Small Animal Distal Limb Flashcards
Label
A. Metacarpus (3 parts). Base of bone
B. Body of metacarpus
C. Head of metacarpus
D. Proximal phalanx (p1)
E. Middle phalanx (P2)
F. Distal phalanx (P3)
G. Metacarpal phalangeal joint
H. Proximal interphalangeal joint
I. Distal inter interphalangeal joint
Label
A. Common digital extensor
B. Dorsal elastic ligament
C. Deep digital flexor (insert P3)
D. Superficial digital flexor (insert P2)
E. Proximal sesamoid bones (2 per joint)
F. Dorsal sesamoid bones
What can go wrong in the metacarpal/metatarsus region? Highlight the most common
- Bones
- Fractured metacarpi/metatarsi
- Hypertrophic osteopathy (see previous lecture)
- MCP/MTP joint
- Osteoarthritis
- Luxations (single/multiple) – NB often concurrent multiple sesamoid ligament failures
- Sesamoid disease
- Fractured sesamoids (esp racing greyhounds)
- Sesamoid disease of young dogs
- Bipartite/tripartite sesamoids
- Soft tissue
- Traumatic injury
- Damage to tendons +/or blood vessels
- Traumatic injury
What is the issue here?
Metacrapal/tarsal shaft fractures
What are the 2 occassions we treat metacarpal/metatarsal shaft fractures surgically?
- Pronounced displacement, esp dorsally
- More than 2 metacarpal fractures (except racing greyhound)
Other than surgery how can we treat Metacarpal/metatarsal shaft fractures?
Splinted bandage, monitor radiographs
What joint is unstable withh a metacarpal/metatarsal distal condylar fractures and why?
Instability of MCP/MTP joint, as collateral ligament attachments affected
How do we treat metacarpal/metatarsal distal condylar fractures?
–Ideally treat with internal fixation and external support
•Closed reduction and external casting often à instability or poor intra-articular alignment of fragments à DJD
Who does sesamoid disease affect the most?
Young dog, especially rottweilers
Which bones are affected with sesamoid disease?
Sesamoids 2 or 7
What is the sign of sesamoid disease?
-Loss of flexion of MCPJ/MTPJ with pain, effusion
How do we diagnose sesamoid disease?
Exclusion of other problems +/- nerve blocks
How can we treat sesamoid disease?
NSAID, neutraceutical, physio
What are the signs of diease of the bipartite/tripartite sesamoids?
-Loss of flexion; swelling but no pain. Incidental finding. No treatment.
How can we treat traumatic damage causing haemorrhage of the distal limb?
- Pressure
- Surgical exploration/ligation if necessary
How do we treat tendon damage of the distal foot caused by trauma?
Bandage foot in slight flexion or cast in flexion to reduce tension on repair
How do we NOT!!!!!!!! cast a tendon damaged foot?
In extenstion
What are the 4 things which affect digits of the foot? Highlight the most common
- Fractures
- Luxations/subluxations
- Osteoarthritis (common)
- Osteomyelitis
How can we treat fractures of shaft P1/P2?
–Closed reduction and external support (unless performance animal)
•Moulded plastic splint for 3-6 weeks.
How can we treat fractures of head/base of phalanges?
–Best treated with internal fixation and external support
–If fragments too small may require amputation (distal to #)
Where do you amputate for a P3 fracture?
Level of P2
What does this show?
Fracture of base of P2
Which digits can undergo luxaton/subluxation and which is more common?
P1/P2
P2/P3 - most common
Where are luxations/subluxations common?
Racing greyhounds
How do you treat luxations/subluxations of of p1-p3?
Intricate surgical repair
Name 4 inidcations for digit amputation (5)
–Neoplasia
–Chronic infection
–Osteomyelitis
–Severe trauma
–Biopsy P3
What are the 2 occassions digit amputation results in amputation?
–>2 digits
–Either of central 2 digits (avoid the removal of these)
If you only remove P3, what do you need to preserve?
Digital pad
What are the steps to digit amputation?
