The modified Dunn procedure provides superior short-term outcomes in the treatment of the unstable slipped capital femoral epiphysis as compared to the inadvertent closed reduction and percutaneous pinning: a comparative clinical study

Purpose: The aim of this study was to compare clinical outcomes and radiographic correction after modified Dunn procedure versus inadvertent closed reduction and percutaneous pinning for the treatment of unstable slipped capital femoral epiphysis (SCFE). Methods: We evaluated 45 patients with unstable SCFE treated using the modified Dunn procedure (n = 27) or percutaneous pinning (n = 18) during a minimum follow-up of one year. Clinical outcomes were assessed using the Heyman and Herndon scores. The Southwick angle, alpha angle, and femoral head-neck offset were used to assess radiographic correction. The occurrence of complications and unplanned re-operations were recorded. Results: At latest follow-up, 67% (18/27) in the modified Dunn procedure group and 28% (5/18) in the in situ pinning group had good or excellent Heyman and Herndon outcomes (p = 0.016). The morphology of the femoral head and neck was improved in the modified Dunn procedure group compared to percutaneous pinning (Southwick angle, alpha angles; femoral head-neck offset; p < 0.001). The proportion of osteonecrosis (26 vs. 28%; p > 0.999) and unplanned re-operations (26 vs. 33%; p = 0.894) was similar in both groups. Conclusion: Compared to inadvertent reduction and percutaneous pinning, the modified Dunn procedure provided better clinical and radiographic outcomes with similar proportion of osteonecrosis and unplanned re-operations following an unstable SCFE.