Orthopedic Surgery Exam 2 Lecture Objectives

Question 1

What is the difference between ACL rupture in humans and CCLD in dogs?

Answer 1

-In humans ACL rupture is typically traumatic
-In dogs, CCLD is a degenerative disease that occurs over time, not due to trauma to a healthy ligament

Question 2

What factors influence CCLD?

Answer 2

-Aging of ligament (degeneration)
-Obesity
-Poor physical condition
-Conformation
-Breed

Question 3

What breeds are at higher risk for CCLD?

Answer 3

-Rottweiler
-Newfoundland
-Staffordshire Terrier
-Mastiff
-Akita
-Saint Bernard
-Chesapeake Bay Retriever
-Labrador Retriever

Question 4

What breeds are at LOWER incidence of CCLD?

Answer 4

-Greyhound
-Dachshund
-Basset Hound
-Old English Sheepdog

Question 5

What are 2 important features to remember about canine CCLD?

Answer 5

1. > 50% of dogs w/ cruciate ligament problems in one knee develop similar problem in other knee
2. Partial tearing of CCL is common & typically progresses to full tear

Question 6

What are the ligamentous supports of the stifle joint & how to they support the joint?

Answer 6

-Cranial cruciate ligament (CCL): prevents cranial tibial translation, hyperextension, and internal rotation

-Caudal cruciate ligament (CaCL): prevents caudal tibial translation

-Medial & Lateral collateral ligaments: Prevent medial-lateral instability

Question 7

What happens with stifle instability that is secondary to loss of integrity of the cranial cruciate ligament?

Answer 7

-Leads to abnormal tibial translation (cranial drawer, tibial thrust) & progressive osteoarthritis and meniscal injury

Question 8

What are some common clinical signs of CCLD?

Answer 8

-Lameness (mild to severe)
-Joint swelling
-Decreased weight-bearing

Question 9

What is the pathophysiology of CCLD?

Answer 9

-Instability causes abnormal wear, inflammation and degenerative joint changes

Question 10

What would you find on a PE, screening tests, and diagnostic imaging associated with CCLD?

Answer 10

-Positive tests: cranial drawer, tibial compression

-Imaging: Radiographs show joint effusion, osteophytes

-Advanced diagnostics: arthroscopy confirms meniscal injury

Question 11

What are some common complications of CCLD?

Answer 11

-Progressive DJD despite treatment
-Meniscal injury
-Contralateral limb involvement
-Surgical complications (e.g. implant infection)

Question 12

Explain the difference between a partial and complete CCL tear

Answer 12

-Partial tear = intermittent lameness, drawer test may be equivocal

-Complete tear = obvious instability, marked lameness

Question 13

Explain the basics of surgical intervention and conservative therapy in treating CCLD.

Answer 13

-Surgery: gold standard, especially for large breeds; can slow arthritis

-Conservative: Only considered for dogs <20-25 lbs. (still develop DJD)

-Braces, rehab: Limited benefit & rarely replace surgery

Question 14

Describe CCLD-associated meniscal tears and summarize the pathophysiology and diagnosis.

Answer 14

-Medial meniscus: most commonly affected due to firm attachment to medial collateral ligament (MCL)

-Common injuries: Bucket handle tear, folded caudal horn

-Diagnosis: “Meniscal click”, arthroscopy, sudden worsening of lameness

Question 15

What are the literature findings with regard to published assessments of outcomes and success rates for surgical intervention for ruptured cranial cruciate ligaments, regardless of the surgical technique used.

Answer 15

-Regardless of technique, there is about 90% success rate

-No techniques prevent OA progression, but can improve quality of life and slow DJD

-Large breeds benefit most from TPLO or similar techniques

Question 16

What does TPLO do and what is the goal of it?

Answer 16

-Levels the tibial plateau to 5-7 degrees
-Goal: neutralize the cranial tibial thrust

Question 17

What does TTA do and what is the goal of it?

Answer 17

-Advances tibial tuberosity to make patellar ligament perpendicular to tibial slops
-Goal: neutralize thrust force by elimination the tibiofemoral shear force with weight-bearing and relieving the function of the CCL

Question 18

What is the overall goal of both TPLO and TTA procedures?

