Stay or go? Outcomes of lower limb arthroplasty in patients travelling away from home for surgery: A cross-sectional analysis of the AOANJRR comparing patient residence and hospital remoteness

Purpose: The relationship between remoteness of patient residence and post-surgical outcomes, such as early implant revision, has yet to be examined. The aim of this study was to assess whether the incidence of all-cause revision at up to 2 years following primary hip or knee total joint arthroplasty varies with the remoteness of a person's place of residence at the time of the primary procedure. Methods: An analysis was performed of data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 1 Sept 1999 to 31 Dec 2022. The Modified Monash Model (2015) of remoteness classification was used to categorise patient residence and hospital location into metro-regional (MM 1-2) and rural-remote (MM 3-7). All-cause revision within the two-year period after surgery for primary total knee arthroplasty (TKA) and primary total hip arthroplasty (THA) for osteoarthritis as the primary diagnosis was selected as the primary outcome. A directed-acyclic graph approach was used to prioritise covariates for inclusion in a Cox proportional hazards regression model. Cumulative percent revision (CPR) rates with 95% confidence intervals was reported with hazard ratios between subgroups of residential and hospital remoteness. Results: The two-year CPR for primary TKA ranged from 1.8% (95% CI 1.7 - 1.9) to 2.2% (95% CI 1.8 - 2.7). Patients residing in rural-remote areas who travelled to a metro-regional hospital displayed a significantly higher rate of revision following TKA compared to patients that were treated at a rural-remote hospital (HR: 1.11, 95% CI 1.05 - 1.18, P = 0.001) within two-year follow-up of the primary procedure. Patients residing in rural-remote areas that stayed in these areas for their operation displayed a significantly reduced revision rate compared to metro-regional patients that stayed in-area for their joint replacement (HR=0.90, 95%CI 0.85 - 0.95, P <0.001). Infection was the dominant reason for TKA revision for patients in the follow-up period. No discernible differences in revision risk were observed between patient and hospital combinations for primary total hip replacement. Conclusions: Travel distance, but not remoteness of a patient's place of residence may be associated with cumulative risk of early revision (within 2 years) of primary TKA, particularly in regional/remote patients travelling out of area, but not for patients undergoing THA. Further work linking service utilisation prior to a revision procedure is required to clarify whether differences in revision between remoteness and travel distances are due to variability in the clinical threshold for offering revision arthroplasty between regional and metropolitan surgeons or improved outcomes of the primary procedure.