['Osteonecrosis of the femoral head (ONFH) is a common and severe complication following femoral neck fractures in young adults. Despite significant advances in surgical techniques, radiological evaluation and comprehensive treatment for the prevention of ONFH, the incidence of traumatic ONFH has remained unchanged at approximately 20% in recent decades. The injury-to-surgery interval is considered as a principal factor affecting the occurrence of ONFH, and traditionally, femoral neck fractures are treated emergently. However, the relationship between the injury-to-surgery interval and ONFH occurrence is poorly understood, and previous reviews have not provided a precise explanation due to the lack of strict selection criteria for studies.', 'We reviewed previously published articles and included in current systematic review those studies with accurate multivariate analyses that included age, fracture type, operation method, follow-up, ONFH occurrence and injury-to-surgery interval.', 'Six case studies were included and reevaluated. The studies included 263 hips for final analysis, with an overall incidence of postfracture ONFH of 17.5%. Patients were categorized into groups of less/more than 8\xa0h, less/more than 24\xa0h, less/more than 48\xa0h and less/more than 3\xa0weeks based on the individual injury-to-surgery interval. The postfracture ONFH incidence ranged from 13.3% (<8\xa0weeks) to 21.7% (>3\xa0weeks). Operations performed within 3\xa0weeks of injury resulted in a lower ONFH incidence compared with operations performed after 3\xa0weeks; however, this difference was not statistically significant. The ONFH incidence remained relatively stable when the operations were performed within 3\xa0weeks of injury.'] Does injury-to-surgery interval affect postfracture osteonecrosis of the femoral head in young adults : a systematic review?