Blood Supply of the Meniscus
Vascular Anatomy
The meniscus has a limited blood supply that is restricted to the peripheral 25% of the lateral meniscus and 30% of the medial meniscus, with vascularity extending only 1-2 mm from the meniscosynovial junction. 1, 2
The meniscus is traditionally divided into three vascular zones based on blood supply:
- Red-red zone (peripheral): The outer 10-25% of the meniscus with direct vascular supply from the perimeniscal capillary plexus 3, 4
- Red-white zone (middle): The transitional zone with limited vascularity 3, 4
- White-white zone (inner): The inner avascular region comprising approximately 75% of the meniscus with no direct blood supply 1, 4
Source of Blood Supply
The blood supply to the meniscus originates from the perimeniscal capillary plexus, which is derived from branches of the superior and inferior medial and lateral genicular arteries. 2 These vessels form a network in the synovial and capsular tissues surrounding the meniscus, with penetrating branches extending into the peripheral meniscal tissue. 2
Clinical Significance for Healing
The vascular anatomy directly determines healing potential after meniscal injury:
- Tears in the red-red zone have the highest healing capacity due to adequate blood supply 3
- Tears in the red-white zone have intermediate healing potential 3
- Tears in the white-white zone traditionally have poor healing capacity, though recent evidence suggests progenitor mesenchymal cells and endothelial cells exist even in avascular zones 1
Meniscal injuries trigger a fivefold increase in blood flow to the meniscus within 4 weeks post-injury, representing a characteristic vascular response that plays a significant role in the healing process. 5 This hyperemic response can be prevented by immobilization, which may negatively impact healing. 5
Surgical Implications
When performing meniscal repair, vascularity can be enhanced through parameniscal synovial abrasion using rasps on both superior and inferior surfaces of the peripheral rim, which improves healing rates from 78% to 91% without requiring resection of meniscal tissue. 2 This technique allows healing of tears with peripheral white rims up to 5 mm while maintaining full meniscal size. 2
Patients undergoing meniscal repair in the red-red and red-white zones demonstrate significantly better postoperative outcomes compared to white-white zone repairs, though all zones show improvement with surgical repair. 3