Exam 2 Flashcards
Lecture 27 Developmental Bone Diseases
- Gait analysis
- PE
- Describetheetiopathogenesis,signalment,history, and clinical signs the common developmental bone diseases in small animal patients
• Panosteitis: uncommon
• Hypertrophic Osteodystrophy: uncommon
• Retained Ulnar Cartilaginous Core: common
• Legg-Calve-Perthes Disease: common
- Knowthediagnosticproceduresusedtodiagnose developmental bone diseases in small animal patients
- Knowthemedicalandsurgicaltreatmentoptionsfor each of the diseases above
Primarily Inflammatory
a. Panoteistis:
shifting leg lameness, Pain on deep bone palpation
-Generally weight bearing, intermittent
-German Shepherds (a.k.a juvenile osteomyelitis)
-Male large breed dogs
-Young dogs <2 years old
-Lameness, bone pain, endosteal bone production and occasional periosteal bone production
-considered a disease of adipose bone marrow
-Repeat radiographs in 7-10 days, clinical signs may precede changes seen in radiographs
-Unknown etiology: theory of high high calorie diet
-Radiographs: radiopaque patchy or molted bone “CLOUDS” trabecular patterns
Tx: Surgical not indicated
-Self-limiting disease
-Nonsteroidal anti-inflammatory drugs
-Exercise restriction when lame
-Recurrence common
b. Hypertrophic osteodystrophy (HOD) (HO: older patients)
-Disease causing disruption o metaphyseal traberculae
-Long bones of young rapidly growing dogs
-Unknown etiology
-Diminished vitamin C? (dogs make their own vitamin C)
-Distemper vaccination? Weimaraner puppies
-GI/respiratory?
Widening of the physis due to increased width of hypertrophied chondrocyte zone
Disturbance of metaphyseal blood supply
Infiltration of neutrophils and mononuclear cells
Osteoclastic resorption: no bone formed on calcified cartilage
-Young large breed dogs
-Acute onset of lameness
-Recent diarrhea
-Inappetence and lethargy
-3-4 months of age mostly signs appear
-Mild to severe lameness in all four limbs
**Septic arthritis, septic physitis, panosteitis.
Radiographs: radiolucent line on metaphyseal side of physics. DOUBLE PHYSIS
Prognosis: Guarded
-Most recover fully and 7-10 days relapses occur
-Euthanasia
-Focused on supportive treatment
-Corticosteroids if bacteremia has been ruled out.
Retained Ulnar Cartilaginous Core disease
-Large, immature breeds. Great Danes
-CARPAL VALGUS
-Forelimb deformities
-No correlation noted between size of lesion, histopathology, and severity of forelimb deformity.
-Retained hypertrophic chondrocytes: failure of growth plate cartilage to convert to metaphyseal bone
-Cones of growth plate cartilage
-Project from distal ulnar growth plate into distal metaphysis
-Radiographs: radiolucent core (triangle) of cartilage
-Tx: cores may disappear spontaneously, if no deformity no treatment, otherwise surgery maybe necessary.
Legg-Calve-Perthes Disease
-Occurs in young patients
-Small breeds <10kg
-Males and females affected, 6-7 its age peaks
-Occurs bilaterally or unilaterally
-Acute onset of lameness, Non-bearing weight
-Reduced appetite, irritability, chewing skin over hip
-Common MPL (medial patella luxation)
-Hip joint pain, limited range of motion.
-Before Capital femoral physics closure
-ak.a: Osteochondritis dissecans of femoral head and avascular necrosis of femoral head.
-Non-inflammatory aseptic necrosis
-Collapse of the femoral epiphysis caused by interruption of blood flow
-Genetic??
-Synovitis or sustained abnormal limb position
-May increase intra-articular pressure
-Collapses fragile veins and inhibits blood flow
-Results in DJD and joint incongruity
-Radiographs: femoral head deformity
-Tx: conservative, if prior to femoral head collapse. Surgical management: Excision of femoral head (Femoral Head Ostectomy). NSAIDs, Canine Rehabilitation, Passive flexion-extension.
