An oblique osteotomy is better for subtrochanteric shortening in total hip arthroplasty for high hip dislocation: a mechanical comparison of four techniques
Dogan Atlihan1, Cem Yildirim1, Osman Gorkem Muratoglu2
1Clinic of Orthopaedics and Traumatology, Haseki Training and Research Hospital, Istanbul, Turkey.
Background:
Subtrochanteric femoral shortening is used during total hip arthroplasty for high hip dislocation in developmental dysplasia of hip patients.
Methods:
We mechanically tested the stability of various commonly used subtrochanteric osteotomy techniques. As the equivalent of a femoral stem placed in a shortened femur without any stable fixation at the osteotomy line, 2 polyvinylchloride pipes were loosely intertwined. 4 different osteotomies (Z-subtrochanteric osteotomy, oblique-45° osteotomy, double Chevron-90° and 120° subtrochanteric osteotomy) were simulated. Torsional and axial loads were applied, and torsional stiffness was calculated for each test model.
Results:
Z, double Chevron-90° and 120° subtrochanteric osteotomy models demonstrated lower mean torsional stiffness than oblique-45° osteotomy. With the highest torsional stiffness oblique-45° provides the best stability for treatment of high dislocation hips when a subtrochanteric osteotomy is added.
Conclusions:
This matches our previous clinical experience. Oblique osteotomy may also provide higher contact surfaces in the osteotomy lines to promote bone healing.
