A 70-year-old woman has had three anterior hip dislocations within 18 months of a total hip replacement. Radiographs show both components are well fixed with acetabular inclination of 42 degrees and anteversion of 20 degrees. The femoral head is a 28 mm metal-on-polyethylene bearing. Abductor strength is grade 4 out of 5. What is the most appropriate definitive management?

• A Closed reduction followed by hip abductor strengthening and activity modification
• B Revision to a dual mobility acetabular construct through an anterolateral approach ✓
• C Exchange of the modular femoral head to a 36 mm cobalt-chrome head retaining the same polyethylene liner
• D Total femoral component revision with a distally fixed modular stem

Explanation

Recurrent dislocation with well-fixed, well-positioned components (inclination under 45 degrees, anteversion within the safe zone) indicates soft tissue insufficiency rather than malposition, so revision with a dual mobility cup is indicated because its large effective head diameter greatly increases the jump distance and stability. Closed reduction alone carries a very high redislocation rate after three events. Simply upsizing the head without changing the liner is not possible since head size must match the existing liner taper, and femoral revision addresses no identified problem.

Reference: Miller's Review of Orthopaedics / Campbell's Operative Orthopaedics, 8th / 14th ed.

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Written and medically reviewed by the StethoPrep medical team.