LA MS 8: Eq Tendon, Ligament And Muscle Dz Flashcards
Tendonitis
Common, debilitating Injury
Fxn of tendon and ligaments
Resolution problematic
–tendon slow to heal
–healed tendon lacks elasticity, strength
–high incidence of recurrence - heal with a fibrous scar that less elastic (weakest pt at jxn of scar and normal tissue)
Microscopic anatomy
Spare tenocytes, fibroblasts
ECM
- water
- collagen - type 1
- elastin
- glycoproteins
Structural Hierarchy
Tropocollagen –> microfibril –> subfibril –> fibril –> fascicle
Blood supply comes from around the tendon
High order - tendon rarely able to reconstruct self
Why the SDF?
Smaller cross sectional area
Most external –> greatest strain, most prone to trauma
Less vascular in the mid-MC –> less likely to heal (whereas DDFT highly vascular until goes over the fetlock canal
Pathogenesis of Tendon Injury
2 broad classes 1. External 2. Internal Intrasynovial vs extrasynovial SDFT > DDFT FL > HL IMPORTANT - LIFE-THREATENING INJURY IF LACERATION INSIDE THE TENDON SHEATH
Pathogenesis of tendon injury: external
Laceration
Blunt trauma
Pathogenesis of tendon injury: internal
Biomechanical overload (strain)
Hyperthermia
Vascular
Phases of Tendonitis
- Pre-clinical
- Clinical - 1-2wks –> IFM
- Repair - peaks 21d after onset of CS
- -tenocyte migration, angiogenesis - Remodeling - up to 18mo
* if you can intervene during the IFM, much better prognosis to return to athletic performance
Biomechanical forces
Altered hoof conformation –under run heels, long toe
Hard or very soft ground
Muscular fatigue near end of performance
PE
Lame
Visual “bow”
Palp: heat, pain, swelling
Should be able to dx SDF or DDF tear by palp and visual exam
To dx suspensory tear, need regional ax and US (black spots on US are fluid-filled but also have a lot of cells - those cells need to be told what to do)
US Exam
Cross section, linear exam
Ecogenic score
BOTH LIMBS
Serial exams - is tx working? Can exercise be increased?
Be sure to examine with both WB and non-WB
Rehab protocols
Time and controlled exercise critical - cells need to know what to do
Acute Phase Care
Stall rest
Control IFX - NSAIDS, cold (water, ice)
Bandage - compression and pain relief
PRP?
Sub-Acute Care
Controlled exercise Serial US exams Med therapy Sx tx Surpass - topical NSAID
Surgical Therapies
- Transaction of the accessory lig of the SDF
- -aka prox check lig desmotomy
- -increases elastic length of m/t unit (lig less elastic than m)
- -accessory ligament attaches to distal radius - Palmar/plantar annular ligament transaction for low bows
- -allows more room for SDF/DDF to move, heal and function
PAL Constriction
Primary --Trauma to PAL --Desmitis of PAL Secondary --Trauma to digital sheath - repetitive or severe --IFX tenosynovitis --Tendonitis of SDF/DDF
Tendon Lacerations - extensor tendons
Heal well
Fair-good functional and cosmetic outcome
Tendon lacerations - flexor tendons
Extrasynovial:
–fair functional/cosmetic outcome
Intrasynovial:
–fair to poor functional/cosmetic outcome
IFX = LIFE THREATENING
CRITICAL EMERGENCY - ATTEND TO IMMEDIATELY
–prog drops to guarded after 24hr
Suspensory Ligament Desmitis
AKA intraosseus - 2-11% muscle
3 subdivisions: head, body, branches
Functions to prevent over-extension of fetlock
Quartet of dz associated with suspensory lig desmitis?
- Suspensory ligament
- Avulsion at origin of the suspensory lig
- Splints - MCII/MCIV
- Sesamoid Bones
CS/Dx of Suspensory Desmitis
Lameness +/- sensitive to palp
Perineural nerve blocks - high 4pt: palmar carpal, palmar MC
–subcarpal block supposedly more specific (blocks deep branch of the lateral palmar nerve)
US: weighted, unweighted
MRI
RADS : sesamoid, splint bones, prox MCIII, also look for avulsion off the back of the cannon bone
Bone scan (origin lesions)
Suspensory desmitis tx
Rest - up to 3mo
Biologics
Shock wave - pain relief
Muscle Dzs
Pain, strain, tears Myopathy Polysaccharide storage dz Hyperkalemic periodic paralysis Stringhalt Fibrotic myopathy
Muscle strains
Highly prone to reinjury
Can lose indicator day or two later - need owner to point out swelling that was there yesterday
Fibrotic Myopathy
Fibrosis of semitendinosis
Uni»_space; bilat
Cause = trauma
Dx Fibrotic Myopathy
Characteristic gait
US, RADS
Tx Fibrotic Myopathy
Semitendinosus tenotomy
Often confused with upward fixation of patella
Stringhalt
Cause = neurogenic, Australian dandelions
Goose step
Non-painful
Tx = lateral digital extensor myotenectomy