Intracavitary and Extracavitary Iliac Extended Fixation Using Porous Metal Augments for Paprosky Type 3 Acetabular Defects in Revision Total Hip Arthroplasty: A Minimum 2 Years Follow-up

Abstract

Background: We proposed a new concept of “iliac extended fixation” in revision total hip arthroplasty (THA) as fixation extending superiorly 2 cm beyond the original acetabular rim with porous metal augments, which was further classified into intracavitary and extracavitary fixation. This study reports the minimum 2 years outcome of the iliac extended fixation technique in patients with Paprosky type 3 acetabular defects. Methods: Thirty two revision THA patients were retrospectively reviewed who underwent reconstruction with the concept of iliac extended fixation from 2014 to 2016 in our hospital. Patients were assessed using the Harris Hip Score (HHS) and the Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC). In addition, radiographs were assessed and patient reported satisfaction was collected. Results: At an average follow-up of 40 months (range 25 – 64 months), the postoperative HHS and WOMAC scores were significantly improved at the last follow-up (p < 0.001). The postoperative horizontal and vertical locations of the COR were significantly improved from the preoperative measurements (p < 0.05). Two (6.3 %) patients were dissatisfied with the outcome. The extracavitary iliac extended fixation group had significantly more horizontal screws fixation (4.6 ± 25.7° vs 41.9 ± 37.8°, p < 0.001) and higher rate of osteointegration in zone 1A (91.7% vs 50.0%, p = 0.023) than the intracavitary iliac extended fixation group. Conclusions: Intracavitary and extracavitary iliac extended fixation with porous metal augments and cementless cups are effective in reconstructing severe superior acetabular bone defects, with promising short-term clinical and radiographic outcome.