Diseases of tendons and ligaments-Morton Flashcards
Tendon
Dense band fibrous tissue, intermediary in attachment of MUSCLE TO BONE
- wrapped in fluid filled sheaths near joints
- kept in place by annular ligaments
Ligament
Tough band or plate of dense, fibrous connective tissue OR fibrocartilage serving to unite or form JOINTS
- BONE TO BONE
- No sheaths
Tendon examples
- SDF
- DDF
- Common digital extensor
Ligament examples
- Check ligament SDF
- Check ligament DDF
- Suspensory ligament
Characteristics ligaments/tendons
- Mostly Type-1 collagen
- Limited stretch
- Force transmitters
- Mostly acellular/avascular (slow healing)
- Collagen bundles renew every 6 months (dynamic)
Injury
Abnormal biomechanical stress
- increased intensity
- increased frequency
- increased duration
Healing
Via fibroplasia
-don’t regain 100% structure/strength
Early passive motion (controlled exercise) promotes earlier parallel fiber arrangements
-better than inactivity (strict stall rest)
Spectrum of pathology
Asymptomatic
-repair exceeds rate of damage
Symptomatic
-mild-mod lameness
Breakdown
-disruption suspensory apparatus
Tendinitis SDFT/DDFT
SDFT > DDFT
Forelimbs > Hindlimbs
Mild tearing to complete disruption
Tendinitis pathogenesis
- Single episode of severe stress
- Failure of tendon after multiple episodes of submaximal strain and microdamage
- Improper application leg wraps (tendon bow)
SDF tendinitis pathogenesis
- Cross-sectional area of SDF smaller in midmetacarpal region
- Strain magnitudes 16% at gallop, can fail at 12-20% strain
- Mechanical failure likely result of multiple episodes strain and microdamage
Evidence for multiple episode strain and damage
- Fibril diameters smaller in center of SDF with training
- Weaker fibril bundles in center SDF with training
- Higher proportion type III collagen in center of tendon
Acute Tendinitis CS
- Mild-moderate lameness
- Usually resolves in a few days with rest - Diffuse swelling palmar/plantar metacarpus
- thick, heat, pain on palpation
Chronic Tendinitis CS
- Fibrosis and firm swelling
- Variable signs active inflammation
- acute on chronic - May be intermittently sound at walk/trot
Tendinitis DX
- PE
- Ultrasound (+re-exam)
- Rads to eval concurrent bony injury
- Thermography
- MRI
Tendinitis/Desmitis TX Goals
- EARLY DX
- Decrease inflammation
- cold (ice) 4-6 times per day 15-30 minutes for 48+ hours, until heat and acute inflammation have resolved
- Compressive, substantial support bandage between tx
- Poultice/Sweat once acute inflammation has resolved
- NSAIDs: topical/systemic - Minimize scar tissue
- Promote restoration normal structure
Tendinitis/Desmitis rehab
- Stall rest only 2-8 weeks
- Stall rest + handwalking 4-8 weeks
- recheck before increasing - Stall rest + tack walking 4-8 weeks
- Gradual increase in activity dictated by clinical and U/S eval every 4-8 weeks
- 6-12+ months total course of rehab
- Must be fit before turnout (fitness/fatigue)
Tendinitis/Desmitis medical TX
- Systemic PSGAGs, HA
- Adequan
- Legend
- Pentosan - Intralesional and regenerative therapies*
- Autologous mesenchymal stem cells from bone marrow or fat
- PRP
- IRAP/ACS - ESWT
- Laser (low/high E)
Tendinitis/Desmitis surgical TX
- Superior check desmotomy
- tx of choice for SDF tendinitis, not routine - Tenoscopy
- SDF, DDF, MF lesions within sheath - Palmar Annular desmotomy
- adjunct or solo - Ultrasound guided puncture and tendon splitting
Superior check desmotomy
- functional lengthening of SDF tendon, muscle belly absorbs more load
- Improves chance of return to racing
- More successful in STB than TBs
- INCREASES RISK SUSPENSORY INJURY
Tendinitis Tenoscopy
- Tenosynovitis
- Diagnostic
- Debride tears of DDF/SDF
- Resection MF
Palmar Annular Desmotomy
- Chronic tenosynovitis +/- tendinitis
- Tenoscopically better than blind
- decompresses tendon and sheath
Tendon Splitting
- Ultrasound guided
- Communication between core and surrounding tissue
- Decompresses hematoma, enhances revascularization and collagen prod
- Sites heal by fibroplasia
- Within 5 days of injury
* better therapies exist
* needle decompression less traumatic
Tenosynovitis
Acute or chronic inflammation of tendon sheath
Causes of tenosynovitis
- Idiopathic (wind puffs)
- Traumatic
- Secondary to tendinitis-SDFT/DDFT/MF
- Infection
Annular ligament constriction CS
- Chronic or severe tenosynovitis
- Distension of tendon sheath proximal and distal to annular ligament
- Characteristic notching in area of annular ligament
- Possible enlargement of SDFT or DDFT if concurrent tendinitis
Palmar Annular ligament transection (desmotomy)
- Intrasynovial approach
- Extrasynovial approach
- Post-op adhesion prevention:
- Hyaluronic acid injections +/- TPA
- Early controlled exercise to promote tendon movement within sheath
- Corticosteroids locally if no tendinitis after surgical incision has healed
Annular lig constriction prognosis
Good-if no concurrent damage to SDF or DDF
Poor-if adhesions develop within tendon sheath
Suspensory apparatus dz
- injuries from extreme hyperextension
- Forelimb-acute > chronic
- Hindlimb-chronic > acute
Suspensory apparatus dz contributing factors
- Conformation
- dropped fetlocks
- straight hindlimbs
- poor shoeing
- fatigue of limb
- PRIMARY SOUNDNESS PROB elsewhere
Suspensory desmitis
- common all performance horses (esp large breeds)
- proxima, mid-body, and branches
- pathogenesis, dx, tx similar to tendinitis
- can be secondary to splint fx, exostosis
- ALSO CAN CAUSE splint fx
Suspensory desmitis CS
Variable!
