Exam 1 Flashcards
Lec 1 orthopedic examination and diagnostic tools
- Explain in detail the steps to performing an orthopedic examination, including the different manipulations required, how to perform those manipulations, and what each is designed to assess.
- Summarize what you are checking for when palpating each bone, joint, or soft tissue structure while performing an orthopedic examination?
- Summarize the factors to consider when evaluating an orthopedic patient.
- Explain in detail the steps to performing an orthopedic examination, including the different manipulations required, how to perform those manipulations, and what each is designed to assess.
Diagnosis of Lameness
(HiPeGaViOr)
- History
-General history and presenting complaint
-Anorexia, fever, depression?
-When first noticed?
-Acute vs. Chronic, trauma
-Progression and response to medications? Improving, static, worsened?
Trauma Stabilize First when long bone fractures present, often soft tissue injuries present. Pneumothorax, traumatic myocarditis, diaphragmatic hernia, ruptured bladder or urethra, pulmonary contusion, fractured liver, ruptured spleen.
- PE
-General PE
-Complete rule out of other DDx
Propioception: Normal or abnormal.
-Abnormal propioception: Patient does not know where limb is placed, Patient knows where the limb is placed, but is unable to correct positioning, Knows where limb is placed but is unwilling to correct (fear or pain), Patient “trained” to tolerate abnormal positioning. - Gait Analysis
-Presenting complaint
-Evaluate all limbs during observation
-Perform gait analysis on floor with traction - Walk: 2, 3, or 4 legs support at any one time
- Trot: most important. Body is supported by two legs on opposite side (contralateral), most important gait to evaluate lameness.
- Pace: limbs on the same side (ipsilateral) symmetrically support the animal.
-Evaluate towards you and away from you
-The leg that is affected: “HEAD BOB” = head lifts when lame leg bears weight. Head drops when weight bearing on normal limb “Down on sound”
-Hind limb: stride length shortened on lame leg. Normal limbs reaches forward faster than lame leg. Oscillation motion during locomotion (towards the normal side). Hip hike on lame leg. - Visual inspection of body and conformation
- Orthopedic/neurologic examination
Quantifying Lameness
What if lameness if bilateral?
0: no lameness
1: Mild weight-bearing lameness
2: Moderate weight-bearing lameness
3: Severe weight-bearing lameness
4: non-weight bearing lameness
Favoring = using it less
Bilateral Lameness
-Weight shifting while standing
-Shortened stride
-Bilateral muscle atrophy
-Bilateral compensatory hypertrophy of unaffected limbs
Visual Inspection
-Observe standing position
-Know breed differences
-Abnormal body condition conformation
-Look for muscle atrophy, hyperflexion or hyperextension of joints
-Nerve root signature: disc irritating the nerve, neurological disease, caudal discs.
-Angular limb deformities: Varus (medial distal deviation) or Valgus (Lateral deviation of joint).
-Posture: body symmetry, areas of muscle atrophy (spine of scapula, greater trochanter, quadriceps)
- Summarize what you are checking for when palpating each bone, joint, or soft tissue structure while performing an orthopedic examination?
While animal is standing
-Check for muscle atrophy and symmetry
- Palpate the neck: deep palpation, ventral and lateral flexion, extend neck.
- Palpate the back: apply pressure to spinous processes down the entire length of the spine.
- Check for lumbrosacral pain: apply pressure dorsally to lumbrosacral joint without loading or extending the hips.
- Check medial aspect of knee joint for swelling “medial buttress” indicator of CRANIAL CRUCIATE LIGAMENT RUPTURE (CCLR)
Localization
Goniometry
2. Summarize what you are checking for when palpating each bone, joint, or soft tissue structure while performing an orthopedic examination?
-without sedation
-neurologic exam done along with orthopedic examination
-Lame leg last
- Lateral recumbency: start at most distal part (toes)
-Move each joint through full range of motion (ROM)
-Apply stress to joint medially and laterally, check for excess laxity - Palpation of bones and joints
-Pain, swelling, heat, instability.
Be consistent
-Asymmetry between limbs
-Abnormal ROM
-Crepitation (griding noise)
-Isolation of joint you are manipulating
Specific Orthopedic Test
- Ortolani sign “Hip dysplasia”
-Grasp flexed stifle and apply pressure dorsally
-Apply counter pressure using other hand dorsal to pelvis.
-Abduct limb slowly
-Positive sign: movement is felt as femoral head clicks back into acetabulum.
-Subluxation of hip
-Abduction and reduction
Dorsal recumbency needs sedation
- Cranial drawer
-Two hands one on femur, other on tibia
-Thumb over lateral fabella, index over patella
-Thumb on fibular head, index on tibial tuberosity
-Move tibia cranially with respect to femur.
-Positive sign = >1-2mm of movement Dx CCLR - Tibial compression test
-Tarsus flexed with force
-Tibia translates cranially with CCLR - Patella luxation
-Luxate patella manually
-Stifle extended (medial)
-Stifle slightly flexed (lateral)
- Summarize the factors to consider when evaluating an orthopedic patient.
- Palpate the lame leg last because it is in pain, so avoid irritating it
Lec 2
- The student will summarize the use of cancellous bone grafts in the repair of fractures in dogs and cats.
- Understand the different methods of fracture reduction: Open vs. Closed; Direct vs Indirect.
- The student will summarize the four major fracture fixation systems commonly used in small animal surgery.
- Given an external skeletal fixator, the student will assign the appropriate classification type to the frame.
- The student will state the use for which a circular external fixator is uniquely suited.
6.
Learning Objectives
The student will explain the “Key Concepts” for…
* Applying External Coaptation * Inserting Fixation Pins
* Applying Intramedullary Pins * Applying Interlocking Nails
* Applying Cerclage Wire * Applying Tension Bands * Applying Bone Plates
* Applying Lag Screws
* Applying and Increasing the Strength and Stiffness of an External Fixator
Surgical Planning
Fracture Reduction is a process of either?
What must be overcome?
- Choose implants and plan procedure
- Evaluate fracture, patient, and client
- Fracture assessment score
- Ensure selected fixation counteracts forces to bone
- Make a detail plan of fracture reduction, sequence of implant application, possibilities for bone grafting.
Failure to plan: prolonged operating times, excessive soft tissue trauma, technical errors
Fracture reduction
a. Reconstructing fractured bone fragments to normal anatomic configuration = ANATOMIC REDUCTION
b. Restoring normal limb alignment, by restablishing length and joint alignment while maintaining spatial orientation of limb.
Overcome: physiological processes of muscle contraction, fracture overriding.
- The student will summarize the use of cancellous bone grafts in the repair of fractures in dogs and cats.
Bone grafting enhances bone healing
-Standard practice in fracture management and joint arthrodesis
-Autograft
-Allograft: within same species
-Biomaterials: demineralized bone matrix, collagen
-Synthetic bone substitutes: tricalcium phosphate ceramics, bioglass and polymers.
-Composites of osteogenic cells: osteoinductive growth factors, synthetic osteoconductive matrix.
- Osteogenesis: ability of cells to survive transplantation and serve as source of osteoblasts
- Osteoinduction: ability of material to induce migration and differentiation of mesenchymal stem cells into osteoblasts.
-TGF beta superfamily, BONE MORPHOGENETIC PROTEIN - Osteoconduction: scaffold ability of material allows for host bone invasion, determines speed of osteointegration
- Osteointegration: surface bonding between graft and host bone.
GOLD STANDARD = CANCELLOUS bone autografts
Provides optimal osteogenic, osteoinductive, and osteoconductive properties and not immunogenic.
-Recommended when rapid bone formation is desired
-Assist when optimal healing not anticipated
-Cortical defects present after fracture repair
-Adult and elderly patients with delayed non-unions, osteotomies, joint arthrodesis, cystic defects.
-Promote bone formation of infected fractures
-Additional time surgical, limited availability.
Harvest sites
-Proximal humerus: make hole NEAR CORTEX, use curette tool, place bone into stainless steel cup with whole blood for temporary storage, loosely pack cancellous bone in fracture gap or along fracture lines.
