Avascular necrosis of the femoral head in patients with cerebral palsy after hip surgery-incidence and impact on quality of life

Purpose This study investigated the incidence of AVN in patients with cerebral palsy who underwent a hip reconstruction surgery (soft tissue release, femur and pelvic osteotomies) and its impact on quality of life. Methods Retrospective study, with clinical and radiographic analysis of 104 patients (128 hips) GMFCS IV and V with a minimum two year follow-up. Reimers migration percentage, the amount of abduction, acetabular index, and the neck-shaft angle were collected before and after surgery. Modified Tonnis classification was used to analyze the hips before surgery, and the Bucholz and Ogden classification was used to identify hips with AVN. Function and quality of life were investigated with the CPCHILD questionnaire after surgery. Results The mean age of participants at surgery was 120.1 months (72-184), and it was not related with AVN (p = 0.946). AVN signs were observed in 62 hips (48.5%). The mean pre-op Reimers value was 68.7% (16-100) in normal hips and 83.1% (0-100) in hips with AVN (p = 0.003). All hips considered as Tonnis IV before surgery developed AVN (p = 0.006). The amount of abduction did not differ between hips that developed AVN and those that did not (p = 0.313). Patients who developed AVN had lower scores of quality of life (p = 0.023) and comfort (p = 0.025) according to the CPCHILD questionnaire. Conclusion We observed a relationship between the greater pre-operative severity according to the Reimers index and the modified Tonnis classification and the development of AVN.