What Are the Relative Associations of Surgeon Performance and Prosthesis Quality With THA Revision Rates?
Authors: Hoskins Wayne , Bingham Roger , Graves Stephen E. , Harries Dylan , Cuthbert Alana R. , Corfield Sophia , Smith Paul , Vince Kelly G. 
Published: August 2024

Background
Many factors, including some related to the patient, implant selection, and the surgeon’s skill and expertise, likely contribute to the risk of THA revision. However, surgeon factors have not been extensively analyzed in national joint replacement registries, and there is limited insight into their potential as a confounding variable for revision outcomes; for example, if surgeons with higher revision rates choose more successful prostheses, would this alone reduce their revision rate?

Questions/purposes
This study used Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) data for patients receiving primary THA for a diagnosis of osteoarthritis to answer the following questions: (1) Will the difference in revision rates among surgeons change or disappear when only procedures performed with the best prostheses or prostheses that have been identified as having higher revision rates are considered? (2) Is the benefit associated with using the best-performing prostheses different among surgeons with different revision rates? (3) Do the reasons for revision differ between surgeons with higher rates of revision compared with surgeons with lower rates of revision?

Methods
All primary THA procedures performed and recorded in the AOANJRR for osteoarthritis from September 1, 1999, to December 31, 2022, were considered for inclusion. Each THA prosthesis used was categorized per the AOANJRR as superior-performing, middle-performing, or identified as having a higher rate of revision by the AOANJRR benchmarking process. Surgeons who had performed at least 50 procedures and had a recorded 2-year cumulative percent revision (CPR) were included. After applying these restrictions, the study consisted of 302,066 procedures performed by 476 known surgeons. For the primary outcome measure of all-cause revision, we examined the variation in all-cause revision rates across individual surgeons when different classes of devices were used to assess whether differences between surgeons persisted when accounting for prosthesis selection. For the purposes of descriptively comparing reasons for revision between surgeons with higher-than-average or lower-than-average risk of revision, surgeons were classified into quartiles and outcomes compared when these surgeons used the same class of prosthesis.

Results
The difference in rates of revision among surgeons remained even after accounting for the effects of the prosthesis used. For any given surgeon, identified prostheses were associated with higher revision rates compared with both superior-performing prostheses (HR 1.73 [95% CI 1.57 to 1.92]; p < 0.01) and medium-performing prostheses (HR 1.31 [95% CI 1.20 to 1.43]; p < 0.01). All surgeons demonstrated a lower revision rate when using a superior-performing prosthesis, but the difference was greatest for surgeons with the highest rates of revision. Surgeons with the lowest rates of revision had a 19-year CPR of 3.9% (95% CI 3.0% to 5.0%) when using a superior-performing prosthesis compared with 5.4% (95% CI 4.0% to 7.3%) for procedures in which an identified prosthesis was used. Surgeons with the highest rates of revision had a 19-year CPR of 10.9% (95% CI 8.6% to 13.8%) when using a superior-performing prosthesis, and this increased to 20.4% (95% CI 18.0% to 23.1%) for procedures in which an identified prosthesis was used. The reasons for revision differ between surgeons, with causes of revision likely preventable and not related to the prosthesis choice being apparent for surgeons with high revision rates.

Conclusion
The choice of implant and the surgeon performing the index procedure both affected the risk of revision as well as the reasons for revision. Surgeons could improve the survivorship of the arthroplasties they perform by choosing implants identified by registries as having lower revision rates. Acceptance of the fact that surgeons have different revision rates is needed, and detailed analysis is required to explain why surgeons with high revision rates have increased rates of likely preventable revisions, and outside of prosthesis choice, how revision rates can be lowered. The influence of training, fellowship completion, ongoing education, patient selection, indications for surgery, and factors underlying prosthesis decision-making should be assessed. The surgeon performing THA is an important confounder that should be considered in future registry analyses.

Level of Evidence
Level III, therapeutic study.