Bone Abstracts

Background: Children and adolescents with cerebral palsy (CP) experience musculoskeletal complications including spinal deformities, hip dysplasia and disuse osteoporosis. Bisphosphonates can improve bone mineral density, prevent fragility fractures. It is unclear if prior bisphosphonate use modifies post-operative complication in children with CP. Our aim was to compare surgical complications in children with CP with and without previous bisphosphonate treatment.

Methods: This retrospective observational cohort study reviewed all children presenting to Children’s Hospital at Westmead bone and mineral clinic and orthopaedic clinic between 2000 and 2016. Cases were defined as children with CP who had received at least one dose of bisphosphonates (Zoledronic acid) prior to surgical correction of their hip or spine deformity. Controls were matched to cases based on age at surgery, GMFCS classification and sex (where possible) by investigators blinded to post-surgical complications. Complications were divided into four categories: Fractures, hardware malfunction, infection and others. The primary outcome was the percentage of any post-surgical complications. Secondary outcomes included the length of hospital stay and duration of immobilization. Unpaired T-Tests and Chi-Square tests were used to compare outcomes between groups.

Results: Twenty-two individuals with CP met inclusion criteria of which 11 cases underwent spinal surgery and 11 had hip surgery. These were compared to 25 bisphosphonate naive controls. The mean age at the time of surgery was 12.7 years (S.D. 3.3). Any cause post-operative complications were similar in both groups (cases 59% vs. controls 36%; P=0.15). When considering only children who had undergone spine surgery, any cause complications were significantly higher in the bisphosphonate group (cases 66.7% vs controls 26.7%; P=0.02). The majority of these post-operative complications (47%) were categorized as fractures or hardware malfunction. Secondary outcomes were similar between groups (P > 0.05).

Conclusion: To our knowledge, this is the first study comparing orthopaedic surgical outcomes between children who had previously received bisphosphonates and those who were bisphosphonate naive. Post orthopaedic surgery complications were similar between groups, however, cases had more complications after spinal surgery than controls. Prospective studies with larger cohorts are needed to clarify the impact of bisphosphonates on orthopaedic post-operative outcomes.

Disclosure: The authors declared no competing interests.