Red Flag: NWB before surgery, severe preoperative muscle atrophy.
Lecture 19 Mechanisms of Bone Healing
- Describe the requirements for primary (contact & gap) versus secondary (indirect) bone healing to occur
- Describe the phases of primary (direct) gap bone healing
- Describe the phases of secondary (indirect) bone healing
- Describe the difference between intramembranous and endochondral ossification
- List and describe types of fracture healing failures (delayed union, nonunion, malunion)
- List and describe the different types of bone grafts
- List and describe the common locations for the collection of cancellous bone grafts
- Describe the requirements for primary (contact & gap) versus secondary (indirect) bone healing to occur
-Osteoprogenitor cells directly from MSCs
-Organic and water: 35 %
-Inorganic:65 % mostly hydroxypatite crystallin form of calcium.
-Anatomy: EMD: Epiphysis, Metaphysis, Diaphysis.
Direct Fracture healing
1. Stable
2. Rigid: plates, small gap
3. Blood supply
-Osteonal reconstruction
-Less than 2% strain
-Rigid fixation
-Minimal or no fracture gap
-Contact healing <300 mm gap: Osteons a.k.a cutting cones, cross fracture plane- one fragment to the other.
-Gap healing < 1mm gap: Osteoblasts form deposit perpendicular lamellar bone in gap. Lamellar bone becomes longitudinally oriented (stronger than perpendicular).
Indirect (secondary) fracture healing
-Most common type
-Enhanced by motion
-Requires callus formation
-Intermediate callus formation
- Endochondral ossification
-Direct bone formation intramembranous = no cartilagenous intermediate.
- Describe the phases of primary (direct) gap bone healing
-Gap < 1mm
-Blood vessels and connective tissue form
-Osteoblast deposit perpendicular lamellar bone in gap
-Cutting cones transverse fracture plane
-Lamellar bone becomes longitudinally oriented, stronger than perpendicular.
- Describe the phases of secondary (indirect) bone healing
BMP: Bone Morphogenic Protein most important
General phases of INDIRECT Fracture Healing
- Hematoma formation (inflammatory phase). Transforming Growth Factor Beta. Periosteal proliferation.
- Intramembranous bone formation (cartilage not present): Soft callus formation (proliferative) phase
- Chondrogenesis: Hard callus formation (maturing or modeling) phase
- Endochondral ossification very similar to metaphyseal growth plate: Remodeling phase
-Less rigid fixation than direct healing with callus formation, external fixators used, pins/wires. Heals faster than direct bone healing.
- Describe the difference between intramembranous (cartilage is not present) and endochondral (cartilage is present) ossification
Ask for review
- Intramembranous bone formation: Soft callus formation (proliferative) phase
- Chondrogenesis: Hard callus formation (maturing or modeling) phase
- Endochondral ossification very similar to metaphyseal growth plate: Remodeling phase
- List and describe types of fracture healing failures (delayed union, nonunion, malunion)
Fracture non-union
Weber-Check classification
a. Viable (vascular)
Viable-Hypertropic Non-union
1. Abundant callus: NOT bridging the fracture site. “Elephant foot” Inadequate stabilization, premature weight-bearing, too much activity of patient.
2. Mild callus: “Horse foot” plate breaks, screws pull out.
Viable Oligotropic Non-union: pins break, never put a pin in a radius.
b. Nonviable (avascular)
Note: Nutrient artery 80-85% of blood supply to bone
1. Non-viable Dystrophic: intermediate fragments of fracture heal to 1 main fragment and not the other. Causes: poor blood supply, instability on vascular site, older or diabetic animals.
2. Non-viable necrotic non-union: fragments have no blood supply, can’t bind to any main fragments. Causes: avascular, infection on site. Sequestrum is an avascular fragment that has no infection.
