What is ACL reconstruction?
A torn ACL does not heal back together on its own. Reconstruction replaces the damaged ligament with a graft — a strip of tendon that is positioned exactly where the original ligament ran and anchored into the bone, where it gradually becomes a living, functioning ligament.
It is performed arthroscopically: through small keyhole incisions, using a camera and fine instruments. This means less disruption to the tissues, smaller scars and a faster early recovery than open surgery.
Who is it for?
Reconstruction is recommended when an unstable knee limits the activities you want to do. It is particularly indicated for:
- Athletes returning to pivoting or contact sports.
- Knees that give way during daily activities.
- ACL tears combined with a repairable meniscus or other ligament injury.
- Active patients for whom rehabilitation alone has not restored stability.
How the procedure works
Choosing the graft
The graft is most often taken from your own body (an autograft) — commonly the hamstring tendons, the patellar tendon, or the quadriceps tendon. The best choice depends on your sport, anatomy and preferences, and is discussed with you beforehand.
The operation
The remnants of the torn ligament are cleared, and tunnels are drilled precisely into the shin and thigh bone. The graft is passed through these tunnels and fixed under tension, recreating the natural path and function of the ACL. Any associated meniscus tear is addressed in the same sitting.
Because ACL tears frequently come with meniscus or cartilage damage, reconstruction is planned as comprehensive knee surgery — not just the ligament in isolation.
Preparing for surgery
A short course of “prehabilitation” before surgery — to reduce swelling and regain full straightening and strong quadriceps — measurably improves the final result. You will also receive clear guidance on fasting, medication and arranging help for the first days at home.
Recovery timeline
Protect & settle
Crutches, swelling control, and early exercises to restore full extension and switch the quadriceps back on.
Motion & walking
Full range of motion, weaning off crutches, and a return to comfortable daily activity.
Strength
Progressive gym-based strengthening; stationary cycling and swimming.
Run & cut
Graded return to running, then agility and sport-specific drills.
Return to sport
Criteria-based clearance using strength and hop testing — not the calendar alone.
Risks & outcomes
ACL reconstruction is a common, well-established and highly successful operation, with most patients returning to their previous level of sport. As with any surgery there are risks — including infection, stiffness, graft re-injury and blood clots — all of which are uncommon and actively minimised through technique, prophylaxis and a structured rehabilitation programme.
Most reconstructions are done as a day case or with a single overnight stay.
Typically around 4–6 weeks, once you have safe control of the leg — sooner for a left-knee operation in an automatic car.
The large majority of patients regain a stable knee and return to sport; outcomes are best when rehabilitation is completed in full.