Preliminary results of rigid fixation (locking plate/screw) after triple pelvic osteotomy without a hip spica cast: A modified fixation method in 21 patients

Abstract

Objectives: The aim of this study is to investigate whether rigid fixation after triple pelvic osteotomy (TPO) utilizing a 3.5-mm locking plate and screws without hip spica cast can provide enough stability and prevent correction loss in pediatric patients with developmental dysplasia of the hip (DDH) and Legg-Calvé-Perthes disease (LCPD).

Patients and methods: A total of 21 hips of 21 pediatric patients (9 males, 12 females; mean age: 9.3±2.0 years; range, 6 to 14 years) who underwent rigid fixation with locking plate/screws after TPO for DDH and LCPD between June 2015 and October 2018 were retrospectively analyzed. Preoperative, immediate postoperative, and six-month follow-up anteroposterior radiographs were compared for the Wiberg's center-edge angle (CE), Sharp angle, acetabular coverage of the femoral head (ACFH), and center-head distance discrepancy (CHDD). The patient demographics, surgery time, perioperative complications were evaluated.

Results: Underlying diagnosis were DDH in 14 patients and LCPD in seven patients. In patients with DDH, postoperative evaluation showed significant increase in the mean CE angle (5.6±16.1° vs. 30.5±9.3°, respectively) and ACFH (46.4±16.8% vs. 84.5±12.1%, respectively), and a significant decrease in the mean Sharp angle (55.3±6.2° vs. 35.6±7.8°, respectively) and CHDD (14.6±10.7% vs. 6.2±5.6%, respectively). The final follow-up revealed that there was no correction loss in these parameters. In the patients with LCPD, postoperative evaluation showed a significant increase in the mean CE (20.1±11.1° vs. 38.3±9.6°, respectively) and ACFH (62.9±18% vs. 91.4±10.1%, respectively), and a significant decrease in the mean Sharp angle (46±3.6° vs. 25.2±5.5°, respectively). The final follow-up revealed that there was no correction loss in radiological parameters. No perioperative complications were noted.

Conclusion: Our study results suggest that rigid fixation construct with a 3.5-mm locking plate and screws without hip spica cast can provide adequate stability to allow early mobilization following TPO in children without any loss of correction, until bony healing at the osteotomy sites.

Figure 1. Measurements of center edge angle (CE) and Sharp angle (Sharp), acetabular coverage of femoral head (ACFH: (X/X+Y) x 100), center-head distance discrepancy (CHDD: (b-a/a) x 100%).

Figure 2. Application of the locking plate. P: Proximal; D: Distal; White arrow: Iliac bone graft in the osteotomy site was also fixed with a screw.

Figure 3. (a-c) Preoperative, postoperative, and six-month follow-up radiographs of a nine-year-old female patient with acetabular dysplasia and coxa valga. She underwent proximal femoral osteotomy in addition to TPO. (d-f) Preoperative, postoperative, and six-month follow-up radiographs of a seven-year-old male patient with Legg-Calvé-Perthes disease.