SAS Exam 4

Pathogenesis of Osteoarthritis

• AKA: DJD degenerative joint disease 

• Arthritis: Inflammation disease within a joint!

• Et: Aberrant repair and degradation of articular cartilage

  • Altered subchondral bone metabolism

  • Periarticular osteophyte formation

  • Synovial inflammation

  • Loss of stiffness and tensile strength of articular cartilage

  • Mobility impairment = pain

• Common sites: Hip, Elbow, Stifle, Shoulder!!

Risk factors for Osteoarthritis (OA)

• Primary: Idiopathic & age! → cats

• Secondary: developmental 

• Age: alters joint structure and function

• Species: cats > dogs

• Body weight: increases joint stress

  • Adipokines:

    • Leptin: inhibits chondrocyte growth

    • Adiponectin: induces cartilage degradation

• Gender/Hormonal factors: Estrogen protective effect from inflammation

Progression of Osteoarthritis

• Stage I: Proteolytic cartilage matrix breakdown

• Stage II: Fibrillation and surface erosion of cartilage

  • Release of breakdown products into synovial fluid

• Stage III: Synovial inflammation, phagocytosis stimulates

  • Cytokine and protease production

Diagnosis of Osteoarthritis

• Cs: Slow to rise, Morning stiffness, Improved after activity, Lameness after exercise(pm), Pain

• Radiography (#1): Evaluates subchondral bone, cartilage lesions, synovium

  • Cons: Not sensitive in early stages, Limited soft tissue evaluation, Poor correlation with clinical signs: do not tx the xray

• Arthroscopy: Direct visualization of joint, diagnostic, therapeutic, assesses cartilage damage

• Synovial fluid analysis Evaluate cell count + types,  color, turbidity, viscosity, detect infectious agents

  • Cons: Risk of introducing infection → sterile prep

  • Preform AFTER xrays/CT/MRI

Diagnosis of Osteoarthritis: MRI vs. CT

• MRI: Soft tissue, cartilage defects, thickness, effusion, synovitis, edema, menisci, ligaments, osteophytes

  • Cons: $$, limited availability, requires anesthesia

  • Pros: Shoulders!

• CT: Bone, osteophyte, complex joints evaluation & combo w/ arthrography

  • Cons: Poor for soft tissue

  • Pros: elbows and tarsals

Lifestyle Osteoarthritis Management

• Considerations: No cure or approved disease-modifying drugs, Multifactorial disease

• Multimodal approach: GOAL- improve quality of life and CS!

• Lifestyle: Weight Control BCS 4/9 and Low-impact exercise

  • Passive range of motion, Water treadmill, Strengthening exercises, Heat/cold therapy, Acupuncture

• Diet: Low fat / weight loss diets! & family support

  • Glucosamine + Chondroitin sulfate: PSGAGs

    • Stimulate chondrocytes

    • Anti-inflammatory

    • Takes 4–6 weeks for effect

  • Omega-3 fatty acids: EPA/DHA, Fish oil

    • Anti-inflammatory

Medical Osteoarthritis Management

• Pain Management: NSAIDs, Gabapentin, Amantadine

  • Anti-NGF ab: IM injections - Librela (dogs), Solensia (cats)

• Stem Cell Therapy: Intra-articular injection of adult multipotent stem cells

  • Anti-inflammatory, regenerative effects

• Platelet-Rich Plasma: Stimulates natural healing response

• Adequan: Semi-synthetic glycosaminoglycan, PSGAGs

  • Disease-Modifying Agent: Inhibits MMPs, prostaglandins, cytokines and promotes HA, collagen, proteoglycan synthesis

• SPRYNG: Intra-articular injection, repeat q 1.5y

• Disease-Modifying Agent: Creates microcushion matrix and absorbs/release synovial fluid with impact

Surgical Osteoarthritis Management

• examples: CCL, patella, articular damage

• Corrective: Slows down progression of OA

  • Goals: Address underlying condition

  • Types: CCL stabilization, Patellar luxation repair, Articular fracture repair, Remove fragmented coronoid process, OCD lesion debridement

