Based on the microvascular anatomy of the meniscus, which of the following tear patterns possesses the poorest intrinsic healing potential and is overwhelmingly most likely to require arthroscopic partial meniscectomy rather than surgical repair?

Explanation:
The correct option is d. The adult meniscus has a highly localized blood supply derived primarily from the perimeniscal capillary plexus, which originates from the medial and lateral geniculate arteries. This vascularity is limited strictly to the peripheral 10% to 30% of the meniscus (the 'red-red' zone). The transitional middle third is the 'red-white' zone, while the inner, central portion is entirely avascular (the 'white-white' zone), relying completely on the diffusion of nutrients from synovial fluid. Because healing requires an inflammatory response driven by a vascular supply, tears in the white-white zone (especially complex, multi-planar degenerative tears) lack the biological capacity to heal even if mechanically repaired. Therefore, arthroscopic partial meniscectomy to remove the unstable, mechanical catching fragments is the standard of care for these specific lesions. Reference: Campbell's Operative Orthopaedics, 14th Edition.