Incidence Of Delayed Anterior Cruciate Ligament Reconstruction in Skeletally Immature Patients With Previous Anterior Tibial Spine Fractures

Objectives: Pediatric avulsion fractures of the anterior tibial spine are injuries similar to anterior cruciate ligament injuries in adults. Sparse data exists on the association between anterior tibial spine fractures (ATSFs) and later ligamentous laxity and need for anterior cruciate ligament (ACL) reconstruction. Understanding that there is a component of stretch injury to the ACL during initial ATSF, and that there is limited ability for the ACL to undergo remodeling of mid substance fibers, it would stand to reason that this injury could cause weakness in the ACL and lead to delayed instability or injury. This research presents a retrospective review of clinical records, operative reports, and patient reporting to characterize the incidence of delayed ACL reconstruction in cases of ATSFs in children. The purpose of this study was to better delineate the incidence of delayed instability or ACL rupture requiring further surgery in the form of ACL reconstruction. Methods: We identified 44 patients who sustained an ATSF and met inclusion criteria for this study between 1996 and 2011. The subjects were aged between 5 and 18 at the time of injury and were separated by the Myers and McKeever classification into type I, II, and III fractures. All patients had at least two-year follow-up after initially injury by clinical examination and/or via telephone. Patients were asked if any further surgical intervention was performed on their injured knee, and if so, operative reports were reviewed thereafter. Results: Eleven percent of children with an ATSF sustained a delayed ACL rupture requiring ACL reconstruction. No delayed ACL reconstruction with type I fractures (0/6) was found. Fourteen percent of type II injuries (4/21) reported delayed ACL reconstruction after a second injury. Six percent (1/17) type III fractures went onto later reconstruction. Conclusion: This data suggests that a small subset of patients with previous ATSF may be at risk for delayed ACL rupture. At this time, it is unclear as to whether these delayed ACL ruptures are related to initial injury or caused only by a secondary event that would have otherwise caused ACL rupture. Further patient follow-up and prospective studies are required. Although ATSF is a rare injury, our cohort of patients suggests that a subset of patients with type II and III fractures will require later ACL reconstruction. There is a need to council patients that delayed ACL rupture is a potential risk after an ATSF.