Case Study 2

Question 1

Orthopaedic exam

Answer 1

Injured limb last because you want to know what the animal’s normal reactions are. Screen neurologic exam as well. Some neurologic diseases will present as lameness.

Question 2

How else can you test if presented with limbness or a joint issue? Or bone issue?

Answer 2

Arthrocentesis (joint fluid, sterile collection)

Bone biopsy- looking for primary or secondary bone neoplasia (early on, you would not necessarily see a tumour)

Also consider peripheral nerve neoplasia or joint neoplasia.

Question 3

Nutritional hyperparathyroidism

Question 4

Insertions and origins of the caudal and cranial cruciate ligaments?

Question 5

Medial buttress

Answer 5

Can palpate and see on cranial cruciate ligament injuries

response to instability- excessive fibrous soft tissue build up to try and stabilize the joint

Question 6

Soft tissue opacity within the stifle joint

Answer 6

Could be fluid- effusion, pus, blood, or tumour

Common with cranial cruciate ligaments

Question 7

Osteophytes

Answer 7

Under the patella and cranial aspect of the tibial plateau. Fabellae more irregularly margined.

Question 8

Cranial Cruciate Disease

Answer 8

Stastically most common cause of canine pelvic limb lameness

Worse after exercise

Worse after periods of rest

Supportive history and supportive radiograph changes

** not well understood but ligament cells become chondrocyte like over time. Cartilage holds up well under compression but not as much under tensile force. ALSO, the cranial cruciate ligament takes the most force out of the ligaments- takes the largest load. (ball rolling down the hill that is tethered- hill will move back if on a frictionless surface)

Question 9

Four functions of the Cranial Cruciate Ligament

Answer 9

Limit cranial subluxation of the tibia relative to the femur

Limit hyper-extension of the stifle

Limit internal rotation of the tibia relative to the femur

Mechano-receptor function- provides feedback to quadriceps and hamstring muscle groups

Question 10

What are the two orthopaedic manipulations to test the cranial cruciate ligament?

Answer 10

1. Cranial drawer
2. Cranial tibial thrust- aka degenerate thrust (can feel finger moving forward- because the tibia is being shunted forward- cranial subluxation)

Question 11

What if the cranial cruciate ligament is only partially ruptured?

Answer 11

(2 bands)- cranio-medial band is usually ruptured first

Cranio-medial band is taught during flexion and extension.

Extension- both bands are taut

If you test the knee in flexion, craniomedial band taut, caudolateral band lax. Ruptured CMB= instability

Question 12

Treatment options for cranial cruciate ligament disease

Answer 12

Weight loss, NSAIDs, joint modifying drugs (pentosan polysulfate), dietary manipulation, exercise restriction, ortho-brace

Question 13

Osteo arthritis

Question 14

Extra-capsular repair

Answer 14

Placed around the fabellae around to holes drilled in the distal patella ligament (?)- monofilament nylon (crushing aluminum tube)

VS.

Probably will be replaced by tightrope- abraided stronger prosthesis placed in a position more like true points of insertion of the cranial cruciate ligament. “Isometry”- points that are isometric around a joint do not change vs. the previous technique was not isometric.

Question 15

Geometry altering techniques

Answer 15

Cut the bone to treat the ligamentous problem. Biomechanics of the stifle

TPLO- Radial osteotomy- semi-circular. Around 24-26 degrees- you can walk without needing the cranial cruciate ligament- caudal cruciate ligament- quadriceps and hamstrings over compensate.

(other camp:)

TTA- separate biomechanical model. Osteotomy- angle between tibial plateau and patella tendon is 90 degrees or less- allows you to walk without cranial cruciate