Cup-cage reconstruction for severe acetabular bone loss and pelvic discontinuity

Background: Management of severe acetabular bone loss and pelvic discontinuity in revision total hip arthroplasty remains a significant surgical challenge. Traditional ilioischial antiprotrusio cages often fail due to a lack of biological ingrowth, leading to mechanical fatigue and hardware failure.

Objective: This article describes the surgical technique and clinical outcomes of cup-cage reconstruction, a hybrid construct designed to provide immediate mechanical stability and facilitate long-term biological fixation.

Key Points: The technique utilizes a porous trabecular metal acetabular component supplemented by an antiprotrusio cage. Key surgical steps include thorough debridement to bleeding host bone, morselized allograft impaction, and precise screw fixation into the ilium and ischium. In a series of 35 cases with Paprosky type 2C to 3B defects, the five-year implant survivorship was 89%. The mean Harris Hip Score improved from 30 preoperatively to 71 postoperatively. While effective, the procedure carries risks of sciatic nerve injury and iatrogenic pelvic dissociation during inferior flange placement. Dual-mobility liners are frequently employed to mitigate the risk of postoperative dislocation in patients with abductor deficiency.

Conclusion: Cup-cage reconstruction is a reliable salvage option for major uncontained acetabular defects and pelvic discontinuity. The construct provides sufficient initial stability to allow for secondary osseointegration of the porous shell, demonstrating favorable mid-term durability and functional improvement in complex revision scenarios.