Porous Tantalum Buttress Augments for Severe Acetabular Posterior Column Deficiency

In revision total hip arthroplasty (THA), consensus is lacking regarding the optimal method for reconstruction of the most severe acetabular defects. Porous tantalum (TM) buttress augments were designed for the most severe postero-superior defects. The purpose of this study was to report the results of a consecutive series of acetabular reconstructions utilizing TM buttress augments. Eight complex acetabular reconstructions utilizing a TM buttress augment were performed at two centers. All were Paprosky 3A or Paprosky 3B bone loss classification, with severe superior and posterior column deficiency where wedge augments were insufficient for mechanical support. The acetabular cup sizes ranged from 64-78, and a buttress shim was used in 7 of 8 cases. Clinical and radiographic follow-up averaged 16.5 months (range, 10-28) and no cases were lost to follow-up. There were no cases of clinical or radiographic loosening, and no case had required reoperation or revision. All patients except one were ambulating with either no assist device or a single cane at final follow-up. There was one complication of an iliac wing fracture noted incidentally on postoperative x-rays in the lone patient in whom a buttress shim was not used. At short-term follow-up, TM acetabular buttress augments appear to effectively substitute for the use of structural allografts or cages, which would otherwise be used in this challenging setting. The potential for biologic fixation is promising for the durability of these reconstructions; however, longer-term follow-up is required for full evaluation.