Meniscal Roots (Posterior)

radices posteriores meniscorum

The posterior meniscal roots anchor the posterior horns of both menisci to the tibia. Posterior root tears — equivalent to a total meniscectomy in terms of load distribution failure — produce rapid medial compartment osteoarthritis progression. The medial posterior root is most commonly torn, producing the characteristic meniscal extrusion visible on MRI where the medial meniscus herniates beyond the tibial plateau margin.

Region: Knee

Biomechanics

Function & Actions

Anchor the posterior meniscal horns to the tibia; maintain meniscal hoop stress for axial load distribution; without them the meniscus loses its load distribution function

Clinical Relevance

Clinical Notes

Medial posterior root tear presents as acute medial knee pain in middle-aged obese patients from a squatting or twisting movement. MRI shows the root avulsion with meniscal extrusion beyond 3 mm. The 'cleft sign' on coronal MRI (vertical cleft at the posterior root attachment) confirms the diagnosis. Transtibial pullout repair — threading sutures through the posterior horn and out a tibial bone tunnel — restores root function. Untreated root tears produce compartment arthritis within 2-3 years.

Pathology

Common Injuries & Conditions

Medial Posterior Root Tear

Medial meniscal posterior horn avulsion producing meniscal extrusion and rapid compartment arthritis progression managed with arthroscopic transtibial pullout repair.