Classifiers of anterior cruciate ligament status in female and male adolescents using return-to-activity criteria.

Purpose: A lack of standardization exists for functional tasks in return-to-activity (RTA) guidelines for adolescents with anterior cruciate ligament injury (ACLi). Identifying the variables that discern ACLi status among adolescents is a first step in the creation of such guidelines following surgical reconstruction. This study investigated the use of classification models to discern ACLi status of adolescents with and without injury using spatiotemporal variables from functional tasks typically used in RTA guidelines for adults.

Methods: Sixty-four adolescents with ACLi and 70 uninjured adolescents completed single-limb hops, lunges, squats, countermovement jumps and drop-vertical jumps. Jumping distances, heights, and depths were collected. Decision trees (DTs) were used to classify ACLi status and were evaluated using the F-measure (F₁), kappa statistic (ĸ) and area under the precision-recall curve (PRC). Independent t tests and effect sizes were calculated for each important classifier of the DT models.

Results: A five-variable model classified ACLi status with an accuracy of 67.5% (F₁ = 0.6842; ĸ = 0.350; PRC = 0.491) with sex as a classifier. Significant differences were found in three of the four spatiotemporal variables (p ≤ 0.002). Separate models then classified ACLi status in males and females with an accuracy of 53.3% (F₁ = 0.5882; ĸ = 0.0541; PRC = 0.476) and 76.9% (F₁ = 0.7692; ĸ = 0.541; PRC = 0.528), respectively, with significant differences for all variables (p ≤ 0.013).

Conclusions: Among the DT models, females were better able to classify ACLi status compared to males, highlighting the importance of sex-specific rehabilitation guidelines for adolescents.

Level of evidence: Level III.