Incidence of Femur Fracture Post Hardware Removal in Children With Cerebral Palsy Who Have Undergone Varus Derotational Osteotomy

Background: Children with cerebral palsy (CP) often undergo hip reconstruction through proximal femoral varus derotation osteotomy (VDRO), with orthopaedic implants used for fixation. Posthealing, hardware may be retained or removed, either reactively due to complications or prophylactically. The controversy surrounding implant removal persists. This study aimed to compare the rate of proximal femoral fractures in children with CP who retained their hardware versus those who had it removed after VDRO. A secondary aim was to identify fracture risk factors after VDRO and report complications related to hardware removal. Methods: This retrospective study included 334 children who met inclusion (VDRO procedure) and exclusion (<2 y postoperative follow-up) criteria; 122 were eligible for the hardware removal group. Patients were followed from the initial VDRO to 2 years, hardware removal, or fracture. After removal, follow-up continued for a minimum of 2 years or until fracture. Frequency distribution summarized categorical variables, while mean and range were used for continuous variables. Median and interquartile range (IQR) was utilized for non-normally distributed data. χ2 testing determined fracture risk factors post-hardware removal, with a significance level set at P-value <0.05. Results: Of 334 patients, 11 (3%) experienced a peri-implant fracture after VDRO; 8 (2%) occurred within 2 years. The median time to fracture was 1.3 years (IQR, 3.2; range, 0.0 to 12.4). In the hardware removal group, 10 (5%) of 212 patients fractured postremoval, all within 2 years. The mean time from removal to fracture was 0.48±0.65 years (range, 0.02 to 1.94). Significant risk factors included prior VDRO revision surgery (P=0.029) and hardware removal within 1 year post-VDRO (P=0.007). Conclusion: No significant difference in fracture rates was found between the 2 groups. However, patients with prior revision surgery or hardware removed within 1 year post-VDRO faced increased fracture risks. This study provides evidence to proceed with caution when removing hardware if a patient has had prior revision surgery and to wait at least 1 year after VDRO to remove proximal femoral implants.