Long-term results of femoral revision with the Wagner Self-Locking stem

Femoral revision total hip arthroplasty may be a complex procedure due to extensive periprosthetic bone loss. Fluted, tapered stems provide secure axial and rotational stability in the distal femur. We retrospectively evaluated the long-term outcome of the cementless Wagner Self-Locking prosthesis (Sulzer Orthopedics Ltd, Winterthur, Switzerland). From 1992 to 1998, 68 consecutive femoral revisions were performed in 66 patients using the Wagner tapered stem. Twenty-five patients deceased for unrelated causes without additional surgery. The studied group consisted of 41 hips in 41 patients, 12 males and 29 females, aged from 29 to 80 years (mean 61 years). Thirty-five hips (85.4%) included severe deficiency of bone stock. A transfemoral approach was carried out in 32 cases (78%). Bone grafting was never supplemented. Average follow-up was 13.9 years (range 10.4 to 15.8 years). Clinical evaluation was performed using Harris Hip Score (HHS). Osseointegration of the stem and progression of periprosthetic bone remodelling were assessed radiographically. Five stems required rerevision because of deep infection (2), progressive subsidence (2) complicated by hip instability and head-neck disassembly, and old dislocation following acetabular component failure (1). Four hips (9.7%) dislocated, and 8 stems (19.5%) subsided significantly. Average HHS improved from 33 points preoperatively to 75 points at the latest follow-up examination (p < 0.001). Thirty-three of the 36 unrevised stems (91.7%) had radiographic evidence of bone ingrowth. A constant or decreased resorption of the femoral bone was detected in 34/36 patients (94.4%). The cumulative survival rates at 15.8 years with femoral revision for any reason and for stem failure as the end points were 92.0% and 96.6%, respectively. The current study documents the efficacy of distal fixation to the diaphysis in revision of bone-deficient femoral components, supporting the use of tapered, fluted stems. Higher-risk complications (dislocation, subsidence) should be minimized by the development of modular stems.