3. Non-viable Defect Non-union: Large defect, they can’t bridge bone. Cause: massive loss of bone at fracture site.
4. Non-viable Atrophic Non-union: The most difficult cases, end result of the other 3 non-union, amputation
c. Malunion
-Fracture that heals in a non-anatomic position. Causes: untreated fracture, improperly treated, premature excessive weight-bearing. Results in limb deformities, shortening, gait abnormalities, degenerative joint disease.
d. Delayed union
-Fracture that has not healed in expected time considering the patient and fracture environment
- List and describe the different types of bone grafts
Bone grafts are a type of treatment for Non-union fractures
- Autogenous: within the same individual
- Allograft: different individuals, same species
- Xenograft: different individuals, different species
The Os of grafting
-Osteogenesis: osteoblast that survive transfer. Very few do.
-Osteoconduction: graft acts as scaffold in which new bone is laid down
-Osteoinduction: grafts induces cells to promote new bone BMP (Bone Morphogenic Protein) from Mesenchymal cells
-Osteopromotion: material that enhances regeneration of bone. Platelet rich plasma.
- List and describe the common locations for the collection of cancellous bone grafts
-Ilial wing
-Proximal tibia
-Humerus
Principles of Minimally invasive Surgery
- Define/explain the common definitions & terminology used in minimally invasive surgery.
- Identify the four basic principles that apply to most endoscopic procedures.
- Summarize the advantages and disadvantages of endoscopic removal of foreign objects.
- Explain precautions to take as a beginning arthroscopist.
- State the most significant diagnostic advantage of arthroscopy.
- Define/explain the common definitions & terminology used in minimally invasive surgery.
Endoscopy: use of an instrument (endoscope) to visualize interior of an organ or body cavity that can not be examined without surgery
Flexible endoscopy: endoscope with flexibility, >180 degrees, can be bend to look around, mover around corners.
Handle: where the scope is held by operator
Insertion tube: part that is inserted into the patient
Umbilical cord: part that attaches scope to light source and video processor.
Biopsy channel: passage to place instruments through scope (e.g., biopsy forceps, foreign body retrieval forceps, aspiration tubes) and aspirate air or liquids.
Flexible immersible scopes: have handles placed in water without risk of damage.
A. Umbilical cord
B. Handle
C. Insertion tube
Rigid endoscopy
-Plastic or metal scope that can not bend
-Obturator: device placed through hollow endoscope to facilitate insertion of scope into an organ (e.g., esophagus, colon).
-Trocar: obturator with sharp point to facilitate penetration through tissue.
-Portals defined by use: scope inserted through scope or camera portal.
-Instrument portal: power or hand tools inserted through instrument portal.
-Cannulas: metal tubes that maintain portals and protect instruments
-Triangulation: visualization of instrument through scope to perform biopsies or therapeutic procedures within body cavity.
Gastroduodenoscopy: endoscopy of esophagus, stomach and duodenum (ocassionally upper jejunum)
-Colonoscopy: endoscopy of colon
-Ileoscopy: endoscopy of ileum (perform with colonoscopy)
-Protoscopy: examination of anus and rectum
-Bronchoscopy
-Laryngoscoy
-Rhinoscopy
-Cytoscopy: urinary bladder, may be retrograde (advancing scope through urethra) or trans abdominal (placing scope through cannula inserted through abdominal wall and bladder).
-Vaginoscopy
-Laparoscopy: peritoneal cavity (biopsies), interventions such as Gastropexy, Jejunostomy tube placement.
-Thoracoscopy: pleural cavity
-Arthroscopy: endoscopy of a joint.
Arthroscopy
-Always done through cannula (protects scope)
-Instrumenting
-Triangulating
-Fluid flowing into joint: inflow or ingress
-Fluid flowing out of the joint: outflow or egress
Second-look arthroscopy: usually research use primarily
- Identify the four basic principles that apply to most endoscopic procedures.
