What it is
The ACL runs through the centre of the knee and keeps the shin bone from sliding forward and rotating under the thigh bone. It is essential for stability during cutting and pivoting.
Most ACL tears happen without contact, when the foot is planted and the knee twists or buckles. Other structures, such as the meniscus, cartilage or other ligaments, are often injured at the same time.
Symptoms
- A "pop" at the time of injury
- Rapid swelling within hours
- A feeling of the knee giving way, especially with turning
- Pain and loss of full motion
Diagnosis
A physical examination, including the Lachman test, is highly informative. X-rays rule out fractures, and an MRI confirms the ACL tear and shows any injury to the meniscus, cartilage or other ligaments.
Treatment options
Non-surgical
- Early rehabilitation to reduce swelling and restore full motion and quadriceps strength
- For some patients with lower-demand activities, structured rehabilitation and activity modification without surgery
- Bracing in selected situations
Surgical
- ACL reconstruction. The torn ligament is replaced with a tendon graft, either from your own body (such as the patellar, hamstring or quadriceps tendon) or from a donor, using arthroscopic-assisted techniques.
- Associated injuries, such as meniscus tears, are addressed at the same time when appropriate.
- Reconstruction is commonly recommended for athletes who want to return to pivoting sports.
Recovery
- First weeks
Focus on swelling control, full straightening of the knee and waking up the quadriceps.
- Strength
Progressive strengthening and balance work over the following months.
- Running
A return to straight-line running is typically introduced a few months after surgery, once milestones are met.
- Return to sport
Return to cutting and pivoting sport is commonly no earlier than about nine months and is guided by strength and functional testing.
Timelines are typical ranges, not guarantees. Recovery depends on the specific injury, the procedure, your health and your rehabilitation, and your plan is individualized.
Questions patients ask
Can I play sports with a torn ACL?
Many people can walk and jog without an ACL, but pivoting sports often cause episodes of instability that can damage the meniscus and cartilage.
Which graft is best?
Each graft option has advantages and trade-offs. The choice depends on your age, sport, anatomy and preference and is discussed individually.
Why does return to sport take so long?
The graft needs time to incorporate and strength, balance and confidence need to be fully rebuilt to lower the risk of re-injury.
This page is general patient education and is not a substitute for an in-person evaluation.