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Download Musculoskeletal System - Catherine Huff`s Site
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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
