A NEW SUBTROCHANTERIC OSTEOTOMY TECHNIQUE FOR TOTAL HIP ARTHROPLASTY IN HIGH DISLOCATED HIPS DUE TO THE SEQUELAE OF A SEPTIC HIP IN CHILDHOOD

Abstract

This study was undertaken to assess the feasibility of a new subtrochanteric osteotomy technique for total hip arthroplasty (THA) in cases with a high dislocated hip secondary to the sequelae of a septic hip in childhood. Eighteen patients (20 hips), aged 25 to 65 years (average 47.3 years), underwent THA using a cement-less conical stem (Cone prosthesis^®; Protek AG, Berne, Switzerland) with a new subtrochanteric osteotomy technique and were followed for an average of 23.6 months. All patients were graded as type III (high dislocation) according to the Hartofilakidis classification, and according to the Crowe classification 3 cases were of type III and 17 were of type IV.

The procedure was performed through a posterolateral approach and a provisional osteotomy was usually performed at the inferior half of the lesser trochanter. All acetabular component was inserted at the true acetabular and the acetabular cup was inserted in 5 cases and only a liner was inserted after cementing in 15 cases. The stem size and the amount of stem insertion was decided according to the preoperative planning and soft tissue tension. After final reduction, the greater trochanter was re-attached to the proximal femur with the hip in the abducted position. Cables or a grip system (Dall Miles^®, Stryker Orthopaedics Inc., Mahwah, NJ, USA) were used for fixation, and if possible, additional screws were inserted.

Postoperatively, range of motion exercises were encouraged after 2 to 3 weeks of bed rest and non-weight bearing crutch ambulation followed. Weight bearing was permitted only after obtaining radiological confirmation of bone union, but then active exercises were strongly encouraged to stretch abductors. Mean duration of surgery was 180.6 minutes, and mean perioperative blood loss was 1424.1ml. There were no intra-operative complications. Post-operative dislocation occurred in 2 cases and partial femoral nerve palsy developed in 1 case. Mean Harris Hip Score improved from 42.4 to 84.2. Mean lateral opening angle of acetabular cup and liner was 34.7 0 and mean anteversion was 20.8 0. All femoral components were implanted in neutral to 5 degrees of valgus, and mean leg lengthening was 36.5mm. The mean time to greater trochanter union was 3.72 months.

Primary THA in highly dislocated hips due to the sequelae of septic hip in childhood using the described subtrochanteric osteotomy and a cone prosthesis was found to be safe and effective at restoring leg length and trochanteric rotation. But more follow-up is required to more comprehensively establish the long-term results of the described procedure.