Orthopedic Surgery Exam 2 Lecture Objectives Flashcards
What is the difference between ACL rupture in humans and CCLD in dogs?
-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
What factors influence CCLD?
-Aging of ligament (degeneration)
-Obesity
-Poor physical condition
-Conformation
-Breed
What breeds are at higher risk for CCLD?
-Rottweiler
-Newfoundland
-Staffordshire Terrier
-Mastiff
-Akita
-Saint Bernard
-Chesapeake Bay Retriever
-Labrador Retriever
What breeds are at LOWER incidence of CCLD?
-Greyhound
-Dachshund
-Basset Hound
-Old English Sheepdog
What are 2 important features to remember about canine CCLD?
- > 50% of dogs w/ cruciate ligament problems in one knee develop similar problem in other knee
- Partial tearing of CCL is common & typically progresses to full tear
What are the ligamentous supports of the stifle joint & how to they support the joint?
-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
What happens with stifle instability that is secondary to loss of integrity of the cranial cruciate ligament?
-Leads to abnormal tibial translation (cranial drawer, tibial thrust) & progressive osteoarthritis and meniscal injury
What are some common clinical signs of CCLD?
-Lameness (mild to severe)
-Joint swelling
-Decreased weight-bearing
What is the pathophysiology of CCLD?
-Instability causes abnormal wear, inflammation and degenerative joint changes
What would you find on a PE, screening tests, and diagnostic imaging associated with CCLD?
-Positive tests: cranial drawer, tibial compression
-Imaging: Radiographs show joint effusion, osteophytes
-Advanced diagnostics: arthroscopy confirms meniscal injury
What are some common complications of CCLD?
-Progressive DJD despite treatment
-Meniscal injury
-Contralateral limb involvement
-Surgical complications (e.g. implant infection)
Explain the difference between a partial and complete CCL tear
-Partial tear = intermittent lameness, drawer test may be equivocal
-Complete tear = obvious instability, marked lameness
Explain the basics of surgical intervention and conservative therapy in treating CCLD.
-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
Describe CCLD-associated meniscal tears and summarize the pathophysiology and diagnosis.
-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
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.
-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
What does TPLO do and what is the goal of it?
-Levels the tibial plateau to 5-7 degrees
-Goal: neutralize the cranial tibial thrust
What does TTA do and what is the goal of it?
-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
What is the overall goal of both TPLO and TTA procedures?
-Restore functional stability of the joint, not anatomical repair
Why do we need to inspect the meniscus during surgery?
-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
What is the long-term outcome of cranial cruciate injury/cranial cruciate disease that is treated with surgical intervention?
-Most dogs regain near-normal function
-DJD progresses, but at a slower rate
-Likelihood of contralateral tear remains
Give an overview of surgical techniques for CCLD.
-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
How do you properly perform a valgus stress test and what does the test evaluate?
-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
How do you properly perform a varus stress test and what does the test evaluate?
-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
What is the common triad of injuries seen with multiple stifle ligament injury in a deranged stifle?
- Cranial cruciate ligament tear
- Caudal cruciate ligament tear
- Failure of primary & secondary medial restraints, including peripheral meniscal tears
What does current literature say with regard to the efficacy of meniscal release in decreasing the incidence of post TPLO meniscal injury?
-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
What are the advantages/disadvantages of performing a partial meniscectomy vs. a total meniscectomy?
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
Summarize the medical management of meniscal injury.
-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)
What is the anatomy and function of the calcaneus?
-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
How does the presentation of a calcaneus fracture look?
-Fractures may cause non-weight-bearing lameness, plantigrade stance, pain, swelling & crepitus
-There may be valgus or varus deviation of the foot
What are the repair considerations for a fractured calcaneus?
-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
What are the major treatment considerations for tarsal fractures?
-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
What are the repair methods for tarsal fractures?
-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
How do the fracture type and number determine the treatment considerations for metatarsal fractures?
-1-2 bones fractured: splint or cast often sufficient; other bones provide internal support
-3-4 bones fractures: internal fixation typically indicated for stability
What are the surgical treatment considerations for metatarsal fractures?
-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
How would you select a method of treatment best suited to a tarsal or metatarsal fracture?
-Number of bones fractured
-Fracture type
-Functional requirements
-Fracture assessment score (FAS)
What general radiograph findings would you expect to see in a pathologic fracture secondary to a pre-existing disease?
-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
What forces at the fracture site are countered by an interlocking nail?
-Resist bending, rotational, and axial forces
What are the common errors during femoral fracture repair?
-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
How can we avoid the common errors during femoral fracture repair?
-Ensuring correct implant selection based on FAS
-Proper pin positioning & cutting the IM pin at the trochanter level
-Maintaining appropriate surgical technique & imaging guidance
How do we properly use bone plates for healing at a fracture site?
Bone plates most appropriate when:
-Rigid fixation required
-Fractures are unstable, comminuted or in weight-bearing bones
-Soft tissue coverage is sufficient
What are two steps that can be done to protect the sciatic nerve while repairing a femoral fracture with an IM pin?
- Shorten the IM pin at the level of the greater trochanter to prevent protrusion
- 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
Why is giving an accurate prognosis difficult when evaluating radiographs in patients with open physes?
-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
Why is stabilization of the fibula seldom necessary?
-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
What is the need for normograde IM pinning in the tibia of dogs and cats and why its important?
-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
