RISK FACTORS FOR ARTHROFIBROSIS IN TIBIAL SPINE FRACTURES: A NATIONAL 10-SITE MULTICENTER STUDY

BACKGROUND: Tibial spine fractures are common pediatric injuries with similar mechanism of injury to anterior cruciate ligament tears. Post-operative arthrofibrosis remains the most common complication following treatment of this injury, and many patients require subsequent manipulation under anesthesia. Several prior studies have examined risk factors for the development of arthrofibrosis, but with small patient populations and varying reported predictors. Therefore, our objective was to identify risk factors for arthrofibrosis in the largest known cohort of pediatric tibial spine patients. HYPOTHESIS/PURPOSE: Identify risk factors for developing arthrofibrosis after TSF treatment. METHODS: This was a retrospective, multi-center study across ten institutions of 448 patients <25 years old who presented to care with a tibial spine fracture between 1/2000 and 2/2019. Patient records were reviewed for a multitude of pre-operative, intra-operative, and post-operative characteristics. Patients were then separated into two cohorts based on if they suffered from post-treatment arthrofibrosis. RESULTS: Chart review demonstrated that 43 (9.6%) of the patients suffered from post-treatment arthrofibrosis. There were no demographic differences observed between the two groups. However, based on MRIs at the time of injury, distal femoral and proximal tibial growth plates were more frequently closed in the arthrofibrosis group (17.6% vs 4.4%, p=0.023 for both comparisons). Additionally, there was no difference in Meyers & McKeever (MM) classification (p=0.597). All arthrofibrosis patients received operative treatment (p=0.003), though there was no difference in fixation technique (p=0.734). Intraoperatively, a higher number of screws were used in the arthrofibrosis group (p=0.002) with the placement of hardware more likely to be epiphyseal (p=0.007). Other operative parameters including number of sutures were not different. Post-operatively, arthrofibrosis patients were more likely to have been immobilized in a cast (p<0.001) with no difference observed for weight-bearing status. After multivariate regression, screw number (OR 8.9, CI 1.9-41.7, p=0.005) and immobilization in a cast (OR 7.8, CI 1.0-60.4, p=0.049) remained significant predictors of post-treatment arthrofibrosis. CONCLUSION: This serves as the largest study of tibial spine fractures to analyze risk factors for the development of post-treatment arthrofibrosis. Our study demonstrates that pre-operative factors were largely similar between groups, but that intra-operative decisions, including the number of screws used for fixation and placement of hardware in relation to the physis, were significant predictors of post-treatment arthrofibrosis. These findings may influence operative decision-making in tibial spine fracture patients. Additionally, post-operative immobilization in a cast should be avoided given the high risk of arthrofibrosis.