Minimum Five-Year Outcomes with Porous Tantalum Acetabular Cup and Augment Construct in Complex Revision Total Hip Arthroplasty

Abstract

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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

“…In the present study, the postoperative COR were significantly lower compared to the preoperative COR, more close to the anatomic COR ( Table 3). The hip biomechanics were therefore improved, which is consistent with previous reports [15]. Restoration of the COR helps decrease leg length discrepancy and avoid increasing the lever arm, which acts on the head/neck taper caused by increased neck length [11].…”

“…Despite this, very few studies have reported the classifications of augment reconstructions in the superior acetabular area. Derek et al reported [5][6][7][8][9][10][11][12] year follow-up of 85 revision THA cases with porous metal augments and classified the use of slope augments in the superior aspect into the three types, namely "flying buttress", "dome" and "footing" [15]. This classification is not contradictory to the concept of iliac extended fixation, as the essence of extended fixation is the bridging of bone defects via augments to establish a supportive superior point; any augment configuration can be used as long as mechanical stability and anatomical COR are achieved.…”

“…Trabecular metal augments made from tantalum (TM Augment; Zimmer, Warsaw, IN) or titanium (Restoration wedge augment; Stryker, Mahwah, NJ) were utilized to reconstruct the superior acetabular defects. There were twelve patients reconstructed with the EIEF technique, using a single buttress augment or combined with other augments, or a flying buttress using slope augments [15] ( Table 1); twenty patients reconstructed with the IIEF technique, fourteen of whom using a single superior slope augment, and the other six with stacked superior slope augments ( Table 2) The average patient age at the time of surgery was 57 years (range 38-78 years), the average body mass index (BMI) was 25.0 (range 18.7-33.7), and 13 (40.6%) patients were female. On average, patients had 1.6 (range 1-5) previous hip operations.…”

“…Magnification was corrected by referring to the already known diameter of the femoral head. The height and the horizontal location of the center of rotation (COR) were determined by measuring the distance from COR to the inter-teardrop line and a vertical line passing the ipsilateral teardrop, respectively [2,15]. Deviation of reconstructed COR was measured as the distance between postoperative COR and the anatomic COR mirrored from the normal contralateral hip to the revised side.…”

“…The introduction of porous metal augments has provided a promising solution to this problem [3,8,13,32], and have been used in the reconstruction of Paprosky type 3 severe superior acetabular bone defects. Jenkins et al classified the use of metal augments in the superior aspect of the acetabulum into the three types, namely "flying buttress", "dome" and "footing" [15]. This classification is according to the augment's location and orientation, and is instructive to the intraoperative application of porous metal augments.…”