Purpose of the study is to investigate the outcome of the patients with Perthes disease who have had a surgical dislocation of their hip for the treatment of resultant symptoms from the disease process.

Retrospective review of consecutive patients treated with surgical dislocation of the hip for Perthes disease. Review of clinical case notes and radiological imaging. Patient outcome was assessed at follow-up.

Between 2010 and 2015, 31 cases of surgical hip dislocation were performed for Perthes disease at our institution by 2 senior surgeons. Age range at time of surgery was 12–33. Male:female ratio was 13:18; right:left ratio was 15:17. Age at the time of Perthes diagnosis was between 3 and 13 years, with 3 diagnosed retrospectively. Mean follow-up was 18months. All patients had an EUA and arthrogram while 61.3%(19/31) had previous surgery for Perthes. 71%(22/31) required a labral repair, 6.5%(2/31) had a peri-acetabular osteotomy at the time of surgery and 3.2%(1/31) required a proximal femoral valgus osteotomy. 22.5%(7/31) required microfracture (femoral head or acetabulum): all of whom had evidence of contained area of degenerative changes on preoperative MRI. 64.5%(20/31) had the trochanteric screws removed.

Complications included 1 greater trochanter non-union, 1 pain secondary to suture anchor impinging on psoas tendon, 1 AVN leading to early THR 12 months post-op. Another 2 had further deterioration of degenerative changes and pain leading to THR 18 and 24 months post-op. All 3(9.7%) had microfracture at the time of the dislocation for established degenerative change and also required custom made prostheses.

Surgical hip dislocation is an option in treating Perthes patient with resultant symptoms such as impingement. Improved outcome is seen in patients who are younger with a congruent hip joint in contrast to those with established degenerative change evident on MRI / intraoperatively and have an arrow shaped femoral head.