Abstract
Introduction
Registry data from around the world demonstrates instability following primary THA is a leading indication for revision. However, the burden of THA dislocation is poorly documented and is not routinely recorded or reported at a national level. Our aim was to determine the rate of dislocation following primary THA in contemporary practice and in doing so determining the burden of THA dislocation to the NHS in Wales.
Method
We considered all Welsh residents who underwent primary THA from 2011–2016. Via clinical coding linkage using Patient Episode Database for Wales (PEDW), the equivalent of HES data in England, we were able determine re-admission for dislocation, revision THA following dislocation and all cause revision at 1 to 5 years follow-up.
Results
In a cohort of 20,816 primary THA the dislocation rate at 1-year follow-up was 1.1% (95%CI 0.97–1.25). This increased incrementally to 2.2% (95%CI 1.78–2.72) at 5 years. At 1 year the overall revision rate was 1.3% of which 0.3% was following instability. The median time to dislocation was 46 days and 67.8% of first time dislocations occurred within 6 months of index surgery. We undertook a clinical coding data validation for a sub-group of 2,677 THA procedures, cross-referencing hospital records and theatre logbooks with PEDW data and demonstrated a correlation of 90.6% (95%CI 75.8–96.8). We observed 229 first time dislocation events, but during the total study period there were 1179 emergency admissions for dislocated THA with a mean hospital length of stay of 5.5 days.
Discussion & Conclusions
This study provides benchmarking data at a national level regarding the risk of dislocation for patients undergoing primary THA. Importantly it demonstrates the significant accumulative burden of dislocation following THA for both patients and impact on NHS resources.
