Slipped capital femoral epiphysis (SCFE) is traditionally treated with in situ fixation using a threaded screw, leading to physeal arrest while stabilizing the femoral head. Recently, there has been interest in alternative methods of fixation for SCFE, aiming to allow growth and remodelling of the femoral neck postoperatively. One such option is the Free Gliding SCFE Screw (Pega Medical), which employs a telescopic design intended to avoid physeal compression. The objective of this study is to evaluate radiographic changes of the proximal femur following in situ fixation using the Free Gliding SCFE Screw.

This study retrospectively evaluated 28 hips in 14 consecutive patients who underwent in situ hip fixation using the Free Gliding SCFE Screw between 2014 and 2018. Initial postoperative radiographs were compared to last available follow-up imaging. Radiographic assessment included screw length, articulotrochanteric distance (ATD), posterior sloping angle (PSA), alpha angle, head-neck offset (HNO) and head-shaft angle (HSA).

Of the 28 hips reviewed, 17 were treated for SCFE and an additional 11 treated prophylactically. Average age at surgery was 11.7 years, with an average follow-up of 1.44 years. Screw length increased by 2.3 mm (p < 0.001). ATD decreased from 25.4 to 22.2 mm (p < 0.001). Alpha angle decreased from 68.7 to 59.8 degrees (p = 0.004). There was a trend towards an increase in HNO (p = 0.07). There was no significant change in PSA or HAS. There were three complications (two patients with retained broken guide wires, and one patient requiring screw removal for hip pain).

With use of the Free Gliding SCFE Screw, there was evidence of screw expansion and femoral neck remodelling with short-term follow-up. More research is required to determine the long-term impact of these changes on hip function, and to aid in patient selection for this technology.