Purpose <p>There is growing evidence that after moderate and severe slipped capital femoral epiphysis (SCFE), in-situ fixation can result in femoroacetabular impingement (FAI). Several different realignment procedures have been described but their use remains controversial due to high complication rates and technical complexity. Our study aims to evaluate the radiological outcomes and complications of patients who underwent open reduction with subcapital shortening osteotomy for moderate or severe SCFE.</p> Methods <p>Radiographic and clinical data of patients with SCFE treated with subcapital shortening osteotomy performed by a single surgeon between October 2018 and July 2023 were retrospectively analysed. We collected patient demographics, pre- and post-operative radiographic measurements (Southwick slip angle, alpha angle and articulo-trochanteric distance (ADT), and post-operative complications. Patient outcomes were assessed using descriptive statistics.</p> Results <p>Eighteen children and adolescents were reviewed, four were excluded due to inadequate follow-up. At the last follow-up, the lateral Southwick slip angle was corrected to a mean of 11 ° (1–31°). The mean alpha angle, measured at the final follow-up, was 59 ° (42–88°). One patient showed signs of radiological coxa breva. There were two patients with severe radiological cam deformities and one case of avascular necrosis (AVN).</p> Conclusion <p>Our findings suggest that the subcapital shortening osteotomy is an effective method for restoring head-neck anatomy in patients with moderate to severe SCFE, with good radiological outcomes. Our low incidence of avascular necrosis further supports the safety of this procedure.</p>