A brand new ACL study landed in my inbox the same morning news broke that Lindsey Vonn had been airlifted after a crash during her Olympic downhill run. The timing was hard to ignore. This paper addresses a question that has been gaining momentum in the surgical and rehab world.
Do all ACL ruptures, even in high level athletes, require reconstruction, or can some heal well enough on their own to allow a return to sport without surgery?
What this new study actually did and why it matters
Kvist J, Liu A, Giannotti N, Filbay S, Hedevik H, Stålman A, Frobell R, Gauffin H, Englund M. (2026).
Structural Changes of the Anterior Cruciate Ligament (ACL), Evaluated by MRI, and Their Relation to
to Clinical Outcomes Under Two Years After ACL Injury: Results From the Pragmatic NACOX Cohort Study.
Journal of Orthopaedic & Sports Physical Therapy. Advance online publication.
https://doi.org/10.2519/jospt.2026.13397
This study followed individuals with acute ACL injuries who were initially managed without surgery. Using advanced 3D MRI, the authors tracked changes in ACL structure over two years and related those findings to knee laxity, episodes of giving way, strength, and patient reported function.
Instead of treating the ACL as simply torn or intact, they evaluated continuity, fiber appearance, and thickness over time. In this context, “continuity” refers to whether the ACL appears as a connected, intact structure on MRI rather than clearly disrupted or separated.
The key finding was that a substantial portion of participants demonstrated restoration of ACL continuity on MRI. Those with restored continuity generally had less knee laxity, fewer giving way episodes, and better quadriceps strength symmetry compared to those whose ACLs remained discontinuous. Not everyone avoided surgery, but the results support the idea that spontaneous healing can occur in some cases and that it may matter functionally.
This adds to a growing body of work challenging the long held belief that the ACL never heals.
A loaded question
Whether an ACL can or should be treated without surgery depends on many factors: training level, overall health, tear size and location, sport demands, level of competition, and the timeline required for return. This is not a simple decision, especially in high risk sports.
Back to Lindsey Vonn
As you may know, Lindsey Vonn ruptured her left ACL shortly before the Olympics. That alone sparked debate about whether she should continue to compete.
It is too early, and we will likely never know, whether her injury contributed to the crash. Downhill skiing offers very little room for error even in a healthy athlete. Unfortunately, the discussion will always center on whether she should have withdrawn and undergone surgery instead. Maybe. Maybe not. The injury occurred close to competition, and even with the best care in the world, there may not have been enough time.
We will never know.
A personal clinical observation
I have personally seen patients zero to four weeks after ACL injury do extremely well with rehabilitation prior to surgery, gathering objective data such as quadriceps and hamstring strength that was similar to the uninjured leg and, in some cases, better than their post surgical results six to twelve months later. Some patients were functioning so well that it made me question whether the MRI was correct and whether they truly had a tear.
I truly believe we have a lot to learn. There is likely another five to ten years of research needed to better answer these questions, but it is important that they are being asked given the physical and mental impact this injury and its treatment has on young people. Not to mention that ACL injury is a multi billion dollar industry.
John De Noyelles, PT, DPT, OCS, CSCS