- Dorsal skin incision
- Extend laterally either side of digit
- Ligate digital vessels and transect tendons/ligaments/joint capsules
- Disarticulate and scrape articular cartilage, or transect phalanx with bone-cutters. Transect is thought to be better
- Appose s/c tissues over bone ends (interrupted absorbable sutures)
- Appose skin with simple interrupted sutures
- Bandage – change ev 2-3 days till stitches out
What conditions affect the digit soft tissue? (Highlight the most common)
- Cellulitis – esp cat bite abscess
- Tendon damage
–DDFT
–SDFT
- Ligament damage – see ‘Luxations/subluxations’ above
- Gangrene
What is gangrene?
–Ischaemia then Necrosis due to inadequate blood supply
How can you treat gangrene?
Debride/ampuate
Antibotics if a secondary infection
What does this show?
Gangrene
Where does the DDFT insert?
P3
When do you get damage to the DDFT?
Puncture wound to foot and goes through it
Does acute or chronic tenosynovitis cause worse lameness?
Acute
What is a knocked up toe?
Pull dorsal but of P3 up and toe sticks up
What are the 2 presentations of knocked up toe?
- Acute sprain/rupture in athletic dogs
- Weakening of tendon in old dogs (chronic)
How do you treat knocked up toe?
NSAIDs and do NOT rest
Where does te SDFT insert?
P2
What happens if the SDFT is affected and what is the significance?
–Rupture/avulsion - ‘dropped toe’
–Rarely any clinical significance
What things affect the foot pad? Which are the most common? (9)
•Cut pads
•Foreign bodies
- Excessive wear
- Burns
–thermal/caustic
- Corns (greyhounds)
- Hyperkeratosis
–keratinisation disorders, distemper!
- Plasma cell pododermatitis (cats)
- Autoimmune disease
–eg pemphigus foliaceus, vasculitis
•Nutrition-related
–eg zinc-responsive dermatoses, necrolytic migratory erythema (NME)
What should you do withh superficial pad loss?
Heal by secondary intention (cannot suture). Bandage, splint (reduces opposition of wound contraction by weight-bearing) and rest till early keratinisation – don’t exercise too early!
What should you do with a laceration to a foot pad?
- Debride to bleeding edge
- Appose deep layers with buried simple interrupted absorbable sutures
- Appose epithelial edges with interrupted sutures (simple, vertical mattress or far-near-near-far) – bites several mm from wound edge as these can cheese wire through due to weight bearing
After sutures what is the regime with a laceration to a foot pad?
- Thick absorbent bandage with spoon/clamshell splint – change every 1-3 days
- Remove sutures 10-14 days, rebandage/splint +4 days, rebandage (no splint) 3-6 days (or Mikki-boot)
- Restrict exercise when bandaged
- Gradual reintroduction of exercise on non-abrasive surface
What clinical sign would make you think a FB in the pad?
Pain on local pressure
What conditions may affect haired skin? (7) Highlight the most common.
•Interdigital draining sinus tracts – interdigital cysts (furunculosis?)
–Includes interdigital foreign bodies
•Parasitic infestation
–Demodicosis
–Harvest mite (Trombicula autumnalis)
–Hookworm
- Trauma
- Hypersensitivity
–Atopy, food, contact; EGC
•Infection
–Bacterial pyoderma
–Malassezia dermatitis
–Dermatophytosis
- Contact irritant
- Neoplasia
What are the causes of interdigital draining sinus tracts?
Multiple causes..
–Deep pyoderma (find cause..)
–Demodicosis (pluck hairs/ examine pus in LP)
–Sterile pyogranulomata – bits of keratin loose in the dermis can act as a FB
Name 2 things wound closure is hampered by (3)
- Limited free skin
- Skin tightly adherent to underlying structures
- High risk of vascular damage
What may Severe trauma/degloving/crush injuries reuire?
Amputation or multiple surgical procedures
What do you suspect here?
Feline ‘lung-digit syndrome’
Why do you radiograph the chest of a cat with suspected feline lung digit sydrome?
