High rate of tibial debonding and failure in a popular knee replacement: A cause for concern

Total knee arthroplasty (TKA) is a common orthopedic procedure with 975,739 performed in the UK between 2003 and 2016. The two most common prosthetics used are P.F.C. Sigma and NexGen. The aim of this study is to compare the experience of a single fellowship-trained arthroplasty surgeon at a single dedicated orthopedic hospital using both of these prosthetics over a 17-year period.

This study was carried out as a retrospective review. Information was gathered from a database of primary TKAs and revision TKAs, as well as medical records, correspondence and operative notes.

A total of 1,511 TKAs were performed between 1999 and 2015 – with a further follow-up period of 2 years. There were 1,161 consecutive P.F.C. primary TKAs done from 1999 to April 2013, after which, 350 consecutive NexGen primary TKAs were performed. Between 2015 and 2017, 26 NexGen revisions were required. 23 (6.6%) of the NexGen knees were carried out for aseptic loosening. The average time for revision from the NexGen index surgery was 30.4 months. The failures all presented similarly – with the tibial component having collapsed into varus and radiographic lucency noted under the implant.

In spite of changes in orthopedic practice and advances in implant technology over the time period of this study, we would not expect this level of implant failure from a surgeon who had no previous significant issues with aseptic loosening using a different prosthetic. Usage of the NexGen knee has been discontinued at this center.