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Concordance of Dislocation Direction and Surgical Approach Is an Approach-Dependent Risk for Recurrent Instability
Lindsey V Ruderman1, Crystal Jing1, David G Deckey2
1School of Medicine, Duke University, Durham, North Carolina.
Insights
Hip dislocation recurrence after total hip arthroplasty (THA) is common, especially with posterior approaches. Matching dislocation direction to the surgical approach predicts recurrence, guiding revision decisions.
Area of Science:
- Orthopedic surgery
- Arthroplasty research
- Biomechanical analysis of joint stability
Background:
- Hip instability is a significant complication following total hip arthroplasty (THA), often necessitating revision surgery.
- Understanding factors influencing recurrent dislocation is crucial for improving patient outcomes.
- The relationship between surgical approach and dislocation directionality requires further investigation.
Purpose of the Study:
- To quantify the risk of recurrent hip dislocation after primary THA.
- To determine the influence of surgical approach (anterior vs. posterior) on dislocation recurrence.
- To assess the impact of dislocation directionality concordance with surgical approach on recurrence rates.
Main Methods:
- Retrospective analysis of 112 patients (114 hips) who experienced dislocation after primary THA.
- Data collection included surgical approach, dislocation timing, direction, and management.
- Concordance was defined as dislocation direction matching the surgical approach; Chi-square analyses were used.
Main Results:
- Posterior approach was most common (62.3%). Most dislocations were posterior (64.9%).
- Recurrence rates were significantly higher for posterior dislocations with posterior approaches (68.4%) compared to anterior dislocations with anterior approaches (41.2%).
- Over half of patients (56.0%) experienced at least two dislocations if not revised after the initial event.
Conclusions:
- Concordance between surgical approach and dislocation directionality is a key predictor of recurrence, particularly for posterior-based approaches.
- Recurrent instability is frequent after initial dislocation, emphasizing the need for careful consideration of revision indications.
- These findings can inform surgical technique selection and post-operative management to minimize dislocation risk.
Background:
Hip instability after total hip arthroplasty (THA), while uncommon, is a leading cause for revision. The purpose of the study was to quantify the risk of recurrent hip dislocation in relation to concordance of dislocation directionality and surgical approach.
Methods:
Included patients underwent anterior-based or posterior-based elective primary THA and sustained at least one dislocation treated at a single institution. Surgical approach, timing, direction, and management of dislocations, including closed reduction and reoperation, were obtained. Concordance was defined as dislocation in the same direction as the surgical approach. There were 112 patients (114 hips) who experienced dislocation after primary THA between January 1, 2013, and November 1, 2025. Chi-square analyses were performed to assess differences in dislocation recurrence, depending upon approach and dislocation directionality.
Results:
The posterior approach was most common (62.3%), followed by anterior (27.2%) and direct lateral (10.5%). The median time to first dislocation was 41 days [interquartile range 18, 103.5], and most were posteriorly dislocated (64.9%). There were five patients (4.4%) who required an open reduction and revision after index dislocation. There were 61 patients who experienced at least two dislocations, accounting for 56.0% of patients who were not revised at the initial dislocation. The median time to second dislocation was 97 days [interquartile range 46, 375]. For posterior approaches, 68.4% of posterior dislocations recurred, while just 28.6% of anterior dislocations recurred (P = 0.006). For anterior approaches, 42.3% of posterior dislocations and 41.2% of anterior dislocations recurred (P = 0.94).
Conclusions:
Concordance between approach and dislocation directionality is a helpful predictor of recurrence for posterior-based approaches. Recurrent instability occurs in more than half of patients after a single dislocation; thus, indications for revision should be closely scrutinized after an instability event.
