I have in my clinic some patients who have had ACL injury many yers ago, and now undergone ACL reconstruction. What I could see in these patients is that very often their complain afeter injury and before surgery was givin way . So, this leads me to think that, when their ACL was healing, and consequently improving functional status of the knee, their activities such as recreational sports, or activity of daily living became better. Thus, in the early phase of healing the ligament is still weak, and with sports activities for exemple, may lead to rerupture of the ACL, becouse the ligament was not strong enough to support tensional loads on the knee. That is why I think we learned that the anterior cruciate ligament doesn't healing. This can be seen in: Costa-Paz M et al. Spontaneous healing in complete ACL ruptures: a clinical and MRI study. Clin Orthop Relat Res. 2012; 470(4):979-85; and Fujimoto E et al. Spontaneous healing of acute anterior cruciate ligament (ACL) injuries - conservative treatment using an extension block soft brace without anterior stabilization. Arch Orthop Trauma Surg. 2002; 122(4):212-6.

hi all, the human body has the power to heal by itself. injured ACL heals by fibrosis, a tissue that can't withstand the shearing forces on it. for patial cut in a non athletic patients rehabilitation with strengthening of the thigh muscles could be an opsion.but for patial tear in athletic patients , and for complete tear, surgery is the best choice , especially if signs of instability of the knees are found

The possible improvements seen in patients following ACL tear go beyond mechanical elements of re-stabilisation.

If the ligament is torn, it will leave the knee short of rotational stability and resistance to shear forces. I believe this will occur regardless of partial or complete tear. The key issue for me is the neurophysiological recovery that may happen following rehabilitation. This involves elements of balance and improvements in sensori-motor interaction.

This type of rehab will affect individuals with a variety of success, whereby some will manage to regain good function in the knee and return to some semblance of their previous level of activity, and others will show limited improvements which will show deficiency when challenged in multidirectional tasks.

I think "healing" in the ligament via the usual process of fibrosis will not be sufficient on its own to make the knee functional again, in my opinion.

In the long term, the ability to remain out of the surgeon's eye, will be determined by factors such as maintenance of meniscus integrity.

The 'spontaneous healing' of the ACL following rupture may also refer to its attachment to the PCL, which is possible if the knee has been immobilised following injury. This reinstates some rotational stability that might be sufficient to avoid surgical intervention as long as it's coupled with physical therapy and a lot of hamstrings muscle work to compensate. There tends to be greater than normal residual knee laxity, so if the demands on the knee are high (i.e. athletic pursuits involving twisting, turning, landing from jumps, quick deceleration etc.) then surgery is probably the best option. I agree with Arturo Lawson, given that the majority of ACL injuries are non-contact and happen exceptionally quickly, neurophysiological rehabilitation is of paramount importance; focussing on rapidity of muscle force generation and sensorimotor performance.

The healing of the ACL depends on the grade of the rupture, sometimes if the is a small rupture you can have "spotaneus healing" but the tissue which is formed is not of the same quality. Not all the ACL ruptures have to go under surgery its a clinical decision to go to surgery and not only an MRI picture. Have in mind that ACL surgery will not prevent osteoarthritis.

Please read and follow this link to the BJSM article on this and look at frobells seminal paper on rehab http://bjsm.bmj.com/content/44/12/833.full.pdf?sid=98846805-9b8b-49af-aed2-d2e864830647

The reason they do not repair is most ACL injuries no longer have any contact between the two ends, therefore no healing. Neuromuscular control is the essential ingredient to rehab see the above paper, basically surgery and rehab is the same outcome as rehab alone therefore rehab is the effective intervention!

One of the most important things to consider in ligament healing is the blood circulation, hence the main route of all nutrients to every tissue. Realizing the limitations will guide us a therapists in educating our patients on when they should return to stressfull activities. while recovery time is different for every patient it is important toi stress the importance and value for following guidelindes set by surgeons for they did the surgery and know better how things look inside, whioch we do not always have knowledge of. There is a need for better communication between us and the surgeons for they will explain excalty what they found for many do not always bring the operation room details to PT clinics.

We need to make sure we employ best practices and not be driven by our patient's motives to return to prior levels of function too early. ACL injuries take long to heal and this has been quoined to us as students in training. We need to use evidence based practice and educate our patients from what we have seen in previous years. It works.

healing is an issue with all the ligaments because of the less blood supply that they have.With ACL weight bearing adds additional problems.

I've always been under the impression that ligaments are poorly vascularized, leading to considerably slower repair rates than something like muscle tissue which is highly vascularized. Grade 1 ACL sprains can usually heal on their own, Grade 2 and Grade 3 (especially Grade 3) tend to require surgical intervention to take care of. Strengthening the muscles around the knee joint via resistance training and dynamic multiplanar movements can help stabilize it and prevent further injuries.

The synovial fluid that surrounds the ACL washes away the blood clot that forms as an early bridge between the two torn ends of the ligament. As a result, there is no scaffold in place to rejoin the two ends of the ligament. Furthermore, the fibrin clot is required for the release of growth factors (TGFb, PDGF etc) that attract immune cells which signal fibroblasts to start the remodelling of a functional scar tissue

Dear Godwing Tong, this is a very good hypothesis, seemed very interesting. Is this  statement has already been published or it's your own opinion?

Please see the following: http://www.aaos.org/news/aaosnow/feb13/research7.asp