Is capsulorrhaphy a necessary step during open reduction of developmental dysplasia of the hip? A randomized controlled trial.

ABSTRACT

PURPOSE: To investigate the necessity of performing capsulorrhaphy during open reduction of DDH. METHODS: A single-centre, prospective, randomized controlled trial was conducted between 2015 and 2020. The study included 82 hips in 67 patients with developmental dysplasia of the hip (DDH) who were treated with open reduction via the anterior approach. Patients were randomized into two equal groups (41 hips in each group); group A (capsulorrhaphy was done) and group B (capsulorrhaphy was not done). Dega osteotomy was performed in all cases, while femoral derotation shortening osteotomy was performed only in four hips in group A and four hips in group B. The mean age at the time of surgery was 33 ± 22.3 months. The follow-up period was 24 months for all patients. At the final follow-up, maintenance of reduction was chosen as the primary outcome and was assessed radiologically by the Severin's grading system. Secondary outcome measures were functional evaluation (by using the modified McKay's criteria), Shenton line assessment, acetabular index measurement, and complications. RESULTS: According to the Severin's grading system, concentric reduction was achieved in 36 hips in group A and 37 hips in group B, subluxation occurred in three hips in each group, and redislocation was encountered in two hips in group A and one hip in group B. There was no statistically significant difference between both groups (p-value = 0.239). According to the modified McKay's criteria, the results were satisfactory (excellent and good) in 34 hips (82.9%) in group A and 36 hips (87.8%) in group B. The difference was statistically insignificant (p-value = 0.352). The rate of complications was higher in group A (17.1%) than group B (12.2%) (p-value = 0.532). CONCLUSION: The stability of the hip joint after open reduction depends mainly on adequate removal of soft tissue obstacles that impede reduction and proper correction of the bony configuration of the hip using pelvic and/or femoral osteotomy. So, the authors believe that capsulorrhaphy is not necessary in the surgical management of DDH, provided that adequate soft tissue and bony gestures are combined.