Clinical and radiological evaluation of modular trabecular metal acetabular cups. Short-term results in 64 hips.

Bone ingrowth and long-term survival of cementless acetabular implants, both in primary and revision hip arthroplasty, are determined by initial implant stability and by the osteoconductive properties of the metal shell. The outcome of a trabecular metal tantalum modular uncemented cup was evaluated in 64 hips in 62 patients. Eleven cups were used in complex primary total hip replacements, 53 cups were implanted in revision hip arthroplasties. The follow-up ranged from 12 months to 48 months. Clinically the Charnley modified Merle-d'Aubigné Postel score improved from 9 to 16 in the primary arthroplasty group and from 10 to16 in the revision group. Serial radiographs demonstrated excellent stability and bone apposition; in the revision cases, graft incorporation was noted in all but one cup. The number of periacetabular gaps detected on initial postoperative radiographs in the revision cases decreased from 15 to 4 and none of the remainder deteriorated with time. Complications included 2 haematomas, 1 dislocation and 1 cup failure in a Paprosky IIIb defect because of cup undersizing. The early results with the trabecular metal modular cementless cup appear promising in both complex primary and revision hip arthroplasty, even in the presence of considerable bone loss that requires additional bone grafting.