In situ pinning or modified Dunn procedure? Which one is superior in slipped capital femoral epiphysis surgery? A case-control study including only stable/moderate cases

Purpose: The study aimed to compare the clinical and radiologic results of in situ pinning and modified Dunn procedure methods in stable-moderate slipped capital femoral epiphyses surgery. Methods: Slipped capital femoral epiphyses cases between January 2000 and December 2022 were retrospectively analyzed. Stable and moderate cases treated with in situ pinning or modified Dunn procedure and those with a follow-up period longer than 1 year were included. Two groups were formed: the in situ pinning group and the modified Dunn procedure group. Radiologically, postoperative alpha angle, Southwick angle, avascular necrosis, and osteoarthritis rates were compared. Clinically, Harris Hip Score and Merle d'Aubign & eacute; score were compared. Total complications were evaluated. Results: The in situ pinning group consisted of 28 patients and the modified Dunn procedure group consisted of 17 patients. The groups were similar in terms of age, gender, affected side, body mass index, Fahey/O'Brien Classification, preoperative slip angles, and follow-up time. Operation time was shorter in the in situ pinning group (p < 0.001). Postoperative Southwick and alpha angle were lower in the modified Dunn procedure group (p < 0.001). In clinical outcomes, Merle d'Aubign & eacute; and Harris Hip Score were higher in the in situ pinning group (p = 0.013, p = 0.005, respectively). The rate of avascular necrosis was higher in the modified Dunn procedure group (p = 0.048). There was no difference between the groups in terms of total complications and osteoarthritis. Conclusions: In situ pinning has an advantage over the modified Dunn procedure in the treatment of stable-moderate slipped capital femoral epiphyses due to shorter operative time, better clinical outcomes, and fewer avascular necrosis rates. Although Southwick and alpha angle measurements were found to be higher after in situ pinning compared to the modified Dunn procedure, this does not constitute a significant disadvantage in terms of osteoarthritis development in the mid-term.