• Salvage: Joint replacement(total hip), (FHNO) Femoral head & neck ostectomy, Arthrodesis(fusion)

Pathogenesis of Hip Dysplasia

• Dev: Abnormal development of the coxofemoral joint

  • Subluxation + Osteoarthritis (DJD)

  • #1 dz of the coxofemoral joint

    • Primary: genetic, Environmental: contributing

• Et: Round lig and joint capsule are stretched → subluxation of femoral head

  • Phase 1: excessive joint lax → phase 2: osteoarthritis

    • Cartilage damage, Trabecular bone microfracture, Synovitis

• Risk: Genetics, rapid weight gain or growth, high Ca + protein diet, activity, flooring, decreased pelvic muscle mass, large breeds

Clinical Presentation of Hip Dysplasia

• Bilateral > unilateral

• <6-8 months: Abnormal gait, Bunny hopping, Asymmetric sitting, Waddling, Reluctant to jump, Mildly painful

• 6-12 months: unilateral/bilateral Hind limb lameness, Difficulty rising, Exercise intolerance, Stiff gait, Thigh muscle atrophy, Pain, Decreased muscle mass

• 10-12 months: Fxn improvement, Joint capsule fibrosis and tightening, Residual lameness

• Long-Term: Lameness, Thigh muscle atrophy, Crepitus, Pain, Chronic low-grade OA, circumduction, hopping

  • lameness worse in AM & after exercise

    • 32% of dogs will also have CrCL rupture

Differentiate from Hip Dysplasia and Lumbosacral Disease

• Direct palpation in lateral/non-weight bearing

• Weakness due to neurologic disease = Conscious proprioception deficits (LS)

• Rectal palpation can identify LS disease(direct pressure)

• hip extension → flexes LS joint, stretch iliopsoas muscle

Laxity Tests for Hip Dysplasia

• Ortolani maneuver: angle of reduction → evaluates for laxity

  • How: Force femur to subluxate then reduce, done under sedation

  • Results: 

    • ‘Clunk’ = laxity present

    • ‘Clunk’ = reduction of hip

      • No laxity, shallow acetabulum, severe OA

• Barlow test: angle of subluxation

  • How: Force femur to subluxate

    • 1st ½ of ortolani maneuver → “how far can we get them to luxate”

• Barden test

  • How: Laterally displace femur

Screening for Hip Displasia

• OFA: Evaluates passive laxity

  • When: Certified >2 years

  • Grades:

    • Normal: excellent, good, fair, borderline

    • Dysplastic: mild, moderate, severe

• PennHip: Evaluates passive distractive laxity

  • When: Certified >16 weeks

  • Grades: Scale 0–1 

    • 0.58 = 58% femoral head displacement

Diagnostic Imaging for Hip Dysplasia

• VD most useful

• Want >50% acetabular coverage!

• Rads: Bone shape, remodeling, osteophytosis(neck), enthesiophytosis (Morgan’s line), laxity

  • Do not treat the radiograph!

  • CT + MRI: not useful and expensive

• Arthrocentesis: Rule out infection or neoplasia

• Arthroscopy: Articular lesion evaluation, prior to TPO

  • Rarely needed

Juvenile Pubic Symphysiodesis (JPS)

• Young, showing CS

• Sig: 12-24 weeks

• Use: Prophylactic and preventative, increase femoral head coverage, fuse pubic symphysis growth plate, decrease OA progression, Improved congruency

• Burns the pubis symphysis 

Triple Pelvic Osteotomy

• Physically rotating acetabulum

• Sig: Age <12m, laxity but no OA, Lg breeds, angle of reduction ≤30°

• Use: Preventative and palliative, rotate acetabulum to increase coverage, cut ilial body, pubis, ischium

  • Cut in 3 places, place plates to stabilize

• Pro: 90% success rate

• Con: OA may still progress but slower

Total Hip Arthroplasty

• Use: Salvage, replace end-stage joint with prosthesis

• Pro: Near-normal fxn, Quick

• Cons: expensive

Femoral Head and Neck Ostectomy (FHNO)

• Adequate muscle mass is present!

