Mid-Term Outcomes of Cemented Stem and Subtrochanteric Shortening Derotational Osteotomy in Total Hip Arthroplasty for Crowe IV Developmental Dysplasia.

Abstract

Performing subtrochanteric osteotomy with cemented components in patients with Crowe IV developmental dysplasia of the hip (DDH) is technically challenging and not widely reported. This study aimed to evaluate the mid-term outcomes of cemented stem total hip arthroplasty (THA) with subtrochanteric femoral shortening and transverse derotational osteotomy in patients with Crowe IV DDH. Data collected from patients with Crowe IV DDH who underwent cemented stem THA with subtrochanteric femoral shortening and transverse derotational osteotomy between 2010 and 2018 were retrospectively evaluated. The cemented Lubinus SP II femoral component and the cementless CombiCup acetabular component were used together in all cases. These data, including Harris hip scores, limb length discrepancy (LLD), severity of limp, Trendelenburg test, bone union, length of the resected femur, limb lengthening, level of the osteotomy site, and length bridging the osteotomy site, as well as complications, were analyzed. A paired Student t-test was used to analyze continuous variables, categorical data were compared using Fisher's exact probability test, and correlation analysis was performed using Spearman's rank correlation coefficient. Among 14 included patients (10 females and four males), the mean age was 60.4 years (range, 47-73). The mean follow-up period was 49.1 months, and no patient was lost to follow-up. The mean Harris hip score improved from 40.7 to 87.7. The mean LLD decreased from 52 to 12.7 mm. The mean length of the excised femoral segment was 38.4 mm, and the mean length of limb lengthening was 27.1 mm. The mean distance between the osteotomy site and the lesser trochanter was 21.1 mm after surgery. The mean length of the femoral stem bridging the osteotomy site was 97.6 mm. Finally, the mean osteotomy union time was 10.6 months. No statistically significant correlation was found between the osteotomy union time and these factors. No neurological deficits were noted. Delayed union was observed in one patient, and postoperative dislocation was observed in two patients. Cement leakage into the osteotomy gap was observed in one patient, however, no revisions were required, and no signs of loosening or migration were observed. Cemented stem THA combined with subtrochanteric femoral shortening and transverse derotational osteotomy is safe and effective in treating patients with Crowe IV DDH. Rather than leading to nonunion, cement leakage may negatively affect bone healing.