Equine Forelimb Flashcards
Name 9 of themain causes of forelimb lameness in horses (11)
- Foot pain
- Cellulitis / lymphangitis
- Pastern joint degenerative joint disease
- Fetlock DJD
- Splints
- Tendon and ligament injuries - covered previously
- Carpal DJD
- Synovial sepsis*
- Fractures*
- Tendon / ligament ruptures*
- Luxations*
What fractures of the forelimb are common?
Second phalanx, first phalanx, sesmoids, metacarpus, splint bones, carpal bones, ulna, shoulder + stress fractures of long bones
How does the aetiology affect the fracture type?
–Kick wounds -> bony prominences (splint bones, olecranon)
–Trauma / concussion (pastern, metacarpus) – usually but not exclusively racehorse
–Stress fractures (metacarpus, radius, humerus, scapula)
–Articular / subchondral bone disease (fetlock, carpus
What is a common site of a fracture in horses?
Splint bone
How do we treat a splint bone fracture?
–Many will heal with conservative treatment and do not require surgical removal
- Rest, bandaging and anti-inflammatories for closed fractures (4-6 weeks healing time)
- As above but plus antibiotics for open fractures – watch out for joint involvement
What shouldbe avoided with splint bone fractures?
GA
What can kick wounds in the splint bone cause?
Non-displaced cannon fracture
How do ulna/olecranon fractures present?
–These can present as ‘dropped elbow’ similarly to radial paralysis as the triceps action is affected (insertion on olecranon, acts to extend elbow)
What does a fracture description evaluate?
Degree of comminution, stability and articular involvement, and this determine whether internal fixation is required
What is the prognosis of an ulna/olecranon fracture?
Fair to good
What is the history of a horse with stress fractures?
- Intense training
- None – “incidental finding”
- None - spontaneous catastrophic fracture
- Subtle loss of performance
- Acute-onset lameness associated with work
What are the clinical signs of a horse with stress fractures?
•Lameness
–Single or multiple limbs
–Variable severity
–Variable presentation
–Variable duration
•Absence of clinical findings in affected limb
- Localised inflammation
- Regional pain response to palpation/manipulation:
- Specific tests (tibial torsion test)
How do you diagnose a stress fracture? (7)
- Diagnostic Anaesthesia
- Scintigraphy
- Radiography
- Ultrasonography
- Magnetic resonance imaging
- Computed tomography
- Screening tools (biochemical markers)
How do we manage a stress fracture?
Modify exercise patterns
- Combination of load, repetition and inadequate recovery = Stress Fracture
- Essential feature of treatment is to break this cycle
- Change intensity,
- level,
- and/or type of exercise
- Value of grading system – tailor exercise
Ensure balanced nutrition
- Vitamin & mineral levels and ratios
–Calcium – 35g/day
–Phosphorus - 23g/day
Extracorporeal shock wave therapy
- Anecdotal evidence
- Variable scientific findings, difference between focused & radial therapy
Surgery
•Few indications
Therapeutics - Bisphosphonates
Which joint do articular fractures affect?
Any joint
What are the common joints affected by articular fractures?
Fetlock, sesamoid bones and carpus, esp racehorses
How can you treat articular fractures?
- Remove small fragments
- Can stabilise (screw) larger fragments
- Treat joint inflammation
- Must recognise and treat these fractures to prevent ongoing cartilage and joint disease
What is the most common site of synovial sepsis?
Distal limb (flexor tendon sheath, pastern joint, fetlock joint)
What are the common lligament and tendon injuries causing forelib lameness? (4)
–SDFT (esp racehorse)
–ALDDFT (all types of work)
–Suspensory ligament (racehorse and performance horse)
–Annular ligament syndrome (all types)
What are the less common tendon and ligament injuries causing forelimb injuries? (3)
–DDFT (pastern)
–Distal sesamoidean ligaments
–Bicipital tendon
Where is common for luxations/subluxations in the FL?(3)
- Pastern
- Fetlock
- Shoulder
Where is a common site of osteochondrosis in the FL? (4)
–Fetlock (common site)
–Carpus (rare)
–Elbow (rare)
–Shoulder
Where are the common sites for subchondral bone cysts?
