Equine Forelimb

Question 1

Name 9 of themain causes of forelimb lameness in horses (11)

Answer 1

• 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*

Question 2

What fractures of the forelimb are common?

Answer 2

Second phalanx, first phalanx, sesmoids, metacarpus, splint bones, carpal bones, ulna, shoulder + stress fractures of long bones

Question 3

How does the aetiology affect the fracture type?

Answer 3

–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

Question 4

What is a common site of a fracture in horses?

Answer 4

Splint bone

Question 5

How do we treat a splint bone fracture?

Answer 5

–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

Question 6

What shouldbe avoided with splint bone fractures?

Answer 6

GA

Question 7

What can kick wounds in the splint bone cause?

Answer 7

Non-displaced cannon fracture

Question 8

How do ulna/olecranon fractures present?

Answer 8

–These can present as ‘dropped elbow’ similarly to radial paralysis as the triceps action is affected (insertion on olecranon, acts to extend elbow)

Question 9

What does a fracture description evaluate?

Answer 9

Degree of comminution, stability and articular involvement, and this determine whether internal fixation is required

Question 10

What is the prognosis of an ulna/olecranon fracture?

Answer 10

Fair to good

Question 11

What is the history of a horse with stress fractures?

Answer 11

• Intense training
• None – “incidental finding”
• None - spontaneous catastrophic fracture
• Subtle loss of performance
• Acute-onset lameness associated with work

Question 12

What are the clinical signs of a horse with stress fractures?

Answer 12

•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)

Question 13

How do you diagnose a stress fracture? (7)

Answer 13

• Diagnostic Anaesthesia
• Scintigraphy
• Radiography
• Ultrasonography
• Magnetic resonance imaging
• Computed tomography
• Screening tools (biochemical markers)

Question 14

How do we manage a stress fracture?

Answer 14

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

Question 15

Which joint do articular fractures affect?

Answer 15

Any joint

Question 16

What are the common joints affected by articular fractures?

Answer 16

Fetlock, sesamoid bones and carpus, esp racehorses

Question 17

How can you treat articular fractures?

Answer 17

• Remove small fragments
• Can stabilise (screw) larger fragments
• Treat joint inflammation
• Must recognise and treat these fractures to prevent ongoing cartilage and joint disease

Question 18

What is the most common site of synovial sepsis?

Answer 18

Distal limb (flexor tendon sheath, pastern joint, fetlock joint)

Question 19

What are the common lligament and tendon injuries causing forelib lameness? (4)

Answer 19

–SDFT (esp racehorse)

–ALDDFT (all types of work)

–Suspensory ligament (racehorse and performance horse)

–Annular ligament syndrome (all types)

Question 20

What are the less common tendon and ligament injuries causing forelimb injuries? (3)

Answer 20

–DDFT (pastern)

–Distal sesamoidean ligaments

–Bicipital tendon

Question 21

Where is common for luxations/subluxations in the FL?(3)

Answer 21

• Pastern
• Fetlock
• Shoulder

Question 22

Where is a common site of osteochondrosis in the FL? (4)

Answer 22

–Fetlock (common site)

–Carpus (rare)

–Elbow (rare)

–Shoulder

Question 23

Where are the common sites for subchondral bone cysts?

Answer 23

Fetlock

Question 24

Name 2 flexural deformities of the forelimb (3)

Answer 24

• DIP joint
• MCP joint
• Carpus

Question 25

Name a common site for angular limb deformities (2)

Answer 25

* MCP joint * Carpus

Question 26

Suprascapular nerve: A) What is it damaged? B) What does it innervate? C) What does damage cause?

Answer 26

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

Question 27

Radialnerve neuropathies: A) What causes it? B) What does it innervate? C) What is the effect?

Answer 27

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

Question 28

What appearance does a hors with radial nerve paralysis have?

Answer 28

Dropped elbow

Question 29

* 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?

Answer 29

–Olecranon/humerus fracture –Radial nerve injury

Question 30

How can we distinguish between radial nerve paralysis and an olecranon fracture? How do we confirm?

Answer 30

* 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

Question 31

What radiographic views will you take of the elbow joint?

Answer 31

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.