• Use: remove pain by excising joint, salvage

• Pro: Cheaper, easier, faster

• Con: worse fxn

• Begin Aggressive rehabilitation ASAP

Treatment of Hip Dysplasia

• Medical: use for as long as possible, treat OA, use until refractory response or muscle loss

• Juvenile Pubic Symphysiodesis

• Triple Pelvic Osteotomy

• Total Hip Arthroplasty

• Femoral Head and Neck Ostectomy

Elbow Dysplasia Clinical Presentation

• Et: Genetics + environ factors

  • Ununited anconeal process, medial compartment disease, medial coronoid disease, OC, OCD, Elbow incongruity

• Sig: Young >>> older, large breeds, rapidly growing dogs

• Cs: lameness

  • #1 cause of forelimb lameness

Medial Compartment and Coronoid Disease

• Growing/developmental disease, Bilateral

• Et: Growth incongruency radius/ulna, abnormal joint stress, pressure on medial coronoid of ulna

• Sig: Large breed dogs, Labs, Bernese Mountain Dog, Male > Female, 6-18 months

• Cs: OA, Lameness with ambulation, Decreased ROM of elbow joint, Pain(PE/palpation), Minimal joint effusion, Muscle atrophy

• Dt: Lateral, AP, flexed, Crlat-oblique

  • Rads: Osteophytes(back of elbow), Effusion, Subtrochlear sclerosis, Joint incongruity

  • CT: Most sensitive 

• Tx: Rx: Management of OA

  • Sx: gold standard

  • Medial arthrotomy:

    • Cons: Limited view, high postoperative morbidity

    • Arthroscopy (#1): gold standard

    • Pro: Min invasive, good view

    • Cons: higher cost, learning curve

Osteochondrosis and Osteochondritis Dissecans

• Et: Defect of normal endochondral ossification

  • Shoulder 

• Sig: large breed dogs, rapid growth, 5-10 months

• Cs: lameness, pain, decreased ROM, muscle atrophy, effusion

• Dt: 

  • Rads: Divot of subchondral bone, OA, free cartilage flap

  • CT: Detects subtle subchondral bone lesions

• Tx: Arthrotomy or arthroscopy

  • Remove cartilage flap, debride subchondral bone, promote fibrocartilage repair

Ununited Anconeal Process

• Et: Anconeal process of ulna fails to unite with proximal ulnar metaphysis

  • Failure of endochondral ossification, Joint incongruity

  • Hereditary, environmental, hormonal factors

• Sig: Large breeds, GSD, Male > female, 5-12 months

• Dt: Radiographs FLEXED lateral!

  • Osteophytes, Effusion, Anconeal process fragment, Joint incongruity

• Tx:

  • Rx: OA management

    • End stage or financial issues 

  • Sx: #1 , <1yr - early sx **

    • Early: primary repair, viable cartilage 

    • Ulnar osteotomy → remove stress, allow fusion

    • Lag screw fixation of anconeal process

    • Chronic: excision of anconeal process

Elbow Incongruity

• Et: Asynchronous growth of radius and ulna

• Dt: radiographs

• Tx: Corrective ulnar ostectomy (short radius syndrome)

  • Redistribute stress in joint

  • Allow bone alignment at joint level

  • Decrease joint stress

Secondary stabilizers of stifle 

• Secondary stabilizers:

  • Menisci

    • Medial: larger, more ovoid

      • Stuck to meniscus/tibia 

    • ruptures w/ CrCL tears

    • Lateral: smaller, more circular

    • Meniscofemoral ligament! protects from CrCL tear

  • Fxn: Protects from injury with a CrCL tear, shock absorption, lubrication, stability

  • Tendons: LDE, patellar, popliteal

  • Fibrous joint capsule

Cranial Cruciate Ligament Disease Pathogenesis

• Et: Chronic inflammatory stimulus, Trama, Genetics

  • Cranial tibial thrust, Repetitive microtrauma to CrCL, Release of degradative products, Synovitis, Articular cartilage damage, Loss of proteoglycans, Increase in cartilage water content, Metalloproteinase production and release, Cytokine production and release