-Proximal tibia
-Ilial wing
-Distal femur
Harvested after fracture stabilization, before primary orthopedic procedure
CORTICAL BONE autografts
-Ribs
-Ilial wing
-Distal Ulna
-Distal fibula
Most commonly used: transplant rib to form segmental strut for mandibular fractures. Done during fracture repair.
-Segmental (between segments) or slidding graft (placed over fracture). Grafts are held in place with same implant to stabilize fracture.
Cortical Bone allografts
-Frozen available commercially
-Used for limb-sparing procedures, rarely used in fracture repair
-Harvested and banked
Cancellous bone allografts
-commercially available: frozen chips or chips mixed with demineralized bone powder
-Reduces OR time, more available, elimination of morbidity at donor site.
-Costly, lack of osteofenic properties in cancellous bone chips
A. Graft placement
B. Vascularization of graft
C. Osteoinduction
D. Osteoconduction
E. Remodeling
Demineralized Bone Matrix
-From processed allograft bone
- Available for dogs and cats
-50:50 combination of DBM with varying sizes of allogeneic cancellous chips
-Frozen or freeze dried
-Indications: same as cancellous bone autograft
- Understand the different methods of fracture reduction: Open vs. Closed; Direct vs Indirect.
- Closed reduction: reducing fractures or aligning limbs without surgical exposure of fractured bones
-Enhances biological environment, preserves tissue and blood supply, speeds healing. Reduced operating time, infection risk. Disadvantage: difficult to accurately reconstruct reducible fractures. - Open reduction: surgical approach. Anatomical reconstruction and held in position with implants. Advantages: direct placement of implants, visualization and direct contact with bone fragments, direct placement of implants possible (cerclage wire, lag screws, plates, ESFs). Results in stronger fracture fixation. Improves mechanical environment. Cancellous bone grafts can be used. Disadvantages: increase surgical trauma to soft tissue and blood supply, Diminished biological environment, greater risk of infection.
-Limited open: small exposure. Secure oblique fracture with lag screws or cerclage, external fixator or interlocking nail.
-OBDT (open but don’t touch). Realigning bone and placing plate, fracture fragments and hematoma not manipulated. - Direct reduction: counteracting muscle contraction. Causes segments to override, major difficulty in anatomic reduction.
-Manual distraction of segments: using bone-holding forceps, eventually fatigues and allows reduction.
-Transverse fractures reduced by applying traction, countertraction and bending forces.
-Using lever: lever between overriding bone segments, periosteal elevator or scapel blade handle, apply gentle pressure and reduce
-Using bone holding forceps
-Rough handling of bone can cause more fragmentation.
-Bone needs to be inspected for fissure fracture lines - Indirect reduction:
-Nonreducible fractures: managed with indirect to preserve biology, bridging fixation provides mechanical support.
-Process of restoring fragment and limb aligment, distracting major bone segments
-Using IM (intramarrow?) pin: pin driven normograde through proximal bone segmented to fracture site. Centered in distal segment and driven distally into metaphyseal bone. Proximal segment held with bone-holding forceps, pin advanced distally. Fractured bone aligned with bone plate or external fixator and maintains reduction.
-Using animals weight: suspend fractured limb from ceiling, weight distracts fracture. Tibial/Radial
Limb suspended, lower operating table, closed or opened reduction, stabilized with external fixators.
Indications for Open or Closed Reduction
Open
-Articular fratures
-Simple fractures allowing anatomic reconstruction
-Cumminuted nonreducible diaphyseal of long bones
Closed
-Greenstick and or non-displaced of long bones below elbow and stifle
-Comminuted non-reducible diaphyseal of long bones with external fixators.
- The student will summarize the four major fracture fixation systems commonly used in small animal surgery.
- Closed reduction
- Open reduction
- Direct reduction
- Indirect reduction
- Given an external skeletal fixator, the student will assign the appropriate classification type to the frame.
- The student will state the use for which a circular external fixator is uniquely suited.
Fracture treatment planning
- Determine fracture assessment score (FAS)
- Choose appropriate implant system, need to counteract axial, bending, torsional loads.
- Select technique for reduction
- Develop plan for applying implants
-Make drawing, helps ensure optimal results - Decide about using bone grafts.
-Cancellous autograft or allograft - Surgical approach or approaches selected
- Check implant and instrument inventory
- Precontour plate if appropriate
After surgery
-Evaluate radiographs
-Were plan goals met?
-Remedial steps desired or needed
6.
Learning Objectives
The student will explain the “Key Concepts” for…
* Applying External Coaptation * Inserting Fixation Pins
* Applying Intramedullary Pins * Applying Interlocking Nails
* Applying Cerclage Wire * Applying Tension Bands * Applying Bone Plates
* Applying Lag Screws
* Applying and Increasing the Strength and Stiffness of an External Fixator
Fracture fixation systems
- External Coaptation: used to provide patient comfort before and after surgery, decreased damage to soft tissue
-Primary repair in some conditions
-For bone to heal with external coaptation as primaty fixation, must be at least 50% reduction of segments at fracture site
-Bandages
-Splints
-Casts: full leg casts: can’t be applied above midhumerus or midfemur. Only distal limb, radial ulnar, tibial, metacarpal or metatarsal.
BIVALVE CASTS: supplements internal fixation devices.
-Bone plate and screws
-Fracture of carpus, tarsus, metacarpal/metatarsal bones and digits
-Carpal or tarsal arthrodesis (surgical inmobilization of joint so that bones grow solidly together, artificail ankylosis)
- External skeletal fixators
- Intramedullary fixation
- Plate and screw fixation
Lecture 3 Principles of Orthopedic Surgery II
External Skeletal Fixators
-Versatile and affordable
Long bone fractures, corrective osteotomies, joint arthrodesis, temporary joint immobilization.
-NOT for articular fractures
-Rarely for spinal and pelvic fractures
-GOOD for stabilization after closed reduction of comminuted fractures.
-CAN be adjusted to improve fracture alignment
-Functional period varies, frame construction, pin loosening
Fixation Frames
- Number of planes occupied by frame
-Unilateral-uniplanar (Ia)
-Unilateral-biplanar (Ib)
-Bilateral-uniplanar (II): maximal type II frames filled with full pins. Minimal type II frames constructed with minimum of two full pins.
-Bilateral-biplanar (III): Type II + Ia (montage). Interconnected for strength. stiffest configuration
Pin Placement
A. Half pins: penetrate both cortices but only one skin surface
B. Full pins: penetrate both cortices and skin surface
- Number of sides of limb from where fixator protrudes
Positive-Profile fixation pins used with external skeletal fixation
Linkage devices (clamps)
- Centrally threaded cortical pin
- centrally threaded cancellous pin
- End threaded cortical pin
- End threaded cancellous
- Mandibular fixation pin
Linkage devices
-Joint fixation pins: to connection bars, connecting bars to each other.
-Larger holes for external connection bars
-smaller holes in bolts for fixation pins
A. Securos Secur-U clamp
B. IMEX-SK single
C.IMEX-SK double
Increasing strength and stiffness
-Pre-drill before inserting positive profile threaded pins
-Increase pin numbers up to 4
-Increase pin size up to 25%
-Put near joints and near fracture
-Decrease distance between pin and pin-clamp
-Increase connecting bar size, number and planes of connecting bars.
-Tie IM pin into fixator frame
Intermedullary Fixation
- IM pins: used for diaphyseal fractures. Hemerus, tibia, ulna, and metacarpal/metatarsal. Contraindicated for RADIUS NO insertion point interferes with carpus.
-Biomechanical advantages: resistance to applied bending loads.
-Poor resistance to axial (compressive) loads, rotational loads, lack of fixation (interlocking) with bone.
-Require supplementation with other implants, cerclage wire, external fixator or plate. Provides rotational and axial support.
-Chisel and trocar (very pointed) types.
-select size 60-70% medullary canal width to pair with cerclage wire
-50-60% .. pair with external fixator
-40-50% .. to pair with plate.
Retrograde or Normograde for humerus and femur
-Retrograde: enter at fraction site, drive pin proximally, reduce fracture and drive pin distally.