Question 32

Describe this fracture

Answer 32

* Open * Comminuted * Articular * Transverse * Ulna fracture * With a large triangular fragment * Proximal displacement of olecranon

Question 33

The owner wants to have the horse referred for internal fixation – how will you prepare this horse to travel to a referral centre? (4)

Answer 33

1. Balanced analgesia - NSAIDs (equipalazone, flunixin, meloxicam, ketoprofen, carprofen etc) +/- opioids (e.g. butorphanol, buprenorphine, pethidine, methadone, morphine) 2. Antibiotics, e.g. IV or IM penicillin and IV gentamicin (open fracture with articular involvement) 3. If possible, load and unload horse on a slope so that the incline on the ramp is minimised 4. 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

Question 34

Name 9 causes of forelimb (11)

Answer 34

* 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\*

Question 35

How do you go about doing a physical exam to diagnose forelimb lameness?

Answer 35

1.Observation –Conformation (look back at Year 1 notes) –Assymmetry (foot size, musculature) –Wear and shape of feet 2. Palpation –Assymmetry –Heat, swelling, pain –Swellings (bony, soft tissue, synovial) 3. Range of movement –Joint range of movement –Adhesions between soft tissues

Question 36

What are the contra-indications of using nerve blocks? (4)

Answer 36

* 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

Question 37

Name 4 perineural anaesthetic techniques (6)

Answer 37

* 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)

Question 38

Radial nerve: A) What is it an extensor of? (3) B) What is the function?

Answer 38

A) Extensors of elbow, carpus and digits B) Skin sensation on craniolateral aspect of limb not dorsal digit

Question 39

Median nerve: A) What is it flexors of? (2) B) What is the function?

Answer 39

A) Flexors of carpus and digit B) Skin sensation on palmar aspect and dorsal digit

Question 40

Ulna nerve: A) What is it flexors of? (2) B) What is the function?

Answer 40

A) Carpus and digit B) Caudal aspect of forearm, lateral and dorsal digit

Question 41

Label the black, green and pink nerve

Answer 41

Black Radial nerve Green: Ulnar nerve Pink: Median nerve

Question 42

Label the nerve block and what it does

Answer 42

1. Palmar digital nerves in pastern region (palmar digital nerve block) 2. Palmar digital nerves on abaxial (away from midline) surface of proximal sesamoid bones (abaxial sesamoid nerve block)

Question 43

Label the nerve blocks and what they do

Answer 43

3. Palmar metacarpal and palmar nerves in distal metacarpus (Low 4 point) 4. Palmar metacarpal and palmar nerves in proximal metacarpus (High 4 point)

Question 44

Label the nerve blocks and what they do

Answer 44

1. Palmar digital nerves in pastern region (palmar digital nerve block) * Removes sensation to palmar foot 2. Palmar digital nerves on abaxial surface of proximal sesamoid bones (abaxial sesamoid nerve block) * Removes sensation to foot, pastern and palmar fetlock

Question 45

Label the nerve blocks and what they do

Answer 45

3. Palmar metacarpal and palmar nerves in distal metacarpus (Low 4 point) * Removes sensation to fetlock and below 4. Palmar metacarpal and palmar nerves in proximal metacarpus (High 4 point) * Removes sensation to metacarpal region and below

Question 46

Name 8 intra-articular anaesthesia sites (10)

Answer 46

–Distal interphalangeal joint –Navicular bursa (you cant tell you’re in the right place without radiograph or contrast) –Digital flexor tendon sheath –Pastern joint –Fetlock joint –Midcarpal joint (communicates with carpometacarpal) –Antebrachiocarpal joint –Elbow joint –Shoulder joint –Bicipital bursa

Question 47

When is radiography the first line of diagnostics? (3)

Answer 47

–Suspected fracture –Suspected bone lesions –Joint pain

Question 48

What are the equine standard radiography views?

Answer 48

–4 views of each joint (LM, DLPMO, DMPLO, DP) –Additional views of carpus and fetlock (racehorse) –Elbow and shoulder (LM and CrCa)

Question 49

When is ultrasound the first line of diagnostics?

Answer 49

For suspected soft tissue lesions (e.g. tendonitis, bursal swellings)

Question 50

Where is gamma scintigraphy used for first line diagnostics?

Answer 50

Suspect fracture

Question 51

When is arthrocentesis used for first line diagnostics?

Answer 51

Suspect joint sepsis

Question 52

When is MRI used in forelimb lameness?

Answer 52

–Used for some difficult soft tissue injuries, e.g. prox suspensory desmitis –Really good for foot stuff

Question 53

When is CT used in diagnosing forelimb lameness?

