Musculoskeletal System

Functions

 Movement  Shape of body

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 metasplint application Schroeder-Thomas splint

Fractures: Long Bone

 External fixation

Fractures: Long bone

 Rx – 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 to ancestral dog Collie

– skin is tight, thin, smooth

Doberman Collie

– slender/trim

Dalmatian I Wolfhound

– muscles are full, hard

G Shorthair

– low fat % (1-2%) – fleet footed, well-coordinated

Afghan hound Belgium Tervuren Siberian Husky

Incidence of HD



Highest prevalence

– giant breeds (2-3 x ancestral dog) – bones are coarse and large – feet are large and splayed – head is wide/oversized – heavy, round, stocky – fat % (5-10% of ancestral dog) – muscles less developed – less graceful, slower – Grow/mature rapidly

St Bernard Newfoundland Bull mastiff Eng Setter Gordon Setter OE Sheepdog S Spaniel Akita Ches Bay Retriever G Retriever Elkhound Rott 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

Normal density of bones

Panosteitis

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 form within muscles of Toxoplasmosis-positive cats

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 – Muscle atrophy and fibrosis

Acute Chronic

 Rx—Glucocorticoids

Myopathies

 Acquired myopathies – Feline myopathy  Usually due to renal dysfunction and loss of K + urine  Signs – Cats of all ages, sexes, breeds – Hypokalemia results in cervical ventroflexion – Wt loss – Periodic weakness, muscle pain  Rx—supplementation of potassium in



Bone Tumors

Most bone tumors are osteosarcomas malignant) (~100% – 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