Root Repair

Meniscal Root Injury

The root attachments of the posterior horns of medial and lateral meniscus are very important for joint health.  When these are torn, the loading of the joint is equivalent to having no meniscus on the affected side.  Thus, these patients can often have early onset arthritis, the development of bony edema, insufficiency fractures, and the failure of concurrent cruciate ligament reconstruction grafts.  For this reason, much research has gone in to meniscus root repairs over the last several years.

Description of a Meniscus Root Repair

The technique of a meniscus root repair involves isolating the root, placing a minimum of 2 sutures in the remaining meniscal attachment, and trying to reposition it back to a more anatomic position.  In some instances, the meniscus posterior horn may need to be released from scar tissue to allow it to be repositioned.  This is important because these repairs are still quite tenuous with current technology, so it is important to try to put the meniscus back into a position where there would not be a lot of tension on the repair with knee range of motion.

After sutures are placed arthroscopically into the meniscal attachment, a small diameter tunnel, usually 5 millimeters in size, is reamed to the meniscal root attachment site, the sutures are pulled down the tunnel, and tied over a button on the anterior cortex of the tibia.  One should assess the range of motion at that point in time that can be performed in a “safe zone” to make sure that the physical therapist does not flex them harder in this time frame.

Post-Operative Protocol for Meniscus Root Repair

Progression of range of motion is more limited than for a standard meniscus root repair, usually limiting patients to 0-60 or 0-90 degrees range of motion for the first 4 weeks and then slowly increasing range of motion as tolerated. Patients are allowed to initiate weightbearing at 6 weeks, but should avoid any significant squatting, squatting and lifting, or sitting cross-legged for a minimum of 5-6 months.  They may start the use of a stationary bike, and may slowly wean off crutches starting at 6 weeks post-operatively.

The results of meniscus root repairs in the literature are encouraging, but more improvement is necessary in the future.  Repairs have been found to delay or improve the findings of bony edema and the early onset of arthritis in many patients.  It has been found that one suture alone for the repair does not work well, so a minimum of 2 sutures is required to maximize meniscal healing.  Further study into meniscus root tears and radial root tears is ongoing by our research laboratory to try to improve the treatment of these complex problems.

Meniscal Root Repair FAQ

What is a meniscus root tear?

The meniscus root is where the meniscus attaches to bone. The meniscus root attachment is important because if the meniscus becomes detached, it can “squirt” out of the joint, called extrusion, which can lead to the meniscus not being functional. Meniscus root tears are a particularly troublesome type of meniscus tear, because a failure to treat them can often result in the rapid development of osteoarthritis. In particular, it has been found that one of the most common reasons why younger patients need total knee replacements is because of a neglected or undiagnosed meniscus root tear leading to the development of osteoarthritis.

What is a meniscus root repair?

A meniscus root repair involves reattaching the meniscus back to bone where it has been torn. The steps in a meniscus root repair are very intricate and our biomechanical studies have validated that the steps are essential. First, one needs to ensure that the meniscus root is repairable and that there is not too much arthritis on that affected portion of the joint such that a meniscus root repair would not be recommended. If a patient does have a meniscus root tear and the cartilage in that same compartment is still relatively good or normal, a meniscus root repair would be indicated. Often, when a meniscus root is torn, it will retract in the joint and become stuck in place.  If one does a meniscus root repair in that extruded position, the chance of a meniscus root repair working over the long term is very minimal. Therefore, most meniscus root tears need to have the scar tissue released so the meniscus can be pulled back into the joint. The second step is to prepare a bony bed where the meniscus repair will be performed. This is called decortication of the medial tibial plateau (for a medial meniscus root repair).  These two steps are considered to be the two main preparation steps, where the release of adhesions to be able to allow the meniscus to be pulled back in the joint and also decortication of bone to prepare a bony bed to repair the meniscus back to the tibia. The next steps involve placing self-capture sutures into the end of the meniscus root and then drilling cannulas into the area that was decorticated such that the sutures placed into the meniscus can be shuttled down the cannulas and then tied over the tibia.

The first step is usually to use especially designed cannulas and guides to drill up into the area that was decorticated. We recommend the use of 2 cannulas such that the meniscus can be pulled down over a broader area and have a better chance of healing to the bone. This step involves making a surgical incision or extending a previous surgical incision (such as with an ACL reconstruction) and ensuring that one is dissected down directly to bone. A surgical guide can then be placed in a drill tip where the cannula around it is placed into the area of the decorticated bone.

The first step is usually to use especially designed cannulas and guides to drill up into the area that was decorticated. We recommend the use of 2 cannulas such that the meniscus can be pulled down over a broader area and have a better chance of healing to the bone. This step involves making a surgical incision or extending a previous surgical incision (such as with an ACL reconstruction) and ensuring that one is dissected down directly to bone. A surgical guide can then be placed in a drill tip where the cannula around it is placed into the area of the decorticated bone. The drill tip can then be pulled out, leaving the cannula in place, which allows one to place a passing stich up it to subsequently shuttle sutures down the tibial tunnel.

The next step involves using a self-capture device to place either sutures or tape into the substance of the meniscus body. We currently use UltraTape to do this. Often, a patient will be placed into an unloader brace if they are bowlegged to take some of the stress off the healing repair.  In addition, because of studies from our biomechanical studies showing significant stress on the meniscus with deep flexion, as well as the fact that many meniscus root tears occur with deep flexion, we have patients avoid squatting, squatting and lifting and sitting cross-legged (which puts extra stress on a root repair) for a minimum of 4 months postoperatively to maximize the healing potential. In general, patients have to develop good quadriceps strength to allow for maximum absorption with activities prior to returning back to any significant hiking, jogging or running activities. It is felt that most meniscus root tear repairs are sufficiently healed to start these activities between 5 and 7 months postoperatively.

Meniscus root tear versus ACL

An ACL tear most commonly occurs from a turning, twisting, or deceleration mechanism in a noncontact mode.  Meniscus root tears usually occur in patients with deep flexion such as skiers, or home gardeners, plumbers, or carpet layers or people doing similar activities.  An ACL tear commonly has a pop on the outside of the knee, whereas a patient who has meniscus root tear commonly feels a pop in the back of the knee.

It is important to recognize that most patients who sustain isolated meniscus root tears happen with a medial meniscus root attachment.  Patients who have an ACL tear have a 10% chance of having a lateral meniscus root tear.  These are totally different.  Lateral meniscus root tears can lead to arthritis, but they also result in the ACL being a little looser and the clunk that comes with an ACL tear (pivot shift) being more unstable.  Thus, when one does sustain a lateral meniscus root tear with an ACL tear, consideration should be given to having a concurrent lateral meniscus root repair so the ACL graft does not stretch out.