Answer 53

Complicated fractured / bone lesions e.g. bone cyst

Question 54

Define cellulitis

Answer 54

Inflammation of subcutaneous tissues (+/- infection)

Question 55

Why might cellulitis happen and where may it be on the limb?

Answer 55

–Site of bacterial entry may be a wound, skin infection (e.g. Mud fever) or deeper infection –Cellulitis may be localised or spread throughout limb

Question 56

Name clinical signs of cellulitis (5)

Answer 56

–Heat, pain, swelling –Usually diffuse swelling, can have localised abscess as well –+/- pyrexia –Varying degree of lameness –Elevated white cell count

Question 57

What is the approach to cellulitis?

Answer 57

1. Identify underlying cause 2. Rule out complicating factors (fractures, synovial sepsis, osteomyelitis) exp. if not clearing up 3. Treat underlying cause (including establishing drainage for pockets of infection) 4. Antibiotics and anti-inflammatories

Question 58

What type of antibiotics are used for cellulits?

Answer 58

–Systemic antibiotics required due to spread of infection through tissues –Penicillin, cephalosporins and potentiated sulphonamides

Question 59

Define lymphangitis

Answer 59

Inflammation of lymphatic system of limb

Question 60

What causing a build up of fluid in the lim with lymphagitis?

Answer 60

Impaired lymph drainage

Question 61

What may tirgger lympangiitis?

Answer 61

Be triggered by infection, and once affected, horses may become predisposed to problem

Question 62

What are the clinical signs of lymphangitis? (6)

Answer 62

–Hindlimbs more common than forelimbs –Bilateral or unilateral –Diffuse soft tissue swelling –Prominent lymphatics –Can progress to serum oozing through skin –May have abrasions / site of infection

Question 63

How do we treat lymphangitis? (3)

Answer 63

1. Identify and treat underlying cause 2. Antibiotics and steroids (dexamethasone IM followed by oral prednisolone) 3. Physical therapy (cold hosing, bandaging, walking exercise) Treat aggressively – affected horses are predisposed to recurrence, and some may develop chronic limb swelling Steroids – if we know its lympangitis not infection

Question 64

What are the three less common causes of forelimb lameness? But should be on your differentials!!!!!!!!!!!!!!!

Answer 64

* Purpura haemorrhagica * Equine viral arteritis * Hypoproteinaemia / fluid overload / cardiac failure

Question 65

What is Purpura haemorrhagica?

Answer 65

–immune-mediated vasculitis following infection –Rare sequela to Strangles

Question 66

What happens if you suspecy equine viral arteritis? What are the other signs (apart from lamenes)

Answer 66

–Reportable disease (repro disease) –Other signs = swelling of periorbital region and genitalia

Question 67

What areas are affected by hypoproteinaemia/fluid overload/cardiac failure?

Answer 67

All dependent areas affected - limbs, ventral abdomen and muzzle

Question 68

Pasterndegnerative joint disease: A) Before clinical signs, what may the disease be? B) What may advanced disease have? C) What may the cause be? D) Where is chronic disease more likely? Sorry there are lots of questions here.. was just the best way to link them.

Answer 68

A) Advanced B) Have palpable bony swelling (make sure bone is articular, non-articular new bone is not clinically significant) C) Have inciting cause (sepsis, fracture, bone cysts / OCD) – OCD is the main one, probably will have had a bony problem in the past D) horses with repeated concussion / turning forces – barrel racing horse

Question 69

What confirms the site of pain in forelimb lameness?

Answer 69

Intra-articular

Question 70

Discuss this radiograph

Answer 70

New bone and osteophyte dorsal P2 and distal P1

Question 71

Discuss this radiograph

Answer 71

Dorsopalmar – osteophyte formation

Question 72

How can we treat pastern lameness (7)

Answer 72

–Mild cases (no radiographic changes) -\> intra-articular medication / anti-inflammatories. Hyaluronic acid - £150+, steroids - £2 –Once radiographic changes are present, disease will continue to progress –Can manage lameness with NSAIDs (takes a long time to fuse on own) –Surgical arthrodesis best option (80% hindlimbs, and 60% forelimbs athletically sound\*) –Arthrodesis also an option for fractures and luxations (low motion joints) –Low motion – can ride as long as there is pain relief. –Rarely – joint will fuse on its own

Question 73

What are the 4 main causes of fetlock disease?

