Journal Article

Comparison of a Hydroxyapatite-Coated Sleeve and a Porous-Coated Sleeve with a Modular Revision Hip Stem: A Prospective, Randomized Study

Clifford, Phillip E., Bolognesi, Michael P., Pietrobon, Ricardo, Vail, T. Parker

2004

Overview

BackgroundBone ingrowth into a cementless prosthesis can be achieved by both porous and hydroxyapatite coatings. The purpose of this study was to compare the performance of a hydroxyapatite-coated proximal sleeve and a porous bead-coated sleeve in patients managed with a modular revision hip system.MethodsBetween August 1992 and December 1996, fifty-three consecutive femoral revisions performed with an S-ROM stem in fifty-two patients were prospectively randomized at the time of surgery to either a hydroxyapatite-coated or a porous-coated sleeve. All patients were evaluated clinically and radiographically at three months, six months, and yearly for a minimum of two years (average, four years; range, two to 7.5 years). Femoral defects were classified according to the criteria of Paprosky et al. Six patients died and four patients were lost to follow-up, leaving forty-two patients (forty-three hips) as the final study group.ResultsFor the entire group, two femoral stems, one of which had been implanted in a hip with a Paprosky type-II femoral defect and the other in a hip with a Paprosky type-IIIB femoral defect, required a repeat revision, one for pain and the other for aseptic loosening. Radiographic evidence of bone ingrowth was observed in 96% (twenty-six) of the twenty-seven femora with type-I or II defects and in 81% (thirteen) of the sixteen femora with type-III defects. Femoral component survival, with use of revision as the end point, was 95% at four years for the entire group. The Harris hip scores were not significantly different when stratified by implant type, but were significantly different when stratified by bone loss (p < 0.05). In the femora with type-I or II defects, no difference was detected between those treated with a hydroxyapatite-coated implant and those that received a porous-coated implant with respect to bone ingrowth. However, in femora with type-III defects, the likelihood of the development of bone ingrowth was 2.6 (95% confidence interval, 1.3 to 5.17) times greater in hips that received a hydroxyapatite-coated implant (all eight developed ingrowth) than in hips that had a porous-coated implant (five of eight developed ingrowth) (p = 0.05).ConclusionsBone fixation was achieved more often with hydroxyapatite-coated sleeves in femora with Paprosky type-III defects, but no significant difference was noted in outcomes between the two implant types when used in bone with type-I or type-II femoral defects. Overall, the S-ROM modular hip stem performed better in femora with type-I or II bone defects than in femora with type-III defects.Level of EvidencePrognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

• Publisher: Copyright by The Journal of Bone and Joint Surgery, Incorporated,Journal of Bone and Joint Surgery Incorporated,Journal of Bone and Joint Surgery AMERICAN VOLUME
• Subject: Adult / Aged / Aged, 80 and over / Arthroplasty, Replacement, Hip / Biological and medical sciences / Coated Materials, Biocompatible / Durapatite / Female / Hip Prosthesis / Humans / Male / Medical sciences / Middle Aged / Orthopedic surgery / Osseointegration / Porosity / Prosthesis Design / Prosthesis Failure / Reoperation / Surface Properties / Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases