BACKGROUND: Displaced tibial spine fractures are frequently treated with surgical reduction and fixation, but no comparison studies have been performed. This study was undertaken to compare fragment reduction and adverse outcomes between open arthrotomy [open reduction and internal fixation (ORIF)], arthroscopy [arthroscopic-assisted internal fixation (AAIF)], and closed management [closed management and casting (CMC)] of pediatric tibial spine fractures. METHODS: A retrospective review of children treated for displaced tibial spine fractures from 2003 to 2011 was performed after categorizing into the 3 treatment groups. Demographics, mechanism of injury, radiographic measures (plain film and computed tomography), treatment, duration of immobilization and follow-up, final range of motion, and complications were recorded. Families were contacted to obtain long-term Lysholm scores, return to activity, pain, and satisfaction with treatment. RESULTS: Seventy-six children (mean age, 12.4 y) met criteria with 29 ORIF, 28 AAIF, and 19 CMC. Radiographic measurements between x-ray and computed tomography scans found a mean error of 1 mm (SD=1.33 mm; inter-class coefficient = 0.977, P < 0.001). Initial fracture displacement was similar between AAIF and ORIF, 10.3 ± 4.4 mm and 10.8 ± 3.9 mm; but, less in CMC group (5.3 ± 2.6 mm). The mean reduction amount was 8.6 ± 4.7, 9.1 ± 4.0, and 2.3 ± 2.6 mm, respectively. A Bonferroni post hoc analysis revealed a difference between surgical and nonoperative reduction (P < 0.001), but not between AAIF and ORIF (P=0.9). Arthrofibrosis occurred with equal frequency in surgical cohorts (AAIF 12.5%, ORIF 11.1%), compared with none in the CMC group. Yet, the CMC group had a 16.7% risk for reoperation secondary to instability, loose bodies, or impingement. Twenty-four percent of each cohort was available (at mean 6.0 y) for interview with mean (median) Lysholm score: ORIF 97.4 (99), AAIF 95 (100), and CMC 86 (97.5), P = 0.35. CONCLUSIONS: Open or arthroscopic treatment of displaced tibial spine fractures affords a better reduction than closed management, but with higher risk for arthrofibrosis. Closed management may be successful when displacement is < 5 mm, and advanced imaging may not be necessary to delineate the amount of displacement.