Medial Meniscus Root Tear in the Middle Aged Patient: A Case Based Review

Abstract

Biomechanical studies have shown that medial meniscal root tears result in meniscal extrusion and increased tibiofemoral joint contact pressures, which can accelerate the progression of arthritis. Repair is generally recommended for acute injuries in the young, active patient population. The far more common presentation however, is a subacute root tear with medial meniscal extrusion in a middle aged patient. Coexisting arthritis is common in this population and complicates decision making. Treatment should be based on the severity of the underlying arthritis. In cases of early or minimal arthritis, root repair is ideal to improve symptoms and restore meniscal function. In patients with moderate or severe medial compartment arthritis, medial unloader bracing or injections can be tried initially. When non-operative treatment fails, high tibial osteotomy or arthroplasty is recommended. Long term clinical studies are needed to determine the natural history of medial meniscal root tears in middle aged patients and the best surgical option.

Keywords: MMRT; Meniscus root tear; arthritis; medial meniscus; meniscus repair; middle age.

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1:

Coronal T2 weighted image showing extrusion of the medial meniscus beyond the dimensions of the medial tibial plateau (upper left), while upper right image confirms avulsion of the root of the medial meniscus. A pathognomonic “ghost sign”, or segmental defect of the posterior root on T1 weighted sagittal MRI image (lower left), and a radial tear of the posterior root as seen on axial T2 weighted image (lower right).

Figure 2:

Note true avulsion of the root (left), while the image on the right demonstrates a complete radial avulsion of the posterior horn, with remnant root still attached.

Figure 3:

Rosenberg x-ray (left) demonstrating mild joint line narrowing. T2 weighted coronal MRI (middle) shows meniscus extrusion with medial femoral condyle defect and was thus treated non-operatively. The patient was seen 7 years later for increasing contralateral knee pain and underwent screening x-rays showing progression of medial arthritis (right). It should be noted that he remains asymptomatic despite radiographic progression of arthritis.

Figure 4:

AP, Rosenberg and lateral radiographs (top) demonstrating mild medial joint line narrowing. MRI demonstrating root tear and extrusion with diffuse cartilage thinning medially.

Figure 5:

Arthroscopic images at time of surgery demonstrate diffuse, Outerbridge Grade II/III chondromalacia, with meniscus root avulsion noted (left). Given the state of the cartilage, meniscus debridement was performed.

Figure 6:

Standing AP, Rosenberg and lateral radiographs demonstrating minimal medial joint line narrowing. Mechanical axis is neutral on AP long-leg x-ray.

Figure 7:

Axial T2, sagittal T1, and coronal T2 weighted images demonstrating complete root avulsion with no significant cartilage loss.

Figure 8:

Arthroscopic images of the right knee revealing displaced, avulsion of the posterior horn of the medial meniscus (upper left). Note the preserved cartilage. Figure-of-eight stitch passed through the meniscus root (upper right). A 5 mm tunnel drilled inside out from the medial tibia in the root anatomic footprint (lower left). Sutures then retrieved through the tunnel and secured over a cortical button on the medial tibia, thus repairing root tear to its footprint.

Figure 9:

Trans-tibial pullout technique (left) and suture anchor technique (right).

Figure 10:

AP and lateral radiographs demonstrate mild medial joint line narrowing with early osteophytes. Mechanical axis passes medial to the center of the knee, which measured 5 degrees of varus (right).

Figure 11:

T2-weighted coronal images demonstrating near full thickness cartilage loss from both the medial femoral condyle and medial plateau with 3.8 mm of extrusion of the medial meniscus (left). Note the radial tear is seen at the junction of the posterior body and root (right).

Figure 12:

AP and lateral radiographs taken 6 months post-op, after high tibial osteotomy (iBalance, Arthrex, Naples, Fl)