Rehabilitation after Anterior Cruciate Ligament (ACL) Reconstruction: A Review of Criterion-Based vs Time-Based Progression

Anterior Cruciate Ligament (ACL) injuries are common among athletes and active individuals, often requiring surgical reconstruction followed by structured rehabilitation. Traditionally, rehabilitation protocols have followed a time-based progression, advancing patients through recovery phases based on predetermined weeks post-surgery. However, emerging evidence supports the use of criterion-based rehabilitation, which emphasizes individualized progression based on specific functional and clinical milestones. This review explores and compares the two approaches, highlighting the strengths and limitations of each. Time-based models offer structure and simplicity but may overlook variations in patient healing and readiness, increasing the risk of reinjury. In contrast, criterion-based protocols focus on objective measures such as strength symmetry, neuromuscular control, range of motion, and psychological readiness to guide rehabilitation. Studies suggest that this individualized approach leads to better functional outcomes, lower reinjury rates, and safer return-to-sport decisions. Despite implementation challenges such as equipment needs and therapist expertise, criterion-based rehabilitation is increasingly recognized as a more effective and evidence-based strategy in modern ACL care.