Modular Porous Metal Augments for Treatment of Severe Acetabular Bone Loss during Revision Hip Arthroplasty

Modular acetabular augments were implanted in 16 patients (16 hips) for support of an uncemented hemispheric acetabular component during revision acetabular reconstruction. Based on the classification of Paprosky, acetabular bone defects were classified as 2A in one hip, 2B in three hips, 2C in one hip, 3A in five hips, and 3B in six hips. Preoperatively, the prosthetic femoral head centers were located at a mean horizontal distance of 18.6 mm (range, -3-46 mm), and a mean vertical distance of 27.6 mm (range, -16-52 mm) from the approximate femoral head center. Postoperatively, the prosthetic femoral head centers were located at a mean horizontal distance of 10.4 mm (range, 1-25 mm), and a mean vertical distance of 7.4 mm (range, -15-25 mm). At final followup, no implant had evidence of migration or loosening. At early clinical followup, this modular acetabular augment system seems helpful in acetabular reconstructions that cannot be treated with an uncemented hemispheric cup that would have required other forms of treatment such as structural allografts, acetabular cages, bilobed acetabular components, or custom acetabular components. Longer term followup is required to determine whether there are untoward effects of using a modular acetabular reconstructive system.