Coxa vara in chondrodysplasia: prognosis study of 35 hips in 19 children.

BACKGROUND: To better understand anatomical and functional outcomes of coxa vara in chondrodysplasia according to the initial presenting hip morphology, disease type, and impact of surgery.

METHODS: Clinical and radiographic records of 19 children (35 hips) diagnosed with coxa vara and with osteochondrodysplasia were reviewed. We classified the hip radiographic findings into 2 groups: (a) group I, coxa vara with a fragmented and/or nonossified head; and (b) group II, coxa vara with a regular femoral head. Surgical indications in coxa vara included decreased range of hip motion (usually diminished abduction, extension, and internal rotation), coxa vara with progression documented on regular follow-up hip radiographs, and/or severe coxa vara with a Hilgenreiner epiphyseal angle (HEA) of 60 degrees or more. Follow-up was until the completion of growth and, for some patients, into early adulthood. Mean follow-up was 8 years.

RESULTS: Twenty-five hips were operated on in 13 patients. In 23 hips, the procedure was a valgus osteotomy fixed by pins and wire. A pelvic extension osteotomy without valgus osteotomy was performed in one patient (2 hips). Coxa vara recurred in 7 hips. In 4 of these hips, repeat surgery with hypervalgus osteotomy was indicated to stop epiphyseal slipping (3 hips) or to improve the arc of motion (1 hip). Functional outcomes were poor in coxa vara associated with poor epiphyseal development (nonossified or fragmented epiphysis) as seen in spondyloepiphyseal dysplasia congenita, spondyloepimetaphyseal dysplasia, Kniest disease, and multiple epiphyseal dysplasia. Coxa vara with physeal instability as observed in spondylometaphyseal dysplasia resulted in deformity recurrence postoperatively during growth. In contrast, outcome was better in cases of coxa vara with nonphyseal/nonepiphyseal involvement, that is, good femoral head morphology, stable physis, and good articular cartilage, as seen in cases of metaphyseal dysplasia and cleidocranial dysplasia.

CONCLUSIONS: Coxa vara with physeal and epiphyseal involvement and severe impairment of the articular cartilage has a poor prognosis even after reconstructive surgery. In coxa vara with an abnormal physis, there were numerous postsurgical recurrences of the deformity during growth if the physis was not stabilized at the time of valgus osteotomy. In these cases, we should delay osteotomy until an HEA greater than 60 degrees. Coxa vara in which only the metaphysis of the femoral neck is involved, the deformity is milder and often requires no treatment. Indications for surgery in this group are increasing coxa vara, Trendelenburg gait, or an HEA greater than 60 degrees.