Differences between bone age and chronological age in patients with open physes and anterior cruciate ligament injury using a Magnetic Resonance Imaging bone age assessment tool of the knee

Purpose: This study examines the efficacy of the Pennock Bone Age Atlas, which utilizes knee magnetic resonance imaging (MRI), in accurately assessing skeletal maturity in paediatric patients with anterior cruciate ligament (ACL) injuries. Specifically, it investigated the differences between chronological and bone ages in skeletally immature patients to inform clinical decision-making for ACL reconstruction. Methods: A total of 79 skeletally immature patients with ACL injuries, treated between February 2022 and June 2024, were included in this study. Bone age was assessed using the Pennock Atlas. The differences between chronological and bone ages were calculated, and the remaining growth potential was estimated. Statistical analyses were conducted to identify any significant discrepancies in growth expectations based on these measures. Results: On average, bone age closely matched chronological age. However, 25.3% of patients showed discrepancies greater than 1 year, particularly in the 12–14 age group. About 15% of patients who were expected to have no further growth according to chronological age had remaining growth potential when assessed by bone age, while 11% showed completed growth despite their chronological age suggesting otherwise. This discrepancy emphasizes the need to consider skeletal maturity rather than relying solely on chronological age in clinical decisions. Conclusion: In the setting of ACL injury in skeletally immature patients, the Pennock Bone Atlas was able to accurately detect differences between bone age and chronological age, identifying a mismatch of more than 1 year between the two ages in up to 25% of cases. This information can be used to guide surgeons in choosing different treatments optimized for the patient's growth potential. Level of Evidence: Level IV case series.