Revision total hip arthroplasty for instability: surgical techniques and principles.

Instability is one of the most common complications after total hip arthroplasty. Fortunately, instability usually occurs as a single episode and can successfully be treated nonsurgically in many instances. However, recurrent instability may require surgical treatment. Although many studies related to instability exist, the etiology and the optimal management of recurrent instability are not well known and continue to be investigated. It is important to understand the principles of management and surgical techniques for the treatment of recurrent instability, including the use of constrained liners.