- Ush very lame acute phase
- MORE LAME ON SOFT GROUND - Difficult to detect swelling (proximal)
- Lameness after harder work
- milder chronic types - Painful on direct palpation of ligament
Suspensory desmitis DX
- PE
- Diagnostic analgesia
- low 5 point/high 4 point, deep lateral plantar/palmar branch - Rads
- position of fetlock and sesamoids
- mineralization
- bony remodeling or avulsion fx at attachment sites - Ultrasound
- weight and non-weight bearing - MRI (Proximal SD)
Proximal Suspensory desmitis
- More difficult to dx and image
- perineural anesth, U/S, MRI - Treat like other tendinitis/desmitis
- Surgical options
- retinacular release +/- DBLP or DBLPI neurectomy (more common hind limb)
- Deep branch of lateral palmar neurectomy only (chronic forelimb)
Proximal Suspensory desmitis prognosis
prognosis better in fore than hind
Proximal Suspensory desmitis hind limb prognosis
- Conservative therapy-generally poor < 30-40%
- Retinacular release +/- neurectomy ~ 60%
- some horses progress - Worse is straight hock/stifle and dropped fetlock conformation
- Regenerative tx and ESWT though to improve
Suspensory Desmitis Branch Dz
- Common all sport horses
- Usually one (primary) branch
- Both branches in hind commonly affected
- DX, CS, TX similar to prox lig dz
- no surgical treatment - Prognosis diminished with poor conformation
- Periligamentous tissue/fibrosis decreases prognosis
Degenerative Suspensory Ligament dz etiologies
- Systemic Proteoglycan Accumulation
2. Suspensory Ligament disruption (older horses)
Systemic Proteoglycan Accumulation
- Pasos
- Bilateral hind or all four limbs
- Initially swelling and pain mid and distal thirds of plantar metatarsus
- Gradual dropping fetlock and involvement branches
- Ligament and other tissues replaced with accumulation proteoglycan, granulation tissue and hyaline cartilage
Systemic Proteoglycan Accumulation TX
- Stall rest
- Bandaging
- Bar shoe
- Adequan
- ESWT
- Palliative
Poor prognosis
Heritable
Suspensory Ligament Disruption in Older Horses
- Horses ush > 15-20 yrs old
- broodmares - Usually hindlimbs
- Branches more affected, thickened
- Fetlock drop
- Minimal exercise may be ok
- SUPPORTIVE SHOEING
- PALLIATIVE LIKE PREVIOUS
Traumatic disruption of suspensory apparatus etiology
Extreme hyperextension while racing or jumping from
- transverse fx of both proximal sesamoids
- rupture of distal sesamoidean ligaments
Traumatic disruption of suspensory apparatus CS
- Dramatic sinking of fetlock
- Severe lameness
- Marked swelling in pastern, fetlock, metacarpus
- Cold distal limb
- Panic reaction
Traumatic disruption of suspensory apparatus DX
- CS
- Rads
- proximal displacement sesamoids
- transverse fx proximal sesamoid bones - U/S
Traumatic disruption of suspensory apparatus TX
- Surgical arthrodesis
- Splinting/casting
- can kimzy splint for transport
- 4-6+ months
- unrewarding
Traumatic disruption of suspensory apparatus prognosis
Guarded for salvage
Potential for contralateral laminitis
Potential for thrombosis later
Goal is joint ankylosis
Rupture of peroneus tertius
Ability to EXTEND HOCK while STIFLE FLEXED
Limb distal to hock flails
Puckering of gastroc
Peroneus tertius is the cranial component of
reciprocal apparatus
Peroneus tertius rupture etiology
- More common in foals
- Laceration to cranial aspect of hock or tibia
- Hyperextension of distal limb
- Fighting full limb cast in hospital
Peroneus tertius rupture TX
- Stall rest several weeks to months, then small paddock turnout
- Take rads to r/o avulsion fx of attachement site at femur
Peroneus tertius rupture prognosis
Favorable- > 70% to full athletic potential
Worse-if severe laceration or avulsion fx
Disruption of caudal component of reciprocal apparatus
- Usually in foals-from a fall
- Disruption of gastroc with damage to SDF muscle
- HOCK FLEXED and STIFLE EXTENDED during weight-bearing
Disruption of caudal component of reciprocal apparatus DX
CS
U/S
Rads-avulsion fx
Disruption of caudal component of reciprocal apparatus TX
- Strict stall rest
2. Immobilization via ROBERT JONES BANDAGE
Disruption of caudal component of reciprocal apparatus Prognosis
Guarded-better in foals
Curb
Desmitis of long plantar ligament
Desmitis of long plantar ligament
- Firm swelling along plantar aspect below point of the hock
- May have concurrent SDF tendinitis
- More common in SB racehorses
Predisposing factors for curb
- Sickle-hocked conformation
2. Incomplete ossification of cuboidal tarsal bones
Desmitis of long plantar ligament DX
- Clinical signs, mild lameness
- U/S
- Rest and controlled exercise
- NSAIDs
usually a self-limited condition
