TREATMENT OF PELVIC OSTEOLYSIS ASSOCIATED WITH A STABLE ACETABULAR COMPONENT INSERTED WITHOUT CEMENT AS PART OF A TOTAL HIP-REPLACEMENT

Thirty-five patients who had had a primary total hip replacement with a porous-coated acetabular component inserted without cement had a rev ision procedure to treat pelvic osteolysis. The mean age at the time o f the revision operation was forty-nine years (range, twenty-nine to e ighty-five years). Forty-six distinct pelvic osteolytic lesions were n oted radiographically around the thirty-five cups. These lesions range d in size from 0.5 by 0.5 centimeter to 6.3 by 2.7 centimeters (mean, 2.6 by 1.7 centimeters). Fourteen of the thirty-five patients had no o r only slight occasional pain at the time of diagnosis of the pelvic o steolysis, fifteen patients had pain attributed to a loose femoral com ponent, one had pain related to a spontaneous fracture of the greater trochanter, and one had pain related to recurrent subluxation, The rem aining four patients had pain in the groin despite radiographically st able implants. All of the metal-backed porous-coated acetabular compon ents were stable according to the preoperative radiographs, and the st ability was confirmed at the time of the revision. The metal shell was left in place and the acetabular liner was exchanged in all thirty-fi ve patients, The osteolytic lesions were debrided, and thirty-four of the forty-six lesions were filled with allograft bone chips. The patie nts were evaluated a minimum of two years (range, two to five years; m ean, 3.3 years) after the revision operation, and all thirty-five sock ets were found to be radiographically stable. The bone grafts appeared to have consolidated, and none of the osteolytic defects had progress ed. One-third of the lesions were no longer visible on radiographs, re gardless of whether or not they had been filled with bone graft. The r emaining lesions had decreased in size.It appears that, in the short-t erm, exchange of the liner and debridement of the granuloma, with or w ithout use of allograft bone chips in the osteolytic defect, is a reas onable alternative to revision of the socket provided that the metal s hell is solidly fixed at the time of the revision operation, If the me tal shell has been markedly damaged by the femoral head, the locking m echanism far the polyethylene liner is not intact, or a satisfactory r eplacement liner is not available, then revision of the porous-coated acetabular component is indicated. These results must be considered pr eliminary. Since osteolysis may take several years to redevelop after a revision, additional follow-up is required.