For a study, researchers sought to determine if there were any changes in clinical and radiographic results between three distinct stem designs for subtrochanteric osteotomy in Crowe type-IV hip developmental dysplasia. A retrospective examination of prospectively collected data from 37 Crowe type IV DDHs treated with non-cemented total hip arthroplasty with chevron subtrochanteric osteotomy in 30 patients was performed. According to the design of the stem, patients are separated into three groups: Ribbed (using Link Ribbed stem; n=14), Synergy (using Synergy stem; n=9), and Link Classic Uncemented (LCU) (using LCU stem; n=14). Clinical and radiological results were assessed. 

All patients were monitored for a period of 36 months. The LCU stem’s bone union time was substantially longer than that of the Synergy stem (P=0.02) and the Ribbed stem (P>0.05); the Ribbed stem’s bone union time was greater than that of the Synergy stem (P>0.05). The Ribbed stem (P=0.000) and the Synergy stem (P=0.001) had considerably greater stem lengths in the distal femur than the LCU stem. The LCU stem had three hips with malunion, stem loosening, and varus alignment. None of these characteristics were seen in Ribbed or Synergy stems. Total hip arthroplasty with a non-cemented stem and subtrochanteric femoral osteotomy for Crowe IV DDH can yield satisfactory to outstanding clinical results in 89.2% of hips (33/37). There were three hips with good clinical results (1 in the Ribbed stem and two in the LCU stem) and one with poor clinical outcomes (LCU stem).

Although the clinical results of the Ribbed, Synergy, and LCU stems are similar, the LCU stem has a predisposition to a varus posture, prolonged union time, malunion, and stem loosening when compared to the Ribbed and Synergy stems. Therefore, the LCU stem is not recommended for Crowe IV DDH with subtrochanteric femoral osteotomy.

Reference:journals.lww.com/jaaos/Abstract/2022/06150/The_Clinical_and_Radiological_Outcomes_of.9.aspx