Lindsey Savage

Learning Issues:

1.	How can the cranial drawer sign be negative when awake but positive when 
sedated?

	A false negative cranial drawer sign occurs when there is excessive pain 
and the animal tenses the surrounding muscles to stabilize the joint.  When the 
animal is under sedation, the muscles are relaxed and allow movement of the 
stifle.  Other causes of a negative cranial drawer test under anesthesia include 
severe swelling and periarticular fibrosis.  A partial rupture will not always 
result in a positive cranial drawer sign.

2.	Is any amount of cranial drawer considered a positive result or is there a 
threshold displacement before it is positive? (ie: is <2mm a positive test?)

	<2 mm is probably not indicative of a cruciate ligament problem since one 
study found that 1-2 mm of cranial drawer is normal with intact cruciate 
ligaments.  However, in that same study, 7-10 mm of cranial drawer was found 
with complete cranial cruciate ligament rupture, so I'm not sure if 4-5 mm of 
laxity indicates a partial rupture or a complete rupture.

3.	Does a cranial drawer sign always indicate a cranial cruciate ligament 
rupture?
	
	Yes-a cranial drawer sign is indicative of cranial cruciate ligament 
rupture.  Concurrent medial buttressing is pathopneumonic however.

4.	What is the normal stifle anatomy? (ligaments, etc.)

	The stifle joint consists of the femorotibial joint (femoral/tibial 
condyles), femoropatellar joint (patella/femoral condyle) and the proximal 
tibiofibular joint.  There are 4 ligaments: cranial cruciate, caudal cruciate, 
medial collateral, and lateral collateral.  Two medial and lateral menisci are 
located between the condyles and are made of fibrocartilage.  They are attached 
to the joint capsule and are responsible for transmitting 65% of the weight 
across the stifle.  The tendons of the popliteal muscle and the long digital 
extensor also run through the stifle.  The cranial cruciate runs from the 
caudomedial lateral femoral condyle to the cranial tibial plateau between the 
tibial condyles.  It prevents abnormal cranial/caudal movement of the stifle, 
internal stifle rotation, and stifle hyperextension.  Innervation to the stifle 
comes from the tibial and common peroneal nerves.

5.	What diseases usually/have the potential to localize to the stifle joint?

	Cruciate ligament rupture, collateral ligament rupture, osteoarthritis, 
joint sepsis, avulsion of long digital extensor tendon, avulsion of 
gastrocnemius origin, fabellar separation, stifle luxation, osteochondrosis, 
fractures, immune-mediated arthritis, and Neoplasia

6.	Is the dog's current diet appropriate for her activity and body condition 
score?

	No-with an estimated 85 lbs BW, she should be getting 1084 kcal/day.  
Instead she is getting 1460 kcal/day.