-Normograde: enter proximally in craniolateral trochanteric fossa, direct caudally - Steimann Pins or Kischner Wires (K-wires)
-Used as crossed pins (wires) placed in triangulated pattern
-Metaphyseal and physeal fractures
-K-wire also as IM pins in very small animals. - Interlocking Nails: placement of interlocking nail in femur
-Innovative animal products
-I-Loc biomedtrix
-Stabilizes simple and comminuted mid-diaphyseal femoral fractures
-Provides resistance to bendings, rotational and axial loading forces.
-Effective IM fixation to bridge nonreducible fractures.
-IM pins secured by proximal and distal transfixating screws. Engage bone to nail to provide axial, bending and torsional stability.
-use the largest nail that fits the bone
-Span length of bone
-Insert normograde
-Holes for screws 2 cm away from fracture
-Secure with 4 screws
Orthopedic Wire
-Used as Cerclage wire or Hemicerclage wire
-supplements axial, rotational, and bending support of fractures.
Cerclage wire
ONLY ANATOMICALLY reconstructed LONG OBLIQUE or SPIRAL fracture.
-18 gauge, large dogs. 20-22 small dogs, cats.
-2-3 per fracture line
-Perpendicular to long axis of bone.
-At least 5mm from fracture line
-Need support
-Space 1-2 times the diameter of bone
-K-wires are used to prevent cerclage wire slippage
-Orthopedic wire placed around circumference of bone
-Can be combined with K-wires, prevents slipping where bone diameter changes.
-Provides stability to anatomically reconstructed long oblique or spiral fractures
-Holds multiple fragments in position
1. Most used implant
2. Most misused implant: postoperative complications
Length of frcture line is 2-3 times diameter of marrow cavity
Maximum of two fracture lines. No more than two main segments and one large butterfly fragment.
Fracture must be anatomically reduced
Stability by generating compression
Always supported by additional implants (IM pins, external fixators, or plates)
-Fails when multifragmented fractures, movement after surgery, collapse.
Hemicerclage wire
-Wire placed through predrilled holes in bone
-Fracture length >2times diameter of bone
Tension Bands
-Covert distractive tensile forces into compressive forces
-Tightening wire exerts force, counters muscle contraction and compresses fracture surface.
-Avulsion fractures: occurs when groups of muscles originate or insert in bone
-Use K-wire or Steinmann pins
-Parallel to each other and perpendicular to fracture.
-Seat wire is opposite cortex
Plate and Screw Fixation
They carry ALL applied loads during early postoperative period
-Ideal for complex or stable fractures, when prolonged healing (bone union) anticipated or when optimal postoperative limb function desired.
1. Compression plate: transverse fractures
2. Neutralization plate: long oblique fractures, with lag screws
3. Bridging plate with or without IM pin: non reducible fracture
Type of crews
-Cortical
-Fully threaded cancellous
-Partially threaded cancellous
Types of Plates
-Buttress: prevents collapse of adjacent articular surface
-Locking plate: Locking screws hold bone in that position
Applying bone plates
-Need to span the bone length for diaphyseal fractures
-Accurately contour not locking plate
-3 screws or secure 6 cortices above and below fracture
-Longer and stronger for bridging plates with IM pin
Lag Screws
-Compress fracture line between 2 bony fragments
-Into plate or directly into bone
-Perpendicular to fracture line
-Bisect angle 90 degrees
-Hole in near cortex: GLIDE HOLE, outside diameter equal to thread of screw
-Hole in far cortex: inner core diameter or shaft of screw equal to hole
Reduce and secure fracture before placing lag screw
optimal compression: screw perpendicular to fracture
Drill near cortex: bit equal to screw thread
Drill far cortex: bit equal to screw core diameter
Partial threaded screws should not cross fracture
-Expose pin insertion site
-Center pin in bone
-Pre-drill pin hole
-Insert pin with low RPM power
-Release incision around pin to prevent skin tension
-Pin drilled into bone at point of greates cross-sectional diameter
Circular external fixators (RING)
-Stabilizes fracture, compresses non-unions, distract fractures.
-DISTRACTION of BONE SEGMENTS
-Results in a new bone formation in trailing pathways, “distraction osteogenesis”
-Small diameter tensioned wires.
-Allow controlled axial micromotion at fracture site without compromising fixator stability.
Lecture 4 Amputations
- List general indications for performing an amputation.
- List the major techniques for performing a thoracic limb amputation and describe how each is performed.
List which muscles are transected for each technique. - List the major techniques for performing a pelvic limb amputation and describe how each is performed.
List which muscles are transected for each technique. - Describe the surgical procedure used for performing a caudectomy.
- List the major complications seen with amputations and discuss steps to avoid these complications.
- Discuss steps considered when determining if a patient is a good candidate for limb amputation.
Common types of amputations
- Tail: traumatic lesions, infection, neoplasia, reconstructive surgery (lateral caudal axial pattern flag), breed standards
-Treatment: change environment, bandaging, topical treatment. Caudectomy (last resort)
-“Tail beater” amputation when bandaging is ineffective or impossible.
Procedure
1. make elliptical incision around base of tail
2. Incise subcutaneous tissues to expose muscles
3. Separate attachments of levator ani retococcygeus, and coccygeus muscles to caudal vertebrae.
4. Transect tail by disarticulation at second or third caudal vertebra
5. Ligate medial and lateral caudal arteries and veins.
6. Appose levator ani muscles and lavage site.
7. Appose SQ tissues in simple interrupted or continuous pattern with monofilament absorbable.
8. Excise redundant skin if needed
9. Apose skin edges, 3-0 nonabsorbable sutures.
-Amputate through disc space
-Generous skin flaps - dorsal flap larger (longer)
-Hemorrhage control
-PAIN CONTROL
-Ear pinna (not covered)
-Digits
-Penile (not covered)
-Thoracic limb
-Pelvic limb
Indications for Thoracic Limb Amputation
Indications
-Neoplasia
-Trauma
-Neurological impairment: radial nerve paralysis, Brachial plexus injury
Types
- Forequarter
-Skin incision dorsal border of scapula over scapular spine to proximal third of humerus
-continue around the limb
-Transect trapezius and omnotransversarius mm at insertions on scapular spine.
-Transect rhomboideus m from attachment on dorsal border of scapula.
-Elevate serratus ventralis m from medial surface of scapula
-Retract scapula laterally to expose axillary artery and nerve for ligation
-Transect brachial plexus, latissimus dorsi m near humeral insertion
-Block brachial plexus.
-Three-forceps transfixation suture technique: three forceps on artery and ligate in crushed area proximal forceps. Transfixation ligature distal to first ligation and cut vessel between middle and distal clamps.
-Transect brachiocephalicus, deep and superficial pectoral mm near humeral insertions and remove forelimb.
-Closure: approximate muscle bellies to cover brachial plexus and vessels and suture SQ and skin.
-Apply soft padded bandage - Midhumeral
-Skin incesion around forelimb at level of distal third of humerus
-Reflect skin
-Abduct limb and separate biceps brachii m and medial head of triceps
-Expose brachial artery and vein for ligation. 3 clamp technique.
-Median, ulnar and musculocutaneous nerves for transection
-Transect triceps tendon
-Cut biceps brachii and brachialis mm at insertions on radius and ulna.
-elevate brachiocephalicus m from humerus.
-Ligate cephalic vein and transect radial nerve
-Osteotomize humerus and remove limb
Pelvic limb amputation
Indications
-Neoplasia
-Trauma
-Neurological impairment: sciatic nerve femoral nerve injury/impairment
Coxofemoral Disarticulation
-Make skin incision around rear limb at level of middle third femur
-On medial side: open femoral triangle by incising between pectineus muscle and caudal belly of sartorius muscle. Expose and ligate deep femoral artery and vein: 3 clamp technique
-Transect sartorius, pectineus, gracilus, and adductor mm. ~ 2cm from inguinal crease
-Transect Iliopsoas m at intersection on lesser trochanter and reflect cranially to expose joint capsule
-Incise joint capsule and cut ligament of head of femur
-On lateral side transect biceps femoris m and tensor fascia lattae at midfemoral level
-Severe sciatic nerve distal to muscular branches
-Transect gluteal muscle close to greater trochanter
-Transect semimembranosus, semitendinosus mm at proximal third of femur.
