Continued growth of the hip after fixation of slipped capital femoral epiphysis using a single cannulated screw with a proximal threading.

Background: The most commonly used method for unstable slipped capital femoral epiphysis (SCFE) remains in situ fixation. Depending on the surgeon's preference, screws or Kirschner wires are used for stabilizing the slipped upper femoral epiphysis. The purpose of this study was to evaluate the ability of a single cannulated screw with a proximal threading to ensure stabilization, growth, and remodeling of the slipped epiphysis.

Methods: A retrospective study was performed identifying 23 children treated for unstable SCFE under 50° by means of a single cannulated screw with proximal threading. All patients attended a radiological evaluation immediately after surgery and at physeal closure. The width of the epiphysis cut by the Klein line, the width and length of the femoral neck, the centrocalcar distance (CCD) angle, and the articulotrochanteric distance (ATD) were evaluated.

Results: All patients had a stabilized epiphysis at the last follow-up, with no case of recurring slip. Radiological comparison of the affected side between the preoperative and the last follow-up evaluation showed a statistically significant improvement in the neck length and width.

Conclusion: Fixation of the epiphysis using proximally threaded screws allows the preservation of femoral neck growth. The cannulated screw with proximal threading seems to be a safe and relevant implant to help to restore a close-to-normal hip at skeletal maturity.