engleski

Total hip arthroplasty in patients with Crowe 3 or 4 through the modified lateral approach compared with arthroplasty through direct lateral approach in patients with Crowe 1 or 2 – new surgical technique improves outcome

The aim of our study was to evaluate and compare postoperative results after total hip arthroplasty in patients with dysplastic hips classified according to Crowe to type 3 or 4 and operated through the modified direct lateral approach with postoperative results in patients with Crowe type 1 or 2 operated through the standard direct lateral approach (Bauer or Hardinge). The modified approach is a variation of a direct lateral and Stracathro approach and it allows excellent anterior and posterior femoral exposure and provides a simple method of proximal femoral shortening and leg length equalization, all while preserving abductor muscle continuity. The study included 51 female patients (61 hips), consecutively operated by single surgeon between 2004 and 2007 because of secondary arthritis due to hip dysplasia. In all patients we used standard C2 femur and SPH-ST acetabular cup, additionally secured with 3 screws (Lima Lto, Udine, Italy). All patients with a minimum follow up of 12 months were invited for a final and independent clinical and radiological evaluation. Clinical evaluation included hip and knee range of motion, hip and knee strength (measured with Chatillon MSC, AMETEK), COOP WONCA, SF 36, Harris hip score, Oxford hip score, Womac hip score, Self-efficacy scale for falls and stability testing with balance platform (Phyaction balance, Uniphy). According to Crowe classification there were 16 type 1, 21 type 2, 13 type 3 and 11 type 4 patients. Preoperatively there was no difference between the 2 groups (between Crowe 1 or 2 and Crowe 3 or 4) regarding age (44y) and BMI (26.6 kg/m2), only difference was in hip dysplasia severity. Postoperatively there was no difference regarding HHS (89 pts), Womac (8.3), Oxford (36), SF36 Physical (48), SF36 Mental (48), Self efficacy scale (15), COOP WONCA (15), all tests in balance testing, in strength and range of motion of hip flexion (66N, 95°), hip abduction (89N, 25°) and hip external rotation (47N, 23°). Our results suggest that, even though patients with Crowe type 3 or 4 hip dysplasia have worse preoperative deformity with larger leg length discrepancy, postoperatively there is no difference between the 2 groups (modified approach improves expected outcome). Modified lateral approach allows simple extremity equalization, removes the necessity for trochanteric osteotomy and preserves abductor muscle continuity, thus improving overall outcome. Since, basically, it is an extension of standard Bauer or Hardinge approach, decision to use it could be taken intraoperatively in cases where ideal acetabular cup placement or exact leg length equalization could not be achieved.

total hip arthroplasty; dsplasia; hip disyplasia; Crowe

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