Transcript Musculoskeletal System - Catherine Huff`s Site

Musculoskeletal
System
Functions
 Movement
 Shape
body
of
Disruption of Function
 Trauma
– Fracture
– Ligament Rupture
 Degenerative
disease
– Osteochondritis dissecans (OCD)
– Degenerative joint disease (DJD)
– Ununited Anconeal Process (UAP)
Disruption of function
 Inflammation
– Myositis
– Panosteitis
 Poor
conformation
– Luxating patella
 Neoplasia
– Osteosarcoma
Musculoskeletal Diseases
 Usually
painful, need
analgesics
– Feel better, heal better,
eat better, etc
 Fractures
– Causes
 Other
traumas
 Bone disease
 Repeated stress
Barbaro
MS Diseases
 Fractures
– Types
 Open
(compound) – broken skin
 Closed – intact skin
 Simple – 1 break
 Comminuted –multiple pieces
 Stable – ends apposed and fixed (ie
greenstick)
 Unstable
 Compression
Fracture????
MS Diseases - Fractures
 Signs
– History of trauma
– Pain or localized tenderness
– Lameness
– Deformity of bone
– Loss of function
– Localized swelling or bruising
 Dx
– X-rays
Fractures - Treatment
 Stabilize
joints above
and below the fracture
 External devices
– Splints
 Permanent
or temporary
 Wood, metal, plastic,
newspaper
 Adequate padding –
protect limb
 Keep dry, decrease
activity
 Foul odor => necrotic
tissue, infection
 Swollen toes => too tight
Fractures – Treatment
 Casts
– Plaster of Paris,
fiberglass
– Permanent
Fractures: Fixation devices
Robert Jones bandage
plastic splint
Schroeder-Thomas splint
metasplint application
Fractures: Long Bone
 External
fixation
 Rx
Fractures: Long bone
– Internal fixation devices
 Intramedullary
pin
– Provides good stability along axis of bone
– Rotation can be problem
– Removed after fracture heals
– Sterile surgical condition
Internal Fixation – Bone Plate
 Comminuted
fracture
 Best stabilization
 Should be removed after healing –
most are not
 Requires specialized instruments and
surgery techniques
 Provides early return to function
Fracture: Bone plate
 Which
bone? Where is fracture?
 http://www.youtube.com/watch?v=
Wls_Pyop-D0&feature=channel_page
Bone Fractures – Client Info
 Restrict
activity
 Watch for drainage, swelling, heat
 Metal (plate, pin) stronger than bone
– refracture may occur
 Follow up x-rays necessary
 Metal should be removed after
healing
 Metal may cause cold sensitivity
Ligament Injury – Anterior Cruciate
Ligament
 ACL
and PCL (posterior cruciate
ligament) stabilize knee joint
 Intra-articular structures
 Ruptured ACL – most common knee
injury => DJD
 May be complete rupture or partial
tear => unstable joint => DJD
Anterior and Posterior Cruciate
Ligaments
ACL and PCL
Occurrence – sudden hyperextension or
lateral extension of knee during exercise
 Middle age, obese, inactive or highly
athletic dogs; rare in cats
 Sudden non weight bearing or limping
 Swelling of knee joint
 Rupture of contra lateral ACL often occurs
within 1 year
 Mensical tear often accompanies ligament
tear

ACL – Dx
 Anterior
drawer movement
ACL – Repair
 Surgical
stabilization most successful
– Goal: stabilize knee to return function
and minimize DJD
– Extra capsular stabilization
 Most
successful <30#
 Suture material from flabella to tibial crest
and imbrication of joint
ACL – Repair
Ligament rupture
 http://www.youtube.com/watch?v=9
jg9E2nBt_E&feature=related
 http://www.youtube.com/watch?v=4
nU2QZjjByg
 http://www.youtube.com/watch?v=1pxxX4TXko&feature=fvw
ACL – Client info

Restrict activity 3-4 weeks post surgery
– Cage rest
– Leash walk only to urinate and defecate
Gradually increase exercise 4-8 wks post
sx
 Full activity 8-12 weeks
 Opposite cruciate often tears within 1 yr
 Weight loss helps
 DJD of stifle joint likely
 If no surgery, joint thickens - fibrosis

