Plan of Action Radiographs of the left stifle-We would take radiographs while the dog is under sedation to prevent the dog from feeling discomfort on manipulation of the joints. Radiographs would allow evaluation of possible osteoarthritis. They can be used to identify alterations in the joint space, osteophyte formation, and the presence of joint erosion and degeneration (as in degenerative joint diseases and in Rheumatoid Arthritis). With non- erosive immune-mediated joint conditions, such as Canine SLE associated arthritis, on observation of radiographs, there should be minimal radiographic change. With this condition, there should be no evidence of bony changes. Some periarticular soft tissue changes will be seen. With septic arthritis, initially there would be no changes seen on radiographs, or a widened joint space due to synovial effusion. Later, lytic subchondral bone changes, periosteal proliferation, and narrowing of the joint space are changes which can be expected to be seen on radiographs. Septic arthritis can be caused by trauma or osteomyelitis. With osteomyelitis, lysis and proliferation of subchondral bone and a widened joint space can be seen on radiographs. Two views should always be obtained for each joint to be evaluated (lateral view and anterior/posterior view). Radiographs of the thorax and abdomen should also be taken in patients with inflammatory joint disease when infectious and neoplastic diseases are suspected. Although radiography is an important tool, it has limitations as well. It often takes weeks or months for evidence of bony changes associated with degenerative and erosive joint diseases to be seen on radiographs after the onset of these diseases. Joint tap-In a dog with normal joints, synovial fluid would have a white blood cell count of 200-3000 and a PMN cell percent of less than 10%. In an animal with normal joints, there would be a normal mucin clot test. In the case of an animal with joint conditions caused by trauma, there would be a variable number of white blood cells and a PMN cell percent of less than 25%. The white blood cell count would depend on the introduction of infectious agents such as bacteria. The mucin clot test would be normal in an animal with joint conditions caused by trauma (at least at an early stage). In a joint tap in a situation with a dog having septic arthritis, one would expect to find a white blood cell count of 40000-280000 and a PMN cell percent of 90-99%. Cells might contain bacteria, and the neutrophils in this situation would likely be toxic, ruptured or degranulated. The synovial fluid with joint sepsis would be increased in volume of turbid, yellow to serosanguinous fluid with low viscosity and increased protein content. An animal with septic arthritis would have a diminished mucin clot. In the situation of a dog with degenerative conditions/diseases in the joint, there would be a white blood cell count of 1000-5000 and a PMN cell percent of 0-12%. With rheumatoid arthritis of an erosive nature in the joint, there would be a white blood cell count of 6000-80000 and a PMN cell percent of anywhere from 20-80%. The synovial fluid with an animal with rheumatoid arthritis would be slightly turbid, yellow to pink in color, have decreased viscosity and a negative culture. An animal with rheumatoid arthritis would have a diminished mucin clot. With immune-mediated conditions in the joint of a non-erosive nature, there would be a white blood cell count of 4000-370000 and a PMN cell percent of 15-95%. These types of non-erosive immune-mediated conditions would tend to be in smaller joints, and synovial fluid would tend to be the same as in other forms of immune- mediated arthritides. The neutrophils in an immune-mediated condition would be expected to of normal appearance. Cranial Drawer Sign-The diagnosis of a cranial cruciate ligament rupture occurs with a positive cranial drawer movement during physical examination. In addition to the cranial drawer sign that was previously performed, we would recommend an additional attempt to elicit a more specific cranial drawer sign in the dog under sedation in order to see if the cranial cruciate ligament is partially or completely ruptured. The increased cranial movement (greater than 3-5 mm) of the tibia relative to the femur indicates rupture of the cranial cruciate ligament. With a complete rupture of the cranial cruciate ligament, there would be a positive cranial drawer sign in full flexion, full extension, and in the 140 degree/standing position. In the case of a partial rupture of the cranial cruciate ligament, there would be an increased cranial drawer sign in the flexed position, minimal movement in the140 degree position, and no movement in the extended position. With meniscal injuries, during all previously mentioned manipulations, upon palpation, there would be evidence of crepitance, clicking, popping, or a Ògiving away.Ó