A one-year-old Thoroughbred colt presented to the Cornell Large Animal Orthopedic Service for evaluation of effusion in the right femoropatellar joint. The owners intended to sell the colt as a yearling and had their local veterinarian take radiographs pre-emptively, who subsequently referred the colt to Cornell for further evaluation. Upon presentation, physical examination of the colt revealed moderate effusion palpable in the right femoropatellar joint. On orthopedic examination, the colt moved with a stiff gait at the trot in both hindlimbs, but neither hindlimb was more affected than the other. The colt’s lameness was graded II/V on baseline at the trot. Following upper right and left hindlimb flexion tests, the colt’s lameness worsened to grade III/V lameness bilaterally. Three-view radiographs (lateromedial, caudo-cranial, and laterocaudal-craniomedial oblique) were taken of the right and left femoropatellar joints, which revealed flattening of the lateral trochlear ridge, sclerosis of the adjacent subchondral bone and a partially mineralized cartilaginous flap. The diagnosis of bilateral osteochondritis dissecans was made based on history, physical examination, lameness examination, and the radiographic findings. The colt was placed under general anesthesia, arthroscopy of the stifle joints was performed bilaterally, and polydioxanone pins were used to reattach the osteochondritis dissecans flaps to the underlying subchondral bone. This report will discuss the pathophysiology of osteochondrosis as well as treatment options for cartilage resurfacing through surgical manipulation (including debridement, reattachment, forage, and microfracture) and post-operative care. The initial criteria for selection of cases in which cartilage flaps may be reattached using polydioxanone pins will be discussed in detail.