Subchondral Cystic Lesion
Subchondral cystic lesions in the medial femoral condyle of the femur form either as a result of a defect in the formation of bone during growth or as a sequela to trauma. A pocket in which there is no bone and is filled with fluid or gelatinous material in end of the femur is present. The joint is usually distended and the horse may have varying degrees of lameness.