Treatment of Hip Instability in Children With Down Syndrome: Keys to Managing a Challenging Problem.

INTRODUCTION: Management of hip instability in children with Down syndrome is a challenging task to undertake for even the most experienced surgeons. As life expectancy of these patients increases, the importance of preserving functional mobility and hip joint stability in order to minimize late hip degeneration and pain has become a priority. The aim of this study is to evaluate the clinical and radiographic outcomes of children with Down syndrome and hip instability who underwent surgical reconstruction with femoral and/or acetabular procedures. METHODS: We performed a retrospective review of all children with Down syndrome age 18 years and younger, who underwent surgical intervention to address hip instability between 2003 and 2017. Data was recorded detailing the patient's demographics, preoperative and postoperative functional status and surgical details. Preoperative and postoperative radiographic analysis was performed as well as 3-dimensional computed tomography scan evaluation, when available. All major and minor complications were recorded and classified using the Severin radiographic classification and the Clavien-Dindo-Sink clinical classification. RESULTS: We studied 28 hips in 19 children that were followed for an average of 4.4 years postsurgical intervention for hip instability. The majority of patients improved in all radiographic parameters. A total of 14 hips (50%) had complications and 9 hips (32%) required a secondary surgery. Of those complications, 2 hips (7%) developed avascular necrosis and 4 hips (14%) developed recurrent instability after the index procedure. Two of these hips had a subsequent anteverting periacetabular osteotomy that produced a stable hip at final follow up. DISCUSSION: Surgical management of hip instability in children with Down syndrome remains challenging. The treating surgeon must have a thorough understanding of the pathoanatomy and design the surgical treatment to meet all of the underlying sources of instability. Combined femoral and acetabular osteotomies plus capsulorrhaphy are often required along with postoperative hip spica immobilization. Although complication and revision surgery rates are high, hip stability and good functional outcomes can be achieved.