Orthopedics Flashcards
When would you use a neutralization vs. compression plate?
Neutralization: reducible, midshaft, comminuted fracture
Compression: transverse fractures, lag screws with oblique fractures can work too
What forces does the bone plate neutralize?
Axial, rotational, torsion, bending
What is the most common cause of nonunion?
Motion
What forces does a cast neutralize?
Bending and a little rotational (not axial loading)
What forces does an IM pin neutralize?
Only bending
What forces does a cerclage wire neutralize?
torsion (these are rarely used on their own)
What forces does a plate neutralize?
Bending (attached to bone), axial loading, Torsion
What forces does External Fixators neutralize?
Bending, axial loading, torsion
Interlocking nail forces neutralize?
Implant that is fixed to the bone: bending, axial compression, torsion
What are the objectives of fracture fixation?
- We want them early weight bearing
- Osseous union (healing) and return to normal function
Things we can control with fracture assessment:
reduction
immobilization
excessive operative trauma
asepsis
What is an example of a high fracture score assessment?
9 week old puppy with a long oblique tibial fracture and the fibula is intact.
Every orthopedic patient requires:
a complete PE, orthopedic exam, and neurological assessment
What is the primary survey for trauma patients?
A - airway B - breathing C - circulation D - disability (BAR,neuro?) E - examination - whole patient
What do we mean by secondary survey for trauma patients?
How is the patient responding to stabilization?
Factors that can influence # of bacteria that cause infection:
Virulence of organism
Condition of the wound
Presence of implants
Host defenses
For fractures above the elbow and stifle what type of external coaptation can you use? (Lateral shoulder luxations also)
Spica splint
For fractures below the elbow and stifle are best coapted with…
Robert Jones, splint or cast
What type of coaptation can you do for craniodorsal hip luxation?
Ehmer sling - keeps femoral head in the acetabulum
For medial shoulder luxations what kind of sling do we use?
Velpeau
Key is with stabilization of long bone fractures with coaptation?
Stabilize the joint above and below the injury
Order of fracture description
Open vs. Closed Salter-Harris Classification Orientation (e.g. comminuted) Location within the bone Bone Displacement
Grade 1 - 3 open fractures?
level of soft tissue trauma
- inside bone poke out then covered
- bone exposed
- high velocity, severe bone fragmentation exposed bone
What are the Salter-Harris fractures?
- Separation along the physis
- Through the metaphysis and then through the physis
- Diaphysis fracture then through physis
- both diaphysis and metaphysis straight up
- Compression of physis (can’t see on rads well) = later on limb deformity
How is prognosis with salter-harris fractures?
Higher the number, the worse the prognosis
What bone can you never really put an IM pin in?
the Radius
What are the for As
For follow up assessment
Alignment - The joint above and below lining up?
Apposition - fracture segments lining up (50%)
Apparatus - type (appropriate), neutralizing forces?
Activity - Do we see healing
What is considered internal fixation of a fracture?
IM pin
Interlocking nail
Cerclage wires
Bone screws and plates
What are the goals for healing?
Adequate reduction
Rigid fixation
early active motion
early weight bearing
What are the principles of atraumatic surgical technique with internal fixation?
Preserve function
Maintain blood supply
Decrease incidence of infection
Minimize invasion of soft tissue
Implant characteristics?
Biocompatible Resist corrosion same alloy (plate and screws) 316L stainless steel Never reuse (set # of cycles)
What can you place an IM pin in?
Humerus Femur Tibia Ulna Metacarpals and metatarsals
What are the pros and cons of an IM pin?
Pro: resist bending
Cons: poor axial loading, rotational, lack fixation
So IM pins should be used supplementary to something like cerclage, exf, or plate
What is the main force with avulsion fractures?
Tension
What is the best fixation for avulsion fractures?
Tension bands, good for:
Greater trochanter
Olecranon
Tibial tuberosity
Concepts for applying bone plates
Select the appropriate plate size
Select a plate that spans the bone length for diaphyseal fractures (70% of bone)
Accurately contour the plate
Place a minimum of three screws or secure six cortices above and below the fracture.
Use a longer and stronger plate as a bridging plate or augment with IM pin
Types of bone healing
Direct (primary)
Indirect (secondary) -
Intramembranous
Factors that affect healing
Biological factors -Age -Fracture location - Cellular response - Circulation - Concurrent soft tissue Mechanical factors -Stability of bone segments and fragments after fixation Clinical factors -Aseptic technique -Activity of patient
What is the normal blood supply of a long bone
Nutrient artery
Proximal and distal metaphyseal arteries
Periosteal arteries
Normal blood flow of long bone vs fracture?
Normal: Centrifugal - from medullary cavity out to periosteum
Fracture: Centripetal from surrounding soft tissue in
What happens do the blood supply during a fracture?
