Explanation
The vascular supply to the menisci originates from the peripheral capsular attachments (superior and inferior genicular arteries). Only the peripheral 10% to 30% of the medial meniscus and 10% to 25% of the lateral meniscus are well-vascularized. This peripheral area is known as the red-red zone and has the highest healing potential after repair. The inner white-white zone is avascular and relies on diffusion, making repairs here prone to failure. Reference: Campbell's Operative Orthopaedics, 14th Edition.