Use of a Novel Reverse Hip Replacement System to Address Dislocation and Instability.

While total hip arthroplasty (THA) is an enormously successful treatment for patients with end-stage degenerative arthritis of the hip, and surgeons have optimized existing hip implants and techniques, dislocation and instability persist as a leading cause of failure. Given the tremendous success of reverse total shoulder arthroplasty in enhancing the stability of shoulder reconstruction by reversing the anatomic seating of the ball and socket components, one manufacturer (Hip Innovation Technology, LLC, Woodstock, Georgia) has developed a novel Reverse Hip Replacement System (Reverse HRS) to address the need for greater stability in reconstruction of the arthritic hip joint. Rather than the traditional anatomic components that replace the head of the femur with a spherical ball and the acetabulum with a socket with polyethylene liner mounted into the pelvis, the Reverse HRS features a cup with polyethylene liner attached to the femoral stem and a spherical metal head attached to a central trunnion inside of the porous-coated acetabular shell fixed into the pelvis. This design provides dramatically enhanced stability and improved range of motion. This article reviews relevant published literature, including results from a Canadian clinical trial and case reports from a multicenter American clinical trial monitored by the U.S. Food and Drug Administration. It also describes the components and surgical technique of reverse THA.