Management Plan

	Surgical correction of the cruciate rupture is recommended due to Bonnie's 
obesity and active life-style.  Conservative management would precipitate the formation 
of degenerative joint disease due to the continued stress placed on the joint from her 
excessive body weight and exercise.  An intra-capsular approach was chosen since 
Bonnie's weight makes the outcome of an extra-capsular approach less certain.  Also, 
intra-capsular approaches maintain the full range of motion while eliminating the cranial 
drawer sign while the extra-capsular approaches decrease the range of motion in the 
stifle.  
	An arthrotomy is performed at the start of the surgery so that the stifle can be 
fully investigated for any pathology missed on the radiographs.  At this time, the 
fragments of the ruptured cruciate are removed since they will cause osteoarthritis if they 
remain.  Also, any developing osteophytes are also removed at this time.  The possibility 
of a meniscal injury should be investigated since a damaged meniscus will negatively 
impact the post-operative prognosis and lead to the development of osteoarthritis.  If 
meniscal damage is noticed, then a partial meniscectomy is performed.  In comparison 
with a total meniscectomy, a partial meniscectomy decreases the impingement of the 
joint capsule between the femur and tibia, stress on the cartilage and articular 
degeneration.  Vascular access channeling increases regeneration of the meniscus due to 
the fibrovascular response of the pluripotential cells.  In this procedure, an incision is 
made from the periphery of the meniscus to the inner edge.  Complications to partial 
meniscectomy include synovitis and arthritis of the medial femoral condyle and tibial 
plateau.
	The intra-capsular under-and-over technique is performed once the stifle has been 
cleared of debris and lavaged.  In this technique, a fascial graft replaces the cranial 
cruciate ligament.  Since the graft roughly follows the path of the cranial cruciate 
ligament, the tibia is prevented from moving cranially during weight-bearing.  A lateral 
arthrotomy is performed and the lateral fascial graft is pulled under the intermeniscal 
ligament.  The graft is then pulled through the joint over the lateral fabella and sutured to 
femorofabella ligament.  Alternatively, to provide more support to the graft, a screw 
could be inserted into the femoral condyle to provide an attachment for the graft.  
However, the screw is associated with post-operative bony lysis and osteomyelitis.  
Immediately following the surgery, stability is provided by the graft then, as the healing 
progresses, fibrocartilage provides stifle support.  
There is a good prognosis with the under-and-over technique provided there are 
no serious complications as a result of the surgery.  With any intra-articular technique, 
there is the possibility of graft failure due to immune-mediated destruction or joint stress 
due to activity.  To decrease the chance of graft failure, Bonnie's left stifle should be 
placed in a splint and she should be confined (cage rest) for the first two weeks.  After 
this initial period, the stifle should be passively exercised with a gradual increase in 
activity.  Prolonged post-operative immobilization promotes muscle atrophy, decreased 
bone-ligament strength and articular cartilage damage while early mobilization provides 
controlled forces that help the healing cartilage.  However, early mobilization can lead to 
repair failure.  Progressive physical therapy can maintain muscle strength, range of 
motion, joint stability and decrease degenerative joint changes.  Immediate post-operative 
care includes oxymorphone, carprofen and cryotherapy to minimize pain and 
inflammation around the surgical site.  Cryotherapy (ice packs) increases 
vasoconstriction and muscle relaxation while decreasing nerve conduction to provide 
mild analgesia and reduce inflammation.  Passive stifle movement maintains the normal 
range of motion, decreases the cartilage damage caused by immobility and improves 
blood flow to the area.  Once Bonnie is able to use her limb, she should be allowed to 
swim since swimming allows movement of the joints without adding the stress of her 
body weight.
An important component of Bonnie's therapy includes weight reduction since 
obesity was a predisposing factor in her injury and can cause degenerative changes in the 
future.  Her daily intake of calories should be 1132 kcal.  Therefore, she should receive 
about 4 cups of Hill's Science Diet Canine Light each day.