Outcomes of Initial Non-operative Management of Partial ACL Tears in Pediatric Patient

Partial anterior cruciate ligament (pACL) injuries are a challenging clinical problem without reliable diagnostic criteria and scant data on outcomes. The majority of prior studies defined a partial tear either arthroscopically or by exam under anesthesia, and focused on the surgical management. This study investigates the outcomes of partial anterior cruciate ligament tears identified with data available in clinic. We conducted a retrospective cohort study with follow up survey of pediatric patients between ages 8 and 18 years diagnosed with a partial anterior cruciate ligament tear in orthopedic and sports medicine clinics at an urban, level 1 pediatric trauma center between 1/1/2009 and 13/31/2019 to determine the prevalence of progression to anterior cruciate ligament insufficiency. Secondarily, we (1) determined the rate of meniscus tears that are associated with partial anterior cruciate ligament tears, (2) determined the mean time of progression to anterior cruciate ligament insufficiency, and (3) assessed risk factors associated with the progression to anterior cruciate ligament insufficiency. Demographic and clinic data was collected from the medical records. Three hundred and sixty-five patients with partial anterior cruciate ligament tears were identified. We had a response rate of 27% (n=99). Fifteen patients had immediate operative management. The remaining eighty-four, treated non-operatively at the onset, were analyzed. Of the whole cohort, 21 of 84 (25%) subjects progressed to anterior cruciate ligament insufficiency. After accounting for censored data, the imputed median survival time of partial anterior cruciate ligament tear was 11.4 months (IQR, 5.5-28.6 months) after returning to sports. No significant differences in sex, sports participation, body mass index, contusion pattern, associated injuries on MRI, physical therapy or bracing length between those that progressed to anterior cruciate ligament insufficiency and those that did not. A substantial proportion (25%) of partial anterior cruciate ligament tears progress to anterior cruciate ligament insufficiency. Progression does not appear to be independently associated with clinical and radiographic findings or management practices. Level III • Our findings suggest that partial ACL tears defined by clinic based data (history, exam, radiology) commonly progress to full ACL insufficiency, in particular in the first year. • A substantial proportion (25%) of partial anterior cruciate ligament tears progress to anterior cruciate ligament insufficiency. • Progression does not appear to be independently associated with demographics, reported clinical factors, exam findings, radiographic findings (bone contusion patterns, associated injuries) or management practices (time out of sports, bracing).