The purpose of this study was to identify the rates of chondral injury, soft tissue impingement, and bony impingement in pediatric patients undergoing the modified Brostrom procedure with ankle arthroscopy for lateral ankle instability. A retrospective review of all patients undergoing a modified Brostrom procedure with ankle arthroscopy performed by two surgeons at a tertiary care children’s hospital between October 2002 and April 2014 was performed. Data were collected regarding demographics, history and initial presentation, nonoperative management, surgical procedure and arthroscopic findings, and clinical follow-up. All patients had symptoms of ankle instability and had failed nonoperative management before surgery. A total of 69 patients were reviewed (75 ankles), of whom 54 (78%) were female and six underwent bilateral surgery. The mean±SD age was 15.2±2.6 years, and the mean BMI was 23.6±5.0 kg/m2. All patients had preoperative radiography and MRI. Preoperative imaging within 1 year before surgery was available for review of 57 (76%) ankles, with 16 (28%) having open physes, 28 (49%) having closing physes, and 13 (23%) having closed physes. All patients reviewed underwent the Brostrom procedure with Gould modification and routine concurrent arthroscopy. During arthroscopy, anterior soft tissue impingement was noted in 49 (65%) ankles, synovitis in 40 (53%), chondral defect in eight (11%), loose body in three (4%), and none were found to have bony impingement. Soft tissue impingement (65%) is common in pediatric patients undergoing surgery for lateral ankle instability. Bony impingement (0%) and chondral injury (11%) are uncommon. This is in contrast to the adult population where bony impingement and chondral injury are more common. Level of Evidence: Level IV Case Series.