Purpose. Habitual hip subluxation and dislocation is a potentially disabling feature of Trisomy 21 and we describe long-term outcomes following the precise use of femoral varus derotation osteotomy. Methods. 16 consecutive hips, 9 children, with Trisomy 21 aged =10 years, were identified from hospital databases. Clinical notes and radiographs from presentation to final follow-up were reviewed. Results. Mean age at first known hip dislocation was 4.1 years (range 3, 7 years). All had a femoral varus derotation osteotomy (VDRO). In 2 hips, significant intraoperative instability persisted and a periacetabular osteotomy and capsulorraphy were required. Mean Femoral neck shaft angle (NSA) fell from 166.7° (+/-6.9°) to 106.0° (+/-5.4°). Mean follow-up was 5.9 years (+/-2.9). 1 hip (6.2%) developed painful arthritis. 14 hips developed peri-trochanteric varus deformities. 2 (12.5%) developed periprosthetic fractures 4 and 8 years post-operatively. Conclusion. Prevention of long term disabling pain from habitually dislocating or recurrently subluxed hips, in patients with Trisomy 21, requires surgical intervention to increase hip containment. In those aged =9 who have not developed hip incongruency, a VDRO with adequate varisation and minimal derotation was sufficient. Reducing the femoral NSA to approximately 100°, intraoperatively stabilised most hips. If instability persisted, a periacetabular osteotomy and capsulorraphy were performed. The 2 hips requiring additional procedures had the least corrected NSAs (115° and 122°) in our series. These patients were also older, aged 7 and 10, a factor that may have also contributed to the need for acetabular correction. We believe surgical management of habitually subluxed or dislocated Trisomy 21 hips allows for a predictable result. We recommend a varus producing proximal femoral osteotomy to correct the NSA to 100-110°. This should be performed before either the age of 8 years or teardrop development. In our experience this has been effective in maintaining hip stability

Percutaneous epiphysiodesis using transphyseal screws (PETS) has been developed for the treatment of lower limb discrepancies with the aim of replacing traditional open procedures. The goal of this study was to evaluate its efficacy and safety at skeletal maturity. A total of 45 consecutive patients with a mean skeletal age of 12.7 years (8.5 to 15) were included and followed until maturity. The mean efficacy of the femoral epiphysiodesis was 35% (14% to 87%) at six months and 66% (21% to 100%) at maturity. The mean efficacy of the tibial epiphysiodesis was 46% (18% to 73%) at six months and 66% (25% to 100%) at maturity. In both groups of patients the under-correction was significantly reduced between six months post-operatively and skeletal maturity. The overall rate of revision was 18% (eight patients), and seven of these revisions (87.5%) involved the tibia. This series showed that use of the PETS technique in the femur was safe, but that its use in the tibia was associated with a significant rate of complications, including a valgus deformity in nine patients (20%), leading us to abandon it in the tibia. The arrest of growth was delayed and the final loss of growth at maturity was only 66% of that predicted pre-operatively. This should be taken into account in the pre-operative planning.

The outcome of displaced hips treated by Somerville and Scott’s method was assessed after more than 25 years. A total of 147 patients (191 displaced hips) was reviewed which represented an overall follow-up of 65.6%. The median age at the index operation was two years. During the first five years, 25 (13%) hips showed signs of avascular change.

The late development of valgus angulation of the neck, after ten years, was seen in 69 (36%) hips. Further operations were frequently necessary. Moderate to severe osteoarthritis developed at a young age in 40% of the hips. Total hip replacement or arthrodesis was necessary in 27 (14%) hips at a mean age of 36.5 years. Risk factors identified were high dislocation, open reduction, and age at the original operation. Two groups of patients were compared according to outcome. All the radiographic indices were different between the two groups after ten years, but most were similar before. It takes a generation to establish the prognosis, although some early indicators may help to predict outcome.