MSK Equine Developmental Orthopedic Diseases Practice Test

The most important factor shaping the outcome after surgical debridement of subchondral cystic lesions is how much of the articular surface is involved by cartilage disruption—the width of the surface defect. When the defect across the joint surface is narrow, debridement can remove the necrotic tissue and restore a smooth, congruent surface more easily, allowing better restoration of joint function and a more favorable prognosis. In contrast, a wide articular surface defect means a larger area must be repaired or filled, making it difficult to achieve true congruity after debridement and increasing the risk of persistent lameness and degenerative joint changes, so the prognosis is poorer even if the cyst itself is addressed. While age, duration of disease, or the absolute size of the cyst can influence healing in some cases, they do not predict outcome as directly as the extent of cartilage involvement on the articular surface.