- medullary supply is disrupted
- Metaphyseal vessels enhanced
- extraosseous vasculature
Which reduction (open vs. closed) provides the least amount of disruption to the fracture blood supply?
Closed
What is the most important thing to give a fracture to allow it to heal?
Stability
what is “biological treatment” method to fracture healing?
Preservation of blood supply
What two fixations are highly biologic?
Cast or External fixation
What is strain?
Motion
The change in the width of the gap over the total width of the gap
What is strain?
Motion
The change in the width of the gap over the total width of the gap
If you have strain on a fracture sight at what stage will the healing stop?
Fibrous tissue, fibrous callus but no bone formation
How much strain can bone formation tolerate?
<2% strain
How close does the fracture gap need to be in order for direct bone healing to occur?
150 microns! basically in contact
Where would direct bone healing be favorable?
Articular fractures or fractures close to a joint (you don’t want callus formation there)
How can you help speed up healing in a low biological scoring fracture (old dog)
Add a bone graft to the fracture site (cancellous autograft)
Where are sources for autogenous cancellous bone?
Proximal Humerus
Proximal tibia
Ilium
What are some important properties of bone grafts?
Osteogenesis and Osteoinduction
Rate of union in terms of clinical union
<3mo Exf: 2 - 3 wks plate:4wks
3 - 6 mo Exf: 4-6 wks Plate:2-3mo
6-12 mo exf:5-8 wk plat 3-5 mo
>1 yr exf : 7 - 12 wks plate: 5mo - 1 yr
Delayed union
Slower healing than it should (at 8 weeks not much healing..)
Reasons for delayed union?
Systemic status of the patient Nature of trauma High energy fracture (open) Poor fixation (too rigid, lg gap etc) Drugs
Non union
Repair process is not happening
Reasons for non union
poor vascularity
hypertrophic non union (so unstable, it can’t heal)
Atrophic nonunion - biologically inactive
What is the main goal with mandibular/maxillary fractures?
If the teeth line up
Tape muzzles work for what?
minimally displaced
caudal fractures
comminuted fractures
Dental bonding is used for what?
works like an external fixator, more stability than the muzzle. work for same fractures as muzzle
Do mandibular or maxillary fractures more often need fixation?
Mandibular (esp. symphysial fractures)
biggest thing is avoiding the teeth
Scapular fractures 50 - 70% of them have concurrent injury
usually its high impact injury - and its over the thorax so look for rib fractures also
When do you need to surgically fixate a fracture of the scapula?
If it is intraarticular, unstable neck fractures
How many fractures do you typically see with a pelvic fracture?
Usually fractures in 3 places since it is a box like structure. (esp. older animals)
Which pelvic fractures require stabilization?
Articular fractures (FHO may work too)
Contralateral injuries (more rigid repair for wt.)
If there is uncontrollable pain (usually a sacral fracture)
Wt. bearing bones (ilium, acetabulum, sacroiliac joint)
If it is narrowing the pelvic inlet (esp. breeding animals)
What should you always warn owners about with pelvic fractures?
Damage to the urinary system (nerves, etc)
What fractures distal to the tibia/radius should you refer?
Carpal/tarsal fractures
When can you do coaptation with?
Non-displaced maxillary fractures
Mandibular symphysial fractures
Transverse fractures below the stifle/elbow (young)
Minimally displaced pelvic/scapular fractures
Most metacarpal/metatarsal fractures (unless lg dog)
What type of humus/femur fractures should you refer?
Diaphyseal and supracondylar fractures
articular fractures
physeal fractures
What is a malunion?
Healed fracture that has poor anatomical bone alignment
Will a non-articular fracture of a long bone lead to OA?
NOPE! only time a long bone fracture MAY lead to OA is if they have a malunion (incorrect loading of the joint)
What are some radiographic evidence of osteomyelitis?
Periosteal reaction
Sequestrum (rare)
Osteolysis (far progressed)
If you have to treat osteomyelitis, how do you select your abx?
Based on culture (at site, not tract)
Abx for 4 - 6 weeks
When do you take out an implant if you have an infection?
If implant is stable, leave until the fracture is healed if unstable, remove and replace (or add External fixator)
Why do you want to place a pin in a femur normograde vs retrograde?
To avoid impinging the sciatic nerve
If you are asked to assess a fracture 4 weeks post - op, what do you assess?
Activity
Apparatus
Alignment (again cuz still can change)
Apposition (again)
What type of healing would you expect with a compression plate on fracture?
Direct (at least minimal callus formation)
Which joints are more commonly clinically affected by OA?
Elbow, Carpus, Hock
How much percent of body weigh is distributed to front limbs?
60%
What are the clinical causes of OA?
Hip Dysplasia Elbow Dysplasia OCD Patella Luxation Trauma Mechanical instability secondary chronic intraarticular degeneration (Tenosynovitis, CCL)
What is an example of first level imaging for OA?
