Corrective Imhäuser intertrochanteric osteotomy.

OBJECTIVE: Surgical correction of deformities of the proximal femur caused by epiphyseal displacement by restorative (usually inflection and internal rotation) osteotomy at the intertrochanteric level with the aim of reducing both the offset disorder of the coxal end of the femur that is causing impingement and the prevalence of secondary coxarthrosis. INDICATIONS: Chronic and subacute manifestations of slipped capital femoral epiphysis with an epiphyseal dislocation in the radiographic axial view of 30-60 degrees (ET angle) and DeltaED > 20 degrees (CCD angle minus ED angle) in the anteroposterior view. CONTRAINDICATIONS: Acute phase or course of slipped capital femoral epiphysis. Secondary coxarthrosis (after slipped capital femoral epiphysis). Traumatic epiphyseolysis. SURGICAL TECHNIQUE: Exposure of the proximal femur (anterior femoral neck, intertrochanteric plane, proximal femoral diaphysis) through an anterolateral approach; fixation of the femoral epiphysis with two 3.0-mm Steinmann nails positioned parallel in a posteromedial direction; the seating chisel is hammered in according to the planned, usually inflectional axial correction; intertrochanteric osteotomy by excision of a wedge oriented in accordance with preoperative planning; adaptation of the osteotomy surfaces and osteosynthesis with a 90 degrees AO adolescent plate under interfragmentary compression. POSTOPERATIVE MANAGEMENT: Mobilization on underarm crutches with unloading of the extremity for 2 months postoperatively; gradual increase in loading depending on osseous consolidation of the osteotomy; radiographic assessment 2 and 4 months postoperatively, further clinical and radiologic follow-up until growth is completed (closure of the growth plate); removal of implants at 1 year postoperatively or thereafter.
RESULTS: Retrospective follow-up of 51 patients with unilateral, moderate to severe slipped capital femoral epiphysis (indication: epiphyseal displacement angle of 30-60 degrees, average preoperative displacement angle 45 degrees) that was corrected surgically by Imhäuser intertrochanteric osteotomy and epiphyseal nailing. After an average observation time of 24 years (range: 20-29 years), 28 (55%) of the 51 hip joints were clinically asymptomatic and radiologically free of degenerative changes; moderate clinical and radiologic changes were recorded for 14 hip joints (28%), and advanced changes for nine (17%). Complications related to surgery were apparent in a total of six hip joints: in one case, the Steinmann nail broke after being damaged by the plate blade; in two cases, revision osteosynthesis of the intertrochanteric osteotomy was necessary due to incorrect implant positioning; partial femoral head necrosis developed in one hip joint; there were two cases of low-grade osteomyelitis that healed after implant removal.