Use of a Conical Fluted Femoral Stem Eliminates the Need for Fixation in Patients Who Have Crowe Type 3 or 4 Coxarthrosis Undergoing Subtrochanteric Osteotomy.

Background: This study aimed to analyze the clinical, functional, and radiographic outcomes of patients who had Crowe type 3 or 4 developmental dysplasia of the hip (DDH) undergoing cementless total hip arthroplasty (THA) using a conical fluted femoral stem in combination with a transverse subtrochanteric femoral shortening osteotomy without internal fixation.

Methods: This retrospective study included the records and radiological data of 114 patients who had Crowe type 3 or 4 DDH who underwent subtrochanteric femoral osteotomy and cementless THA at our institution between 2015 and 2022. The mean age was 46 years (range, 28 to 80), comprising 76 women and 38 men. The mean follow-up duration was 55 months (range, 25 to 85). Patients underwent clinical and radiological evaluations at two, four, eight, 12, and 24 weeks postoperatively and were called for a final evaluation. Radiographic bone union, Harris Hip Score (HHS), true limb-length discrepancy, and Trendelenburg sign were assessed.

Results: A total of 112 hips (98.2%) achieved union at the osteotomy site, with a mean healing time of 5.4 months. The mean preoperative HHS was 50 (range, 42 to 61), which improved significantly to 86 (range, 75 to 98) postoperatively (P < 0.001). The mean preoperative limb-length discrepancy was 3.8 cm (range, two to 5.2), which was reduced to 1.1 cm (range, zero to 1.9) postoperatively (P < 0.001). There were no revisions or component exchanges that were required during the follow-up period, and no patients experienced severe limping postoperatively.

Conclusions: The use of a conical fluted femoral stem in patients who had Crowe type 3 or 4 DDH undergoing subtrochanteric femoral osteotomy provides stable fixation and excellent functional outcomes while eliminating the need for additional internal fixation.