Management Plan:

	Because Bonnie is a large breed dog as well as being overweight, we would recommend surgical correction over conservative management.  Surgical therapy also offers the advantage of being able to assess damage to the medial meniscus, which could have been damaged as a result of the tear of the cruciate ligament.  Should the meniscus appear grossly abnormal, it will need to be removed.
	Many surgical techniques have been described.  However, no single technique has been proven more effective than another.  We prefer one of the intra capsular techniques in order to adequately evaluate meniscal damage and it is regarded as a better choice for large breed dogs.  Due to the high incidence (greater than 80%) of meniscal damage occurring as a sequelae to complete cruciate ligament tears, we feel it is important to evaluate the meniscus.  During the intracapsular procedure we will also examine for articular erosions, osteophytes, and other ligamentous injuries.
	The goal of the various surgical techniques is to either repair, stabilize, supplement or replace the damaged cruciate ligament.  Of the many intra capsular reconstruction techniques, all of them consistently have a high success rate of 78 to 95%.
	The most popular of the intra capsular reconstruction techniques is the "under and over" method.  This technique stabilizes the joint by using a fascial graft to mimic the action of the cranial cruciate ligament.  The lateral third of the patellar tendon is dissected away including a strip of the fascia lata.  The graft is left attached to the tibia, passed through the joint and attached to the caudal and lateral side of the distal femur.  This graft acts like the natural cruciate ligament and will prevent cranial displacement of the tibia.  A screw is placed in the femur to anchor the distal portion of the graft.  The graft is looped around the screw and sutured to itself.
	Post operative care for Bonnie will include confinement to a crate or one room for at least fourteen days while she regains strength in the joint.  Two weeks postoperatively controlled exercise can be initiated.  By twelve weeks post surgery, Bonnie is expected to have regained normal function.  Bonnie will be prescribed phenylbutazone to control pain and inflammation.
One of the complications of this procedure is possible irritation by the screw, so we will monitor Bonnie for this adverse reaction.  Another possible complication with any of these surgical techniques is graft failure.  Bonnie's progress will need to be monitored for at least six months.  At this time, the screw can be removed.
Another option, should the owner choose,  is conservative management.  However, large working breeds often do not show a satisfactory recovery with this approach.  Conservative management would include enforced rest for two months, as well as analgesics such as phenylbutazone or aspirin.  The goal is fibrosis of the joint and effective stabilization of the joint to minimize movement and thus limit pain.  If the lameness persists after eight weeks of strict confinement and rest, Bonnie will then be considered a candidate for surgery.  A common sequela of conservative therapy in large breed dogs is severe degenerative joint disease.
In either option, Bonnie's obesity worsens the prognosis; therefore, weight management will be discussed with the owner.