Answer 73

–Developmental (OCD and bone cysts) –Trauma / repetitive injury (older horses going on to develop JD) –Articular fragments –Major fractures that extend to joint

Question 74

Discuss this and what the plan would be

Answer 74

* DP view articular proximal phalangeal fracture * Will have swelling * Non displaced – need 4 views! * Needs a screw * Cant work it

Question 75

Discuss this and what the plan would be

Answer 75

* LM view osteochondral fragment of dorsoproximal P1 and proximal sesamoid bone * Next – need to radiograph the other side!! Can then arthroscopy

Question 76

What is this?

Answer 76

Fetlock Luxation

Question 77

How can you diagnose fetlock disease? (4)

Answer 77

–History and palpation (fractures, joint effusions) –Nerve blocks (NOT SUSPECTED FRACTURES) * ABSNB – does not affect dorsal aspect * Low 4 point – blocks whole joint * Intra-articular – confirms joint involvement –Radiography usually first line diagnostics for most diseases –May require specialised obliques for some conditions

Question 78

What do you do for: A) Articular fragments? B) Large fragments? C) OCD lesions?

Answer 78

A) Remove B) Stabilise C) Remove/debride

Question 79

What do you do for: A) Bone cyst? B) Subchondral bone disease? C) Synovitis? D) Chronic OA?

Answer 79

A) Debride B) Rest C) Medicate D) Anti-inflammatories and analgesia

Question 80

What are the splint bones?

Answer 80

2nd and 4th metacarpal and metatarsal bones are ‘splint bones’

Question 81

What is meant by the term "slints" and what is it thought to be caused by?

Answer 81

–The term ‘splints’ is used to describe bony enlargement of this region –Thought to be caused by trauma and subperiosteal haemorrhage

Question 82

What are the clinical signs of splints (5)

Answer 82

–Usually seen in younger horses starting or increasing work –Forelimb more common than hindlimb –2nd metacarpal more common than 4th –Some, but not all cause lameness –‘Bench knee’ conformation may predispose

Question 83

Name 3 things found on physical exam with splints (5)

Answer 83

–Heat, pain, swelling around proximal splint bone –Soft tissue or bony swelling

Question 84

How can you diagnose splints? (3)

Answer 84

–Usually diagnosed on clinical signs –These are common and the bony swellings persist, therefore you will see old chronic injuries which are not clinically significant –Can confirm on radiography, or use nerve blocks to confirm site of pain

Question 85

Name 3 ways of treating splints (4)

Answer 85

–Anti-inflammatories and reduce / stop work until lameness settles – bute –Bony swelling will persist (although will remodel and usually become smaller if caught in the acute phase) –Swellings a cosmetic problem – cold hose, stop and cute –Rarely, new bone formation impinges on suspensory ligament and requires surgical removal

Question 86

Name4 clinical signs of osteoarthiritis of the carpus (5)

Answer 86

–Lameness –Joint effusion (which joint is affected?) –Bony swelling (peri-articular, physeal) –Reduced range of movement (know your normals!) –Pain on flexion (flexion tests)

Question 87

What is osteoarthiritis often secondary to?

Answer 87

Other problems

Question 88

How can you diagnose carpal joint disease?

Answer 88

–Joint effusion and pain on palpation -\> radiography –Suspected fracture / sepsis -\> radiography

Question 89

What does this show?

Answer 89

Radiocarpal joint effusion

Question 90

When localising signs, which carpal nerve blocks can we treat as one?

Answer 90

Middle carpal and carpometacarpal always communicate

Question 91

When doing nerve blocks of the carpus which do we have to treat as seperate?

Answer 91

Middle carpal and antebrachiocarpal rarely communicate

Question 92

How do you treat carpal disease? (5)

Answer 92

–Remove articular fragments\* –Stabilise large fragments\* –Rest horses with subchondral bone disease –Medicate synovitis (intra-articular meds) –Anti-inflammatories and analgesia for chronic OA

Question 93

The midcarpal and antebrachiocarpal joints are high motion joints, what happens if there are radiographic signs of OA?

Answer 93

Poor prognosis

Question 94

In general: A) What if there is a small bone fragment? B) What if there is a big bone fragment?

Answer 94

A) Take it out B) Mend it

Question 95

Where is the fracture? Which treatment is most appropriate?

Answer 95

Antebrachial carpal joint – chip Small – take it out If it was a slab fracture – screw and stablise