Patella Luxation
 Grades
– I - Patella manually displaced but pops
back into place
– II – Spontaneously or manually
displaced till manually repositioned or
patient extends stifle joint
– III – Patella luxated most of the time
but can be manually replaced;
movement of stifle joint reluxates
patella
– IV – patella permanently luxated;
unable to replace
Patella Luxation
 Grades
III and IV – crouching,
bowlegged or knock-kneed stance for
medial or lateral luxations,
respectively
 Pain: occurs as patella relocates or
abrasion creates contact with bone
Patella Luxation
Patella Luxation
Medial Patella Luxation
 Patella
is in circle
 Patellar groove indicated by arrow
Patella out
of groove
Patella in
groove
Patella luxation: Lateral
Seen in older dogs as the soft tissue of stifle
deteriorates; often accompanies hip dysplasia
Produces more functional disruption than medial
luxation
 Clinical
signs
– Acute lameness often associated with
trauma or strenuous exercise
– Knock-kneed stance is sometimes seen
– If bilateral, animal may be unable to
stand
Patella luxation: Medial
75% of cases
 1 of most common stifle joint abnormalities
in dogs
 Bilateral involvement - 50% of cases
 May occur in cats but not suspected, not
lame
 Clinical signs

–
–
–
–
–
Usually bilateral
Young (5-6 mo)
Cow-hocked (knock-kneed)
Foot twists laterally when weight bearing
Skipping or intermittent hindlimb lamesness
Patella Luxation - Medial
 Dx
– Toy and miniature dog breeds (yorkies,
Poms, Pekes, Chihuahuas, Boston
terriers
– Palpate patella when knee is flexed
– X-rays show deformity and patellar
displacement
Patella Luxation
 Diagnostics
– Labs - ?
– X-rays – indicated for Grade III & IV
luxations
– Arthrocentesis/synovial fluid analysis –
minimal changes
Patella Luxation
 Treatment
– I & II – outpatient treatment
 NSAIDS
– minimize pain, decrease
inflammation
 No steroids: SE and articular cartilage
damage in long term use
 +/- chondroprotective drugs –
glucosamines, chondroitin sulfate
Patella Luxation
 Treatment
– II, III & IV –
– Surgical repair only option
 Deepen
trochlear groove
 Tibial crest transposition for malalignment
 Imbrication of joint capsule to stabilize
patella in groove
Patella luxation: Repair
 Rx
– Surgical repair is only treatment
(3 surgical options)
– 1) Deepen trochlear groove
Patella luxation: Repair

1A) Trochlear block resection (also deepens trochlear
groove)
Patella luxation: Surgical repair
2) Transposition of tibial crest
Medial luxation
patella
 http://video.google.com/videosearch
?hl=en&q=patella+luxation+surgery
&um=1&ie=UTF-8&sa=N&tab=wv#
 http://www.youtube.com/watch?v=G
fnQbIk284g
Patella Luxation
 Client
info
– After Sx, limit exercise for 2-3 wk
– Support bandage (1-2 wk) should be
kept dry
– NSAIDs for pain relief
– Ice pack for 5-10 min q 8 hrs for 3-5
days post surgery
– Physical therapy for rehab (swimming)
helpful for animals reluctant to bear wt
– Will probably have some DJD later in life
Patella Luxation
 Client
Info
– May be inheritable
– Can worsen overtime esp without
surgery
Hip Dysplasia
Def: Malformation and degenearion of the
coxofemoral joint
 Pathophysiology

– Developmental defect initiated by a genetic
predisposition to subluxation of the immature
hip joint
– Poor alignment between femoral head and
acetabulum => abnormal forces on joint=>
irregularly shaped acetabula and femoral head
– Also overload articular cartilage =>
microfractures and osteoarthritis
Hip Dysplasia
 One
of most common
skeletal diseases in
dogs
 Incidence in cats
lower that dogs
 Breeds:
Large breed
dogs – St. Bernards,
G. Shepherds, Labs,
Golden Ret,
Rottweilers
Hip Dysplasia

Lowest prevalence are nearest in size
Collie
to ancestral dog
–
–
–
–
–
skin is tight, thin, smooth
slender/trim
muscles are full, hard
low fat % (1-2%)
fleet footed, well-coordinated
Doberman
Collie
Dalmatian
I Wolfhound
G Shorthair
Afghan hound
Belgium Tervuren
Siberian Husky
Incidence of HD

Highest prevalence
–
–
–
–
–
–
–
–
–
giant breeds (2-3 x ancestral dog)St Bernard
Newfoundland
bones are coarse and large
Bull mastiff
Eng Setter
feet are large and splayed
Gordon Setter
head is wide/oversized
OE Sheepdog
S Spaniel
heavy, round, stocky
fat % (5-10% of ancestral dog) Akita
Ches Bay Retriever
muscles less developed
G Retriever
Elkhound
less graceful, slower
Rott
Grow/mature rapidly
G Shep
 Within
a breed, the faster growers are more prone to
HD
 Pups of wolves, foxes are slow growing, late maturing
vs dogs
Hip Dysplasia – Clinical Signs

