General (Surgery)

Question 1

Indications for ALDDFT tenotomy

Answer 1

1) DIPj FLD
2) Chronic/unresponsive desmopathy of ALDDFT
3) DDFT tendinopathy non-responsive to conservative tx

Question 2

2 reasons commonly cited for poor regenerative capacity of articular cartilage

Answer 2

1) Highly differentiated function and low mitotic activity of chondrocytes
2) Relatively avascular structure of adult articular/hyaline cartilage

Question 3

Predominant cartilage type in bone, tendon, articular cartilage, blood vessels

Answer 3

Bone - type 1

Tendon - type 1

Cartilage - type 2

Blood vessels - type 1

Question 4

Prevalence of SSI reported following use of metallic orthopaedic implants reported by Curtiss et al (2019 VS).

What were the risk factors for developing SSI and non-survival to DC?

Answer 4

Overal 14.2% SSI rate

• Incr odds of SSI with fetlock arthrodesis or ulnar fracture were more likely to develop SSI.
• Local AB therapy was asooc with incr risk of SSI
• Horses with SSI were 12.5x less likely to survive to DC (95% withouth and 45.5% with)
• Those with Fetlock and carpal arthrodeses as well as femoral, radial, and humeral fractures were identified as having a higher risk of nonsurvival to hospital discharge

Question 5

Most commonly affected muscle with fibrotic myopathy.

Which other muscles can be affected?

Answer 5

Semitendonosus most commonly (17/22 Noll et al 2019 VS)

Biceps femoris, semimembranosus and gracilis may also be affected

Question 6

Treatment and prognosis for fibrotic myopathy reported by Noll et al 2019 (VS)

Answer 6

Standing myotomy of affected mm (ID on US)

Fair px - 8/12 athletic horses returned to prev use, 10/16 owners satisfied

PO complications (incisional drainage (4) or fever (1)) in 5-22 operated horses

Question 7

What are the 2 types of polydactyly described in horses

Answer 7

1) Teratogenic form = RARE

The basipodal elements are split resulting in two completely separate digits usually with one metacarpophalangeal joint; although exact manifestations of the teratogenic form can vary depending on where the split occurs. Tends to rx in cloven footen appearance

2) Atavistic form = MORE COMMON
The supernumerary digit is most commonly located at the distal end of the medial splint bone on either forelimb although there are reports of both forelimbs being affected

Question 8

Treatment of polydactyly (both forms)

Answer 8

1) Teratogenic form - (i.e. supernumerary digit located distal to the fetlock), the digits are almost universally small and both in contact with the ground which makes removal of the extra appendage difficult as the remaining digit will be unable to bear the weight of the horse. Thus, removal of the extra appendage in the teratogenic form is not recommended in most cases
2) Atavistic form - sugical excision is recommended for cosmesis and avoiding interference. The rudimentary digit is typically small and not weight bearing. 2 sx approaches are described:

• Disarticulation of the rudimentary MCP joint
• Osteotomy and amputation of the affected metacarpal bones - this is the surgical technique cuttently recommended as it rx in a more cosmetic and functional outcome than disarticulation

May choose to delay sx until distal MC3 physeal closure or weaning although don’t delay long if ALD is also present

Generally excellent px providing it is atavistic and the primary weightbearing limb (McIII and digit) is anatomically normal.

Question 9

Layers of physeal growth cartilage (from epiphysis to metaphysis)

Answer 9

Resting zone

Zone of proliferation

Zone of hypertrophy & maturation

Zone of provisional calcification

NB longitudinal bone growth is progressing from metaphysis - diaphysis