-Cut external rotator mm and quadratus femoris m at attachments around trochanteric fossa
-elevate rectus femoris m from origin on pelvis
-Remove limb
Midfemoral amputation
-Skin incision around rear limb at level of distal third of femur
-On medial side: transect gracilus, caudal belly of sartorius at midfemur.
-Isolate and ligate the femoral vessels: 3 clamp technique, transect pectineus m through musculotendinous junction, transect cranial belly of sartorius muscle.
-Transect quadriceps mm group proximal to patella
-Transect biceps femoris m at same level as quadriceps muscles.
-Isolate and cut sciatic nerve at level of third trochanter
-Transect semimembranosus, semitendinosus, and adductor mm at midfemoral level
-Elevate insertion of adductor m from linea aspera of femur
-Cut femur at junction of proximal and middle thirds of diaphysis and remove limb.
Lecture 5 Surgery of the Hip 1
Canine Hip Dysplasia
CHD
-Hereditary developmental condition of the coxofemoral joint (hip) that leads to degenerative joint disease (DJD)
- The most prevalent genetic based orthopedic disease of dogs
Definition: abnormal, characterized by subluxation or incomplete luxation of femoral head in younger patients and mild to severe DJD in older patients HIP LAXITY
Young dogs: is painful, wear of articular cartilage exposes pain fibers in subchondral bone. Laxity causes stretching of soft tissue
Older dogs: hip dysplasia causes pain through osteoarthritis
Degenerative Joint Disease
Cartilage damage
Osteophyte formation
Subchondral Sclerosis
-Luxation: complete separation between femoral head and acetabulum
-Subluxation: partial or incomplete separation between femoral head and acetabulum
What is a common sign of Hip dysplasia?
Exercise intolerance
clinical signs often do not correlate with radiographic findings
Some dogs with moderate or severe dysplasia are asymptomatic
What is the etiopathogenesis/causes of hip dysplasia?
What breeds have the highest incidence?
-Hereditary: pylogenetic multifactorial
-Environmentally influenced
-HIPS NORMAL at BIRTH
-Restricting growth rate can reduce onset, severity and incidence of CHD.
-CHD can not be eliminated, only reduced by breeding only dogs with normal hips.
-Phenotypically normal dogs can produce dysplastic dogs.
Large breed dogs
-German shepherds, Rottweilers, Labrador, Retrievers, Golden Retrievers, Saint Bernards.
Biomechanics/Pathophysiology
Hip Laxity
-Decreases surface area of articulation, concentrating stress over a smaller area.
-Favors development of CHD
Physiological response to laxity
-Increased joint fluid volume
-Proliferative fibroplasia of joint capsule
-Increased trabecular bone thickness
Mechanical response to Laxity
-Joint capsule stretching
-Acetabular bone deformation
-Periosteal nerve tearing
-Sharpey’s fibers rupture, bleed and form osteophytes
-Microfractures of acetabular trabecular cancellous bone
What structures support the hip and act in concert?
-Round ligament
-Joint capsure
-Periarticular musculature
-Capsular hydrostatic constraints
-No structure is most important
What are the clinical signs in dogs 4-12 months?
-Sudden onset of unilateral lameness
-Abnormal gait: short stride, bunny hopping.
-Pain
-Poor muscle development hind limbs
-Joint laxity
-Positive Ortolani Sign
-Angle of reduction: measure point where femoral head slips back into acetabulum when limb is abducted.
-Angle of subluxation: measured point where femoral head slips out of acetabulum when limb is adducted
Clinical signs in dogs >15 months old
-Chronic lameness, worse after exercise
-Often bilateral lameness
-Decreased muscle mass in pelvic limbs
-Waddling gait Bunny hopping
-Crepitus (granting or crackling sound) and pain on palpation
-Rises slowly with difficulty
-Shoulder muscle hypertrophy
-Difficulty climbing stairs
Differential diagnosis
Young dogs
-Panosteitis
-Osteochondrosis: osteochondritis dessicans
-Physeal separation
-Hypertrophic osteodystrophy
-Cranial cruciate injury
-Patellar luxation
-Trauma
Older dogs
-Degenerative myelopathy
-Cauda equina neuritis
-Intervertebral disk disease
-Lumbrosacral stenosis
-Cranial cruciate injury
-Polyarthritis
-Bone neoplasia
Diagnosis
-Signalment: breed predisposition
-History
-Physical Exam
-Radiography
PE young dogs
-Pain on external rotation and abduction
-Poorly developed pelvic musculature
-Exercise intolerance
-Increased laxity by Barlow test (first part of Ortolani test-subluxation)
-Ortolani test Postive sign
PE Older dogs
-Pain on hip extension
-Reduced range of motion
-Atrophy of pelvic musculature
-Exercise intolerance
-Crepitus on palpation
Are radiographs required for Dx of CHP?
Yes
OFA: orthopedic foundation of animals
PennHIP
Aspect evaluated:
-Acetabular margin
-Subluxation/luxation
-Size, shape, and architecture of femoral head and neck.
-Presence of exostosis or osteophytes
-Subchondral bone eburnation
OFA
-Advise encourage, and establish control programs to lower disease incidence
-Encourages and finances research
-Receive funds and make grants
OFA Dysplasia Contrl Registry
-24 months or older to register
-Positioning specific VD radiographs (hip extended view)
-Film identification requirements
-Evaluated independently by 3 radiologists based on breed, sex, and age.
-Consensus report produced
OFA Consensus Report 7 grades
- Excellent hip conformation (normal)
- Good hip conformation (normal)
- Fair hip conformation (normal)
4.. Near normal (borderline) - Mild hip dysplasia
- Moderate hip dysplasia
- Severe hip dysplasia
how would you classify this radiograph of immature dog?
VD
Subluxation of femoral heads and minimal evidence of DJD
-Typifying a candidate for triple pelvic osteotomy (TPO)
how would you classify this radiograph of this dog?
VD
Advanced hip dysplasia and osteophyte formation
-May be candidate for total hip replacement (THR) or femoral head osteoctomy, if clinical signs can not be managed medically
OFA Criticisms
Tests non-physiological hip position
Subjective/intra and inter-observer variation
Lack of uniform reporting
Influence of age on reliability
Procedure for Radiograph
-Extend hips and internally rotate tibias until patellas lie directly over trochlear grooves
-Pelvis straght
-Symmetric rotation of obturator foramina
Univ of Penn Hip Improvement Program
-recognized need for accurate and early diagnosis of CHD
-Objectives of selective breeding
-Stress radiographic diagnostic method
-Database/Registry
-International network of hip evaluation centers
Measures Maximal Passive Hip Laxity
-Passive vs. functional laxity
-On average shows 2.5 x >laxity than visible on hip extended view
-Statistically predictive at 16 weeks of age
Procedure
-Sedation/anesthesia
-3 separate radiographs 2 positions
-Measurement quantified, report interpretation
1. Hip extended radiograph: hind legs in extension, hip extended view.
2. Compression radipgraph: hips placed in neutral stance position. Femoral heads gently seated into acetabula
3. Distraction radiograph: hips placed in same neutral position as compression radiograph. Special device (distractor) is used to reveal inherent joint laxity
PennHIP Distraction Index
-Measure of hip laxity
-DI closer to 1.0 high degree of laxity
-<0.3 unlikely to occur
Criticism
-Training
-Certification
-Mandatory submission of all films
-Encourage positive ID
Treatment of CHD
Factors influencing treatment
-Patient’s age
-Degree of discomfort
-Physical and radiographic findings
-Client expectations
-Finances
- Medical conservative management: 75% of young patients return to acceptable clinical function
-Complete rest 10-14 days
-Moist heat
-Physical therapy
-Nosteroidal anti-inflammatory drugs
-Chondroprotective agents?
