Meniscus Tear Types Explained: Shapes, Zones, and Treatment

Horizontal (Cleavage) Tears

Horizontal tears split the meniscus into upper and lower halves, running parallel to the tibial plateau. They are the most common degenerative tear pattern, typically found in patients over 40 as part of age-related meniscal wear. On MRI, a horizontal tear appears as a bright line on sagittal images that extends to either the superior or inferior articular surface (or both). These tears are frequently asymptomatic and found incidentally. When symptomatic, treatment is typically conservative with physical therapy. Surgical repair is generally not feasible due to the degenerative nature, but partial meniscectomy (removing only the damaged flap) provides good symptom relief when needed.

Vertical Longitudinal Tears

Vertical longitudinal tears run parallel to the long axis of the meniscus, splitting it into inner and outer portions. These are the most common traumatic tear pattern in young, active patients. On MRI, they appear as a vertical bright line on coronal images. Because these tears often occur in the vascular peripheral zone (the red-red zone), they have the best healing potential and are the most amenable to surgical repair. Small, stable longitudinal tears in the vascular zone may heal without surgery if they are under 10 mm in length and the knee is otherwise stable.

Bucket Handle Tears

A bucket handle tear is a displaced vertical longitudinal tear where the inner fragment flips into the intercondylar notch (the center of the knee), like the handle of a bucket. This is a significant tear that often causes mechanical locking of the knee — the patient is unable to fully straighten or bend the knee because the displaced fragment blocks movement. On MRI, the classic finding is a fragment in the intercondylar notch (the double PCL sign on sagittal images) and an absent or truncated bowtie sign on sagittal images (normally the meniscal body shows a bowtie shape on two consecutive slices).

Bucket handle tears typically require surgical repair rather than removal, as they involve a large portion of the meniscus. The repair success rate is good (80-90%) when performed in the vascular zone, and preserving the meniscus significantly reduces the risk of future osteoarthritis compared to removing it.

Radial Tears

Radial tears run perpendicular to the long axis of the meniscus, from the inner free edge toward the periphery. They are clinically significant because they disrupt the circumferential fibers that give the meniscus its hoop stress resistance — the ability to distribute compressive forces across the knee. A complete radial tear effectively renders the meniscus non-functional in the affected area, similar to removing that portion. On MRI, radial tears can be difficult to detect and may appear as a truncated or blunted meniscal appearance on sagittal images, or as a bright cleft on coronal images.

Root Tears

Root tears occur at the attachment points (roots) where the meniscus anchors to the tibial plateau. They are functionally equivalent to a total meniscectomy because the meniscus loses its ability to transmit hoop stresses when its anchor is disrupted. Posterior medial meniscus root tears are most common and are often associated with acute onset medial knee pain and a pop, frequently in middle-aged women during a deep squat or kneeling. On MRI, the root tear appears as absence of the normal meniscal root on axial images, with a bright signal or ghost sign on coronal images at the root attachment.

The Vascular Zones: Healing Potential

The meniscus has three vascular zones that determine healing potential. The red-red zone (outer third) has good blood supply and the best healing potential — tears here can be repaired surgically with 80-90% success rates. The red-white zone (middle third) has moderate vascularity and intermediate healing potential. The white-white zone (inner third) has no blood supply and very limited healing capacity — tears here rarely heal, even with surgical repair. The location of the tear within these zones is one of the most important factors in determining whether repair or removal is the best treatment strategy.

Key Takeaways

• Horizontal tears are the most common degenerative pattern and often asymptomatic
• Vertical longitudinal tears have the best repair potential, especially in the vascular peripheral zone
• Bucket handle tears cause mechanical locking and usually require surgical repair
• Radial tears disrupt the meniscus hoop stress mechanism and compromise its function
• Root tears are functionally equivalent to total meniscectomy and accelerate osteoarthritis
• Tear location within the vascular zones (red-red, red-white, white-white) determines healing potential

Frequently Asked Questions