Chiari Osteotomy in the Children: Mid-term Follow-Up Results

Introduction The Chiari osteotomy enlarges the acetabulum to increase coverage of the femoral head. It is performed as a salvage procedure on a noncongruent, yet in-place, hip. This study aims to assess the clinical and radiographic outcomes of Chiari pelvic osteotomy for treating hip dysplasia in children. Methods This is a case series conducted in the pediatric orthopedic trauma department of the Centre Hospitalier Universitaire Hassan II, Fez, Morocco, over a 10-year period from January 2011 to December 2020. The study included patients who were being treated for hip dysplasia and had undergone a Chiari osteotomy. Two types of assessments were used to evaluate global hip function: a clinical assessment using the Merle d'Aubigné and Postel score, and a radiological assessment involving measurements taken from frontal pelvic radiographs. Results A total of 12 Chiari osteotomies were performed in nine patients. The mean age at surgery was 10.8 ± 1.7 years and the mean follow-up was 4.6 ± 2.78 years. The clinical assessment score improved statistically during the last follow-up compared with the preoperative measurements for pain (p< 0.001), mobility (p = 0.002), walking (p<0.001), and total score (p< 0.001), for which 3.8 ± 1.9 points could be gained. Surgically, the osteotomy line height was 5.4 ± 2.6 mm, the osteotomy angle was 12.5 ± 2.2°, and the translated distance was 18.5 ± 3.2 mm. Regarding radiological evaluation, the comparison of angle measurements between preoperative and final recoil was statistically significant for both the vertical center edge (VCE) angle (p<0.001) with a mean gain of 16.33 ± 4.79° and the high transverse edge (HTE) angle (p = 0.002) with a mean loss of 12.67 ± 10.88°. Conclusion Chiari pelvic osteotomy is a complex procedure that requires very precise techniques. However, it results in remarkable relief for patients, providing an immediate impact on the Merle d'Aubigné and Postel score, particularly with regard to pain.