Repair of a Complete Radial Tear of the Lateral Meniscus

Video Transcript

In this video, we will discuss the indications and surgical technique for repair of a complete radial tear of the lateral meniscus.

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In this case presentation, our patient is an 18-year-old male college football player who presented with a right knee injury 2 days after getting hit from the side during a football game. The patient developed an effusion overnight, described 6/10 pain that worsened with walking, denied catching or locking, and had no history of prior knee problems. Physical examination revealed range of motion from 3° of hyperextension to 120° of flexion, 2+ effusion, positive lateral joint line tenderness, and a positive McMurray test.

Radiographs were acquired and demonstrated no acute fractures or traumatic malalignment with preserved joint spaces. Long-standing mechanical axis views are not typically required in acute cases but can be helpful in more chronic tears or meniscus deficiency. In these cases, an osteotomy may be considered.

Advanced magnetic resonance imaging (MRI) was acquired as well and demonstrated a complete radial tear of the lateral meniscus. This can be seen here in the T2 axial, coronal, and sagittal images and has been marked with a yellow arrow for clear identification. It is important to look for meniscal tears in the axial cut. If the MRI slice is not in plane with the menisci, they can be difficult to assess. In this case, the menisci and the radial tear are clearly present on imaging. Evaluating the menisci in all 3 planes is important to better understand the configuration of the tear.

The finding of a complete radial tear is important as this tear pattern completely transects all the circumferential, longitudinal collagen fibers that make up the meniscus. This results in a loss of hoop stresses and renders the meniscus nonfunctional for load sharing of axial forces. This is evidenced by a study that reported a greater risk of developing osteoarthritis with greater radial involvement of meniscal tears. This is especially a problem on the lateral side of the knee in which there is a convex or flat tibial plateau, compared with the medial tibial plateau that is concave. The convex surface of the lateral tibial plateau increases contact pressure on the articular cartilage exponentially and can lead to rapid arthritic changes, sometimes in just a few months.

The diagnosis of a lateral meniscus complete radial tear was made and supported by joint effusion, lateral joint line tenderness, positive McMurray test, and MRI findings. For treatment, we recommended a repair of the radial tear for long-term success, given the patient’s young age, activity levels, acute injury presentation, and tear location and pattern. This type of tear in a high-level athlete should not wait until the end of the sports season because of the potential for irreversible articular cartilage damage. Other factors to consider when evaluating a patient for repair include chronicity of the tear, associated knee instability, alignment, and the presence of degenerative changes. In the case of a patient with a chronic degenerative tear with poor potential for healing, a repair is not recommended.

Presented here is a 3-dimensional diagram of the procedure for the radial tear (Figure 1). As noted, the top of the meniscus is represented by the red side, the front of the meniscus is represented by the blue side, and a radial tear is present in the middle. The inner margin is trimmed on either side by resecting damaged tissue in the white-white zone. To start the repair, an upside-down pass from top to bottom is made. Then, the sutures are crossed underneath the meniscus, and a right-side up pass from bottom to top is made. Next, an outside-in approach is used to create a horizontal mattress stitch. Last, the sutures are shuttled out separately and tied over a capsular bridge so that the radial tear is approximated back to its anatomical position.

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Figure 1.

A 3-dimensional diagram of the procedure for the radial tear.

The lateral meniscus complete radial tear is seen here through an inferomedial portal with the leg in a figure-of-4 position. It was located at the junction between the body and the anterior horn of the meniscus. An accessory medial portal was created to have the correct trajectory to fix the tear; however, this is not always necessary. The torn meniscus was debrided with a biter and shaver to prepare the tear for repair. The self-capturing suture passer was used to pass a size 0 high-strength suture through the meniscus. First, we pass the free ends of suture from top to bottom on both sides of the tear. Tangles, as seen here, can be sorted using an atraumatic grasper. The free ends are then crossed on the bottom of the meniscus to create an X configuration. These free ends are then passed from the bottom to top slightly further back from the first suture passes. An angled, self-capturing suture passer can be beneficial in this location. This creates a single suture crossing over the top of the tear, and an X configuration of sutures crossing the tear on the bottom, with the free suture ends coming through the top of the meniscus. A small laterally based incision along the joint line was created. A needle can be used as an outside-in technique to demonstrate the best site for incision, and in this case, it was about 2 cm in length parallel to the joint line, posterior to the iliotibial band. A spinal needle was then used from outside-in to perforate the periphery of the meniscal tear on each side. A chia snare was used to shuttle a separate suture tape in a side-to-side manner across the tear to reinforce the repair with a knot tied on the outer capsule. The iliotibial band can be retracted when tying over the capsule. The chia snare was used once again to shuttle the size 0 sutures to the exterior portion of the knee. A free needle was used to get some capsule between suture ends, and the knots were tied on top of the capsule. Alternatively, separate passes with the spinal needle and chia to shuttle the ends of the X-configured suture can be performed to enhance coaptation. Here you can see the tear has been approximated back to its anatomical position.

Listed are potential complications associated with a radial tear repair. These include iatrogenic chondral damage, potential chondral abrasion from knots on the meniscal surface, damage to the peroneal nerve, and entrapment of ligaments and neurovascular structures. It is important to be familiar with your repair device to help avoid these complications. The inside-out technique presented here avoids knots on the surface of the meniscus.

Our protocol for postoperative management is 25% weight bearing and 0° to 90° range of motion in a brace during the first 6 weeks. Weight bearing restrictions are important as any axial load acts to distract the tear edges and can affect healing. Further range of motion without weight bearing is permitted as tolerated but deep squatting is avoided for the first 3 months. With an isolated radial tear repair, typically there is a 5-month minimum for return to sport, but this may vary depending on the ability to perform functional, sport-specific activities without provoking knee pain or swelling.

The patient outcomes of radial tear repair demonstrate great results. It has been found that isolated radial tear repairs improve both International Knee Documentation Committee (IKDC) and Tegner scores. Winkler et al found that radial tear repair reduced lateral meniscus extrusion from 3.15 to 2.13 mm. Furthermore, the compression-associated increase in meniscus extrusion did not differ significantly between the injured and healthy knee. Second-look arthroscopy demonstrated complete meniscus healing in 86.4% of patients and partial healing in 13.6% of patients. In addition, there were significantly improved IKDC, Lysholm, and Tegner scores. Overall, radial tear repair provides excellent results for patients.

From the Department of Orthopaedics at the University of Virginia, we thank you for watching.