Soft tissue injuries within the foot

Question 1

Clinical history

Answer 1

VARIABLE

Some horses have acute injuries with matching clinical histories:
*Acute, unilateral, severe lameness
* Associated with athletic activity

Some horses have degenerative pathologies and histories to match:
* Insidious/gradual onset / progressive/intermittent lameness
* Can be unilateral or bilateral

Question 2

CE findings

Answer 2

NON-SPECIFIC

• Palpation unremarkable in many cases
• Some acute pathologies may have transient increased digital pulses, but these can return back to normal very quickly
• Exception to this are severe collateral ligament injuries
• Sometimes sensitivity to hoof testers in heel region – unreliable

Question 3

Dynamic evaluation findings

Answer 3

UNPREDICTABLE

• Usually worse on hard surface
  – Sometimes worst on soft surface
• Usually worse on the inside of a circle
  – Sometimes not
• Not usually positive to distal limb flexion
  – Collateral ligaments are exceptions

Question 4

Radiographic findings

Answer 4

• Identifies bony evidence of soft tissue disease

Examples:
* Navicular bone changes seen with DDFT disease
* Ossified collateral cartilages are associated with collateral ligament disease
* Enthesious changes seen with impar ligament disease and collateral ligament disease

When you see signs of navicular dz radiographically, always consider that the soft tissues closely associated with it are likely not normal either

Question 5

Transcuneal ultrasound findings

Answer 5

• Small window through the frog to visualise a section of the DDFT and DSIL
  – Requires careful foot preparation (pare away all the rough outer surface of the frog) and overnight
  soaking (wrapped in US gel)
• Proximal navicular bursa visible between heel bulbs
  – With a microconvex probe
  – Can just see the DDFT as it comes down the limb and as it turns the corner around the navicular bone
  – Not very fruitful but can sometimes detect an effusion of the navicular bursa

Question 6

Gold standard imaging

Answer 6

MRI - benefits:
* Likely definitive
diagnosis/diagnoses
* More accurate prognostication
* Guided specific medical
treatments
* Specific indications for farriery
– i.e. whether there’s specific soft tissues we want to load and unload

Question 7

Most common soft tissue injury in the foot

Answer 7

• DDFT pathologies

Question 8

DDFT pathologies

Answer 8

• core lesions
• sagittal splits
• of the dorsal border

Question 9

DDFT pathologies - core lesions

Answer 9

• Seen with various severities
• Found at different locations along the length of the tendon (within the body of the tendon)
• Can propagate proximally/distally with time
• Likely enlargement of the tissue around the lesion

Question 10

DDFT pathologies - sagittal splits

Answer 10

• Often seen at the level of the navicular bone
• Often propagate proximally/distally with time
  – Especially after neurectomy
• Involve tendon surface so can lead to adhesion formation and bursitis
• Lameness often severe but very variable
• DDFT likes to do this in the foot, but nowhere else

Adhesion formation:
- if have fibrillated tendon surface being pushed against the surface of the navicular bone, adhesions between the 2 structures can be quite common

Question 11

DDFT pathologies - dorsal border

Answer 11

• Dorsal border fibrillation
  – Irregularity to the dorsal surface
• Often causes bursitis and adhesion formation (due to exposure of the fibrous tendon into the bursa and onto the navicular bone)
• More of a degenerative pathology rather than acute injury
• All tend to happen at the level of the navicular bone or thereabouts

Question 12

Tx focus

Answer 12

• on the navicular bursa

Question 13

Tx

Answer 13

Intrabursal medications:
* Biologics in the acute phases of injury (to try and augment the healing process slightly)
* Corticosteroids to manage long-term signs (or degenerative processes)

Navicular bursoscopy:
* Indicated for all lesions seen to communicate with the bursa
* Sagittal splits and dorsal fibrillation particularly
* Can break down adhesions surgically
* Debride fibrillated tissues which are drivers
for synovitis

Question 14

Risk factors and prevention

Answer 14

FOOT BALANCE

A foot with dorsopalmar/dorsoplantar foor imbalance will cause increased loading of palmar/plantar soft tissues:
* SDFT, DDFT, SL, DSIL

A foot with poor lateromedial imbalance will cause increased loading of lateral and medial soft tissue structures:
* Collateral ligaments, navicular suspensory ligament

Question 15

The T ligament divides which 3 synovial structures?

Answer 15

• The DIP joint
• The digital flexor tendon sheath
• The navicular bursa

Question 16

What are enthesious changes?

Answer 16

• Chages to the bone surface where the soft tissue attaches

Question 17

DSIL

Answer 17

= distal sesamoidean & impar ligament