Poster 246: Epidemiology of Tibial Spine Fractures in Children: A National Multicenter Study

OBJECTIVES: Tibial spine fractures (TSFs) are avulsion fractures at the insertion of the anterior cruciate ligament at the tibial intercondylar eminence. TSFs are rare injuries thought to occur most frequently in skeletally immature children aged 8 to 14 years. Historically, it was thought that the most common mechanism was falling off of bicycles, but recent research suggests a variety of additional mechanisms. Treatment for TSFs can be operative or nonoperative depending on fracture type/severity, concomitant injuries, and surgeon and patient/family preference. Estimates of the epidemiology of this patient population are limited to primarily single-center reports. The objective of this investigation was to characterize epidemiology, including demographic information, injury mechanism, fracture type, and selection of surgical or nonsurgical treatment, in this injury population across eight geographically distinct institutions using retrospective data. METHODS: IRB and reliance approval was obtained for each participating hospital. Patients younger than 25 years treated for TSFs between January 1, 2000 and January 31, 2019 were included. Patients with multiple lower extremity fractures or other traumatic injuries were excluded. Data was collected regarding demographics, mechanisms of injury, imaging reports, treatment, and concomitant injuries. Data were presented as medians and interquartile ranges. Categorical data was presented as counts and percentages and was stratified by sex and/or Meyers and McKeever fracture type. RESULTS: 661 patients met inclusion criteria. Median age at presentation was 12.2 years (IQR 9.7-14.1), with a higher prevalence in boys than girls (66.1%, 437/661). Diagnosis at a study center occurred at a median of 4.0 days (IQR 1.0-9.0 days) after injury. Of these patients, 71.6% (432/603) had first been seen elsewhere, most commonly by emergency department physicians (40.7%, 176/432). The most commonly reported injury mechanisms were contact (44.4%, 244/549) and twisting, non-contact (42.8%, 235/549), with hyperextension injuries representing a much smaller proportion at 3.6%. Injuries occurred most frequently during sports at 56.8% (355/625), which were primarily skiing (127/352, 36.1%) and football (97/352, 27.6%). Distal femur and proximal tibia growth plate status were classified as open in 67.1% and 72.6% of cases, respectively. Both growth plates were classified as closed in only 5.8% of cases. Meyers and McKeever fracture type was most commonly Type II (40.4%) or Type III (44.4%). Treatment was surgical in 83.3% (549/659) of cases, and of these, most were treated arthroscopically (ARIF) (470/549, 86.1%). CONCLUSIONS: This study represents, to our knowledge, the largest epidemiological report to date of pediatric patients with tibial spine fractures. TSFs were more common in males than females (66.1% male), and the median age at injury was 12.2 years, which falls within the commonly reported range of 8-14 years. Furthermore, only 5.8% of patients had closed regional physes, corroborating the theory that TSFs are more likely to occur in skeletally immature individuals. We believe the data presented in this study can be useful towards patient counselling by providing a comprehensive view of the common presentations of and treatment pathways for tibial spine fractures in the pediatric population.