Cages/ reconstruction rings (Burch-Schneider/ Ganz) for reconstruction of chronic pelvic discontinuity

Background

Chronic pelvic discontinuity is an uncommon and difficult problem in the setting of revision total hip arthroplasty. It is usually seen in conjunction with Paprosky III-A, III-B, and II-C defects and is more common in females and rheumatoid patients. The treatment goals include achieving union across the discontinuity, restoration of bone stock, and implantation of a stable mechanical construct with potential for long-term biologic fixation.

Treatment options for chronic pelvic discontinuity include reconstruction with cages, rings with or without adjuvant plating and bulk allografts, distraction technique using porous tantalum augments and tantalum shell, cup-cage constructs, and custom triflanges. Traditional indications for ilioischial devices (Burch-Schneider cages) include acetabular defects associated with significant anterosuperior and posteroinferior column bone loss, with less than 50% residual host bone contact which would be non-supportive of a cementless hemispherical acetabular component. This would typically entail the use of bulk allografts for reconstitution of acetabular host bone for future revisions. Mechanical failure rates between 0% and 15% and radiographic loosening rates of 0% to 24% have been reported at mid-term follow-up, but most series do not collect selective results of using cages only for the most severe defects. Unfavorable results (50%-60% failure) have been reported with the use of ilioischial devices for chronic pelvic discontinuity.

In the Asian population, the small size of the native acetabulum typically precludes the routine use of a cup-cage construct (minimum acetabular size of 60 mm would be needed to accommodate the smallest cage, 44 mm). Furthermore, in developing countries, patients are responsible for purchasing their implants, and thus cost constraints make routine use of porous metal shells with and without porous modular augments or custom triflange components extremely difficult. We describe the use of a cage with impaction grafting for the treatment of severe acetabular bone loss and an associated chronic pelvic discontinuity. Premise: The use of ilioischial devices in conjunction with acetabular impaction grafting is a relatively cost-effective procedure in patients with severe acetabular bone loss with the potential to restore bone stock for a future revision.

Surgical technique