[Subtrochanteric end-to-side valgus osteotomy for severe infantile coxa vara].

OBJECTIVE

Healing of the frequently associated femoral neck pseudarthrosis. Restoration of a proper length-tension relationship of muscles and lever arms of the hip. Regulation of forces acting on the femoral neck. Realignment of the leg length. Adjustment of the greater trochanter apophysis to allow regular growth.

INDICATIONS: Severe infantile coxa vara (CCD [collodiaphyseal] angle<or=100 degrees) with or without femoral neck pseudarthrosis.

CONTRAINDICATIONS: All coxae varae based on local or systemic bone diseases, especially coxa vara in osteogenesis imperfecta, rickets, osteomalacia and meningomyelocele. Secondary coxa vara combined with dysplastic acetabulum.

SURGICAL TECHNIQUE: Preoperative planning. Standard lateral approach to the proximal femur. Insertion of a guide wire according to the preoperative planning followed by a cannulated chisel. After removal of both the chisel and the guide wire, insertion of the plate chosen in the preoperative planning. Subtrochanteric osteotomy (one femoral shaft width distal to the plate) in an anterior-posterior direction. Reposition of the bone fragments (end-to-side) and securing of the plate to the femoral shaft using standard cortical screws. Closure of the wound.

POSTOPERATIVE MANAGEMENT: 6-week spica casting till the age of 7 years or further on depending on compliance.

RESULTS

13 children with 20 affected hips (13 developmental coxae varae/spondyloepi-metaphyseal dysplasias, five postosteomyelitic coxae varae, two coxae varae following avascular necrosis) underwent the above procedure at an average age of 7.1 years. Responder rate at follow-up (mean age of 13.4 years) was 100%. All femoral neck pseudarthroses healed. One hip developed a recurrent coxa vara requiring reoperation.