Client Education Cruciate ligament injuries are common in people as well as dogs. Many high-profile athletes have had careers shortened by these types of injuries. Rupture of the cranial cruciate ligament (CCL) is often due to excessive trauma. However in BonnieÕs case it may have been due to several predisposing factors including but not limited to her conformation, activity level, and her overweight status. These injuries tend to occur when the knee is subjected to an abnormal or exaggerated motion. Large breed dogs, if they are overweight are definitely at risk for CCL, but small breeds can be affected as well. There are two cruciate ligaments in each knee joint. They are referred to by their anatomic location and are termed cranial and caudal cruciate ligaments. They run from the femur (thigh bone) to the tibia (shin bone) and are contained entirely within the knee joint itself. They act as stabilizers, keeping the tibia from sliding cranially beneath the femur when the limb bears weight and limiting the medial rotation of the tibia when the stifle is flexed. The most common injury we see is rupture of the CCL. These dogs generally have an acute (sudden) onset of lameness in the affected leg. The soft tissues around the knee joint may be swollen, and the joint itself is painful when manipulated. The dog may bear some weight on the leg or carry it off the ground. The diagnosis of CCL rupture is made based on history and palpation (feeling and manipulation) of the joint involved. Since many of these dogs tend to be quite large and strong, the palpation of the joint is sometimes carried out under sedation. When examining, we look for a typical type of instability in the joint cased by CCL rupture. This instability may present as a sliding forward of the tibia (shin bone) in relationship to the femur (thigh bone). This abnormal motion causes wear and tear on the joint cartilage causing damage and pain that leads to arthritis. This motion can also put excessive stress on the meniscus (c-shaped pieces of cushiony cartilage within the knee joint) causing damage to the knee. We took X-rays (only use this term with clientsÉnot medical professionals!) of the leg as well to rule out other causes for the lameness (possible fracture.arthritis, abnormal bone changes). Treatments include medical and surgical therapies. Most CCL injuries are treated surgically as it is truly only corrective measure for CCL in active dogs. There are quite a few techniques used to stabilize the joint and treat the ligamentous injury. Many variables are considered in deciding which technique is most appropriate for a given patient. Age, size, activity of dog as well as the surgeons personal experience and preference are factors that need to be considered. In BonnieÕs case we chose to use an intracapsular Òover the topÓ method. We also occasionally see partial ligament tears and injuries to the CCL. These can be more difficult to assess, but also may be treated surgically. We strongly believe that obesity plays a key role in CCL injury. Each pound of body weight puts that much more force on the joints and ligaments of the body with each step the dog takes. Lean, well conditioned dogs are less likely to develop these injuries. Post- operative care is critical to long term success. Bonnie is a prime candidate for weight reduction especially since 37% of dogs that undergo operative repair of CCL suffer contralateral CCL within one year. Proper management post-operatively may help. This will include switching Bonnie to a reduced calorie diet such as Science Diet light and cutting out any table scraps or extracurricular treats. The most critical element of post- surgical care is confinement to a small area. After surgery the knee is bandaged in a stable, walking configuration for 1 to 2 weeks. After that time the bandage and sutures are removed and we suggest physical therapy consisting of passive range of motion exercises that requires a few minutes three to four times daily. In a few weeks we want Bonnie to begin exercise to lose weight without being weight bearing. We would like to initiate water therapy (swimming) for a few weeks. We will gradually work up to short walks before Bonnie is back here for screw removal in 6 months. The importance of confinement when not working (therapy) cannot be overemphasized and despite BonnieÕs apparent ability and desire to run and jump reinjury or new injuries are likely during this period if not properly managed. Avoid slick floors, jumping, running, stairs until recovery is complete which may be 6-12 weeks. Medically nonsteroidal anti-inflammatory drugs (eg. Aspirin, carprofen, phenylbutazone) alleviate pain and discomfort from inflammation. Prognosis after surgery is good as there is a 78-95% success rate. However Bonnie is likely going to experience degenerative joint disease in the form of arthritis in years to come. Weight loss and good post-surgical care will help to maximize her quality of life.