If ACL injury is multifactorial, why is return-to-sport testing not? A determinant-alignment framework for ACL rehabilitation and return to sport.

Anterior cruciate ligament (ACL) injury is multifactorial. Return-to-sport (RTS) practice after ACL reconstruction has also become increasingly multidimensional, but its dimensions are not weighted equally: physical capacity is assessed more routinely and objectively than perceptual, neurocognitive, contextual, and representative sport demands. Strength testing, hop performance, movement assessment, and patient-reported outcomes remain essential, but they sample only part of the system in which athletes are re-exposed to sport. This Masterclass proposes a determinant-alignment framework for late-stage rehabilitation and RTS assessment. Here, testing refers to discrete measures of capacity or performance, whereas assessment refers to the broader integration of tests, movement behavior, psychological readiness, exposure progression, and sport context. The framework is a hypothesis-generating clinical heuristic rather than a validated taxonomy, prediction algorithm, or evidence that broader assessment reduces second ACL injury. Its purpose is to identify potential assessment gaps and to progress from foundational capacity toward load management, perception-action integration, and representative sport re-exposure. The objective is alignment, not prediction.