ACL Injury: Symptoms, Treatment and Recovery Timeline

Dr. Peeyush Yadav · Chief Orthopedic Surgeon

The ACL — the anterior cruciate ligament — is one of the main stabilisers of the knee, and one of the most common serious injuries in sport. It usually happens the same way: a sudden change of direction, an awkward landing, or a direct blow to the knee while the foot is planted.

What it feels like

Most people describe a specific moment, not a gradual ache — often a "pop" felt or heard at the time of injury, followed by swelling within a few hours and a knee that feels unstable, like it might give way under weight. That combination — a sudden twisting injury, rapid swelling, and instability — is what usually prompts an urgent look rather than a wait-and-see approach.

How it's diagnosed

A clinical examination can strongly suggest an ACL tear on its own, through specific stability tests on the joint. An MRI confirms it, and also shows whether the meniscus (the knee's cartilage cushion) or other ligaments were injured at the same time, which is common and changes the treatment plan.

Surgery isn't automatic

Not every ACL tear needs reconstruction. The decision usually comes down to how unstable the knee is day to day, and what you need it to do — a partial tear in someone who isn't returning to pivoting sport may do well with physiotherapy and bracing alone. A complete tear in an athlete who needs to cut and pivot competitively is a different conversation.

When surgery is the right call, it's arthroscopic — keyhole — using a graft to rebuild the ligament, not open surgery.

A realistic recovery timeline

Every recovery is different, and this is a guide, not a promise — but roughly:

• Weeks 0–2: Swelling control, restoring full knee extension, gentle range-of-motion work.
• Weeks 2–6: Weight-bearing progresses, walking normalises, quadriceps and hamstring strength work begins in earnest.
• Months 2–4: Strength and balance training intensifies; running usually starts here if progress allows.
• Months 4–9: Sport-specific drills — cutting, pivoting, jumping — are reintroduced gradually and tested, not just timed.
• Month 9+: Return to competitive pivoting sport, once strength and control have actually been tested, not just calendar time passed.

That last point matters more than the timeline itself: the graft needs time to mature biologically, and returning to sport is decided by objective strength and stability testing — not by how many months have passed. Going back too early is the single biggest risk factor for re-tearing the graft.

The physiotherapy is not optional

Whether or not surgery happens, physiotherapy is where the actual recovery takes place — the operation restores the ligament; rehabilitation is what restores the knee's strength, control and confidence to trust it again.