Fetlock
Name 2 flexural deformities of the forelimb (3)
- DIP joint
- MCP joint
- Carpus
Name a common site for angular limb deformities (2)
- MCP joint
- Carpus
Suprascapular nerve:
A) What is it damaged?
B) What does it innervate?
C) What does damage cause?
A) Damaged by blunt trauma to point of shoulder
B) Innervates supraspinatus and infraspinatus muscles
C) Causes muscle atrophy and lateral luxation of shoulder joint
Radialnerve neuropathies:
A) What causes it?
B) What does it innervate?
C) What is the effect?
A) Post-anaesthetic neuropathy or caused by trauma
B) Innervates extensor of elbow, carpus and digit, and dorsal skin sensation
C) Animal cannot protract limb and Ulna fractures can present
What appearance does a hors with radial nerve paralysis have?
Dropped elbow
- You have been asked to examine a 9 year old Thoroughbred cross which was found in the field acutely lame and unable to weight bear on its right forelimb.
- The horse is sweating and distressed and reluctant to move. On observation, there is a wound over the right olecranon, and the right olecranon is dropped lower than the left.
- What are your two main differentials in this case, and how will you distinguish between them?
–Olecranon/humerus fracture
–Radial nerve injury
How can we distinguish between radial nerve paralysis and an olecranon fracture? How do we confirm?
- Distinguish by clinical signs consistent with a fracture (localised pain and crepitus) cf nerve damage (unable to protract limb or fix carpus +/- sensory deficits on dorsal aspect of limb and absence of pain
- Confirm on radiography
What radiographic views will you take of the elbow joint?
Mediolateral and craniocaudal
Can’t take 45o degree obliques so these answers would be wrong
Think about where you would place the plate and X-ray machine – you can only take these views in the orientation I have described – e.g. the machine has to be cranial and the plate behind the olecranon.
Describe this fracture
- Open
- Comminuted
- Articular
- Transverse
- Ulna fracture
- With a large triangular fragment
- Proximal displacement of olecranon
The owner wants to have the horse referred for internal fixation – how will you prepare this horse to travel to a referral centre? (4)
- Balanced analgesia - NSAIDs (equipalazone, flunixin, meloxicam, ketoprofen, carprofen etc) +/- opioids (e.g. butorphanol, buprenorphine, pethidine, methadone, morphine)
- Antibiotics, e.g. IV or IM penicillin and IV gentamicin (open fracture with articular involvement)
- If possible, load and unload horse on a slope so that the incline on the ramp is minimised
- Stabilisation during transport – you cannot splint this region, some horses may walk better with a dorsal splint to stabilise the carpus, some may be better without, cross-tie in box so can use ropes to stabilise, ensure partitions across so can lean on them. Ideally travel facing backwards, so if driver has to brake suddenly the horse is not forced to weight-bear on leg
Name 9 causes of forelimb (11)
- Foot pain
- Cellulitis / lymphangitis
- Pastern joint degenerative joint disease
- Fetlock DJD
- Splints
- Tendon and ligament injuries - covered previously
- Carpal DJD
- Synovial sepsis*
- Fractures*
- Tendon / ligament ruptures*
- Luxations*
How do you go about doing a physical exam to diagnose forelimb lameness?
1.Observation
–Conformation (look back at Year 1 notes)
–Assymmetry (foot size, musculature)
–Wear and shape of feet
- Palpation
–Assymmetry
–Heat, swelling, pain
–Swellings (bony, soft tissue, synovial)
- Range of movement
–Joint range of movement
–Adhesions between soft tissues
What are the contra-indications of using nerve blocks? (4)
- Unstable limbs
- Suspected fractures
- Severe soft tissue injuries (such as DDFT ruptures)
- Risk of infection
- Current infection at injection sites, such as mud fever
- Where you cannot perform technique
Name 4 perineural anaesthetic techniques (6)
- Palmar digital nerve block
- Abaxial sesamoid nerve block
- Low four point (fetlock and below)
- High four point (metacarpal region and below)
- Lateral palmar nerve block (proximal suspensory ligament)
- Median and ulna nerve block (carpus and below)
Radial nerve:
A) What is it an extensor of? (3)
B) What is the function?
A) Extensors of elbow, carpus and digits
B) Skin sensation on craniolateral aspect of limb not dorsal digit