ACL Laxity and Knee Braces

A doctor discusses ACL Laxity and Knee Braces. The ACL is the duct tape in the knee that holds the big thigh bone (femur) to the leg bone (tibia). It stabilizes (along with the PCL) the knee in a front-back direction. A knee brace can be used to help the ACL. An ACL knee brace allows the knee to flex and extend while holding the thigh and leg bones in alignment. However,is there a better way than wearing a knee brace all the time? Knee surgeries to replace or reconstruct the ACL should only be performed (in my opinion) if the ACL is completely gone. if the ACL is just lax, an older method of treatment is prolotherapy. This is the injection of a substance to tighten the ligament. Reeves has shown that the ligament can be tightened in this way using monthly shots for about 6 months. Newer options already being performed in the US include seeding the patient’s own adult stem cells onto the ACL ligament to repair the damage. This only works if there are ACL fibers left to seed. Eventually, this same technique may be used to inject an ACL scaffold material into the knee with adult stem cells that can create a ligament. So if you have a stretched ACL and you’re using a knee brace for ACL laxity, investigate some of the injections that can help you loose the brace!

ACL Laxity and Knee Braces

ACL Laxity and Knee Braces.  The ACL is the inner duct tape (otherwise known as a ligament) that holds the knee together in a front-back direction.  This means that it prevents the lower shin bone (tibia) from moving forward on the thigh bone (femur). This ligament can be stretched or torn completely.  In these cases the joint is said to be “lax” and in need of either surgical repair, non-surgical repair, or knee bracing.  Bracing a knee with ACL Laxity involves stabilizing the femur and tibia in a front-back direction. However, there are pros and cons.   One of the problems is that bracing still allows some movement, which ultimately injuries the joint.  Up until now, there has been no way to repair a stretch injury to the ACL without surgery. However, the development of injection based therapy for partial ACL tears and laxity has been a big advancement beyond surgical grafts.  As an example, the Regenexx procedurenow allows doctors to inject the patient’s own stem cells onto the stretched ACL ligament and tighten that ligament back to it’s normal strength and length.  This development allows the patient to get rid of the brace all together.  Since there is no surgery needed, the recovery is much quicker and bracing is only used for a few weeks after the procedure if the laxity is severe.  This newer technique doesn’t work when there is no ACL left, but only if there are ACL fibers that can still be detected on MRI.  

As a physician who treats patients with these injuries, the best brace is the one that fits well.  For general fitting and measuring instructions, click here. Also, I often advise my patients to consider getting a slightly used brace.  Ebay can be a great place to to find a knee brace that will help with ACL laxity.

Below is a short video on the topic of repairing ligament tears by injecting your own stem cells.  While this shows an ankle ligament example, this could just as easily be a partial ACL tear.

mri knee anterior and posterior ligament tears

MRI knee anterior and posterior ligament tears. The knee has ligaments in the font and back (ACL and PCL) that keep the knee stable in a front-back direction. These ligaments can be seen on MRI and will usually have bright areas in them under certain special MRI sequences if they are partially torn or stretched. These areas are called “high signal intensity” in medical radiology jargon. If the ligament tears are complete (broken in half), then surgery is needed to reconnect those ligaments. However, if the ligaments are only partially torn or stretched, newer techniques to treat these ligaments without surgery are available. Surgery to treat an ACL/PCL partial ligament tear may cause more problems than it’s worth, in that sewing these ligaments may result in ligaments that are too tight. Ligaments that are too tight can rapidly increase the wear and tear forces on the knee. This can lead to further degeneration of the cartilage and arthritis. However, leaving the ligaments stretched out and too loose may result in the same fate, as the extra motion of the knee joint will lead to extra wear and tear as well.

While surgical repair may well lead to more arthritis down the line, non-surgical repair has advanced greatly in the past few years. The ability to inject the patent’s own stem cells into the partially torn ligaments without surgery may be able to heal these tears without over tightening the ligaments. Research in the arena of using adult stem cells (not from embryos, but from the patient) has blossomed. This technique (see the first link in the above paragraph) allows for much less downtime than surgery and also allows the patient to remain active while the ligaments are healing. In addition, it’s believed that this more physiologic repair reduces the risk of over tightening the ligament.

For more information on these ligaments, see below:

The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are the primary restraints to front and back motion of the tibia on the femur. The femur (thigh bone) sits on top of the tibia (shin bone), and the knee joint allows movement of the mid leg. Without ligaments to stabilize the knee joint, the joint would be unstable and prone to excessive wear and tear and loose much of it’s bio mechanical advantage. The ACL and PCL prevents the tibia from sliding too far in the font-back direction. The ACL and PCL also contribute stability to other movements at the joint including rotation at the knee joint. The other major ligaments of the knee are the medial and lateral collateral ligaments (MCL and LCL, respectively).

What happens when there is an ACL or PCL injury?
When an ACL injury occurs, the knee becomes unstable. The ACL injury is a concern because this instability can make pivoting movements difficult, and it may make the knee more likely to developing arthritis and cartilage injury.

Why are ACL and PCL tears a big problem with daily activities?

When the knee is unstable, patients complain of a feeling that the knee will ‘give out’ from under them. When this “giving way” is because of an ACL injury, the knee joint is sliding around too much. This can be a problem because each occurrence of instability (the ‘giving way’ feeling) can lead to damage to the knee cartilage. Therefore an ACL or PCL injury can make a patient more likely to develop knee arthritis and meniscus tears.