• Sig: 2-10 years, Neutered, Large breeds

  • Breeds: Labrador, Boxer, Newfoundland, Rottweiler

  • Conformation: Straight stifle joint, Narrow intercondylar notch, Excessive tibial plateau slope

Cranial Drawer

• Cranial translocation of the tibia

  • How: lateral recumbency, stabilize femur, move tibia cranially

    • One hand: thumb on fabellae, index on patella

    • Other hand: thumb on fibular head, index on tibial crest

  • Results: 

    • Present in flexion only = partial tear

    • Present in flexion and extension = complete tear

Tibial Thrust

• Tibia translates cranially relative to femur

  • How: Stabilize stifle, flex hock, feel tibia move cranially

    • One hand: cup distal femur/stifle, index on tibial crest

    • Other hand: grasp paw distal to hock

  • Results: 

    • Absent = normal or partial tear

    • Present = torn CrCL

Cranial Cruciate Ligament Disease Diagnosis

• PE: Crouched hindlimbs, external rotation of affected limb, Failed “sit test”

  • Acute clinical presentation

• Meniscal Click: Torn meniscus pops due to shear with range of motion

• Radiographs: Joint effusion, Medial periarticular fibrosis(medial buttress), Osteophytosis, Cranial drawer placement, OA

Cranial Cruciate surgical repairs

• Arthrotomy: Debride CrCL + torn meniscus

• Extracapsular Stabilization: Lateral suture stabilization eliminates cranial drawer and tibial thrust

  • Limb fixed at standing angle

  • Suture placed in path of CrCL

  • Long-term stabilization via periarticular fibrosis

• TPLO: Mechanically alters angle of proximal tibia and eliminates tibial thrust

  • Faster return to fxn, lower failure risk, working or active dogs

• CBLO: cora-based leveling osteotomy (reverse TPLO)

• TTA: tibial tuberosity advancement

• Primary repair of meniscus: not feasible

Cranial Cruciate Ligament Disease Treatment

• Rx: Crate rest × 6 weeks, limited activity, OA management, pain control

  • Poor anesthetic candidate, Financial constraints, Patient <15 kg

  • Continue lifelong OA management even with Sx

• Sx: Debilitation, CrCL tear, lameness without obvious instability

• Px: High risk of tearing contralateral CrCL within 2 years, meniscus tear risk, OA progression

Patellar Luxation Pathophysiology

• Et: Traumatic, Congenital

  • Shallow trochlear groove, malalignment of extensor mechanism, abnormal hip joint conformation, femoral malformation, tibial malformation, quadriceps tightness

• Sig: Medial most common, 98%

  • Medial: Small breeds, young age

  • Lateral: large breeds

Grading Medial Patellar Luxation

• Grade 1:

  • Patella can be luxated but returns to normal position spontaneously

  • Functionally normal

• Grade 2:

  • Patella luxates out of groove occasionally

  • Can be replaced manually or reduces spontaneously

• Grade 3:

  • Patella luxates most of the time

  • Can be replaced manually

• Grade 4:

  • Patella luxates all of the time

  • Cannot be replaced back into the groove

  • Requires corrective osteotomy!!!

Patellar Luxation Diagnosis

• Cs: Skipping, kicks leg straight backwards, non-weight-bearing lameness

• Attempt to elicit luxation: Fully extend stifle joint, Internally rotate tibia, Apply medially directed pressure to patella while flexing stifle

• Evaluate for CrCL tear: 15–20% of chronic MPL patients have CrCL tear

• Radiographs: Stifle, pelvis, angular limb deformity, OA

Patellar Luxation Treatment

• Rx: OA management, rest 8 weeks, Modified Robert Jones bandage 2 weeks

• Sx: Only when CS and patient is effected!