-Weight control
-Exercise
-NSAIDs: Carprofen (ramadyl), Derocoxib (Deramax), Meloxicam (Metacam), Previcox (Firocoxib).
-Chondroprotective agents: Parenteral Polysulfated Glycosaminoglycans (Adequan), Glycoflex, Cosequin, etc. - Surgical treatment: when conservative treatment not effective. Athletic performace required, slow progression of DJD and enhanced probability of good long-term limb function.
Lecture 6 Hip dysplasia 2
Surgical Treatment
1. Triple Pelvic Osteotomy (TPO)
2. Femoral head and neck excision (FHO)
3. Total hip replacement (THR)
4. Pectineus muscle myotomy/myectomy (historical significance)
5. Juvinile Pubic Symphysiodesis (JPS)
Triple of double Pelvic Osteotomy
Note axial rotation and lateralization of hemipelvis
THR Biomedtrix
a. Cemented canine THR parts: CFX femoral head, femoral stem, acetabular cup.
b. Cementless canine THR implants
c. Kyon THR
Coxofemoral Luxation
Traumatic displacement of femoral head from acetabulum
-typically results in craniodorsal displacement of femoral head relative to acetabulum. Most affected animals due to trauma, motor vehicle accidents
-Ventrocaudal displacements much less frequent. Femoral head may lodge with obturator foramen, associated with fracture of greater trochanter.
-Round ligament of femoral head always fails completely. Maybe interstitial rupture, or ovulsion of ligament from fovea capitis.
-Fibrous joint capsule completely torn for dislocation of femoral head.
-Tear in joint capsule may be small rent through which femoral head is dislodged. Or completely fraying of entire capsule.
TREAT A.S.A.P
Early reduction = rapid return of nutrient source for articular cartilage
Associated with trauma
-Half of patients have major injury in addition to hip luxation
-Careful PE before induction of anesthesia and treatment to identify current trauma.
What are some of the signs of Coxofemoral luxation
-Carriage of limb in craniodorsal position
-Paw beneath body and external rotation of stifle.
Hip Luxation Test “Thumb Test”
-Place thumb in space caudal to greater trochanter and externally rotate femur
If joint intact, trochanter displaces thumb
If joint luxated, trochanter rolls over thumb.
Diagnosis
-Position of greater trochanter related to Ilial Crest and Tuber Ischii
CFL treatment
-Radiographs carefully evaluated
-Avulsion of fovea capitis
-Associated hip joint fractures
-Degenerative changes secondary to hip dysplasia
Spontaneous Luxation Secondary to hip dysplasia = POOR PROGNOSIS (pic)
Surgical Technique
Capsular reconstruction
-If joint capsule salvageable (rare)
-Most cases: capsule can’t be securely closed and additional stability needed.
-Other reconstructive procedures performed to ensure hip stability for 3-4 weeks until capsular healing occurs
Reconstructive procedure
-Synthetic capsular with suture and bone screws or suture anchors
-toggle pin placement
-Additional stability gained by translocation of greater trochanter
-Reconstruction of joint capsule as sole means of stabilization requires dorsal joint capsule identifiable, and normal conformation of hip joint.
Capsulorrhaphy
-Interrumpted sutures places apposed joint capsule
Placement of prosthetic Capsule
-Bone screws in dorsolateral acetabulum
-Suture material passed from screws through predrilled tunnel in dorsal femoral neck and tightened.
-Suture prevents craniodorsal reluxation
-May be perfomred using suture anchors
Toggle Pin Suture
-Drill hole centered through femoral neck
-And through acetabular fossa
-Attach multiple strands nonabsorbable suture to toggle pin
-Made from Krischner wire
-toggle rod now available
-Pass toggle pin/rod through hole in acetabular fossa and pull to set pin/bar
-Pass sutures through hole drilled in femoral neck
-Reduce hip and secure sutures
Translocation Greater Trochanter
-Prepare new site distal and slightly caudal to normal anatomic position
-Stabilize greater trochanter in position with small pins and orthopedic wire (tension band)
Tension Band wiring
-Wire exerts force that counters force of muscle contraction
-Compresses fracture surface
Legg-Perthes Disease
-Non inflammatory aseptic necrosis of femoral head
-Occurs in young patients BEFORE closure of capital femoral physis
-Synomyms: Avascular necrosis, Osteochondritis dissecans of femoral head.
-Management: FHO (femoral heand and neck excision), THR
Medial Patellar Luxation
-Displacement of the patella from trochlear sulcus
-Common cause of lameness in small breed dogs
-Also occurs in large-breed dogs
-Associated musculoskeletal abnormalities: medial displacement of quadriceps, lateral torsion of distal femur, lateral bowing of distal one third of femur. Femoral epiphyseal dysplasia. Rotational instability of stifle joint. Tibial deformity.
Deformities: Distal femoral physis
-pressure in medial aspect causes less growth
-Less pressure in lateral aspect allows accelerated growth
-Lateral bowing of distal femur
-Abnormal growth continues while quadriceps displaced medially and physes are active
Degree of lateral bowing depends on severity of patellar luxation and patient’s age at luxation.
-Medial displacement of quadriceps apparatus
Diagnostic Imaging
Grade I or II
-Patella within trochlear sulcus or displaced medially
-Care taken to properly position limb to eliminate artifactual appearing luxations.
Grade II or IV
-Standard craniocaudal and medial-lateral radiographs. show patella displaced medially.
What radiographs may show
-Varus or valgus deformities
-Torsion of tibia and femur
-Special views or CT in severe cases help determine specific type and degree of deformity. Coronal or sky view of femur.
Surgical Anatomy
Extensor mechanism of stifle joint
-Quadriceps muscle group: extends stifle and aids in stabilizing joint. Converges as patellar tendon on proximal patella. Continues distally as straight patellar ligament.
-Patella: sesamoind bone, embedded in tendon of quadriceps muscle. Inner articular surface smooth and curved to articulate with throchlea. Normal gliding articulation of patella and trochlea necessary for maintaining nutrition for throchlear and patellar articular surfaces. Essential component of functional extensor apparatus. Maintains even tension during extension of stifle, acts as a fulcrum in a lever arm. Increases mechanical advantage of quadriceps muscles.
-Trochlear groove
-Straight patellar ligament
Patellar ligament must be identified before making parapatellar incision to enter joint.
Lateral capsule is stretched and thin, medial is contracted and thickened. Medial trochlear ridge and ventral surface of patella may be worn. Always check!
Tibial tuberosity
-Alignment of quadriceps, patella, throchlea, patellar ligament and tibial tuberosity must be normal for proper function.
-Malalignment of any of theses structures may lead to patellar luxation.
Patient positioning
-Dorsal or lateral recumbency with leg hanging over end of table. Need access to lateral side.
Deepening of trochlear Groove
-Best to preserve as much of medial ridge as possible
-Trochlear wedge or block recession
Trochlear block recession
Trochlear wedge recession
Tibial Crest transposition MPL
Lateral Imbrication
Do not transect distal periossteal attachment
Stabilize tibial tuberosity with 1 or 2 small K-wires
Lateral Patellar Luxation Tibial Crest Transpositon
-For lateral patellar luxations transpose tibial crest medially
-Stabilize tibial tuberosity in new location with 1 or 2 K-wire and figure 8 wire screw.
Release of Medial Joint Capsule
-Medial thicker and contracted with grade III or IV
-Capsule and retinaculum released allows lateral placement of patella
-Placement of loose suture prevents iatrogenic lateral luxation. It should not close tissue gap.
Lateral Imbrication
-Reinforcement of retinaculum
-Place suture through femoral fabellar ligament and lateral parapatellar fibrocartilage
-Grade III and IV if patella mostly out of position. Retinaculum opposite side of the luxation will be stretched
-Once patella is reduced-excise excess retinaculum and joint capsule allowing tight closure or arthrotomy.
-Or close retinaculum with VEST-OVER-PANTS suture pattern: a horizontal mattress pattern. Tissues are overlapped instead of meeting end to end. Sutures pass trhough both layers at both edges.
