The anterior cruciate ligament (ACL) runs through the centre of the knee and stops the shin bone sliding forwards and rotating under the thigh bone. It is usually torn in a non-contact twist: landing from a jump, a sudden change of direction or an awkward fall when skiing. Tears are partial or complete, and the meniscus or other ligaments are often injured at the same moment.
A torn ACL does not heal back reliably. Some people cope well with structured rehabilitation alone, particularly if they avoid pivoting sports. Others have a knee that keeps giving way, which damages the meniscus and cartilage over time. Reconstruction restores stability; it does not remove the raised long-term risk of knee osteoarthritis.
Symptoms
- A pop felt or heard at the time of injury
- Rapid swelling within a few hours
- Pain and inability to carry on playing
- The knee giving way on turning, stepping off a kerb or going downstairs
- Loss of full straightening in the first weeks
- Catching or locking if the meniscus is also torn
Causes and risk factors
Most tears happen without contact, when the foot is planted and the knee twists inwards or is forced straight beyond its limit. Football, basketball, handball, netball and skiing are typical settings. Women have a rate two to eight times that of men in the same sports, related to anatomy, landing mechanics and hormonal factors. Poor neuromuscular control, fatigue, previous ACL injury on either side and playing surface also contribute. Prevention warm-up programmes reduce the risk substantially.
How it is diagnosed
- Clinical examination: The Lachman and pivot shift tests assess forward and rotational looseness. They are most reliable once the first swelling has settled.
- MRI: Confirms the tear and shows meniscus, cartilage, bone bruising and other ligament injury, which shape the surgical plan.
- X-ray: Excludes a fracture, including the small Segond fracture that signals an ACL rupture.
- Instrumented laxity testing: A device that measures forward movement of the shin compared with the uninjured knee.
Treatment options
- Early care: Ice, compression, crutches for a few days and exercises to regain full extension and quadriceps activation.
- Rehabilitation without surgery: A 3 to 6 month supervised programme. A reasonable first choice for lower-demand knees and for people willing to modify sport.
- ACL reconstruction: Arthroscopic replacement of the ligament with a graft from your hamstring, patellar or quadriceps tendon, or a donor graft in selected cases.
- Meniscus repair: Done at the same operation when the tear pattern allows, and a reason not to delay surgery too long.
- Lateral extra-articular tenodesis: An added procedure on the outer side of the knee for young, high-risk or revision cases to reduce re-rupture.
- Return to sport testing: Strength and hop tests before pivoting sport, usually 9 to 12 months after surgery. Going back earlier increases re-injury.
When it is urgent
Seek local emergency care after a knee injury if the leg looks deformed, the foot is cold, pale or numb, you cannot bear any weight, the knee is locked and will not straighten, or the calf becomes swollen and painful in the following days, which may indicate a blood clot.
Travelling to Türkiye for treatment
ACL reconstruction is planned surgery, best done once swelling has gone and the knee moves fully, often 3 to 6 weeks after injury, so there is time to arrange a trip. Expect roughly 7 to 10 days in Istanbul. The operation is only the beginning: the outcome depends on 9 to 12 months of physiotherapy at home, so find a therapist and share the surgeon's protocol before you go. Long flights soon after knee surgery raise clot risk; ask about prevention.
Send your reports, scans and a short history and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Do all ACL tears need surgery?
No. It depends on instability, associated meniscus damage, age and sporting goals. A trial of rehabilitation is reasonable for many adults.
Which graft is best?
Hamstring, patellar and quadriceps tendon grafts all work well, each with different donor site effects. Donor grafts fail more often in young athletes.
Can I damage my knee by waiting?
Repeated giving way can tear the meniscus and cartilage. If the knee is unstable despite rehabilitation, surgery is advisable.
What is the chance of re-tearing?
Higher in teenagers and young adults returning to pivoting sport, in whom it can approach one in five counting both knees. It is much lower in older recreational patients.