Eq2- mid1- diseases of tendons, ligaments, sheath and bursae Flashcards
What is a Energy storing tendon?
Tendons: connects muscle to bone, its purpose is to move a joint
Energy storing tendon:
- support the hyperextended metacarpophalangeal joint during weight bearing
- release energy when the limb is protracted
- horse bounces up and down on springs
Mechanical properties
- Stress-strain curve
1: toe - elimination of crimp
2: linear phase
3: yield point - beyond its irreversible damage
4: rupture
Incidences of tendon injuries:
- Traumatic: any type of horse
- Strain induced
Strain-induced types of tendon injuries:
- Racing thoroughbreds: SDFT in forelimb
- Elite show jumpers: forelimb SDFT and DDFT injuries
- Elite eventers: forelimb SDFT injuries
- Dressage horses: hindlimb suspensory lig. injuries
Complete rupture, loss of function in Deep digital flexor tendon
- toe flips out
- if ruptured in the metacarpal/metatarsal region and outside the DFTS: it can heal satisfactory if immobilised
- if ruptured near insertion or within the DFTS: very poor to hopeless prognosis
Complete rupture, loss of function in Superficial digital flexor tendon
- reasonable prognosis if immobilised: cast or Robert-Jones bandage
- often transected together with DDFT
Complete rupture, loss of function in Suspensory ligament
- fetlock drops
- grave (bad) prognosis
- degenerative/traumatic/catastrophic
Repair of tendon and ligament injuries
- no regeneration!
1. Intratendinous haemorrhage
2. inflammatory reaction - designed to remove damaged tendon tissue
- but excessive and causes further damage
- reparative phase
- starts within a few days
- angiogenesis
- scar tissue formation
- higher ratio of collagen type III/I
- remodelling phase
* gradual, incomplete replacement of type III to type I
Superficial digital flexor tendon - site of injury and diagnosis
- Most common site: mid-metacarpal region.
- common injury in racehorses and jumpers
- Within the DFTS and the carpal sheath: less common
- In the pastern region: often traumatic
- overreach
Diagnosis:
- beware if UL too quickly
- true extent of the injury may not be apparent
- repeat UL a week later
Treatment: Acute, subacute and chronic phase
Superficial digital flexor tendon - principles of treatment of Acute phase
- Acute phase:
- aim to minimise inflammation and limit the action of proteolytic enzymes
- physical therapy
- rest, cold, immobilisation
- systemic short-acting corticosteroids in first 24-48 hr
- never intralesional steroids
- ccalcification!
- NSAIDs
- some controversy
- (surgical treatment - tendon splitting, desmotmy ofAL-SDFT)
Superficial digital flexor tendon - principles of treatment of Subacute phase
- Subacute (fibroplastic) phase:
- progressive mobilisation
- ultrasonographic monitoring
- regenerative therapies:
- Mesenchymal stem cell therapy: stem cells differetiante into tenocytes, regenerate matrix
- PRP (protein rich plasma): autologous blood, centrifugation, gravity filtration.
- Soup of growth factors - stimulate cell proliferation and matrix synthesis
Superficial digital flexor tendon - principles of treatment of Chronic phase
- Chronic (remodelling) phase:
- controlled exercise
- regular UL monitoring
- To prevent re-injury
- takes time, at least 6-12 month before returing to full work
Deep digital flexor tendon - site of injury and diagnosis
Site of injury:
- Metacarpal region: majority of injuries within the DFTS
- Pastern region: down to insertion. Most distal part can only be imaged with MRI or CT
- generally poor prognosis
- Lesions in the fetlock region - typical to high level show jumpers
- Limited healing ability of tendons within synovial environment
- adhesion formation
MRI indications:
- If lameness cant be explained by finding of conventional diagnostic imaging
- most commonly imaged regions is the foot
- possible up to carpus and hock (stifle)
- Time consuming: 2feet –> at least 1.5-2 hr
- only a small area can be examined: multiple sequences, hundreds of images
- interpretation requires specialist knowledge
Suspensory ligament
Proximal aspect:
- central muscle and adipose tissue
- forelimb; medial and lateral lobes
Branches Proximal suspensory desmitis/desmopathy
- different disease process and prognosis in the forelimb and in the hindlimb
Forelimb proximal suspensory desmitis - clinical findings
Pain on palpation:
- but many horses show some response when pressure is applied to SL
- pain when pressure is applied to the bone
Difficult to palpate the most proximal aspect
Typically lamer with the limb on the outside of the circle
Forelimb proximal suspensory desmitis - Acute form
- reasonable prognosis
- can return to exercise in 3-4 months
- controlled exercise
- +/- intralesional therapy
Forelimb proximal suspensory desmitis - Chronic form
- more difficult to manage
- guarded prognosis
Hindlimb proximal suspensory desmopathy - clinical findings
- usually no localising signs
- typically lamer with the limb on the outside of the circle
- but often bilateral
- can present as a poor performance case with poor hindlimb impulsion
- usually degenerative process
- common in dressage horses but can be seen in any dicipline
- straight hock
- predisposes
Hindlimb proximal suspensory desmopathy - treatment
- conservative management: poor success rate
- most successful treatment: surgery –> plantar neurectomy and fasciotomy –> 80% success rate if no other contributing problems
Branches of the Suspensory ligament - clinical findings
- any discipline
- +/- distension of McP(MtP joint - thickened SL branch (periligament thickening?)
- pain
- response to flexion
Branches of the Suspensory ligament - treatment
- management
- depends on type of injury, age, use
- conservative treatment: U/S findings often persist for a long time
- Shock wave, regenerative laser?
- Surgery: Arthroscopy for axial lesions
Accessory ligament of the deep digital flexor tendon - clinical findings
- much more common in the FL than the HL
- usually painfull on palpation
Acute cases: rest, cooling, intralesional treatment, regenerative laser, shockwave
Chronic, non-responsive cases: desmotomy
Accessory ligament of the deep digital flexor tendon - treatment
Acute cases:
- rest, cooling, intralesional treatment, regenerative laser, shockwave
Chronic, non-responsive cases: - desmotomy
