Early Prosthetic Hip Dislocation: Does the Timing of the Dislocation Matter?

Area of Science:

• Orthopedic Surgery
• Arthroplasty Research
• Biomedical Data Analysis

Background:

• Early dislocation is a frequent complication following total hip arthroplasty (THA), often necessitating revision surgery.
• Understanding the impact of dislocation timing on revision risk is crucial for patient management and surgical outcomes.

Purpose of the Study:

• To investigate whether the timing of dislocation after THA influences the risk of requiring revision surgery.
• To compare revision rates and causes between early (0-7 days) and later (7-90 days) dislocation episodes.

Main Methods:

• Retrospective analysis of a national administrative database (2010-2020) including 45,352 primary unilateral THA patients.
• Identified 2,878 patients with dislocations within 90 days, matched 1:1 with a control group (no dislocation).
• Compared demographics, indications, comorbidities, 10-year revision rates, and complications using multivariable logistic regression.

Main Results:

• Dislocation at any early interval (0-90 days) significantly increased 10-year revision odds (OR 25.60-33.4, P < .001).
• Acute dislocations (0-7 days) showed similar all-cause revision rates but a higher risk of revision for instability (85.7%) compared to later dislocations (53.9%).
• Primary diagnoses of post-traumatic arthritis, hip fracture, and osteonecrosis were strongly associated with revision after early dislocation.

Conclusions:

• Dislocation within 90 days post-THA is a significant predictor of subsequent revision surgery.
• While early dislocations (0-7 days) have comparable overall revision-free survival, they carry a higher likelihood of revision due to instability.