Does an ACL tear need surgery?
Not always. The choice depends on how stable the knee feels, your work and sport, and whether other parts of the knee are also injured. Some people manage with physiotherapy. Others choose reconstruction.
Common symptoms
- A pop at the time of injury, and the knee giving way
- Swelling within 24 hours
- Loss of full knee movement
- Discomfort when walking
Swelling and pain may settle by themselves, but the knee can still be unstable. Returning to sport too early can cause further damage.
Treatment without surgery
This relies on physiotherapy, usually for at least 3 months, and sometimes a brace. It may suit people with:
- A partial tear and a stable knee
- A complete tear with no giving way in daily activities, who do not play pivoting or cutting sports
- Light manual work or a less active lifestyle
Some people still injure the knee again when it gives way, and this can damage the meniscus or cartilage.
When surgery is considered
American guidance states that complete tears usually need reconstruction, and more so in active people. These factors favour surgery:
- Work or sport that involves pivoting, hard turns or heavy manual labour
- A knee that keeps feeling unstable
- Other injuries in the knee, such as a meniscus or cartilage tear
Activity level matters more than age. The usual operation is reconstruction, which replaces the ligament with a tendon graft from your own body or from a donor. American guidance suggests about 12 weeks of treatment without surgery for an isolated tear and, if appropriate, surgery within 5 months.
Risks of surgery
Risks include infection, stiffness, blood clots, a numb patch near the wound, pain when kneeling, a knee that stays unstable, and rupture of the kneecap tendon or a kneecap fracture. Donor grafts carry a rare risk of passing on a virus. Your surgeon can explain the risks for your knee and graft.
Recovery
Exercises start soon after surgery. Most people are allowed to return to full sport within 6 to 12 months. Return depends on strength, movement, balance and control, and not on time alone.
Children and teenagers
Surgery can affect the growth plates, and waiting can risk further knee damage. The surgeon explains both when planning treatment.
When to seek prompt review
See a doctor promptly if the knee swells quickly after an injury, locks, or cannot take your weight.
This page gives general information. It cannot diagnose your condition or tell you which treatment suits you. See a registered doctor for advice about your own symptoms.