Assessing the non-inferiority of prosthesis constructs used in hip replacement using data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man: a benchmarking study

Abstract

ObjectivesTo investigate the relative performance of hip prosthesis constructs as compared with the best performing prosthesis constructs and illustrate the substantial variability in performance of currently used prostheses.DesignA non-inferiority study.SettingThe National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR).ParticipantsAll patients with a primary total hip replacement registered in the NJR between 1 April 2003 and 31 December 2016.Main outcome measuresKaplan-Meier failure function for hip prosthesis constructs. Failure difference between best performing construct and remaining constructs.MethodsUsing a non-inferiority analysis, the performance of hip prosthesis constructs by brand were compared with the best performing contemporary construct. Construct failure was estimated using the 1-Kaplan-Meier survival function method, that is, an estimate of net failure. The difference in failure between the contemporary benchmark and all other constructs was tested.ResultsOf the 4442 constructs used, only 134 had ≥500 procedures at risk at 3 years postprimary, 89 of which were not demonstrated to be inferior to the benchmark by at least 100% relative risk. By 10 years postprimary, there were 26 constructs with ≥500 at risk, 13 of which were not demonstrated to be inferior by at least 20% relative risk.Even fewer constructs were not inferior to the benchmark when analysed by age and gender. At 5 years postprimary, there were 15 constructs in males and 11 in females, aged 55–75 years, not shown to be inferior.ConclusionsThere is great variability in construct performance and the majority of constructs have not been demonstrated to be non-inferior to contemporary benchmarks. These results can help to inform patients, clinicians and commissioners when considering hip replacement surgery.