# Predictors of failed reduction after prosthetic hip dislocation

## TL;DR

This study found that the location of the procedure and its duration are key factors in the success of reducing dislocated prosthetic hips.

## Contribution

The study identifies non-ED procedural location and shorter duration as novel predictors of successful closed reduction in prosthetic hip dislocations.

## Key findings

- Non-emergency department (ED) locations had significantly higher odds of successful reduction.
- Procedure duration in the ED was inversely associated with success, with an optimal threshold around 25 minutes.
- BMI, age, comorbidities, and implant type did not predict reduction success.

## Abstract

Prosthetic hip dislocation remains one of the most common complications following total hip arthroplasty (THA), often managed with closed reduction under procedural sedation. This study aimed to evaluate how sedation strategy, procedural location, and patient-specific factors influence the success of closed reduction in prosthetic hip dislocations. We hypothesized that higher body mass index (BMI), use of dissociative agents, and emergency department (ED) setting would be associated with lower reduction success.

A retrospective review was performed of adults presenting with prosthetic hip dislocations to two tertiary centers (2014–2024). Demographic, procedural, and pharmacologic data were abstracted from medical records. Logistic regression was used to assess associations between reduction success and location, sedation class, BMI, and procedural duration. Receiver operating characteristic (ROC) analysis identified thresholds for escalation.

Among 201 reduction encounters (111 patients), overall success was 73.1% (ED 54.3%, OR 94.4%). In multivariable analysis, non-ED location was the dominant predictor of success (OR 38.4, 95% CI 8.0–184; p < 0.001), while no medication class independently predicted outcome. Procedure duration was inversely associated with success in the ED (OR 0.88 per minute; p = 0.047), with an escalation threshold of approximately 25 min (AUC 0.72). BMI, age, comorbidities, and implant type were not associated with reduction success.

This study demonstrated reduction location was the dominant predictor of success, with non-ED settings demonstrating substantially higher odds of achieving closed reduction. Longer procedure duration was inversely associated with success, suggesting that protracted or repeated attempts should prompt early operative escalation. Standardized sedation protocols, adequate muscle relaxation, and algorithmic triage for high-risk cases may enhance success rates and reduce resource utilization in the management of prosthetic hip dislocations.