Revision of Outcomes and Complications Following Open Reduction, and Zigzag Osteotomy Combined with Fibular Allograft for Developmental Dysplasia of the Hip in Children

Abstract

Background: Reports of the efficacy of open reduction and Zigzag Osteotomy combined Fibular Allograft (ZOFA) for developmental dysplasia of the hip. The purposes of this study were to evaluate the long-term outcomes and complications after surgery. Methods: We performed a retrospective match-controlled study in which 158 patients had 181 hips with developmental dysplasia of the hip. Radiographs were found of acetabular index, height of dislocation, Tönnis grade, abduction angle in the spica cast, and Severin grade. At final follow-up, deformity of femoral head or neck or acetabulum was evaluated according to the Severin. Avascular necrosis was rated according to Kalamchi. Clinical evaluation was made according to modified McKay criteria. Results: Between 2009 and 2012, 133 girls (84.2%) and 25 boys (15.8%) with developmental dysplasia of the hip underwent open reduction and ZOFA; 135 (85.4%) were unilateral, and 23 (14.6%) were bilateral. Patients were divided into 2 groups: group 1 included 54 patients (62 hips) aged 12 months - ≤18 months and group 2 included 84 patients (119 hips), aged >18 months - ≤36 months. According to Tönnis system: type 3 appeared in 127 hips (70.2%), and Type 4 in 54 hip (29.8%). The anterior approach was used to expose inner table of the ilium and ZOFA in all cases. Acetabular index was improved; preoperation was 42.95°, and latest follow-up 17.26°. The Kirschner Wires (KW) were not used to fix the fibular allograft at the pelvic osteotomy site. All of the fibular allografts were completely incorporated in mean time of 14 weeks (range, 12 weeks - 17 weeks) post-surgery. Clinical evaluation according to modified McKay criteria: satisfactory result (excellent and good) was achieved in 141 hips (77.9%). Avascular Necrosis (AVN) happened in 61 hips (33.7%), redislocation in 18 hips (9.9%), coxa vara in 4 hips (2.2%), trendelenburg gait in 4 hips (2.2%), and supracondylar femoral fractures in 2 hips (1.1%). Conclusions: On the basis of this study, ZOFA was strength and graft was not resorption, graft problems; without medial displacement of the distal fragment. Acetabular index was improved, without KW problem. Surgical technique with ZOFA did not expose outer table of the illium, limiting abductor muscle injury with negative trendelenburg gait; on the other hand, the blood loss from this procedure is acceptable. Some complications have been seen in this study: AVN, redislocation, coxa magna, coxa vara, trendelenburg gait, and distal femoral fracture.