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"Two Strikes, You're Out": Contemporary Revision Patterns Following Instability After Posterior and Anterior Approach
Daniel A Driscoll1, Carmelo Burgio2, Michael Viggiano1
1Stavros Niarchos Foundation Complex Joint Reconstruction Center, Hospital for Special Surgery, New York, New York.
Insights
Revision after total hip arthroplasty (THA) is common after a second dislocation event. Late dislocations, occurring more than 90 days post-surgery, significantly increase the odds of revision surgery for instability.
Area of Science:
- Orthopedic Surgery
- Arthroplasty Research
- Biomedical Engineering
Background:
- Dislocation is a significant complication following total hip arthroplasty (THA).
- Previous thresholds for revision (≥3 dislocations) may not apply to modern THA implants and techniques.
- Contemporary data are needed to re-evaluate instability management strategies.
Purpose of the Study:
- To assess the relationship between dislocation recurrence and timing with revision risk in primary THA.
- To identify factors associated with revision following dislocation in a contemporary cohort.
Main Methods:
- Analysis of 40,315 primary THA cases (2016-2024), identifying 285 patients with dislocations.
- Patients were followed for a mean of 5.7 years, with 84.9% undergoing revision for instability.
- Logistic regression analyzed recurrence (1, 2, ≥3 dislocations) and timing (early ≤90 days vs. late >90 days) against revision risk.
Main Results:
- Revision risk increased significantly after the second dislocation (OR 7.70), with no significant increase beyond that.
- Late dislocations (OR 7.76) were more likely to require revision than early dislocations (97.0% vs. 74.9%).
- The association between recurrence, timing, and revision risk was consistent across surgical approaches.
Conclusions:
- In current THA practice, revision is frequently indicated after a second dislocation.
- Late dislocations pose a higher risk for revision compared to early dislocations.
- Further multicenter research is essential to optimize instability management protocols.
Background:
Dislocation remains one of the most challenging complications after total hip arthroplasty (THA). Previous studies suggested that three or more dislocations were a threshold for revision; however, these data predate contemporary implants and modern surgical approaches. We used a contemporary cohort of primary THA patients to evaluate the relationship between dislocation recurrence, timing of instability, and subsequent revision for instability.
Methods:
There were 40,315 patients who underwent primary THA at our institution from 2016 to 2024. Among these patients, those who sustained a dislocation event were included. Keyword and diagnosis code search were performed to identify patients, and charts were reviewed to confirm dislocation. A total of 285 patients (0.7%) were included at a mean 5.7-year follow-up, of whom 242 (84.9%) ultimately underwent revision for instability. Instability was categorized by recurrence (one, two, or ≥ three dislocations) and timing ([early ≤ 90] versus late [greater than 90 days)]). Multivariable logistic regressions were performed to identify factors independently associated with risk of revision.
Results:
Revision risk increased sharply with recurrence, rising from 69.1% after one dislocation to 93.9% after two and 98.5% after three or more. Patients who had two dislocations had significantly greater odds of revision than those who had one (odds ratio 7.70, 95% confidence interval 3.28 to 20.49, P < 0.001), while risk did not significantly increase beyond the second dislocation. Late dislocations were more likely to result in revision than early events (97.0 versus 74.9%, P < 0.001) and remained independently associated with revision (odds ratio 7.76, 95% confidence interval 2.46 to 35.10, P = 0.002). The association between recurrence, timing, and revision risk was consistent across both approaches.
Conclusions:
In contemporary THA practice, revision frequently occurred after a second dislocation, and late dislocations were more likely to require revision than early events. Future multicenter studies are needed to further refine instability management strategies.
