ULTRA-SHORT ANATOMIC NECK SPARING CEMENTLESS FEMORAL STEM: EARLY OUTCOME IS PREDICTABLY SUCCESSFUL

Abstract

Architectural changes in occurring in the proximal femur (resorption) after total hip arthroplasty (due to stress shielding) continues to be a problem. In an attempt to reduce these bony changes the concept of short and femoral neck sparing stem designs have been advocated. The purpose of this study was to evaluate the early clinical and radiological results, especially stem fixation and bone remodeling of proximal femur after total hip arthroplasty.

A total of forty-five patients (fifty-four hips) were included in the study. There were twenty men and twenty-five women. The mean age at the time of operation was 53.9 years (range, twenty-six to seventy-five years). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients one week after operation and at the final follow-up examination. The mean follow-up was 1.3 years (range, one to two years).

The mean preoperative Harris hip score was 45 points (range, 15 to 48 points), which improved to a mean of 96 points (range, 85 to 100 points) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. One hip (2%) required open reduction and fixation with a cable for calcar femorale fracture. Bone mineral densitometry revealed a minimal bone remodeling in the acetbulum and proximal femur.

The geometry of this ultra-short anatomic neck sparing cementless femoral stem has proved to provide effective initial stability even without the diaphyseal portion of the stem. We believe that femoral neck preservation and lateral flare of the stem provide an axial and torsional stability and more natural loading of the proximal femur.