Orthogonal bilateral radiographs
What is diagnosis of OA based off of?
History, Clinical signs and radiographic findings (Not response to treatment)
What are the multimodal management strategies for OA?
- Weight reduction
- Exercise modification (PT/Rehab)
- NSAIDs/DMOAs
What is the general weight loss strategy for OA?
Reduce dietary intake by 1/3-1/2 per day
Weigh regularly/monitor with BCS (target 4/9)
When are glucocorticoids indicated as a treatment for OA?
END STAGE ONLY, shone to make OA worse
True or False: NSAIDs used in multimodal therapy are used as part of a daily dosing regimen for OA.
FALSE, if used long term only to be used PRN (as needed)
What is a drug you can give to inactivate metalloproteinases?
Tetracyclines
For patients with OA that have sx and those that don’t they should both get what other tx?
individualized multimodal approach for tx of clinical signs of OA
Differentials for thoracic limb lameness due to dysplasia
OCD
UAP
MCPD
Medial compartment disease
Why is the incidence of hip dysplasia and elbow dysplasia less than reality with OFA reports?
Owners don’t have to submit the radiographs if they don’t want to.
What is the pathogenesis of Medial Coronoid Process Disease?
Overloading of the medial side of the coronoid (sometimes its a fracture, or erosion, etc)
What is the pathogenesis of ununited anconeal process (UAP)
Asynchronous growth of the proximal ulna and radius -> radius grows faster than ulna -> Sheering forces on humeral condyle -> salter harris type 1 like fracture of the anconeal process
Pathogenesis of Medial compartment disease?
Incongruency and overloading of medial compartment of articular surfaces -> cartilage erosion, can be concurrent to MCPD
5-8 mo of age, slight lameness, worse after exercise, prominent after resting, discomfort marked on flexion/extension of elbow
OCD and MCPD, MCD
Where will the lesions be on radiographs with elbow OCD?
Weight bearing side of the medial condyle (cranial caudal view)
and osteophytes off the epicondylar ridge and one off the radial head
Where will you see an osteophyte in ANY elbow joint disease?
off the medial coronoid process
With any elbow joint disease what type of diagnostics should you do?
BILATERAL RADIOGRAPHS
What is a unique radiographic finding for MCPD?
Kissing lesion (on the non-weight bearing surface of the medal condyle)
What elbow diseases can you rule in/out with plain radiographs?
OCD
UAP
Diagnosis of UAP
Large breed dogs with separate centers of ossification of the anconeal process
Clinical signs with UAP
7-8 mo old, moderate lameness, circumduction of forelimb! externally rotated paw.
When should the physis of the anconeal process close?
5 - 5.5 mo
For the elbow dysplasia, how is the prognosis for lame free function is..
Erosion dependent
Small dogs and cats with patellar luxation get OA True or False?
FALSE
What are the medial patellar luxation grades?
1 - in, in (in and you can move it out but put it back in)
2 - in, out
3- out, in
4 - out, out
What do neonates and older puppies usually have what grade(s) of patellar luxation?
3-4
What grades do young to mature dogs get?
2-3
Older dogs?
1-2
Any age but subclinical
1-3
What is the lameness due to with patellar luxation?
Mechanical function rather than pain
High calcium puppy diets do what to the joints?
Can set them up for OCD
Which joint is most commonly associated with OCD?
The shoulder joint (humeral head)
If the dog comes in with a single limb lameness but you find out it is OCD, what should you check?
Its a bilateral disease so check the other limb
If you have a young dog with stifle pain on flexion and extension, the joint is effusive and thickened. What are your differentials?
OCD (young puppies)
CCL (usually middle aged)
Trauma/injury
If you see a young dog with hind limb lameness with hyperextension of the tarsal joint, with palpation you notice marked effusion of the medial side of the joint, what is your top differential?
Tarsal OCD (would be lateral in Rottweilers)
Which radiographic view gives you the best view of shoulder OCD?
Bilateral lateral radiographs
Where is the OCD lesion for stifle usually?
The lateral side of the medial femoral condyle or the lateral femoral condyle and osteophytes
Which OCD lesion usually involves a large fragment of bone as well?
The tarsal/hock OCD lesions
What is the only OCD lesion where early conservative management may improve the clinical signs?
Shoulder joint (if there is no mineralization present and they are < 6 months old)
Is OCD considered a heritable disease in dogs?
YES
How is the hind limb held when they have a craniodorsal luxation of the femoral head? caudoventral luxation?
CD: Stifle is externally rotated, limb is adducted
CV: Stifle is internally rotated and limb is abducted
What is critical to determine the orientation of the luxation and potential fractures of the Coxofemoral joint?
Orthogonal views
How soon after hip is luxated do you have to do a closed reduction?
