Diagnosis Case 5 Non-Union of Fracture of Metacarpals III and IV, Osteomyelitis, and Contracted extensor Tendons The obstetrical chains placed around the calfŐs front legs during extraction placed excessive pressure on the left front leg. The 3rd and 4th metacarpal bones fractured under the tension created by the calf jack and the chains. A heavy bandage was placed on the fractured limb at this point. The heavy bandage did not keep the end of the bones stabilized or reduced. Most likely the heavy bandaged hindered the fracture healing by weighing the distal limb, causing an increased distance between the fractured ends of metarcarpals III and IV. Swelling of the limb and probable moisture and debris trapped under the heavy bandage caused skin irritation, pressure necrosis and skin sloughing. If the bones had been properly reduced, there should have been inflammation and bleeding at the fracture site. A clot would have formed and the bone ends would have started forming a connection. The hematoma would have formed a support network for the fibroblasts to migrate onto and concurrently the blood supply in the area would have increased from the surrounding tissues until normal vasculature could have been established. The fibroblasts would have laid down fibrous tissue where the hematoma formed and this would have been replaced by cartilage and then by bone. The bone would then undergo remodeling to become more like normal bone. However, in this case because the fracture was never reduced properly, a hematoma could not form between the fracture ends and therefore the whole process was hindered. Bone can fill in some gaps, but not when the fracture is unstable and the bone ends are too far apart. When the heavy bandage was removed 2 weeks later, the metacarpal fractures had not healed and the limb was still unstable. A half limb cast was placed on the leg for another 3 weeks. When the cast was removed and radiographs were taken, it was observed that there was non-union of the fractures of metacarpals III and IV. There were also proliferative changes where the limb had tried to heal but it appeared that the fracture was not reduced enough to allow healing of the bones. There was a defect (significant loss of bone leaving a gap at the fracture site) and continued lameness. There is an angular deformity of the limb (valgus), a draining tract, and movement at the fracture site. The fracture is also 3 months old. All of these qualifiers lead to the defining of the fracture as a non-viable delayed union. The uniform swelling is most likely due to the cast being applied to tightly. The swelling is also due to inflammation and callus formation at the fracture site. Staph aureus and E. coli were cultured from the fracture site. It could be possible that when the chains were used to pull the calf, they created lesions which allowed the entry of the S. aureus and the E. coli. However, the presence of the pink epithelium over the fracture also lends to the theory that perhaps the fracture was an open fracture and the contamination happened directly from the open wound and the pink epithelium is new skin that has grown over the injury. And one more theory would be that the sloughing of the skin created a possible site of entry for the E. coli and S. aureus. Any of these theories allow for the proliferation of S. aureus and E. coli and would explain the purulent exudate and draining tract on the dorso-medial side of the leg. These findings are consisitent with osteomyelitis. Osteomyelitis would also contribute to the formation of a non-union fracture. The tight bands of tissue palplated on the dorsum of the foot are the medial and common digital extensors. With the limb being placed in either the heavy bandage or the cast, the calf was unable to use its limb from day one of life, therefore, the tendons contracted. The contracted tendons are palpated as tight bands on the dorsum of the foot and are causing the toes to be raised.