Post-Op
-6-8 weeks restricted physical rehab exercises and leash walking
-Radiographs at 6-8 weeks
-Gradual return to normal
Cruciate ligament anatomy and pathophysiology
-Patellar ligament
-Cranial tibial ligament of the medial meniscus
-Transverse ligament
-Cranial cruciate ligament
-Caudal ligament of the medial meniscus
-Medial meniscus
-Caudal cruciate ligament
-Caudal ligament of the lateral meniscus
-Meniscofemoral ligament
-Lateral meniscus
-Cranial tibial ligament of the lateral meniscus
Ligamentous support of the Stifle
-Medial and lateral collateral ligaments: limit medial and lateral movement of tibia
-CCL and CaCL (caudal cruciate ligament): restrain joint motion.
-CCL: restrain cranial displacement of tibia on femur, restrain hyperextension of stifle joint, limits internal rotation of tibia on femur, limits virus and valves motion in flexed joint.
-CaCL: restrains caudal displacement of tibia on femur, restrains hyperextension, limits internal rotation… same as CCL
During flexion they twist on each other
What are the key structures in cruciate disease?
What components are affected during partial rupture?
- Cranial cruciate ligament (CCL prevents cranial translation of the tibia)
- CaCL
- Meniscus
-Insert rows rupture CCL, tibia is displaced forward and crushes meniscus
Partial rupture
-Large caudolateral band: taut (pull tight) in extension NO DRAWER SIGN
-Small craniomedial band: taut in all phases of flexion and extension. DRAWER during FLEXION
Dx
-May require advanced imaging MRI
-Surgical exploration, arthrotomy, arthroscopy
-Severe lameness not initially noticed especially if bilateral disease, difficult jumping and rising, decreased activity level
-“Meniscal click” popping noise
-Medial butters: palpable thickening of medial aspect of stifle, grossly or radiographically visible
-Non-wt bearing if complete rapture or meniscus is torn
Ddx
-Canine hyp dysplasia
-Patella luxation
-Neurological disease IVDD
-Bone/tissue cancer
-Fractures, OCD, panosteitis etc.
Loss of CCL results
-Progressive DJD, loss muscle mass, decreased limb use, decreased performance
-Synovial joint inflammation, production of osteophytes, meniscal damage.
-Long-term impairment due to arthritis: loss of range of motion, stiffness, evidence of pain
-Tearing of meniscus: frequently damaged. Excise damaged parts = PARTIAL MENISCECTOMY
Examination/Screening
-Palpation of knee
-radiographs: do not show status of CCL, but assess joint effusion, degree of arthritis, aid in surgical planning, rule out neoplasia/concurrent disease. Loss of fat pad and destination of caudal joint
-Cranial drawer test
-Tibial thrust test
-May need sedation but try without it first unless painful patients. Dexmedetomidine/Butorphanol combos
-Range of motion: Pain on extension
-Tibial compression test, cranial translation of tibia. Index finger over patella, fingertip on tibial tubercle
-Sit test
-Cranial drawer test: negative test does not rule out CCL tear
Tibial Thrust test
CaCL considerations
-RARE as only injury
-CCL and collateral ligament damage usually
Dx
-Caudal drawer movement
-Tibia appears sublimated caudally due to muscle pull
-Reduction of subluxation with drawer movement of tibia cranially
-RADIOGRAPHS
-Need to check for other injuries
Surgery Techniques
-Extracapsular: imbrication techniques are utilized. surgically correct all injuries simultaneously
CaCL considerations
-RARE as only injury
-CCL and collateral ligament damage usually
Dx
-Caudal drawer movement
-Tibia appears sublimated caudally due to muscle pull
-Reduction of subluxation with drawer movement of tibia cranially
-RADIOGRAPHS
-Need to check for other injuries
Surgery Techniques
-Extracapsular: imbrication techniques are utilized. surgically correct all injuries simultaneously
What is the meniscus function?
-Acts as shock absorber
-Aid in lubrication
-Peripheral 15% vascularized,
-85% nourished by synovial diffusion
Isolated meniscal injuries are rare
-Secondary injury due to stifle instability
Anatomy
-Attached to femur and tibia by 6 ligaments
-Biconcave, semilunar discs of fibrocartilage
-Medial meniscus firmly attached to joint capsule and medial collateral ligament
-Lateral meniscus attached to femur, more movable-spares injury after CCL tear.
-Cranial horn, Body, Caudal horn (lateral and medial sides)
Injuries
-MOST COMMON INJURY occurs to MEDIAL meniscus during abnormal internal rotation
-Often associated with rupture of CCL
-Due to excessive forces/crushing during instability
-Result in meniscocapsular detachment, separation in substance of meniscus.
-Caudal horn of medial meniscus most often damaged, can be folded. Medial femoral and tibial condyles crush and shear it during weight bearing
-Radial tears: run in axial to abaxial direction
-Circumferential tears: follow the curvature of meniscus at site of tear
-Bucket handle tears: circumferential tears with separation of meniscus at site
-Meniscal release: incision of medial meniscus intended to prevent future impingement and damage
Meniscal injuries
- Isolated lateral meniscal tears are RARE, usually with CCL. Meniscofemoral ligament prevents it usually
Meniscal click: sound during palpation indicates injury
-A meniscus may act as a wedge and prevent drawer movement in an acutely injured stifle
Dx
-Radiography
-Arthroscopy
-Surgical exploration
Surgical treatment
-Intracapsular or extra capsular reconstruction techniques: focus on re-creation of passive constraints of stifle joint (CCL, joint capsule fibrosis).
-Corrective osteotomy: TPLO, TTA, TWO, and CBLO
-Injury of contralateral ligament in >50% of cases, percentage increases if “injured joint” visible in radiographic changes
-Depends on: surgeon preference, patient size and function, cost of procedure.
-Nearly 90% success rate regardless of technique used
-Intrascapular reconstruction: passing autogenous tissue through joint “over the top” method, passing tissue through predrilled holes in femur or tibia. Fascia late tissue used. Advantages: most closely mimic position and biology of original CCL. Disadvantages: invasive, tendency of graft to stretch or fail
-Extrascapular:
involves the placement of sutures outside the joint or redirect of lateral collateral ligament. Incorrectly referred to as imbrication sutures. Numerous patterns and combinations, origins and insertions.
Significant effects on isometry of the joint.
Sutures also secured from bone anchors, bone tunnels.
Monofilament nylon or siding or leader line. Manufactured orthopedic wire. Braided orthopedic wire
Sutures tied or connected with crimp, crimping suture alters biomechanics properties of loop.
Extrascapular reconstruction
-Extrascapular:
involves the placement of sutures outside the joint or redirect of lateral collateral ligament. Incorrectly referred to as imbrication sutures. Numerous patterns and combinations, origins and insertions.
Significant effects on isometry of the joint.
Sutures also secured from bone anchors, bone tunnels.
Monofilament nylon or siding or leader line. Manufactured orthopedic wire. Braided orthopedic wire
Sutures tied or connected with crimp, crimping suture alters biomechanics properties of loop.
Tightrope stabilization
-Drill guide wire femur distal to lateral fabella all the way across, exit proximal tibia on medial side.
Tibial Plateau Leveling Osteotomy TPLO
Tibial Plateau Leveling Osteotomy TPLO
-intend of surgery: attain slope of ~5-7 degrees , the quadriceps muscle group help.
-“Pivot shift” is failure to control internal rotation resulting in drawer, outcome following TPLO surgery is uncertain
-Preferred for larger active dogs, long-term rehab and postoperative care.
Tibial Wedge Osteotomy
The tibial anteroposterior (AP) axis is defined as a line drawn perpendicular to the surgical epicondylar femoral axis and passing through the center of posterior cruciate ligament (PCL) attachment.