Depends on degree of joint laxity, OA, and
chronicity of disease
– Early – related to joint laxity
– Later – related to jt degeneration
– May present as early as 4-5 months

HX
– Decreased activity


Difficulty rising
Reluctance to run, jump, climb
– Intermittent or persistent hind limb lameness;
worse after exercise
– Bunny hopping or swaying gait
– Narrow hind limb stance
Hip Dysplasia – PE
 Pain
on palpation of hips
 Joint laxity (positive ortolani
sign) – early disease –
subluxation of hip
 Crepitus
 Decreased ROM of hip joints
 Atrophy of thigh muscles
 Hypertrophy of shoulder muscles
Hip Dysplasia
 Dx
– X-rays provide definitive diagnosis
 Quality
depends on positioning, exposure
technique, darkroom technique
– VD position
– Hind limbs extended fully and parallel
– Totally rotate legs medially
– Bilateral symmetry
– Flattening of femoral head,
– Shallow acetabulum
– Periarticular osteophyte production
– Thickening of femoral neck
Hip Dysplasia

OFA Certification
– Anesthesia/sedation usually required for
positioning
– OFA requires animals to be >2 yr of age; 7
grades of hips
 Excellent—near
perfect hips
 Good—normal
 Fair—less
than ideal, but within normal limits
 Near normal—borderline conformation
 Mild Dysplasia—minimal deviation with slight
flattening of femoral head
 Moderate Dysplasia—
 Severe Dysplasia—complete dislocation of hip w/
flattening of acetabulum and femoral head
Hip Dysplasia: Normal hips

Normal hips
– round head except where lig of
femoral head attaches
– Joint space (J) is consistent
Hip Dysplasia: OFA guidelines
Borderline—no consensus between radiologists to classify hip as Normal or Dysplastic
Good positioning
Normal dog
Poor positioning
1.
2.
3.
4.
5.
6.
femurs not parallel
Obturator foramen less rounded on R and
wing of ileum larger on R
R acetabulum appears shallower
L acetabulum appears deeper
Fabellae appear more medial to femur midline
Wedge-shaped jt space due to lateral femoral
rotation (looks like HD)
Hip Dysplasia
 Penn
Hip Registry – distraction
radiography
 Dorsolateral subluxation (DLS)
 Dorsal acetabular rim view x-rays
Hip Dysplasia – Treatment

Medical
– Outpatient
– Analgesics and Antiinflammatories

Minimize joint pain=> use legs => decrease atrophy
– Does not correct problem; degenerative process
progresses anyway
– Temporary relief of pain
– Carprofen, erodolac, deracoxib, tepoxalin
– Avoid corticosteroids – articular cartilage damage in long
term use
– Do not combine NSAIDS
– Do not combine NSAIDS with steroids
– Wait several days when changing NSAIDs
– Glucosamine and chondroitin sulfate supplements chondroprotective
Hip Dysplasia – Treatment
 Surgical
– TPO – triple pelvie osteotomy
 6-12
months age
 Preventive to correct alignment of joint
– Juvenile Pubic Symphysiodesis
 Pubic
symphysis fused early
 Causes better alignment of acetabulum with
femoral head
 Can be done 3-4 months; minimal effect
after 6 mo
Hip Dysplasia – Treatment

Surgical
– Total hip replacement
 Salvage
procedure in mature dogs with severed DJD
unresponsive to medical Tx
 Pain free in 90% of cases
 Unilateral replacement provides acceptable function
in 80% of cases
– Excision Arthroplasty or Femoral Head
Ostectomy
 Forms
“false” joint
 Removal of femoral head and neck to prevent joint
pain
 Salvage procedure when medical treatment not
working and other sx too expensive
 Best - < 20#; good musculature
 Abnormal gait
Total Hip Replacement and FHO
Hip dysplasia
 http://www.youtube.com/watch?v=H
Twi8TRs6z8
Hip Dysplasia – Client Info
Weight control important to decrease load
on painful joint
 Swimming excellent activity
 Physiotherapy – decreases joint stiffness,
helps maintain muscle integrity
 Joint degeneration progressive
 May be heritable – do not breed
 Special diets designed for fast growing
dogs may decrease severity

Legg-Calve-Perthes Disease (LCP)






