The association between surgeon training grade and risk of revision following total hip replacement: analysis of a national joint replacement register

Background:
Total hip replacements (THRs) are performed by surgeons at various stages in training with varying levels of senior supervision, but we do not know if this is safe practice with comparable outcomes to consultant performed THR. Our aim was to examine the association between surgeon grade, the senior supervision of trainees, and the risk of revision following THR.

Methods and findings:
We analysed data from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR). We included adult patients (≥18 years) who underwent primary THR for osteoarthritis, recorded in the NJR between 2003 and 2016. Exposures were the grade of the operating surgeon (consultant, or trainee) and whether trainees were directly supervised by a scrubbed consultant, or not. Outcomes were all-cause revision, the indication for revision, and the temporal variation in risk of revision (all up to 10 years). Net failure was calculated using Kaplan-Meier analysis and adjusted analyses used Cox regression and flexible parametric survival analysis (adjusted for patient, operative, and unit-level factors).

We included 603,474 THRs in 534,830 patients, of which 58,137 (9.6%) procedures were performed by a trainee. There was no association between surgeon grade and all-cause revision up to 10 years (crude hazard ratio [HR] 1.00, 95% CI 0.94 to 1.07; P = 0.97); a finding which persisted with adjusted analysis. Adjusted analysis demonstrated an association between trainees operating without supervision by a scrubbed consultant and an increase in all-cause revision (HR 1.10, 95% CI 1.00 to 1.21; P = 0.04). There was an association between trainee performed THRs and revision due to instability (crude HR 1.14, 95% CI 1.01 to 1.30; P = 0.04). However, this was not observed in adjusted models, or when trainees were supervised by a scrubbed consultant.

Conclusions:
Within the current training system in the United Kingdom, trainee surgeons achieve comparable outcomes to consultant surgeons when supervised by a scrubbed consultant. Revision rates are higher when trainees are not directly supervised by a scrubbed consultant but remain within internationally recognised acceptable limits.