-Based on the same principles of biomechanics than TPLO
-Results in change of relative position of the tibia
-May result in complication of stifle extensor mechanism
-Management of CCLR and increased TPA in young dogs
-OPEN PROXIMAL TIBIAL PHYSES, the TWO will not affect phases as can TPLO
Tibial Tuberosity Advancement (AP)
-Osteotomy of non-wt-bearing limb portion of the tibia
-Patellar ligament is aligned perpendicularly to tangent of femorotibial eliminating cranial tibial thrust
-Relieves the function of the CCL
-TPLO accomplishes the same redirection of vector at the TTA by rotating tibial plateau to neutralize the tibiofemoral shear force, but it may increase tension
-TTA theoretically reduces patellar ligament, has less postoperative patellar ligament inflammation than TPLO, does not affect joint congruency, does INCREASE LOADING of caudal cruciate
-TTA places patellar ligament perpendicular to slope of tibial plateau by advancing its insertion in a cranial direction. Eliminates tibiofemoral shear force with weight bearing and relieving the function of the CCL
TTA (AP)
CBLO, Cobra Based Leveling Osteotomy
Cobra: center of rotation and angulation
-Applied for angular limb deformity correction in orthopedics
-Circular osteotomy in opposite direction to TPLO
Physical Rehabilitation protocol following TPLO, TTA, TWO, MPL, Lateral Patellar Luxation
Regardless of technique used, Ruptured CCL,
-Inspect meniscus by arthrotomy or arthroscopy
-Identify tears
-Damage to caudal body of medial meniscus seen in 50-75% of patients, most have bucket handle tear, which MUST BE EXCISED
85-90% patients improve
DJD progresses regardless of treatment
Decline in activity overtime
Increasing level of disability
Adverse response to cold weather
Stiffness after inactivity related to progressive DJD
Femoral Metaphyseal and Articular Fractures
What is the angle of inclination and ante version?
-Femoral neck fractures: Occur at base of neck where it joins metaphysics of proximal femur
-Articular fractures involve joint surface
-Epiphyseal and metaphyseal occur in trabecular bone at proximal and distal end of the femur
-Angle of femoral neck normally 135 degrees inclination
-Normal angle of anteversion is 15-20 degrees : external rotation of proximal femur relative to distal femur. Important consideration when screw or pins are implanted
Femoral Metaphyseal and Articular Fractures
What is the angle of inclination and ante version?
-Femoral neck fractures: Occur at base of neck where it joins metaphysics of proximal femur
-Articular fractures involve joint surface
-Epiphyseal and metaphyseal occur in trabecular bone at proximal and distal end of the femur
-Angle of femoral neck normally 135 degrees inclination
-Normal angle of anteversion is 15-20 degrees : external rotation of proximal femur relative to distal femur. Important consideration when screw or pins are implanted
Femoral head and neck fractures
-Craniolateral approach to hip
-If alignment difficult trochjnteric osteotomy performed
-Best stabilize with lag screws or K-wire
Femeral Condylar Fractures
Unicondylar fractures done with lag screw
bicondylar requires lag crew, Steinmann pins (dynamic cross pinning), or bone plate
Femoral Physical Fractures
Most affected <10mts old animals
Young males more likely trauma because of tendency to roam.
Young heavy cats male neutered <6mts also at risk
-Capital physical injuries may occur without significant trauma bc femoral physical fracture occurs through cartilage of growth plate
-Capital physics functions to provide femoral neck length until ~8mts of age
-Distal physis functions to provide most femoral length
-In most fractures growth cartilage damaged by traumatic incident, in post traumatic period, or during surgery
Physical fractures heal rapidly, most do not continue to function
The younger the animal the more traumatic effects of premature closure of injured physis
Surgical treatment
-Intervention required to prevent DJD and lameness
-Anatomic reduction and stabilization with K-wires or small pins that are smooth
-Smooth implants generally sufficient
-Prevention of movement
-With greater trochanter separation: physis must be anatomically reduced and stabilized with tension band, counteract distractive forces of gluteal muscles.
Tarsal Fractures
What is “dropped hock”?
What do they cause?
What does Plantigrade stance look like?
Are tarsal fracture common in small animals?
How do calcaneal fractures occur?
They cause loss of wt-bearing support
Plantigrade stance: occurs when foot positioned so plantar surface of calcaneus contacts ground
Valgus position: an outward deviation
Varus position: an inward deviation
Rare in small animals Mostly working breeds
Fractured calcaneus not rare
-Often disabling bc tarsal joints serve a major wt-bearing function
-Without treatment joint incongruity and development of osteoarthritis lead to severe lameness
Calcaneal Fractures
-Distracted by pull of gastrocnemius muscle. Prevents bone contact between fragments and interferes with healing
-Treatment methods must resist tensile force
Talar Neck and Condylar Fractures
-Occurs in cats and occasionally in dogs
-Anatomic reduction and rigid fixation a must
-Difficult reconstruction due to small size of trochlea and degree of comminution, arthrodesis when not possible
Fractures of the Central Tarsal Bone
Common in racing Greyhounds
Rarely seen
-Repair with one or more small lag screws
-When buttress effect of central tarsal bone lost, fractures of 4th tarsal and calcaneus occur.
Buttress = support
PE findings, Central tarsal bone
-Non-wt-bearing lameness
-Attempts to place wt on limb cause tarsus to collapse in plantigrade stance
PE findings , Calcaneus
-May walk plantigrade on limb
-May be non-wt bearing
-Pain, swelling, heat, crepitus present
-Varus or valgus deviation usually present
Diagnostic imaging
-Require sedation
-Dorsoplantar, medial-lateral, and oblique usually sufficient to make diagnosis
DDx
-Calcaneal fractures differentiated from lacerations or rapture of Achilles tendon.
-Acute lacerations to achilles tendon: open wound and soft tissue swelling around area proximal to calcaneal tuberosity.
-Fractures of calcaneus: swelling caudal to tarsus and crepitation elicited on palpation.
Medical/conservative management not indicated
Surgical Tx
-Calcaneal: pull gastrocnemius m. tension, wire, lag screws or plate.
-Talar fractures: anatomically reduced and rigidly stabilized for optimal outcome.
-If fracture repair not feasible, arthrodesis of tarsocrural joint considered
Pre-surgery
-Stabilized, examined for concurrent injury
-Check for open wounds: clean, protect from further contamination.
-Mason metasplint or bivalve cast applied for comfort and protect soft tissue from further contamination or injury by bone fragments.
-Analgesics provided to post traumatic animals.
Surgical Anatomy
-Calcaneus is the largest of the tarsal bones: has two distal facets and processes that articulate with talus
-Tuber calcaneus forms sturdy prominence to accommodate INSERTION OF THE ACHILLES TENDON
-Talus: second largest: articulates with tibia and fibula and distally with central tarsal bone. Medial and lateral trochlea (articulate with tibia and fibula). Sides of trochlea articulate with medial and lateral malleoli
Stabilization of Calcaneal Fractures
-Transverse fractures: tension band wire or plate
-Oblique fractures: lag screws
-Articular surface: diverging Kirschner or lag screws
How do stabilize the neck of talus?
Large screw, angled from caudal medial surface of head of talus into trochlea, from there into calcaneus
Luxations of metacarpophalangeal joints or interphalangeal joints
Whether the fracture segments are reducible (can be put back together to enable weight bearing while healing) or non-reducible (cannot be reconstructed into a solid configuration, necessitating surgical implants to completely take over load bearing throughout the healing process).
-Mostly working dogs or racing Greyhounds
-Early surgical repair better results
-Chronic instability leads to DJD and les optimal function
Diagnostic imaging
-Dorsoplantar and mediolateral views from tarsus to end of digits
-Oblique views with digits spread
-A lateral view affected digit pulled cranially with tape or gauze
-Stress radiographs may need to displace distal digit to show joint instability
Medical management
-Analgesics for postraumatic pain
-Conservative tx with fiberglass bivalve cast or metasplint: used for nondisplaced metatarsal diaphyseal fractures of 1 or 2 bones
especially 2nd and 5th digits Non-wt-bearing
-Coaptation (joining or reuniting two surfaces): cats with comminuted non reducible features.
-Most phalangeal fractures and acute sesamoid bone fractures
-Cast or splints not removed until radiographic evidence that fracture bridged w/bone, usually 4-8 weeks.
