[Tear_25] Ramp lesion_Type 4A: complete peripheral posterior horn meniscal tear

Type 4 lesions as described by Thaunat et al. involve a complete longitudinal vertical tear in the posterior horn of the meniscus, leading to meniscotibial ligament instability as seen with type 3 lesions.
To better account for the instability pattern seen with complete tears, Grief et al proposed further two subtypes of this type 4 ramp lesion.

The subtype 4A is a complete longitudinal vertical tear of the red-red zone of the meniscus, with the meniscocapsular and meniscotibial ligaments intact but connected to a portion of the posterior horn junction via a free-floating fragment of the meniscus, thus leading to instability of both structures



MR image shows vertically oriented increased signal intensity contacting both articular surfaces of the posterior horn of the medial meniscus in the red- red zone, consistent with a complete longitudinal-vertical tear.

The axial image shows how this type of injury parallels the long axis of the meniscus, maintaining the same distance from the periphery.
This type of tear characteristically remains equidistant from the inner and outer margins

Because of the location of this tear pattern, the healing potential after repair is significantly higher than other ramp lesions, and may thus be more aggressively repaired.

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