ACL tears and ACL reconstruction

The anterior cruciate ligament stabilizes the knee against pivoting and forward shifting of the tibia. Tears usually happen without contact — a cutting, landing or deceleration movement — often with a pop, rapid swelling within hours, and a sense that the knee is unreliable when changing direction.

ACL tears frequently occur with other injuries: meniscus tears, cartilage injury, bone bruising and occasionally collateral ligament injury. Identifying those associated injuries is part of planning treatment, because a repairable meniscus tear changes both the urgency and the operation.

The pattern is usually distinctive, and many patients suspect the diagnosis before imaging confirms it.

Most ACL tears are non-contact injuries in pivoting sports — basketball, soccer, football, skiing and volleyball — where the knee rotates over a planted foot. Contact injuries and work or motor-vehicle trauma account for the remainder, and those are more often associated with additional ligament injury.

A knee that swells rapidly after a twisting injury should be evaluated. Prompt assessment matters most when the knee locks or cannot be straightened, which can indicate a displaced meniscus tear, and when a return to pivoting sport or physical work is the goal.

Examination tests the ligament directly and assesses the menisci and the other ligaments. X-rays rule out fracture and assess alignment; MRI confirms the tear and defines associated injury.

Before surgery, the priority is a calm knee: full extension, minimal swelling and reactivated quadriceps. This prehabilitation phase measurably improves how the knee recovers afterward.

Not every ACL tear requires reconstruction. Patients whose activities do not involve cutting or pivoting can often function well with a structured program that restores motion, quadriceps and hamstring strength and neuromuscular control, sometimes with a brace for specific activities.

This route is reassessed over time. Persistent giving way, a meniscus tear that needs protection, or a plan to return to pivoting sport moves the conversation toward reconstruction.

Reconstruction replaces the torn ligament with a graft, since a torn ACL generally does not heal back to functional length. The graft is passed through tunnels placed at the native attachment sites and fixed on both sides so it can be loaded during rehabilitation while it incorporates.

Meniscus tears are repaired or trimmed at the same time when present, and cartilage injury is addressed as indicated. Surgery is performed primarily arthroscopically and is usually outpatient.

ACL reconstruction uses a tissue graft to replace the torn ligament. An autograft uses your own tissue; an allograft uses donor tissue.

Dr. Horner makes graft selection together with each patient, considering age, activity goals, previous surgery, and personal preferences. His usual approach includes:

LET is an additional procedure performed on the outside of the knee that may be combined with ACL reconstruction to improve rotational stability.

Research supports its use in selected patients at higher risk of another ACL injury. For example, the STABILITY randomized trial found fewer graft ruptures when LET was added to hamstring tendon autograft ACL reconstruction in young, high-risk patients.

Dr. Horner considers LET individually and is more likely to recommend it for patients who:

Recovery depends on your progress and whether other procedures, such as a meniscus repair, are performed alongside ACL reconstruction.

Dr. Horner is a board-certified orthopedic surgeon with fellowship training in sports medicine and shoulder surgery at Rush University Medical Center, and he has cared for professional athletes in Chicago. ACL injuries in athletes and active adults are a central part of his practice, and rehabilitation is planned alongside surgery rather than after it.

Patients are seen at Oak Brook on Mondays, Little Village on Wednesdays and St. Charles on Thursdays.