Progressive Subsidence After Total Hip Arthroplasty Using a Tapered, Proximally Coated Femoral Stem with Immediate Postoperative Weight-Bearing

Subsidence of the femoral stem has been suggested to be related to design characteristics of the implant. A single surgeon performed 130 consecutive cementless total hip arthroplasties with a tapered, proximally HA- and porous-coated femoral prosthesis. Within hours of surgery, patients began weight-bearing as tolerated. Once discharged from the hospital, patients were allowed to progress from a walker to a cane to using no assistive devices as soon as they were comfortable. There was significant progressive subsidence between 6 weeks (0.7 ± 1.2 mm) and 1 year (1.3 ± 1.7 mm, P < .001). At 6 weeks, 2.3% of the hips demonstrated subsidence greater than 3 mm, which increased to 10% at 1 year. To date, 2 hips (1.5%) have been revised for femoral loosening secondary to excessive subsidence. Therefore, we conclude that the use of a tapered, proximally HA- and porous-coated femoral stem in combination with immediate postoperative weight-bearing appeared to result in progressive subsidence during the first postoperative year.