Meniscal Repair

Karl F. Bowman Jr, MD

Christopher D. Harner, MD

Dr. Harner or an immediate family member has received research or institutional support from DePuy and Smith & Nephew and serves as a board member, owner, officer, or committee member of the American Board of Orthopaedic Surgery, the American Orthopaedic Association, the American Academy of Orthopaedic Surgeons, and the American Orthopaedic Society for Sports Medicine. Neither Dr. Bowman nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

PATIENT SELECTION

Advances in the understanding of the role of the human meniscus in the transmission of forces across the knee joint and as a secondary stabilizer to pathologic motion have led to increased efforts to repair meniscal injuries. The meniscus provides a significant role in load bearing, and shock absorption across the tibiofemoral joint and tears of the meniscus are associated with progression of articular cartilage disease. A strong correlation also exists between meniscectomy and the increased risk of developing radiographic signs of knee osteoarthritis.¹^,²^,³^,⁴ The primary goal in meniscal preservation surgery is to protect the articular cartilage by preserving the function of the meniscus and minimizing the changes in joint contact pressures seen with meniscal deficiency.⁵ Much of our philosophy in meniscal repairs is driven by more than 20 years of experience with meniscal transplantation and the rapid symptomatic deterioration of the meniscus-deficient athlete. We approach all meniscal tears as being potentially repairable and are increasingly aggressive about preserving the maximum amount of meniscal tissue with decreasing patient age. In this chapter, we will review the indications and techniques for meniscal body tears. Meniscal root tears are reviewed in the accompanying chapters.

Indications

The indications for meniscal repair are based on patient age, tear pattern, chronicity, and the presence of concomitant injuries. We initially approach every meniscal tear as repairable. Histologic studies have demonstrated that the vascular supply to the meniscus is provided by perforating vessels originating from the medial and lateral geniculate arteries. The peripheral capsular attachment of the meniscus has a robust blood supply, but the meniscus becomes increasingly avascular in the central portion. Three distinct zones have been described to classify tears according to their vascular supply. These include the richly vascular red-red zone, the transitional red-white zone, and the avascular white-white zone.⁶^,⁷

Classification of meniscal body tear pattern helps to characterize the type of injury sustained to the meniscus and correlates with both the collagen fibers that are disrupted and the anticipated success of meniscal repair. The meniscus consists of longitudinal fibers running parallel to the long axis of the tissue, radial tie fibers that bind the longitudinal fibers, and interstitial fibers that provide additional strength to the tissue.⁸^,⁹ Acute tears are generally classified as longitudinal (bucket-handle) tears; radial split tears; horizontal flap tears; or a combination of longitudinal and radial tearing in a parrot beak pattern (Figure 1). Tears may be additionally classified as simple, complex, or degenerative. The ideal candidate for meniscal repair is a longitudinal tear in a young patient involving the vascular red-red zone. Radial tears and parrot beak tears are also amenable to repair, especially in a young patient, or if the tear involves the vascular portion of the meniscus. The success of meniscal healing following repair is highest in the setting of concomitant anterior cruciate ligament (ACL) reconstruction, likely due to the increased marrow elements in the knee from drilling the tibial and femoral tunnels.¹⁰ The healing rates of isolated meniscus repairs can similarly be enhanced with additional procedures such as a fibrin clot, capsular rasping, and microfracture of the intercondylar notch.¹¹^,¹²^,¹³

Contraindications

Although we believe that no true contraindication to meniscal repair exists, tears with significant intrasubstance degeneration, isolated tears of the avascular white-white zone, the presence of tricompartmental arthritis, or unstable displaced meniscal fragments are less amenable to repair. Despite these relative contraindications, every attempt should be made to preserve the maximal amount of meniscal tissue to minimize the detrimental effects of meniscectomy on the articular cartilage.

Clinical Evaluation

Patient evaluation of a suspected meniscal tear includes a thorough history and physical examination. The knee is evaluated for signs of joint line tenderness, effusion, and
limitation of range of motion. A detailed ligamentous examination is also performed to detect the presence of ligament laxity such as an ACL or posterior cruciate ligament, medial or lateral collateral ligament, or medial patellofemoral ligament injury. Specific provocative maneuvers can also be useful such as the Apley’s and flexion McMurray’s test.

FIGURE 1 Illustrations show acute meniscal tear patterns.

If a displaced meniscus tear is present blocking knee range of motion, an attempt to reduce the displaced fragment should be performed. Displaced medial tears can be reduced by applying a valgus force on the knee at 10° to 30° of flexion and gradually bringing the knee into full extension. Lateral tears are reduced with a varus force applied at 20° to 60° of knee flexion (ie, figure-of-4 position) followed by gradual extension. If the displaced fragment is successfully reduced, the knee is immobilized in extension until surgery to prevent re-displacement or further meniscal damage. If the displaced fragment cannot be reduced, then a surgical reduction and repair is performed as soon as possible to minimize the risk of arthrofibrosis and chondral damage.

PREOPERATIVE IMAGING

Standard radiographs of both knees are obtained in all patients with suspected meniscal pathology, including a
flexion PA (Rosenberg) view, lateral view, and Merchant patellofemoral views. Standing long leg films are also obtained when indicated to evaluate mechanical alignment. Radiographs are carefully assessed for joint congruency, patellar height, subtle avulsion fractures, and signs of arthritis such as joint space narrowing. MRI assists in the identification and classification of meniscal injury and associated pathology of the cruciate and collateral ligaments, chondral surfaces, and related structures¹⁴ (Figure 2). Oblique coronal images in the plane of the anterior cruciate ligament are routinely obtained, and these sequences can be particularly useful to identify pathology of the meniscal roots.¹⁵ MRI findings are reviewed with the direct input of musculoskeletal radiologists before establishing an individualized treatment plan.

FIGURE 2 Sagittal MRIs demonstrate various meniscal tear patterns. A, T1-weighted MRI shows a displaced longitudinal (bucket-handle) tear of the medial meniscus. The displacement into the notch creates the classic “double posterior cruciate ligament” sign. B, A radial split tear of the lateral meniscus presents as a gap on the T2-weighted MRI. C, T2-weighted MRI shows a nondisplaced longitudinal tear of the lateral meniscus in the red-red zone.

Repair Technique

There are three established techniques for meniscal repair: the inside-out technique, the outside-in technique, and the all-inside technique. The inside-out technique consists of passing sutures through metallic cannulas introduced intra-articularly and retrieved through a counter incision in the skin. Outside-in involves passing a cannula, usually an 18-gauge spinal needle, from an extra-articular location and passing a suture that is retrieved within the joint. All-inside techniques involve placing sutures arthroscopically without using a counter incision. Multiple commercial devices exist that allow all arthroscopic meniscal repair, and studies have demonstrated that adequate repair stability can be achieved with all three techniques. Meniscus repair is a highly technical procedure, and regardless of technique chosen the skill of the surgeon in addressing the meniscal tear pathology is a very important factor in achieving a successful repair.

Only gold members can continue reading. Log In or Register to continue