Deformity correction with external fixator in pseudoachondroplasia

Patients with pseudoachondroplasia have complex, difficult to correct deformities including angular deformity, rotational deformity, and ligament laxity. We retrospectively reviewed seven patients (two children, five adults) with 26 segmental deformities (12 femora, 14 tibiae). We performed bilateral femoral and tibial osteotomies in six patients and bilateral tibial osteotomies in one patient. Distraction osteogenesis was used in 20 segments and acute deformity correction was done in six segments. External fixation was applied to all segments. Of 26 segments, there were five good, 12 fair, and nine poor radiographic results with nine major and 12 minor complications. Recurrent deformity in children and refracture in adults were related to poor results. Of 14 limbs, there were four good, five fair, and five poor clinical results with five major and 14 minor complications. Knee stiffness was the most common complication related to poor results in our series, and occurred particularly in patients with simultaneous correction of the ipsilateral tibial and femoral deformities. Therefore, two-stage surgery including bilateral tibial osteotomies first and then bilateral femoral osteotomies is recommended instead of simultaneous correction of the ipsilateral tibial and femoral deformities to avoid knee stiffness.