  • Soft tissue: Medial retinacular release, Lateral retinacular imbrication

  • Bone: Tibial crest transposition(laterally), recession trochleoplasty(deepens groove), femoral/tibial osteotomies, anti-rotational suture, lateral stabilization, patellofabellar suture

• Px: OA progress slowly, Half reluxate postop

  • Good: Grades 1-3

  • Poor/guarded: Grade 4

Shoulder Luxation

• Et: congenital or trama

  • Ligamentous laxity, Glenoid dysplasia

• Sig: Young small breeds (congenital)

• Cs: lameness

• Tx: 

  • Congenital: MCL repair, arthroplasty

  • Acquired: Medial, Closed reduction, Bandage 2 weeks, rest 2 weeks, sling, MCL repair

    • Velpeau sling: for medial luxation

    • Neutral sling: for lateral luxation

  • Salvage: Arthrodesis, Glenoid excision

Elbow Luxation

• Et: Traumatic most common

  • Traumatic: Radius and ulna luxate laterally

    • large medial condyle of humerus prevents medial luxation

  • Congenital: abnormally shaped radius/ulna/ humerus

• Cs: Unable to bear weight, Forelimb abducted and externally rotated (elbow out, paw rotated in)

• Dt: limb resists extension, prominent radial head, PAINFUL, Radiographs AP views! 

• Tx: 

  • Acquired: Closed reduction under GA + brachial plexus block

    • _{Flex elbow to 100° and internally rotate}

    • _{Extend elbow slightly, adduct and inwardly rotate antebrachium while applying medial pressure on radial head}

    • Immobilize 2 weeks w/ spica split

  • Congenital 

    • If reducible → place transarticular pin while still growing!! remove later on

    • If non-reducible → arthrodesis when older in standing position

Carpal Hyperextension or Luxation

• Et: Palmar fibrocartilage and ligaments torn of loss of support

  • fall or hyperextension injury

• Cs: Non-weightbearing lameness, Stand with carpus hyperextended, Palmigrade stance

• Dt: Radiographs

• Tx: arthrodesis

  • Splinting does not work

Hip Luxation Pathophysiology

• Et: Results from failure or tear of Joint capsule or Round ligament

  • Most common joint luxation in dogs

• Types:

  • Craniodorsal (#1): hit-by-car or blunt trauma

  • Caudoventral: fall with abduction

Hip Luxation Diagnosis

• Cs: Crepitus, pain, shortened limb length(craniodorsal), pelvic asymmetry

• Palpate: Iliac crest(wing), Greater trochanter of femur, and Ischiatic tuberosity form a straight line

  • Normal = shallow triangle

• Thumb test: Place thumb in ischiatic notch and externally rotate limb

  • Normal = Thumb should be pushed out of notch

• Radiographs: lateral & VD

Hip Luxation Treatment

• Closed Reduction:

  • Craniodorsal luxation: 

    • External rotation → Pull limb caudally and distally  → Internal rotation

    • Ehmer sling 2w → Maintain abduction + internal rotation

  • Caudoventral luxation: 

    • Abduct limb → Provide distraction  → Apply lateral and proximal pressure

    • Hobbles 2w → Maintain adduction

• Open Reduction and Fixation:

  • Why: Closed reduction unsuccessful

  • How: Toggle pin technique

    • Creates synthetic round ligament

    • Hip must have no evidence of OA

• Salvage:

  • Why: Chronic luxation’s, Damaged articular cartilage, OA

  • How: Total hip replacement or Femoral head and neck ostectomy(FHNO) more common(cheaper)

Collateral Ligament Injury

• Et: Can occur in any joint

• Cs: Varus or valgus, lameness

• Dt: radiographs

  • I: Stretching of fibers

  • II: Incomplete tear

  • III: Complete tear

• Tx: 

