Arthroscopy of a torn medial meniscus shows the tear running through the peripheral third of the meniscus, adjacent to its capsular attachment. Why does this tear have the best prognosis for repair rather than partial meniscectomy?

• A The peripheral zone has the highest density of chondrocytes
• B The peripheral third receives blood supply from the superior and inferior genicular arteries (red zone) ✓
• C The inner two thirds contain type III collagen which heals faster
• D Synovial fluid directly nourishes the peripheral attachment

Explanation

The menisci are vascularized peripherally by branches of the superior and inferior genicular arteries forming a perimeniscal capillary plexus that penetrates roughly the outer one third (red zone), whereas the inner two thirds (white zone) are avascular and nourished only by synovial diffusion. Tears in the red or red-white zones can heal after suturing because cells and vessels reach the site; tears confined to the white zone generally do not heal and are debrided.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.