Review Question - QID 219949

Imaging demonstrates acetabular component failure with bone loss secondary to osteolysis. To plan for reconstruction and detect a possible pelvic discontinuity, a CT scan should be performed (Answer 1).

Severe acetabular bone loss in revision total hip arthroplasty (THA), with or without pelvic discontinuity, poses distinct reconstructive obstacles for arthroplasty surgeons. The most difficult acetabular bone defects, categorized as Paprosky types 3A and 3B or American Academy of Orthopaedic Surgeons (AAOS) types III and IV, typically involve a major portion of the acetabular rim with compromised support from the anterior and/or posterior column. Reconstruction techniques include custom triflange acetabular components, cup cage constructs, or acetabular distraction.

Malahias et al. conducted a systematic review on the management of chronic pelvic discontinuity (PD). The authors included 18 articles and 569 total patients with PD. Overall survivorship at midterm follow-up was 85%, with aseptic loosening (10%), dislocation (8%), PJI (5%), and periprosthetic fracture (2%) being the most common causes for revision surgery. They report several treatment strategies including the use of custom triflanges, cup-cages, and highly porous shells with and/or without augmentation. Inferior outcomes were reported for conventional cementless shells combined with acetabular plates, as well as ilioischial cages and reconstruction rings. Despite positive results, the authors conclude that there is still no consensus regarding the impact of different types of acetabular reconstruction methods on optimizing the healing potential of PD.

Sculco et al. created an international consensus committee to better outline the diagnosis and treatment of acetabular bone loss in revision hip arthroplasty. The authors outline (1) preoperative planning and postoperative assessment; (2) implant selection, management of osteolysis, and management of massive bone loss; (3) the treatment challenges of pelvic discontinuity, periprosthetic joint infection, instability, and poor bone biology; and (4) the principles of reconstruction and classification of acetabular bone loss. Surgeons are encouraged to consult these guidelines when treating patients who require complex revision surgery.

Berend et al. performed a multicenter, retrospective review of 95 complex acetabular reconstructions using a custom triflange acetabular component. While most patients saw improvement in their Harris Hip Scores, nearly one-quarter of patients had a complication with dislocation, infection, and femoral revision being the most common. The authors conclude that triflange custom acetabular component provides predictable fixation with complication rates that are similar to those of other techniques.

Figure A demonstrates acetabular component failure with significant bone loss. Illustration A is the post-operative radiograph with a custom triflange acetabular component in place. Illustration B is the Paprosky classification of acetabular bone loss.

Incorrect Answers
Answers 2-3: The radiograph demonstrates osteolysis and bone loss, most likely secondary to polyethylene wear, not a metal-on-metal articulation.
Answer 4: The patient has normal inflammatory markers, reducing the likelihood of infection and the need for additional confirmatory tests, including alpha defensin.
Answer 5: Judet views or CT scans are more effective at detecting bone
loss and possible pelvic discontinuity compared with bone scans.