entity158 and satisfaction were obtained at follow-up. RESULTS: Sixteen @entity1 in the study population experienced AKP. Incidence of AKP (fixed bearing 13/44; AP-glide bearing baring 3/17) was not dependent on type of insert (n.s.). There were no statistical differences in patella position and tibiofemoral contact point between the AKP group and the no AKP group (n.s.). KSS, KOOS, NRS- @entity158 and NRS-satisfaction were significantly lower for the @entity1 with AKP (all p  <  0.05). CONCLUSION: Twenty-six percentage of the @entity1 experienced AKP 10  years after balanced gap TKA. Postoperative patella positioning was not found to be a determinant for anterior knee @entity158 after TKA. However, patellar displacement does not seem completely favourable. Moreover, type of bearing was not found a determinant for AKP at long-term follow-up. LEVEL OF EVIDENCE: Lower quality prospective cohort study (<80  % follow-up, @entity1 enrolled at different time points in disease), Level II.
