A 79-year-old woman with Parkinson disease and documented abductor muscle weakness undergoes primary total hip replacement through an approach that has compromised her hip stabilizers. To minimize her markedly elevated risk of postoperative dislocation, the bearing construct of choice is:
- A Standard 28 mm metal-on-polyethylene bearing with a posterior capsular repair alone
- B Ceramic-on-ceramic bearing with a small head
- C Dual mobility acetabular construct with a large diameter polyethylene head articulating inside a fixed metal shell ✓
- D Metal-on-metal resurfacing
Correct answer: C. Dual mobility acetabular construct with a large diameter polyethylene head articulating inside a fixed metal shell
Explanation
The dual mobility cup provides a second, larger articular surface between a mobile polyethylene liner and the metal shell, increasing jump distance and range to impingement, giving dislocation rates below those of standard bearings. It is preferred in patients at high risk of dislocation: elderly patients, neuromuscular disease, abductor deficiency, and revision for instability. Ceramic bearings offer low wear but do not address instability, and metal-on-metal is abandoned due to adverse reactions to metal debris.
Reference: Miller's Review of Orthopaedics, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.