Lecture 15: Tenosynovitis and Desmitis Flashcards
Muscles attach to periosteum via
Tendons
What are tendons made of
Ropes of collagen fibers
What is the tendon composed of
Tenocytes/fibroblasts (sparse)
What are tenocytes/ fibroblasts responsible for
synthesis and turnover of ECM
Metabolism of tenocytes and fibroblasts are regulated by ___
Biomechanical and mechanical stimuli
What is the ECM of tendons made of
- Water- 65%
- Collagen- type I- 30%
- Elastin
- Glycoproteins
Tendon Collagen fibers are oriented ___to long axis of bone which it’s important for ___
Parallel, elasticity and energy storage (makes horses run fast)
Tendons allow for __motion
Gliding
What is the vascular supply of the tendon
- Muscle/bone at origin/insertion
- Paratenon and endotenon in tendon proper
Compared to tendons ligaments have less ___, ___ and ___
Collagen, elastic and organization
___generates movement and __resist movement
Tendons, ligaments
What are some internal causes of tendonitis
- Bio mechanical overload (strain)
- Hyperthermia
- Vascular
What are some external causes of tendon injuries
Blunt trauma, wounds
Are flexors or extensors more commonly affected with tendonitis
Flexors
Is the SFDT or DDFT more commonly affected with tendonitis
SFDT
Why is resolution of tendonitis problematic
- Slow to heal- poor blood supply
- Inferior in strength and elasticity
- High incidence of recurrence
Which tendon has the smallest cross sectional area and is most external so experiences the greatest strain and trauma
SDFT
SDFT is less vascular in the ___region which is where most lesions occur
Mid-metacarpal region
Identify 1-4
- SDFT
- Inferior check
- DDFT
- Lateral suspenory ligament
Which venogram is DDFT and which is SDFT
left: DDFT- more vascularized
Right: SDFT
What bio mechanical forces contribute to overload in tendonitis
- Altered hoof conformation- under run heels and long toe
- Work on very hard or very soft surfaces
- Muscular fatigue at end of race- tendons take on load
What hoof conformation contributes to tendonitis
Underrun heels an long toe
what is wrong with this hoof confirmation and what does it predispose them to
Underrun heels and long toe
Tendonitis
What occurs in the subclinical phase of tendonitis
Degradation of ECM, weakened tendon
What occurs in clinical phase of tendonitis (1-2 weeks)
Acute inflammation- lame, warm, swollen
What occurs during reparative phase of tendonitis (3 weeks)
- Tenocytes migration
- Fibroplasia
- Angiogenesis
What occurs in remodeling phase of tendonitis
- Type III collagen replaced with type I
- Formation of cross links
- Re-orientation of fibers with max tension- parallel to axis of limb
What is the result of repaired tendonitis
Scar tissue with reduced strength and increased stiffness/less elasticity
__% of SDFT injuries reoccur
60%
Reinjury of tendons occurs at ___interface
Scar/normal tendon interface
What are the clinical signs of tendonitis
- Lameness
- SDFT bow
- Lesion within tendon sheath- tendon effusion
- Pain on palpation
What is wrong here
Tendonitis, SDFT bowing
What modality do you use to evaluate tendon injuries
Ultrasound
What data is obtained during ultrasound of tendon injuries
- Lesion echongenicity grade (1-4)
- % loss of linear fiber pattern
Lesions usually look worse on ultrasound __weeks post injury
2 weeks
What is wrong
SDFT injury- black spot is hematoma
What is grade 1 lesion echogenicity
Tendon enlargement with lesions appearing only slightly hypoechoic (bright). Minimal fiber pattern disruption and minimal infiltration of inflammatory fluid
What is grade 2 echogenicity lesion
Approximately half echoic and half anechoic. Fiber pattern disruption and local inflammation
What is grade 3 echogenicity lesion
Mostly anechoic and represent significant fiber tearing
What is grade 4 echogenicity lesion
Totally anechoic, rupture. Lesions appear homogenous black areas within a structure and indicate almost total fiber tearing with hematoma formation
