Abstract
Background: The purpose of this study was to explore that how to equalize the leg length in total hip arthroplasty (THA) with shortening subtrochanteric osteotomy (SSTO) or not for unilateral Crowe type IV developmental dysplasia of the hip (DDH) through the evaluation of the postoperative full-length anteroposterior radiographs. Methods: The postoperative radiographs of 60 patients with unilateral Crowe type IV DDH from July 2012 to May 2019 were retrospectively reviewed. These data included leg length, femoral length, height of center of rotation (COR) of hip, height of greater trochanter, and depth of the sleeve or cone. Patients with leg length discrepancy (LLD) < 10 mm were defined as the non-LLD group. Results: In the non LLD group (26 patients of SSTO and 22 of non-SSTO), the femoral length both SSTO and non-SSTO groups were significantly shorter on operated side, compared with the contralateral side, and the mean discrepancy in SSTO group was approximately equal to the mean length of SSTO. The mean height of COR of hip on operated sides both SSTO and non-SSTO groups were 13.2 mm, and the contralateral sides were 15.2 mm and 15.5 mm, respectively. The depth of the sleeve or cone between SSTO and non-SSTO groups were 21.7 mm and 30.6 mm, respectively. The depth of the sleeve or cone in SSTO group was negatively correlated with the length of SSTO. The height of the greater trochanter of the operated and contralateral sides were 5.3 mm and 16.6 mm in SSTO group, and those in the non-SSTO group were 13.2 mm and 17.2 mm. Conclusions: SSTO leaded to femoral shortening on the operated side for patients with unilateral Crowe type IV DDH. The position of sleeve or cone should be close to the apex of greater trochanter to compensate the lengh of SSTO.
A simple technique to strengthen the initial and mid-term to long-term stability of the cup during total hip arthroplasty in developmental dysplasia of the hip