Custom Triflange Acetabular Components for Revision Hip Arthroplasty in the Patients with Severe Acetabular Defects: Planning, Surgical Technique, Outcomes

Employment of custom triflange acetabular components (CTAC) is one of the few options for pelvic reconstruction in the patients requiring complex acetabulum revisions with Paprosky 2 C, 3 A and 3 B defects and pelvic ring disruption.

The purpose of the study was to describe the features of planning, surgical technique, and short-term treatment outcomes of the patients with significant acetabular defects, in which the revision hip arthroplasty was performed using the CTAC.

Materials and Methods. A single-center analysis of a series of consecutive patients was performed: 50 complex acetabulum revisions in 47 patients (16 men and 31 women). The average age of the patients was 60±12 years (from 31 to 82; Me 62 years), the average body mass index was 29.7±6.3 kg/m² (18.4 to 46.3; Me 29.0 kg/m).

Results. The mean follow-up was 22±13 months (from 3 to 3.6 years; Me 20 months). The average Harris score increased from 27±7 (from 15 to 39; Me 27) before surgery to 64±16 (from 22 to 90; Me 67) a year after (p<0.001). The level of pain according to VAS before surgery was 7±1 points (from 5 to 9; Me 7), after treatment it decreased to 2±1 points (from 0 to 7; Me 1, p<0.001). In 17 cases out of 50 (34%), there was at least one complication: dislocations — 7 (14%) cases; infection — 3 (6%); loosening — 2 (4%); complications associated with the femoral component — 4 (8%), including 3 intraoperative fractures and 1 postoperative, associated with loosening of the implant; pronounced disturbances of static and locomotor functions — 2 (4%). 12 cases out of 50 (24%) required another surgery, all of which were performed in a year. The Kaplan-Meyer survival rate for the hip implants was 0.71, for the CTAC — 0.87.

Conclusion. Employment of the CTAC for revision hip arthroplasty in the patients with significant acetabulum defects and pelvic ring disruption allows reliable fixation of the endoprosthesis components. The STAC placement technique is more anatomical than use of structural allografts, several augments or sup-cage systems. It allows reconstruction of extensive bone defects, theoretically avoiding the long-term problems with allografts, modular trabecular components, antiprotrusion systems and cup-cage. Although, to prove this, the longer follow-up is needed.