Superior Pubic Ramus Screw Placement During Complex Acetabular Revision: Acetabular Distraction for Treatment of Pelvic Discontinuity

Insertion of a superior pubic ramus screw may be indicated for the treatment of a chronic pelvic discontinuity when utilizing acetabular distraction in revision total hip arthroplasty (THA), especially in the setting of severe bone loss in the ischium. The aim of this procedure is to stabilize and prevent abduction failure of the acetabular component when utilizing acetabular distraction. With the patient in the lateral decubitus position, the acetabulum is exposed from a standard posterior approach for a revision THA. The location of the superior pubic root is identified after making a recess within the anteroinferior capsule. In order to ensure that the appropriate trajectory is obtained, C-arm imaging (inlet view and orthogonal obturator outlet views) is utilized to safely predrill the screw trajectory into the superior pubic ramus. A Kirschner wire (K-wire) is then placed into the hole. With use of a metal-cutting burr on the back table, customized peripheral screw holes are placed and then the acetabular component is slid and impacted into place over the K-wire. After cup insertion, the K-wire is removed and the superior pubic ramus screw can be placed and confirmed on fluoroscopy. In general, chronic pelvic discontinuity requires surgical management with revision THA and has historically employed the use of a cup-cage construct, custom triflange implants, and/or jumbo acetabular cups with modular porous metal augments . With these treatment options, it is typically necessary to insert "kickstand" screws, which function to prevent abduction failure of the acetabular cup . However, in many cases of discontinuity, there may be severe ischial osteolysis, making ischial screw placement difficult or impossible. The superior pubic ramus, however, remains a reliable option that can be utilized for inferior screw fixation, even in cases of severe acetabular bone loss, and thus is especially beneficial in these difficult cases. The technique of acetabular distraction was developed because of limitations with alternative techniques. This procedure achieves cementless biologic fixation and eventual discontinuity healing as a result of lateral or peripheral acetabular distraction and resultant medial or central compression across the pelvic discontinuity. Acetabular distraction allows for intraoperative customization and cement unitization of the acetabular construct. This procedure requires the use of a "kickstand" screw or of inferior screw fixation in order to