Purpose. This report compares midterm results of open neck osteoplasty + neck osteotomy vs arthroscopic osteoplasty for severe Slipped Capital Femoral Epiphysis (SCFE). Method. Database from 2006 to 2013 identified 22 patients out of 187 operations for SCFE. 12 underwent Open Neck Osteotomy (ONO) and osteoplasty by Ganz surgical dislocation approach. 10 underwent Arthroscopic Osteoplasty (AO). The mean follow-up for the ONO and AO groups were 59 (46 – 70), 36.1 (33 – 46) months respectively. Results. The unpaired t-test showed that the post-operative corrections were significantly better in the ONO than the AO group. Slip angle (16.7° (1°–28.6°) Vs 47.1° (40.2° – 53.5°) p = .0003), head neck offset correction (5mm (2–13mm) Vs 0mm (0mm – 2mm) p = 0.0003), alpha angle (34.6° (23.2°–45.6°) Vs 61.88° (52.1° – 123°) p= 0.0003), Modified Harris Hip Score (MHHS) (90(86.2–99) Vs 75.5 (58.75 – 96.8) p= 0.003) and internal rotation p= 0.0002. Paired t-test showed significant improvement in corrections within the individual groups compared with their own preoperative values. The results of AO group were oblique plane slip angle (55° (47.7° – 63.2°) Vs 47.1° (40.2° – 53.5°) p= 0.001), alpha angle (90.7° (65° – 131°) Vs 61.88° (52.1° – 123°) p= 0.0001), head neck offset (0mm (−3 mm to 0mm) Vs 0mm (0mm – 2mm) p= 0.001) and MHHS (52.7 (28.7 – 89.1) Vs 75.5 (58.75 – 96.8) p= 0.0005). Complications in ONO group were varus malunion (1) and non-union(1) of the osteotomy. In the arthroscopic group persistent impingement in 3 patients and 5 were not able to return to sports. Conclusion. Our results showed improved hip function following arthroscopic osteoplasty in severe SCFE. Considering the risks of an open surgical dislocation we could find that arthroscopy contributed worthy improvement in hip function in low demand patients