How do you evaluate rehabilitation protocol and gradual return to work from tendonitis
Serial ultrasounds every 6 weeks
What is treatment for acute/clinical phase of tendonitis/desmitis
- Stall confinement
- Control inflammation: NSAIDS, ice boots, cold hosing, game ready
- Bandaging
___is critical for treatment of tendon injury in repair phase and beyond
Controlled exercise
What does this progression show (left to right)
Realignment of tenocytes
How long does it take for tendon and ligament injuries to heal
6-7 months
What are some treatment options for repair phase and beyond for tendon/ligament injuries
Intra-lesional injections (PRP, stem cells, IGF-1, hyaluronic acid(
What are some surgical options for tendon and ligament injuries
- Tendon splitting
- Proximal check ligament desmotomy
- Palmar/plantar annular ligament desmotomy
What is tendon splitting
Insert scalpel into core of lesion and fan it longitudinally through entire lesion- open and drain hematoma and fluid and also increase blood supply
Where is the proximal check ligament
Comes off back of radius, right above the knee
What is a proximal check ligament desmotomy
Cut it and it will increase elastic length of muscle tendon-unit and decrease tension
What is a palmar/plantar annular ligament desmotomy performed for
Low bows of SDFT and DDFT
What is the purpose of palmar/plantar annular ligament desmotomy
Allows more room for tendon to move, heal and function
What are some primary causes of palmar/plantar annular ligament constriction
Trauma to PAL, desmitis of PAL
What are some secondary causes of palmar/plantar annular ligament constriction
- Repetitive or severe trauma to sheath
- Infectious tenosynovitis
- SDF/DDF tendonitis
What is the most frequent MRI diagnosis of the foot
Distal tendonopathy of DDFT
Where is the lesion located and what is it associated with for distal tendonopathy of DDFT
Lesions at level of navicular bone
Associated with navicular syndrome
What is treatment for distal tendonopathy of DDFT
Intra-lesional medication, navicular bursoscopy
What is prognosis for distal tendonopathy of DDFT
Fair to poor
____tendon lacerations heal well
Extensor
What tendon is lacerated when you see hyperextension of fetlock
SDFT
What ligament is lacerated when you see hyperextension of fetlock
Suspensory ligament
What ligament is lacerated when you see toe up
DDFT
What ligament is lacerated when you see fetlock on the floor
SDFT, DDFT, and SL
Which tendon lacerations have fair to poor cosmetic and functional outcomes
Flexor tendons
What are the three subdivisions of suspensory ligament
- Origin
- Body
- Medial and lateral branches
What is the function of the suspensory ligament
Prevent fetlock hyperextension
What structures can be affected near the suspensory ligament
- Splint bones
- Proximal sesamoid bones
Warmbloods get suspensory ligament desmitis where and what limbs
Origin/proximal suspensory in the hind limbs
What do you do to evaluate traumatic suspensory desmitis
Nerve blocks, ultrasound, nuclear scintigraphy
Where do thoroughbreds and standards breeds typically get traumatic suspensory ligament desmitis and what limbs
Body and branches/insertion in front limbs
What do you do to evaluate a traumatic suspensory ligament desmitis in body and branches
Nerve blocks and ultrasound
How can you tx traumatic suspensory ligament desmitis
- Intra-lesional meds
- Shock wave
What treatment can you do for hindlimb proximal suspensory traumatic desmitis
Fasciotomy and neurology of deep branch of lateral plantar nerve
The deep branch of lateral plantar nerve provides ___ to suspensory ligament
Sensory (no motor)
What breeds are genetically predisposed to degenerative suspensory ligament desmitis
- Peruvian paso
- Arabians
- Saddlebreds
What is the treatment and prognosis for degenerative suspensory ligament desmitis
No treatment, very painful, poor prognosis
An Arabian presents with chronic dropping fetlocks what is it most likely
Degenerative suspensory ligament desmitis
