Unstable total hip arthroplasty: detailed overview.

Hip dislocation is one of the most common complications of THA. Good preoperative planning, good postoperative patient education, accurate intraoperative component positioning, rigorous intraoperative testing of hip stability, and good repair of soft tissues during closure all help prevent dislocation. Early postoperative dislocations and first or second dislocations usually are treated with closed reduction and a hip guide brace or hip spica cast, but when dislocation becomes recurrent, surgical treatment usually is needed. When possible, surgical treatment is based on identifying and treating a specific problem leading to the dislocation, such as implant malposition, inadequate soft-tissue tension, or impingement. In selected circumstances, constrained implants or bipolar or tripolar implants provide powerful tools to restore hip stability.