Spontaneous degeneration of the femoral head
and neck leading to collapse of the coxofemoral
joint and osteoarthritis
Avascular necrosis of femoral head and neck
Cause unknown
Infarction of the blood vessels of the proximal
femur
Necrosis of subchondral bone => collapse and
deformation of femoral head
Articular cartilage thickened, cleft development,
fraying
LCP

Signalment
– Miniature, toy and small breeds, terriers
– 5-8 months old; range 3-13 mo

Clinical signs
–
–
–
–
–
Lameness, gradual onset over 2-3 months
Usually unilateral
Pain on manipulation of hip
Occasional crepitus in hip
Atrophy of thigh muscles
LCP
 Diagnosis
– X-rays
 Early
- Decreased bone density of epiphysis,
sclerosis and thickening of femoral neck
 Later- lucent areas in femoral neck
 End-stage – flattening and extreme
deformation of the femoral head, severe
osteoarthritis
LCP
Legg-Perthes Disease
Collapse of femoral head
14 mo post-op FHO
LCP
 Treatment
– Rest and analgesics
– Analgesics, anti-inflammatory drugs and
cold packing 3-5 days post
– ROM exercises
LCP
 Client
education
– Recovery from surgery takes 3-6
months
– Glucosamines and chondroitin sulfate
– May be hereditary – do not breed
– With sx – good to excellent prognosis
for full recovery
– Conservative therapy – alleviate
lameness in 2-3 months in 25%
Osteochondrosis Dissecans (OCD)

Definition of osteochondrosis
– Pathologic process in growing cartilage,
primarily characterized by a disturbance of
endochondral ossification that leads to
excessive retention of cartilage
– Ossification is slowed, cartilage thickens, is
weaker and susceptible to stress, disrupts
blood supply => necrosis of bone
– Osteochondrosis dissecans - Formation of a
cartilage flap over the area of bone necrosis
– Bilateral disease common
– Most commonly affected joints: shoulder,
elbow, stifle, hock
OCD: Pathology
OCD

Signalment:
Large and giant breeds
– Great Danes, Labs, Newfoundlands,
rottweilers, Bernese Mountain dogs,
Englishsetters, Old English sheepdogs
– Age: 4-8 months

Hx:
– Lameness – sudden or slowly increasing
1
or more limbs
 Worse after exercise

Risk Factors:
– Diet with 3x rec levels of Ca
– Rapid growthand weight gain
OCD
 PE:
– Pain on palpation or movement of
affected joint
– Usually weight bearing lameness
– Joint effusion common
– Muscle atrophy if chronic
– Hock OCD- hyperextension of the
tarsocrural jt
OCD: Shoulder m. atrophy
OCD – diagnosis
 X-rays
– Flattening of subchondral bone or
subchondral lucency
– Flap visualized if calcified
– Calcified bodies within the joint (joint
mice)
 Joint
tap and analysis of synovial
fluid
 Arthroscopy
OCD: Dx
OCD: lesion
Great Dane humeral heads
OCD
normal
OCD – Treatment
 Early
– no flap
– Restrict activity level
– Weight control
 Flap
(OCD)
– Surgical removal of flap or joint mice
– Antiinflammatories
– No corticosteroids
– Chondroprotective drugs (gluocosamine,
etc)
OCD – Client Info
 Heritibility
– do not breed
 DJD may develop even with surgery
 Limit activity for 4-6 weeks
 PT early on
 Control weight
 Restrict weight gain and growth in
young dogs
OCD – Prognosis
 Shoulder
– good to excellent
 Elbow, stifle, hock – fair to guarded
Panosteitis
Definition: a self limiting condition
affecting one or more of the long bones of
young medium to large breed dogs that is
characterized clinically by high density of
the bone marrow cavity
 Cause unknown
 Painful
 May be one leg or become a shifting leg
lameness

Panosteitis

Signalment
– Age – 5-18 months
– Dogs

Hx:
–
–
–
–
–
No trauma
Lameness of varying intensity
Usually front legs but hind legs also
Can be shifting leg lameness
Severe: inappetance, weight loss, depression
Panosteitis
 PE
– Pain on deep palpation of long bones in
affected limbs
– +/- low grade fever
– +/- muscle atrophy
Panosteitis
 Diagnostics
– X-rays: radiographic densities within
the medulla of long bones
Panosteitis
Normal density of bones
Panosteitis
Panosteitis
 Treatment
– NSAIDs- minimize pain; decrease
inflammation
– Does not affect duration of disease
– Acetominophen not recommended
Panosteitis
 Client
Info
– Recheck q 2 weeks
– Self-limiting disease
– Treatment symptomatic
– Multiple limb involvement
– Lameness – few days to months
Luxations
Hip luxations are most common
Joint capsule must tear and ligament of femoral head
must tear