Answer 18

-Restore functional stability of the joint, not anatomical repair

Question 19

Why do we need to inspect the meniscus during surgery?

Answer 19

-Medial meniscus is often damaged and needs intraoperative assessment
-Most common injury is a bucket handle tear
-Meniscal release or removal may be performed to prevent future damage

Question 20

What is the long-term outcome of cranial cruciate injury/cranial cruciate disease that is treated with surgical intervention?

Answer 20

-Most dogs regain near-normal function
-DJD progresses, but at a slower rate
-Likelihood of contralateral tear remains

Question 21

Give an overview of surgical techniques for CCLD.

Answer 21

-Extracapsular Stabilization: suture mimics ligament; better for small dogs

-TPLO: Alters biomechanics by leveling tibial slope

-TTA: Advances tibial tuberosity

-CBLO & TWO: Osteotomy alternative adjusting load-bearing

-Fibular Head Advancement: Rare; alters muscle-tendon biomechanics

Question 22

How do you properly perform a valgus stress test and what does the test evaluate?

Answer 22

-Evaluates the medial collateral ligament (MCL)
-Patient placed in lateral recumbency
-One hand stabilizes the femur while the other grasps the distal tibia and applies an abduction (outward force)
-Opening of the medial joint line indicates injury to the MCL, joint capsule, or peripheral meniscal ligaments

Question 23

How do you properly perform a varus stress test and what does the test evaluate?

Answer 23

-Evaluates the lateral collateral ligament (LCL)
-Patient placed in lateral recumbency
-One hand stabilizes the femur while the other grasps the distal tibia and applies an adduction (inward) pressure to the tibia
-Opening of the lateral joint line indicates LCL injury or associated lateral joint structures

Question 24

What is the common triad of injuries seen with multiple stifle ligament injury in a deranged stifle?

Answer 24

1. Cranial cruciate ligament tear
2. Caudal cruciate ligament tear
3. Failure of primary & secondary medial restraints, including peripheral meniscal tears

Question 25

What does current literature say with regard to the efficacy of meniscal release in decreasing the incidence of post TPLO meniscal injury?

Answer 25

-No clinical studies definitively demonstrate the efficacy of meniscal release in reducing post-TPLO meniscal injury -It compromises meniscal function, reduces hoop stress, and increases contact pressure on articular cartilage & can contribute to DJD -It is still widely used, but remains controversial

Question 26

What are the advantages/disadvantages of performing a partial meniscectomy vs. a total meniscectomy?

Answer 26

**Partial Meniscectomy**: -**Preferred** in most cases, especially for bucket handle tears -Removes only the damaged portion -**Preserves meniscal function**, leading to less DJD -Lower morbidity compared to total meniscectomy **Total Meniscectomy**: -Only indicated when the **peripheral rim is too damaged** to allow primary suturing -Removes entire meniscus -Leads to **rapid onset and progression of DJD** due to loss of joint congruency & shock absorption -Considered **last resort**

Question 27

Summarize the medical management of meniscal injury.

Answer 27

-**Medical conservative management is not recommended for** most meniscal injuries b/c the torn meniscus continues to slide back and forth causing pain & joint damage -Conservative management may be **briefly considered only in a very stable joint**, but is rarely effective -**Surgical treatment is the standard** (typically a partial meniscectomy to remove damaged portion)

Question 28

What is the anatomy and function of the calcaneus?

Answer 28

-The calcaneus is the largest of the tarsal bones -It forms a stable joint with the talus and serves as the **insertion point for the Achilles tendon**, particularly at the tuber calcanei, playing a crucial role in **weight bearing & locomotion**

Question 29

How does the presentation of a calcaneus fracture look?

Answer 29

-Fractures may cause **non-weight-bearing lameness, plantigrade stance, pain, swelling & crepitus** -There may be valgus or varus deviation of the foot

Question 30

What are the repair considerations for a fractured calcaneus?

