Percutaneous pinning after prolonged skeletal traction with the hip in a flexed position for unstable slipped capital femoral epiphysis

BACKGROUND Unstable slipped capital femoral epiphysis (SCFE) has a relatively high risk of avascular necrosis of the femoral head. Standard treatment for unstable SCFE is still controversial. We reviewed unstable SCFE case series treated with the standardized protocol, which consisted of percutaneous pinning after prolonged skeletal traction. METHODS Our treatment regimen for unstable SCFE patients included 1 week or more of skeletal traction with the hip in a flexed position of 45 degrees, and subsequent percutaneous pinning after unintentional reduction. Eleven patients were treated in our institution and an affiliated hospital between 2003 and 2013. Sex, age at surgery, body mass index, the presence of hormonal abnormality, duration between onset and surgery, head shaft angle, posterior tilting angle, and modified Harris hip score were investigated from the medical records and radiographs. RESULTS There were 8 male and 3 female with an average age of 11.7 years and an average body mass index of 24.5 kg/mm. No patients had hormonal abnormalities. The duration between onset and surgery ranged from 8 to 16 days. The average preoperative and postoperative head shaft angles were 126 and 141 degrees, respectively. Postoperative posterior tilting angle was averaged of 30.7 degrees, which decreased to 21.5 degrees during follow-up period. One patient showed mild avascular necrosis only confirmed by magnetic resonance imaging, but he was uneventfully treated without additional procedures. As a result, all patients had a perfect modified Harris hip score of 91 points. CONCLUSIONS Prolonged traction with the hip in a flexed position may not only provide gradual reduction of posteriorly displaced epiphysis but also decrease intra-articular pressure before surgery. Although percutaneous pinning after unintentional reduction leaves mild displacement of the femoral epiphysis, remodeling could be expected during remaining growth period.