Majority of digital carcinomas in cats are metastases from primary pulmonary carcinomas, though rarely show pulmonary signs…
Where do highly keratinised epidermal structures grow from?
Corium of proximal P3
What is this?
P3 –covered by corium (dermis)
What is this?
Sole of claw
-soft horn
A) Wall of claw
B) Ungual crest
Label
A) Dermis (corium)
B) Epidermis
C) Sole
Red circle - growth
How should you place claw clippers?
Place blades on lateral side
Name a styptic (2)
- AgN03
- KMnO4
Why do we avoid guillotine clippers?
Clip DV
Which law mentions dew claw removal and what does it say?
–Veterinary Surgeons Act 1966:
•Anyone of/greater than 18 years old can remove dew claws of a dog before its eyes open
–Subsequent animal welfare legislation:
•Anaesthesia mandatory once eyes open
According to the RCVS when is the removal of first digits justifiable?
‘The removal of the first digit of the fore limb is justified only if, in the veterinary surgeon’s professional opinion, the particular anatomy/appearance of the digits invites possible damage’
How can you remove a dew claw in a puppy under 5 days old?
–Aseptically prepare skin
–Abduct dew claw, transect web of skin between dew claw and paw with Mayo scissors
–Disarticulate MCP/MTP joint with scalpel blade or Mayo scissors
–Control haemorrhage with pressure/electrocautery
–Appose skin margins with tissue adhesive/single suture or allow to heal by secondary intention
How do you remove a dew claw in a dog ovr 3 months?
–Perform UGA, usually >3mo old, often when neutered
–
–Clip, aseptically prepare skin
–Elliptical incision around base of digit and MCP/MTP joint
–Dissect s/c tissue
–Ligate dorsal common and axial palmar arteries
–Disarticulate MCP/MTP joint or transect P1
–Appose s/c tissue with 3-0 or 4-0 simple continuous/interrupted absorbable sutures
–Appose skin with simple interrupted sutures
–Soft padded bandage 3-5 days
Define:
A) Paronychia
B) Onychodystrophy
C) Onychomadesis
A) Paronychia - inflammation of claw fold and claw-bed
B) Onychodystrophy - abnormal claw growth
C) Onychomadesis – sloughing of claws
Define:
A) Onychomalacia
B) Onychorrhexis
C) Onychogryposis
D) Onychoschizia
A) Onychomalacia – softening of claws
B) Onychorrhexis – longitudinal splitting of claws
C) Onychogryposis – hypertrophy and abnormal curvature of claws
D) Onychoschizia – splitting +/or lamination of claws, usually from distal end
What diseases affect the claw/clawfold? (7) highlight the most common.
•Traumatic
–Torn/avulsed claws
–Overweight/poor foot conformation
•In-growing claws
•Infection
- Immune-mediated
- Neoplasia
- Nutritional/metabolic
- Idiopathic
How do we treat a torn/avulsed claw?
- Remove loose claw with artery forceps.
- Keep clean, protected (dress 2-3 days +/- silver sulphadiazine), prevent licking
- Systemic antibiotics
- Monitor regrowth for onychodystrophy
What is this and what are the signs?
–Malassezia
- Claws may show brown staining
- Rarely lame
- Claw licking
Name 2 immune mediated diseases affecting the claws (4)
What is this?
Feline pemphigus foliaceus
What would you suspect with gradual progression over several months to involve multiple/all claws – come in with claw loss.. Then another.. Then another?
Symmetrical lupoid onychodystrophy
When is there pain with Symmetrical lupoid onychodystrophy?
Sloughing
How do you treat Symmetrical lupoid onychodystrophy?
–Treat medically once loose claws removed but radical total P3 amputation if unresponsive
•Treat as autoimmune disease
What is the most common digitaltumour in dogs? Which breeeds are commonly affected?
Squamous cell carcinoma
–Especially large black dogs – lab, giant schnauzer
What must you do with a digit melanoma?
–Stage fully (local LN excision, thoracic radiography, blood screen) before excision
How do you treat digit neoplasia?
Amputation of digit at MCP joint
What does this show?
Polydactyly
