Background: It is difficult to achieve a successfull revision total hip arthroplasty when a patient has severe proximal femoral bone loss. From a biomechanical viewpoint, cementless fixation of a tapered stem has some advantages compared with other techniques to treat severe proximal femoral bone loss in reconstructive hip surgery.
Methods: We reviewed 129 consecutive revision arthroplasties of the femoral component in which the tapered Wagner self-locking revision stem was used. The indication for revision was aseptic loosening in 97 hips, periprosthetic feacture in 13 (one of which also had an infection), and septic loosening in 16. In the 3 remaining hips, a Wagner revision stem was inserted during a second stage reimplantation after the performance of a Girdlestone resection arthroplasty to treat chronic deep infection. the prerevision defects were classified with the system described by Pak et al. as well as with our system. A functional evaluation of the patients and a survival analysis of the revision stems were performed.
Results: The mean follow-up of patients without rerevision of the stem was 8.1 years (range, 5.1 – 14.1 years). Six revision stems required rerevision (malpositioning, one stem; subsidence, one stem; periprosthetic fracture, one stem; deep infection, three stems) between 0.13 and 4.6 years postoperatively. Using removal of the stem for any cause as end point, the cumulative survival at 14.1 years was 95.2%. The average Merle d‘Aubigné score improved from 7.7 points preoperatively to 14.4 points at the latest follow-up. Because of new bone formation, the most recent radiographs showed clear, good, or excellent restoration of the proximal femur in 88% of patients.
Conclusions: Because of the encouraging results of implantation the Wagner revision stem, the principle of tapered revision stems with distal fixation obiously is a successfull technique. Considering possible late complications such as osteolysis of the femur, aseptic loosening, periprosthetic fracture and late infection, the shortest stem that ensures sufficient mechanical stability should be used. It may be easier to achieve high primary stability in short stems with a tapered design than with other short stem designs.
