Abstract
Introduction
Dislocated hip hemiarthroplasties (HA) are associated with a 45% revision rate and 40% mortality rate.
Implant selection for HA operations vary with no universally accepted implant choice. The WHiTE3 trial suggested older designs such as the Thompson has equitable outcomes to more modern and expensive implants such as the Exeter V40+Unitrax.
Our multi-centre consecutive series of NOFs patients treated with HA assesses the impact of surgical and patient factors on dislocation risk.
Methods
Medical and radiographic records for patients treated between 1stJanuary 2009 and 30thSeptember 2017 with a HA at three acute hospitals were reviewed.
Implant and dislocation data were recorded. Patient demographics, comorbidities and operation details were extracted from the medical records and NHFD. Patients were excluded if there were no postoperative radiographs or when HA had been performed as a revision procedure.
Results
We identified 4305 consecutive patients with 189 excluded. There was no difference in patient characteristics between the hospitals or implant types (p>0.05). Four HA implants were used during the study period; Thompson, Austin-Moore, Furlong and Exeter V40+Unitrax.
63 dislocations were identified (1.5%), median time to dislocation was 24 days. Dislocation rates for Thompson HAs were significantly higher (p=0.004) at 3.7%.
No association was demonstrated with cemented versus uncemented, bipolar versus monopolar, fixed versus variable offsets, operating surgeon grade and dislocation rates (p>0.05). Patient factors (preoperative AMTS, postoperative AMTS, preoperative mobility and ASA grade) had no effect on dislocation (p>0.05).
Discussion
Our study which is reflective current implant choices, demonstrates that Thompson implants for HA after NOFs have a significantly higher dislocation rates than other common prostheses, and their continued use should be reconsidered. This effect has not been demonstrated in previous studies.
Patient, implant construct and surgeon factors had little bearing on the subsequent dislocation rate.
