Short answerIn a trial of young, active adults, early reconstruction was no better at five years than rehabilitation with the option of surgery later. About half of the rehabilitation group did go on to have surgery.
Probably does not help, as a routine first step
What it is
The anterior cruciate ligament, or ACL, is a main stabiliser of the knee. A tear often follows a twisting injury in sport. Reconstruction replaces the torn ligament with a graft, usually from a tendon. Rehabilitation is a structured program of strengthening and movement training. It can be followed by reconstruction if the knee keeps giving way.
What the research shows
enrolled 121 active adults, with an average age of 26, who had an acute ACL tear in a knee that had not been injured before. Sixty-two had early reconstruction plus rehabilitation. Fifty-nine had the same rehabilitation, with reconstruction available later if needed.
At five years the groups did not differ in knee scores, in return to earlier activity, in later meniscus surgery, or in X-ray signs of arthritis. The knee score rose by about 43 points in the early surgery group and about 45 points in the other group on a 100 point scale. Thirty people in the rehabilitation group, 51 in 100, had a reconstruction within five years. Most of these had it within the first year or so. Results did not differ between knees reconstructed early, reconstructed later, or never reconstructed.
This is one trial from two Swedish hospitals. It included only people with a first ACL injury to a knee that had not been hurt before.
Risks and effort
Surgery needs an anaesthetic and months of rehabilitation. Rehabilitation also takes months of effort. A knee that keeps giving way can damage the meniscus and cartilage, which is why surgery stays an option.
What usually works instead
A structured, supervised rehabilitation program is the starting point, and reconstruction is offered if the knee stays unstable. See ACL Injury and ACL Reconstruction.
Questions people ask
Does this mean I should not have surgery?
No. The trial showed that early surgery was not needed to get good results in many people. If your knee gives way in daily life or you return to sports with pivoting, reconstruction is a reasonable choice.
Will the knee develop arthritis either way?
At five years, X-ray signs of arthritis did not differ between groups. The trial cannot tell us about 20 years from now.
What about a very high level of sport?
The trial enrolled active adults with an average age of 26. Talk to your surgeon about your sport and your goals.
Is it worth having an ACL reconstruction?
For many people it does not need to be the first step. In the KANON trial of 121 active adults, early reconstruction was no better at five years than rehabilitation with surgery available later. About half of the rehabilitation group did go on to have a reconstruction, mostly within the first year or so. Reconstruction is a reasonable choice if the knee keeps giving way, or for pivoting sports.
Can you recover 100% after an ACL injury?
The trial did not measure a return to 100 percent. Knee scores rose by about 43 to 45 points on a 100 point scale in both groups, and return to earlier activity did not differ between them at five years.
Sources
Select a source to read what the study or guideline found, in plain words, with a link to the original.
Last reviewed 24 October 2026. Next review due October 2027.