Answer 30

-Fractures are often **distracted by the pull of the gastrocnemius muscle**, which impedes healing -Surgical stabilization is required -> tension band wire, lag screws, or plate fixation used to resist tensile forces -Poor stabilization can result in nonunion or delayed union

Question 31

What are the major treatment considerations for tarsal fractures?

Answer 31

-Surgical repair is necessary -> conservative management is not indicated -Achieving anatomic reduction & rigid fixation is essential to avoid joint incongruity & OA -Postoperative management includes pain control, computation (bandages or splints) and controlled activity

Question 32

What are the repair methods for tarsal fractures?

Answer 32

-Calcaneus: tension band wiring, lag screws, or plating depending on fracture type -Talus: Diverging K-wires or lag screws for articular surface; arthrodesis if reconstruction is not feasible -Central tarsal bone: small lag screws, especially in racing greyhounds

Question 33

How do the fracture type and number determine the treatment considerations for metatarsal fractures?

Answer 33

-1-2 bones fractured: splint or cast often sufficient; other bones provide internal support -3-4 bones fractures: internal fixation typically indicated for stability

Question 34

What are the surgical treatment considerations for metatarsal fractures?

Answer 34

-Athletic or racing dogs require anatomic reduction and rigid stabilization (plates/screws) for optimal performance -Large avulsed fragments require open reduction & lag screw fixation -IM pins, external fixators, and bridging plates may be used based on FAS

Question 35

How would you select a method of treatment best suited to a tarsal or metatarsal fracture?

Answer 35

-Number of bones fractured -Fracture type -Functional requirements -Fracture assessment score (FAS)

Question 36

What general radiograph findings would you expect to see in a pathologic fracture secondary to a pre-existing disease?

Answer 36

-Cortical lysis & new bone formation in the area of the fracture -These often present as lytic-proliferative lesions, most commonly due to primary or metastatic bone tumors -Fractures may occur through the tumor site, but not always

Question 37

What forces at the fracture site are countered by an interlocking nail?

Answer 37

-Resist **bending, rotational, and axial forces**

Question 38

What are the common errors during femoral fracture repair?

Answer 38

-Improper placement of implants, especially w/ IM pins that can damage the **sciatic nerve** -Not shortening retrograde IM pins or incorrect pin trajectory can injure surrounding structures -Inadequate implant selection, particularly in relation to the FAS

Question 39

How can we avoid the common errors during femoral fracture repair?

Answer 39

-Ensuring correct implant selection based on FAS -Proper pin positioning & cutting the IM pin at the trochanter level -Maintaining appropriate surgical technique & imaging guidance

Question 40

How do we properly use bone plates for healing at a fracture site?

Answer 40

Bone plates most appropriate when: -Rigid fixation required -Fractures are unstable, comminuted or in weight-bearing bones -Soft tissue coverage is sufficient

Question 41

What are two steps that can be done to protect the sciatic nerve while repairing a femoral fracture with an IM pin?

Answer 41

1. **Shorten the IM pin** at the level of the greater trochanter to prevent protrusion 2. During retrograde pin placement, maintain the hip in extension & the femur adducted to guide the pin properly through the trochanteric fossa, minimizing the risk of nerve injury

Question 42

Why is giving an accurate prognosis difficult when evaluating radiographs in patients with open physes?

Answer 42

-B/c it is challenging to determine the extent of physeal damage & predict growth disturbances -The rads may not show subtle physeal injury or predict how the injury will affect future bone development, making prognosis unreliable

Question 43

Why is stabilization of the fibula seldom necessary?

Answer 43

-The tibia bears weight, making fibular repair usually unnecessary -Unless the fibula fracture affects the stability of the stifle or hock, particularly the lateral collateral ligament support

Question 44

What is the need for normograde IM pinning in the tibia of dogs and cats and why its important?

Answer 44

-It is the **preferred method** in tibial fractures b/c retrograde pinning risks **joint injury or misdirection** -Helps avoid complications due to narrow medullary canal & proximity of the stifle & hock joints -Provides excellent resistance to bending but requires additional support for rotational & axial stability