Abstract
Background
Excellent results with use of tapered wedged cementless stem have been reported. The purpose of this study was to clarify the indication of tapered wedged cementless stems for patients with poor bone quality.
Method
Sixty-five hemiarthroplasties in 79 patients with diagnosis of femoral neck fracture were performed between February 2004 and August 2011. 14 patients were lost to follow-up after surgery, and it is 19 patients among the leaving 65 patients had the stovepipe canal. There were 2 men and 16 women, with a mean age at time of surgery 85 years (range, 75–92 years). All components were tapered wedged cementless stem (LINEAR: Encore, Kinectiv: ZIMMER). Evaluation of patient followed includes radiographic analysis (canal flare index, canal fill rate, stem alignment, bone reaction, and stem stability) and recording complication.
Result
Follow-up averaged 9.4 months (range, 3–32 months). All patients were stovepipe canal, the average of canal flare index was 2.57±0.34 (range, 1.69–2.94). Canal filling rate of proximal level (upper border of the lesser trochanter) was 76.5% (range, 63–86), mid level (mid stem) was 84.1%(range, 68–96), and distal level (1 cm proximal to the tip of the stem) was 58%(range, 46–81). 2 patients had varus alignment of the femoral stem, 4 patients had valgus, and 13 patients were within 2°of neutral in coronal plane. Spot-welds consistent with bone ingrowth were identified in 15 patients (83%). 2 patinets showed grade 1 stress shielding, and 3 patients grade 2. Stem subsidence (over 2 mm) showed in 2 patients, because they were used undersized stems (low canal filling rate in mid level) and one of them was loose. The other patient shows no evidence of radiographic loosening. Intraoperative fracture was 2 patients and they were performed wiring. There were no infections or clinical evidence of venous thrombosis or pulmonary embolism.
Conclusion
Taper wedged cementless stem in poor bone quality patients appears to be promising treatment, if there is not even canal-implant mismatch.