Surgical Treatment
-Metatarsal fractures in athletic or racing dogs: require anatomic reduction and rigid stabilization, plates and screws
-Plate fixation: when FAS is low or when athletic function is desired
Bridging plate: digit 2, span and support comminuted
Compression plate: for transverse fractures, digit 3-4
Lag screw: Digit 5, oblique fracture, neutralizing plate.
-Large avulsed (An avulsion fracture occurs when a small chunk of bone attached to a tendon or ligament gets pulled away from the main part of the bone) fragments from base of 2nd and 5th metatarsals: require open reduction generally and internal fixation
-Lag screws: used to counteract pull of adjacent ligament or compress oblique fractures.
Treatment considerations for metatarsal fractures
1 & 2 bones: splint or cast
3 & 4 bones: internal fixation
Large displaced avulsion fractures with lag screws
Splint or bivalve cast applied after internal fixation until radiographic evidence of bone healing achieved same for metacarpal
Intramedullary (IM) Pinning Technique
-Multiple transverse or short oblique fractures with high FAS patients
-Slot in distal metaphysics, pin through slot, drive proximally
Fractures of phalanges are less frequent, most amenable to splinting
Treatment considerations for Luxations
Acute phalangeal laxations in working or racing dogs: open reduction and suturing of joint capsule, lateral collateral ligaments.
Chronic laxations of 2nd and 5th toe treated with amputation
Arthrodesis of metatarsophalangeal and interphalangeal joints result in good function and pain relief
Surgical Treatment
-Orthopedic wire
-IM pins
-External fixation
-Plates and screws
External Fixation of Metatarsal Fractures
-Connect fixation pins with acrylic bars: provides rigid stabilization of comminuted fractures
-Fixation does not interfere with open wound treatment
-OR place pins type Ib configuration and connect with acrylic
Phalangeal Fractures and Luxations
-Handled same as for the forelimb
-Digit masses: amputate same as for the forelimb
-Digit amputation: performed same as for the forelimb
Fracture Assessment Score
Tibial and Fibular diaphyseal Fractures
Paucity (the presence of something only in small or insufficient quantities or amounts; scarcity) of soft tissue increases potential for open fractures, decrease of extra osseous blood supply. Both can delay bone healing.
Paucity advantageous for placing ESF (external skeletal fixators), but Tissue irritation, cold hypersensitivity
-Mostly trauma fractures, entire animal needs to be evaluated for concurrent injuries. Rib fractures, pneumothorax, pulmonary contusions, traumatic myocarditis, may include extensive soft tissue damage or loss.
Diagnosis
-Signalment: any age, breed, cat or dog.
-history: non-wt-bearing lameness of affected limb
PE
-Crepitation and pain, palpable swelling,
-Often appear to have abnormal propioceptive response bc they are reluctant to move limb.
-Requires sedation for radiographs, painful.
-Radiographs of contralateral limb useful, used to contour bone plate more precisely, approx size of implants, compare bone light and shape.
-Evaluate for neoplasia or metabolic disease if trauma not definitive Dx.
Medical management
-Analgesics, antibiotics for open fractures.
Conservative: splints and casts for closed, non displaced or greenstick in immature animals (A greenstick fracture occurs when a bone bends and cracks, instead of breaking completely into separate pieces. The fracture looks similar to what happens when you try to break a small, “green” branch on a tree).
-Cast/splint fixation appropriate bc joint above and below (stifle and hock) can be immobilized. Should heal quickly
Surgical treatment
-Decision to perform open or closed reduction based on:
1. Fracture configuration
2. Fracture assessment score
3. Implant selected
-Open reduction: autogenous cancellous bone indicated (sites for harvest: Ipsilateral proximal humerus, wing of the ilium, ipsilateral distal femur)
-Fixation systems include: Casts, IM pins with cerclage wire or ESF support, interlocking nails, ESF (linear, circular, hybrid). Bone plates
Preoperative
-Open wounds management: swabs for bacterial culture and susceptibility testing
-Culture results before antibiotics administration
-ROBERT JONES bandage temporary stabilization
-Decrease swelling, protect and enhances comfort until surgery
-Analgesics, anesthesia for fracture fixation, prophylactic antibiotics.
Positioning
-leg prepared from hip to below hock
-Donor site prepared, if using harvested cancellous bone
-Closed reduction or limited open reduction: leg suspended from ceiling.
-Open reduction and plate application: can also be performed with leg suspended. If IM pin or interlocking nail application = dorsal recumbency and limb draped out and released to expose medial surface
External Coaptation
-FAS 8-10: full cylinder cast, immobilizes stifle and hock, limb in extension with slight virus angulation. Cast bivalve: apply over multiple layers of padding, cutting lateral and medial aspects. Secure with elastic tape.
Application of IM pins
-Tibial diaphyseal fractures: excellent resistance to bending, additional implants for axial and rotational support.
- Transverse or short oblique, requires ESF splint to control rotation.
Length of fracture line is 2-3 times diaphyseal diameter
-Multiple cerclage wires
-Avoid interference with stifle, retrograde pinning may damage intra-articular structures in dogs and patellar ligaments in cats.
-NORMOGRADE a must
-Pin inserted through skin on medial aspect of proximal tibia
Type Ia and Ib, high, low and moderate FAS patients
Type Ia: on craniomedial surface of tibia to stabilize transverse fracture.
Type Ib: anatomic reconstruction with cerclage wire, restores bony column and allows load sharing with type Ib ESF
Type II: minimal type II constructed with unilateral fixation pins, LOW FAS
Plates, compression, neutralization
Compression plate: transverse fractures
Neutralization plate: support long oblique fractures with lag screws
Bridging Plate with or without IM pin to span non reducible fracture, with pin: plate-rod construct
Failure to reproduce normal cure of tibia = valgus or varus angulation of the limb.
Complications
-Osteomylitis
-Implant migration
-Malunion
-Delayed union
-Non-union
-Pin loosening and drainage
Poor implant choice most common reason for complications
-Cats treated with rigid ESF may be at risk for delayed healing or non-union
Prognosis
-Generally good
Tibula and Fibular Metaphyseal and Articular Fractures
-Occur infrequently in mature dogs and cats
Proximal metaphysics and epiphysis
-Transverse oblique or short oblique usually, may be comminuted severe trauma, gun shot
Distal metaphysics and epiphysis in mature animals
-Usually involves malleoli and erosion injuries that remove malleoli, from loss of collateral ligament function and talocrural instability.
-Accurate alignment of articular surface of malleolar fractures and rigid fixation needed to achieve joint stability and minimize development of DJD
Surgical Treatment
-High FAS, IM pin, K-wire and figure 8 wire added for rotational stability. Crossed K-wires may be used
-Malleoli repair: Lag wire screws, tension band wires high FAS
Prognosis next slide
Prognosis
Metaphyseal fractures usually heal quickly due to large amounts of cancellous bone surrounding the fracture
In general tubercular bone heals with minimal formation of callus
Physeal fractures occur through cartilaginous growth plate in immature animals = slipped physes: weaker than surrounding tissue bone and ligaments, more susceptible to injury and may or may not be displaced. Salter Harris classification on basis of radiographs and histologic appearance
Salter Harris I and II with concurrent fracture of fibula: epiphysis may be displaced cuadolateral to tibial diaphysis, collateral ligament injury may occur.
-Open reduction and internal fixation: restore normal anatomy so required.
-Compare to radiographs of opposite limb, particularly with tibial tuberosity avulsions. Radiographs taken at time of injury NOT much information about damage to blood supply
-Difficult to give an accurate prognosis for growth
-FAS 8-10 most common, need surgical treatment. young animals heal quickly and mostly affected. Implants need to function for a long time
-K-wires or small pins plus anatomical reduction, use smooth pins so it doesn’t interfere with physical function, perpendicular to physics.
Prognosis for Physeal Fractures
Excellent for healing
Growth function depend on amount of damage, good if zone of hypertrophied cells is separated at cartilaginous physis
Most trauma-induced physical fractures sustain damage to growing cells and have a guarded prognosis for growth
Caudal malalignment of proximal tibial epiphysis may result in increase tibial plateau angle
Premature closure of tibial tuberosity physis can alter conformation of proximal tibia, results in impaired function and stifle DJD.