  • Rx: Grade I → external coaptation x 6–8 weeks

  • Sx: Grade II-III → surgical stabilization + external coaptation

Tarsal Injuries

• Et: Usually shearing injuries

  • Collateral instability, Open fractures, Sheared bone, Soft tissue injury

• often medial collateral damaged → excessive valgus 

• Tx: Reconstruction, Arthrodesis

Arthrodesis

• Use: Salvage procedure, for carpals/tarsals 

  • Tarsal injuries, Carpal Hyperextension, Carpal Luxation, Shoulder Luxation 

• How: Permanent fusion of joints with plates, screws, pins or ESF

  • Remove cartilage and maintain limb at normal standing angle

• Px: Eliminates flexion/extension of joint and results in mechanical lameness

Legg-Calve-Perthes

• Et: Avascular necrosis of the femoral head

  • Vascular damage, necrosis, collapse of femoral head → pain and arthritis

• Sig: Young (4-11m), small breed dogs - inherited

  • Miniature Poodle, Cairn Terrier, Manchester Terrier,cats

• Cs: Acute onset hindlimb lameness, P Pain on PE, OA,  weight-bearing issues

  • Unilateral or bilateral

• Dt: signalment & Radiographs

  • Early: Increased opacity of lateral epiphysis (femoral head) and joint space due to effusion

  • Late: Collapse/flattening/thickening of femoral head + neck, ± Femoral neck fracture

• Tx: (Early stages)Robinson sling, Pain control, (late stages)Total hip arthroplasty, Femoral head and neck ostectomy(FHNO)

  • Splint needs to be non-WB and goes past leg

Panosteitis

• Et: Disease of endosteum and bone marrow in the long bones

  • Increased IO pressure due to protein accumulation near nutrient foramen (near major BV), medullary vessels leakage

  • ulna, humerus, radius, femur, tibia

  • Forelimb > hindlimb

• Sig: 5-18 months, male > female, large breed

• Cs: Shifting leg lameness, Lethargic, Pain (cyclic), Anorexia, Fever

• Dt: 

  • PE: pain on palpation of diaphysis of long bone

    • pain receptors in periosteum

  • Radiographs: Radiodense, patchy infiltrates, Widening of nutrient foramen

    • Late periosteal response – smooth, thick cortex appearance

• Tx: Analgesics, Rest, Self-limiting (1-2w)

• relapse can present in other bones

Hypertrophic Osteodystrophy (HOD)

• AKA: Scurvy, Moeller-Barlow disease, Metaphyseal osteopathy, Osteodystrophy type I & II, Hypovitaminosis C

• Et: Disease of long bones, especially distal metaphyses

  • Capillary loops become necrotic, vascular congestion, edema, metaplastic cartilage/bone

  • Forelimbs > hindlimbs

• Sig: Juvenile large breed dogs, Rapid growth, <12 months

• Cs: Acute onset of lameness, Fever, Lethargy, Anorexia, Diarrhea, Pain at metaphyses, Heat at metaphysis on all 4 limbs!!

• Dt: Radiographs

  • Irregular, radiolucent line in metaphysis adjacent/parallel to physis (“double physeal line”)

  • Metaphyseal flaring + sclerosis

  • Subperiosteal and extraperiosteal new bone formation

• Tx: Analgesics, antibiotics,self-limiting

Osteochondrosis + Osteochondritis Dissecans

• Et: Defect in normal endochondral ossification

  • Shoulder(most common), Elbow, Stifle, Hock

• Path: Failure of cartilage to ossify → thickened cartilage (OC) → poor nutrition → mechanical trauma → cartilage fissuring/flap(OCD) → synovial inflammation → pain

• Sig: Juvenile large breed dogs

• Cs: Lameness, Pain, Decreased ROM, Muscle atrophy, Joint effusion palpable

• Dt: Radiographs, CT

  • Caudal humeral head – lateral view

  • Medial humeral condyle – oblique view(elbow)

  • Medial aspect of lateral femoral condyle – AP view

  • Medial/lateral trochlear ridges of hock – AP/oblique views

• Tx: Arthrotomy, arthroscopy, remove cartilage flap, debridement of subchondral bleeding bone

• Px: 

  • Shoulder: excellent

  • Elbow/Stifle: good

  • Hock: guarded

Hypertrophic Osteopathy (HO)

