Meniscal Root Tears: Identification and Repair
Intact menisci are capable of converting the axial load of tibiofemoral contact into hoop stress that protects the knee joint. Total meniscectomy leads to rapid degeneration of the knee. Strong clinical and biomechanical data show meniscal root tears and avulsions are the functional equivalent of total meniscectomy. Lateral root tears commonly occur with knee ligament sprains and tears. Medial root tears are generally more chronic, and can be caused by preexisting knee arthritis. Meniscal root repair is indicated when there is identification of a meniscal root tear in a knee with minimal to no arthritis. Chronic root tears in the setting of osteoarthritis are treated conservatively. Meniscal root tears can acutely occur with cruciate ligament tears, can exaggerate symptoms of instability, and will have negative ramifications on outcomes of anterior cruciate ligament reconstruction if not addressed concomitantly. In this review, we describe the importance of the menisci for knee joint longevity through anatomy and biomechanics, the diagnostic workup, and ultimately a transosseous technique for repair of meniscal root tears and avulsions.
Once the guide pin has been inserted and is visualized at the center of the root footprint, it is held in place by a hemostat or grasper placed intra-articularly. Next, the guide pin is overreamed with a 4.5-mm cannulated drill bit. The transosseous tunnel is then further prepared using a shaver to remove excess soft tissue surrounding the tunnel entrance at the tibial plateau. Further rasping around the edges of the tunnel is performed to make final preparations.
Attention is then turned back to the meniscal root. Using a FastPass Scorpion (Arthrex), 2 or 3 size 0 fiber wire sutures are passed through the root, and a cinch stitch is then secured leaving four to six stands (2 from each Scorpion pass) in the root. A FiberStick is then introduced into the tibial bone tunnel and each strand of the 0 fiberwire is retrieved. Once the FiberWire attached to the meniscal root is in the tunnel, the meniscus should be directly visualized as the appropriate tension is toggled to reduce the meniscal root into its footprint. In order to securely fasten the meniscal root, an Arthrex SwiveLock 4.75-mm suture anchor is used. The meniscus is again probed to assess the integrity of the repair. Of note, an alternative method of fixation is accomplished by tying the fiberwire over an Arthrex suture button at the anterior tibia.
Postoperatively, weight bearing restriction is warranted, along with range of motion restrictions. During the first 2 weeks, patients will be counseled to be touch down weight bearing with the use of crutches or a walker. During this period, range of motion will be restricted by hinged knee brace to 30° of flexion and full extension. The next 2-week period will advance to progressive partial weight bearing, again with crutches or a walker. Range of motion will also be expanded to 60° of flexion. After a month, the patient will then be allowed to be full weight bearing as tolerated and be weaned from assistive ambulation devices. Range of motion will then be 90° of flexion. It is paramount that full extension be achieved and maintained in the early postoperative period. Quadriceps strengthening should also proceed with unlimited straight leg raises throughout this period as well.
