What happens if an ACL tear is not treated?

The anterior cruciate ligament helps control forward movement and rotation of the knee. When it is torn, the knee may buckle during turning, stopping or uneven-ground activities. Repeated episodes can irritate or damage the meniscus and the smooth cartilage that helps the joint move. Ongoing swelling, reduced confidence and loss of strength can also make normal activity harder. An ACL tear does not automatically require reconstruction; the right approach depends on stability, activity goals, associated injuries and examination findings.

Arrange an orthopaedic or physiotherapy assessment to confirm the injury and check for meniscus, cartilage or other ligament damage. Early rehabilitation usually addresses swelling, knee movement, quadriceps strength, balance and safe activity choices. A knee brace may help selected people during activities, while prehabilitation can prepare the knee before a possible reconstruction. If returning to sport is a goal, use a staged Return-to-Sport Programme guided by Sports Physiotherapy. ACL Reconstruction may be considered when instability persists or the knee demands high-level pivoting activity.

Seek prompt medical assessment after a twisting injury with marked swelling, inability to fully move the knee, repeated buckling or difficulty bearing weight. Urgent care is appropriate if the foot becomes cold, pale, numb or unusually weak, or if severe pain follows a new injury. Knee swelling can be assessed alongside the injury rather than treated as proof of a specific tear.

Ask whether the tear is complete or partial, whether imaging is needed, and whether the meniscus or cartilage is also injured. Discuss how stable your knee is, which activities to pause, what rehabilitation targets should be met, and how reconstruction would change your recovery plan.