• Et: Diffuse periosteal reaction, new bone formation around metacarpal/metatarsal/long bones (running up/down bone)

  • Paraneoplastic syndrome(lung tumor)

• Path: Altered pulmonary function → increased blood flow → connective tissue congestion → periosteal bone formation

• Sig: old dogs (rare in cats)

• Cs: Reluctance to move, Swelling of distal extremities, Lethargy

• Dt: Radiographs: affected limb/chest/abdomen

  • Uniform periosteal proliferation progressing proximally

  • Normal articular surfaces

• Tx: Treat underlying disease

Primary Bone Neoplasia

• Et: Osteosarcoma, Chondrosarcoma

• Cs: Lameness, Muscle atrophy, Bone swelling

• Dt: Radiographs #1, CT, Bone biopsy 

  • Osteolysis, Osteoproliferation, Soft tissue swelling

  • “Away from the elbow, toward the knee”

  • proximal humerus, distal radius/ulna & distal femur, proximal tibia

• Tx: 

  • Amputation: Eliminates pain, MST 6 months

  • Amputation + Chemo: Eliminates pain, MST 12 months

  • Primary Stabilization + Chemo: Allows mobility, MST 12 months

• Chemo adds extra time of survival!!

Systemic Infection in Bone

• Et: Fungal or bacterial infection

• Cs: Lameness, Muscle atrophy, Soft tissue swelling

• Dt: Radiographs, Urine!! histoplasmosis antigen (Mira Vista), CT scan,

• Bone biopsy and culture

  • Fungal: fresh

  • Bacterial: fresh/frozen 

Shoulder Injury

• Et: 

  • Supraspinatus / Biceps / Subscapularis tendinopathy: Chronic, repetitive microtrauma

  • Infraspinatus contracture: Acute muscle fiber injury and Fibrous tissue formation

• Sig: young, large breed, active dogs, Brittany Spaniel(infraspinatus contracture)

• Cs: Shoulder pain

  • infraspinatus contracture: External rotation of shoulder → elbow abduction + outward rotation of paw(away from body)

• Dt: US, Radiographs, MRI, Arthroscopy

• Tx: steroid injections→ everyone bedside infraspinatus

• platelet-rich Plasma

• SX → transect biceps(best), supraspinatus, infraspinatus

Common Calcaneal Tendon Injury

• Et: Mid-tendon laceration, Avulsion of tendon from calcaneus, Fracture of calcaneus

  • Cushing’s, Hypokalemia (cats), Diabetic neuropathy (cats)

• Sig: Middle-aged to older, large breed dogs

• Cs: Flexed tarsus with extended stifle (“dropped hock”) & flexion of toes w/ WB (gripping floor, SDF intacted)

  • Usually unilateral 

  • Mild = flexion of hock

  • Severe = full collapse

• Dt: Chronic = thick tendon/minerals

  • Radiographs: Increased soft tissue opacity, Mineralization, Bone avulsion, Gas in soft tissue

  • US: Focal hypoechoic area in tendon

• Tx: Surgical repair + EC (#1), (sx not option) EC w/ Hock in moderate extension 8w post-op

  • Repair tendon or avulsed calcaneus, tension band fixation

  • External coaptation alone is not effective

• Px: Long, frustrating recovery process

Iliopsoas Tendinopathy

• Uncommon

• Et: Due to chronic overuse or traumatic abduction(hind legs splay)

  • Often coexists with other hip conditions

• Cs: Lameness, Hip pain during internal rotation or extension or medial palpation (inguinal area)

• Dt: PE, US, MRI

• Tx: NSAIDs, strict rest

  • reinjury very common

Pes Anserinus Contracture

• Unilateral or bilateral

• Et: Unknown

  • Muscles Involved: Sartorius, Gracilis, Semitendinosus

• Sig: GSD

• Cs: Ambulates like a horse with string-halt gait, Palpable thick, ropy band at muscle location, flicks/swings hind legs 

• Tx: NSAIDs, rest, irreversible! 

  • Surgical resection not beneficial

• Px: poor