Abstract
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.
