Long-Term Results of Cementless Total Hip Arthroplasty Using a Modular Stem in Patients with Femoral Head Osteonecrosis

Cementless modular stemwas designed to allow the surgeon to independently match the anatomy of the metaphyseal and diaphyseal regions of the femoral canal of an individual patient.1 S-ROM stem (DePuy/Johnson & Johnson), which has a hollow proximal sleeve and separate cylindrical core, was introduced in 1984. So far, long-term results of this prosthesis have been excellent in osteoarthritis, developmental dysplasia of hip, multiple epiphyseal dysplasia, and revision surgery.2–4 However, fretting and generation of metallic wear debris from the modular sleeve-stem junction and femoral stem-sleeve junction failure remain concerns.3,5 In addition, long-term results using this type of modular cementless femoral stem in patients with femoral head osteonecrosis has not yet been determined. Femoral head osteonecrosis commonly occurs in younger adults than osteoarthritis of the hip. Total hip arthroplasty (THA) with use of traditional metal-on-polyethylene articulation in osteonecrotic patients was associated excessive wear, osteolysis, and early loosening.6 Since the late 1990s, hard bearings (metal-on-metal and ceramic-on-ceramic bearings) have been used as alternatives to themetal-on-polyethylene articulation.7,8