- Valuable only when successful
- Eliminates need for more invasive surgery
-Not useful if unacceptable trauma to tissue occurs, biopsy sample is not useful, mucosal surface can not be examined, etc. - Training and expertise required for optimal procedure, regular practice needed
- Patients should be referred if no expertise available.
- Summarize the advantages and disadvantages of endoscopic removal of foreign objects.
Grastroduodenoscopy
-Gastric and intestinal biopsy/cytology for diagnosis of infiltrative and lymphatic disorders
-Removal of gastric polyps
-Location of ulcers, etc.
Esophagoscope
-Identification and removal of foreign objects
-Biopsy tumors
Proctoscopy and Colonileoscopy
-Diagnosis of cecocolic intussusception (also ultrasound)
-Identification of occult whipworm infestation
-Biopsy of colon, rectum, ileum, or cecum.
Laryngoscopy
-Identification of laryngeal paralysis, biopsy, mass removal, etc.
Cystoscopy
-Diagnosis of ectopic ureters
-Urethra and bladder
Thoracoscopy
-Performance of minimally invasive surgery
Bronchoscopy
-Collapsed trachea, stents evaluation/placement, etc.
Rhinoscopy
-Aspergillomas in German shepherds
-Identification and removal of foreign objects.
Posterior Nares (Choanal) Examination
-Identification of nasal mites, stents placement, etc.
Laparoscopy
-Minimally invasive surgery. Ovariohysterectomy
- Explain precautions to take as a beginning arthroscopist.
-Identification of lesions
-Removal of loose bodies (cartilage fragments, bone fragment, torn meniscus).
-Topical management of osteoarthritis
-Joint lavage for sepsis
Flexible vs Rigid endoscopy
-Flexible more expensive
-Rigid more durable
-Easier to learn to use
-Capable of larger biopsies than flexible
-Alligator biopsy forceps
Rigid Laparoscope
-Autoclavable
Four principles for most endoscopy procedures
- Advance scope only if you can see where you are going
- If you can not see what is happening, back scope out a little or insufflate a little with air/infuse some fluid into lumen or both.
- Do not insert endoscope into patient any harder than you would want a physical to insert it into you
- Aim scope toward center of lumen unless looking at a specific lesion.
- State the most significant diagnostic advantage of arthroscopy.
Arthroscopy
-Vastly superior to radiography in diagnosis of joint disease
Most significant advantage: Ability to asses condition of cartilage surface
-Most common use is fragment removal
-Osteochondritis Dessicans (OCD).
-Fragmented Coronoid Process (FCP)
-Treatment of meniscal injury
-Assessment of cartilage and intra-articular injuries
-Synovial biopsy
-Tenotomy (biceps tendon)
-Arthroscopic assisted fracture repair.
Advantages of Endoscopy removal of foreign objects
-Faster than surgery
-Less stressful to patient
-Reduced tissue trauma, morbidity and recovery time
-Reduced cost to client
Disadvantages
-Cannot remove all objects
-Can hurt patient with careless technique
-Requires assortment of expensive foreign body retrieval devices
Arthroscopy view of shoulder joint
As you begin arthroscopy be prepared to perform an arthrotomy if unsuccessful removal of fragments occurs.
Routine Elbow procedures
-OCP
-FCP
-Microfracture
-Abrasion
a. Glenoid cavity
b. Medial collateral ligament
c. Subscapularis ligament
d. Humeral head
Most common diagnosis for FCP elbow
Most common Cruciate or meniscal disease stifle joint
Principles of Orthopedic Surgery
- The student will explain how a Fracture Assessment Score is derived, what the general groupings are for the scores, and the implications for implant selection and fracture healing based upon a given fracture assessment score.
- Given a fracture involving the physeal region of a long bone, the student will assign the fracture a Salter-Harris classification.
- The student will define common orthopedic terms.
- The student will classify a fracture using the 5 areas addressed as bases for fracture classification.
- The student will match common fracture patterns to the forces known to be associated with the fracture pattern.
