Incidence of Avascular Necrosis of the Femoral Head Post Hip Reduction Surgery in Children With Cerebral Palsy

Abstract

Avascular necrosis (AVN) of the femoral head confers a risk of morbidity amongst cerebral palsy (CP) patients. Meanwhile, the proportion who develop AVN post hip reduction surgery is unclear, and the risk factors are not established. To estimate the incidence and risk factors for AVN post hip reduction surgery in CP patients, we reviewed and analysed literature from Medline, Embase, and Web of Science repositories between January 1, 1990, and August 31, 2024. The included publications were reviewed for the incidence and risk factors in this cohort of patients. Findings were appraised using the methodological index for non-randomised studies, and scores and results were descriptively analysed. Given the marked heterogeneity of retrieved data, results were reported as standardised values, including the mean weighted incidence rate. A total of 1619 hip reduction surgeries were performed on 1045 CP patients across 12 retrospective studies with 424 cases of AVN. The mean age at surgery ranged from 7.3 to 16.2 across studies. The mean incidence was 0.482% ± 0.06945 per person-year. Most patients were in gross motor function classification system V, with a preoperative mean Reimers index of 54.11-80%. The average methodological items for non-randomised studies score was 10.08/16 ± 0.28 for all studies (n=12). AVN has a definite relationship with hip reduction surgery. The low methodological quality of reviewed studies informs the need for well-designed prospective randomised controlled studies to understand the mechanics of this relationship in terms of age of surgery and Reimers hip migration index, guide surgical timing, and patient selection.