3 days (less than 7)
What are the open reduction techniques for Coxofemoral luxations?
Capsulorraphy Toggle Pin Transarticular pinning Prosthetic capsule Transpostision of the greater trochanter (all are trying to restablish the ligementum of teres)
What is the exception to the rule of closed reduction before open in Coxofemoral joint luxation?
Hip dysplasia (their hip joints/ligaments are already lax) open reduction works best for these guys
True or False, A cause common of hind limb (hip joint) lameness in dogs is typically OA
False, dogs with hip dysplasia often have SEVERE OA but can get around just fine
What is the common breed and direction of displacement of shoulder luxations?
(75%) medial - small breeds
- potentially congenital (look at the patella’s too)
Clinical signs of a medial shoulder luxations?
forelimb is abducted and externally rotated, joint swelling, greater tubercle is medially displaced, pain and instability of joint.
Which way does the shoulder joint need to be displaced in order to use a Velpeau sling?
Medially
How long do you keep them in the sling?
2 weeks
What do you do for close reduction if the shoulder is luxated laterally?
Spica (2 weeks)
What keeps the shoulder joint stable normally?
Active stabilizer- -subscapularis tendon (medial side) Passive stabilizers- medial glenohumeral ligaments labrum
What is the common luxation of the elbow?
Lateral luxation
What is the treatment?
Closed reduction - modified Robert jones - or spica
Open reduction - collateral ligaments (do if not reducing)
Traumatic luxation of stifle
uncommon
rupture of collateral ligaments, CCLs
non weight bearing
Treatment?
Surgery, small and large dogs, External fixator with a trans-articular joint
Carpal sprains
common, hyperextension
splint primary and secondary sprains.
How do you treat tarsal sprains?
same as carpal sprains
Congenital elbow luxation in dogs will have
limited range of motion and progressive osteoarthritis
True or False: the reduction of traumatic Coxofemoral luxations should be delayed as long as possible to preserve as much hyaline cartilage of the joint as possible
False
Collateral ligament injuries are common on what part of the body?
Carpus and tarsus
What instability do you see if you see Varus?
Lateral collateral ligament
Valgus?
Medial collateral ligament
What is treatment for collateral ligament injury?
Conservative (ice 3 days, then heat, NSAIDs, splint 4 wks)
Primary repair - suturing CL
Secondary repair - prosthetic (suture)
Which joints should you try closed reduction first?
Hip, Shoulder, Elbow
Which joints should you NOT try closed reductions first?
Stifle, carpus, tarsus
What is the use of CCLs besides mechanical use?
Loss of proprioception (loss of stabilization of the joint)
Pathogenesis of CCL Rupture
Early spaying and neutering (<6mo)
Progressive - immune-mediated (Degeneration)
What three breeds of dogs are over-represented with CCL disease?
Lab
Rottweiler
Newfinland
Newfies usually present… why?
bilateral CCL, genetic identified
True or False, the risk of CCL rupture on the contralateral hind limb after a single CCL rupture increases esp with excessive weight
FALSE, not correlated with studies
What are the radiographic findings of CCL
Effusion (caudally)
Osteophytes
medial buttress (stifle instability)
When can you do conservative treatment with CCLs?
< 15 Kg, or clinically normal
What about cats with CCL?
Weight management
When should you do rehab for CCLs?
With conservative treatment AND post op!
Which is better TPLO or TTA?
TPLO
What is required for a TPLO to function?
intact caudal cruciate ligament to function
What is hoop stress?
Loss of edges of the meniscus and results in joint instability
Pathogenesis of meniscal tear?
Constant sheering on the medial meniscus
If you have a click on stifle palpation what is likely?
meniscal tear
Treatment for meniscal tears?
Take it out (aren’t lame from it)
Strains
junciontal (myotendinous jct, tenosseous)
PE findings with myo/tendonopathies
heat, swelling, pain, fibrous tissue, loss of continuity, alteration in function
Strains are not graded like sprains
based off of severity of damage
Medical
chronic
surgical
acute
Medical treatment for acute strains
ice (24 - 72 hr) heat (>72 hr) NSAIDs Methocarbamol Hydrotherapy (later in healing) acupuncture
Supraspinatus myopathy/tendon mineralization - muscles/tendons involved?
Supraspinatus, Biceps
PE and diagnostics
PE: no pain on palpation, discomfort on biceps palpation
Dx: radiographs, ultrasound!! (best)
How do you treat non-mineralized
medical, NSAIDs, PRP rest 6 weeks +/- rehab
Tx for mineralized?
NO PRP (platelet rich protein), go in arthroscopically partial tenectomy, restrict activity 6 weeks, rehab
When do you see shifting limb lameness?
Bilateral disease (e.g. tenosynovitis of biceps tendon)
panosteotis
Radiographically what do you see with biceps tenosynovitis
osteophytes on intertubertcular groove