Types
– Craniodorsal
 most
common
 leg appears shorter
 stifle rotates outward
– Cranioventral
 Usually
results from unsuccessful reduction of
craniodorsal luxation
 Stifle rotates inward
 Leg appears longer
Hip Luxation
 Signs
– Hx of trauma
– Acute lameness; non wt-bearing
– Possible swelling dorsal to hip joint
– Luxated limb shorter if legs extended in
VD position
Hip Luxation: Dx

Dx
– Thumb between greater trochanter—ischial
tuberosity
 Rotate
femur away from body
– Disparity in leg lengths
– X-ray to r/o femoral neck fracture, Legg-Perthes
Hip Luxation

Hip Luxation
Rx
– Closed reduction
 anesthesia
required for proper muscle relaxation
– Using traction, rotate and pull head back in
place
– Open reduction
 Replace
head of femur and
suture soft tissue around
acetabulum to keep it in place
– Either way, bandage in
abduction x 2 wk (Ehmer sling)
Hip Luxation
 Client
info
– Px depends on:
 Stability
of the reduced joint
 Soft tissue damage
 Length of time prior to reduction of luxation
– Arthritis may occur
– Consider FHO/hip replacement if hip
does not stay reduced
Luxation – Elbow
 Less
common
 Difficult to reduce
DJD
 http://www.youtube.com/watch?v=P
XMRDRetmgU
Myopathies
Def—Diseases of muscles

Inflammatory myopathies
– Bacterial myositis (dogs and cats)
 Occurs
following bite wd or contamination following
Sx
 Usually Staphilococcus and Clostridium spp
– Protozoal myositis
 Cysts
cats
form within muscles of Toxoplasmosis-positive
Myopathies - Immune-mediated
Myopathies

Polymyositis—immune-mediated disease of dogs
and cats
– Signs
 Large
breed dogs, middle-age
 Weakness that gets worse with exercise
 Stiff, stilted gait
 Hyperesthesia on palpation
 Fever, depression
 Megaesophagus may develop (w/ aspiration
pneumonia)
 Muscle atrophy
 Idiopathic
 Dx—
– Elevated muscle enzymes (CPK)
– Muscle biopsy
 Rx—Prednisone
(2.2 mg/kg daily)
Myopathies

Immune-mediated Myopathies
– Masticatory muscle myositis (atrophic myositis,
eosinophilic myositis)
 Signs
– Involves muscles of mastication (temporalis, masseter)
 These muscles have a special fiber type that has
antigenic properties similar to antigenic properties
of bacteria
– Muscles swelling initially
Acute
Chronic
– Muscle atrophy
and fibrosis
 Rx—Glucocorticoids
Myopathies

Acquired myopathies
– Feline myopathy
 Usually
urine
 Signs
–
–
–
–
due to renal dysfunction and loss of K+ in
Cats of all ages, sexes, breeds
Hypokalemia results in cervical ventroflexion
Wt loss
Periodic weakness, muscle pain
 Rx—supplementation
potassium
of
Bone Tumors

Most bone tumors are osteosarcomas (~100%
malignant)
– Cause: unknown
– Signs (dist radius, prox humerus, dist femur, prox
tibia)
 Middle-age,
large-breed dogs
 Lameness
 Wt
loss
 Pain, swelling of affected limb
Dx: x-rays show lysis/proliferation of new bone
tissue
Bone Tumors
video
 http://www.youtube.com/watch?v=t
88NK39rO_o
Bone Tumor

Dx
– Biopsy for definitive diagnosis
– Thoracic radiographs to r/o metastatic disease

Rx
–
–
–
–

Amputation of affected limb
Chemotherapy
Radiation therapy
No recommended drug therapies for cats
Client info
–
–
–
–
Bone cancer is a fatal disease
Survival time up to 12 mo with aggressive therapy
Biopsy is needed to confirm diagnosis
Amputation is necessary for comfort of animal, but it doesn’t
affect likelihood of metastasis or survival
– Drug therapy and follow-up lab work are expensive
Declaw




Considered “inhumane” by some people
Outlawed in some European countries
San Francisco “advises” against it
It is an amputation of the last joint of cat’s toes
Declaw

Reasons why owners declaw cats
– Shredded furniture, drapes
– Scratched by cat

Procedure
–
–
–
–

Apply tourniquet to leg
Anesthetize, remove claws
Tight bandages x 3 d
Send home
Do not declaw outside
cat
Dock Tails
 Also
banned in some European
countries
 Done at 2-5 days old
 No anesthesia
 1 stitch