Distal limb conditions and injuries and the examination of the lame dog and cat Flashcards
What are the different types of conditions affecting the distal limb?
Trauma
* Fractures
* Soft tissue injuries including sprains and associated subluxations
* Puncture wounds and lacerations (including flexor tendons)
Infection
* Puncture wounds and associated cellulitis
* Foreign bodies
* Pododermatitis
Miscellaneous
* Sesamoiditis
* Nail injuries
* Pad injuries
* Corns
What fractures and subluxations affect the tarsus? How are they treated?
- Those of the talocrural/tibiotarsal joint are commonly associated with RTAs and involve the medial and lateral malleoli with associated subluxations and luxations
- Those involving the tarsal bones including the central and quartal bone or T4 as seen in the racing greyhound. Primary repair is possible but if fracture is comminuted or there is an associated subluxation of the joint arthrodesis is the most appropriate treatment
- Tarsometatarsal subluxations with associated fracture e.g. the base of metatarsal 5 are again better treated with arthrodesis
What injury is seen in these xrays? How has it been repaired?
Luxation of the talocrural/tibiotarsal joint repaired with prosthetic ligament and single K wire to the lateral malleolus
What fractures and subluxations affect the carpus?
The only high motion joint is the antebrachiocarpal
The intercarpal and carpometacarpal are both low motion joints and therefore arthrodesis of these results in little functional change
Damage/rupture to the collateral ligaments of the antebrachiocarpal joint are uncommon cf. talocrural. They may be associated with fractures to the medial or lateral styloid processes upon which they originate. Due to a normal degree of valgus deformity seen in the dog those of the medial collateral are more significant.
An uncommon injury is luxation of the radiocarpal bone which is associated with rupture of the medial/radial collateral ligament
Intercarpal and carpometacarpal subluxations are common and associated with carpal hyperextension injuries (to the palmar ligaments and palmar fibrocartilage)
How are metatarsal, metacarpal and phalangeal fractures repaired?
- These are generally as a result of trauma e.g. RTA, heavy object falling on paw or trapping and twisting the paw
- There are several techniques that can be employed
- External coaptation with dressings or splints. This can be employed if at least one of the metatarsal or metacarpal bones is intact to act as a splint
- Pinning combined with external coaptation or inclusion in an external fixator
- The application of plates
- Phalangeal fractures rarely require surgical treatment and coaptation is usually adequate
How are soft tissue injuries repaired?
- Antebrachiocarpal and talocrural subluxations can be managed by reconstructing the ligamentar support with artificial ligament material or arthrodesis of the joint
- Subluxations of both the intertarsal and intercarpal joints are treated with arthrodesis
Shear injuries.
* These occur when the animal is dragged along the road with the loss of, usually the medial soft tissues and occasionally bone
* Ligament loss results in joint instability or subluxation
* These instabilities can be managed with the use of artificial ligament material including monofilament nylon, braided nylon and orthopaedic wire anchored around bone screws or especially designed bone anchors
* If external support is required then a transarticular external fixator can be applied
How can you determine the integrity of the flexor tendons?
- Make the dog weight bear by picking up the other limb and then examine the toe position.
- If knocked up or collapsed either the superficial or superficial and deep flexor tendons will have been cut
What can small lacerations to the palmar or plantar aspect of the paw affect?
- Flexor tendons
- This often occurs between the digital and main pad
- May be accompanied by significant haemorrhage
How do paw puncture wound present? How can they be investigated? How should they be treated?
- Present with acute lameness, soft tissue swelling to affected pad and pain on palpation
- Radiographs may be appropriate if the presence of a radio opaque foreign body is suspected e.g. glass
- Surgical exploration with the use of a hypodermic needle may allow the retrieval of glass fragments and blackthorns
- Flush the wound with Hartmann’s solution and leave open to drain
- Apply dressing to protect the wound and prevent further contamination
- The use of broad spectrum antibiotics can be justified in this situation
How does cellulitis present in a cat? How can you diagnose it? How is it treated?
- Cellulitis as a result of bite from another cat is the most common cause of lameness in this species
- Acute onset lameness 2-3 days after fight which may have been observed by owner
- Swelling to limb and may be pyrexic and off-colour
- Careful palpation may reveal scabs either side of the limb where the canine teeth have punctured the skin
- The limb is swollen and painful and the cat may show a variable lameness up to the point where it fails to weight bear at all.
- Treat with drainage, bathing to encourage the pus to drain and broad spectrum antibiotics
What are the most common foreign bodies? How do they present? How are they treated?
- Grass seeds are the most common
- Occur primarily in the dog
- Seasonal (July-September)
- Swelling to interdigital area and then progression to a swelling proximal to the main pad and in the forelimb to the shoulder and hind limb to the hip
- Avoid antibiotics - these will result in a rapid improvement but the swelling will return and the foreign body may have moved on to a less accessible site
- Poultices maybe helpful e.g. boric acid (Animalintex)
- Allow the foreign body to form a small abscess (point) and then lance (no. 11 blade) and explore. This can be performed in the tractable conscious animal
What breeds are mostly affected by pododermatitis/interdigital pyoderma? How are they treated?
- A significant cause of lameness in particular breeds including the English bulldog and bull terrier
- A dermatological condition requiring extensive work up (beware localised demodex!) Patient conformation appears to be a significant contributory cause of this condition
- Previous treatment was with prolonged courses of antibiotics and anti-bacterial washes but laser excision of the affected tissue has proven an effective treatment reducing the volume of buried hair shafts and follicles. The wounds are allowed to heal by second intention
- It is managed rather than cured
- On occasions surgery maybe helpful e.g. fusion podoplasty
- This surgery removes the interdigital areas and fuse each digital pad to its adjacent one
What is sesamoiditis? How does it present? How is it treated?
- An inflammatory condition with associated fragmentation of the sesamoid bones seen particularly in greyhounds
- The sesamoids lie within the joint capsule of the metacarpo- or metatarso-phalangeal joints. They have multiple ligament attachments and act as pulleys for the flexor tendons.
- A profound acute lameness is exhibited with pin point pain on applying pressure over the affected sesamoid and flexing and extending the metacarpo- or metatarso-phalangeal joints
- The lameness may resolve with rest only to recur with exercise.
- Rest and analgesia (non-steroidals) for 3-4 weeks
- If the above were to fail local instillation of a depo steroid preparation (methyl prednisolone) followed by a similar period of rest
- If this also fails surgical excision of the affected sesamoid
What is the most common nail injury? How does it present? How is it treated?
- The most common is the torn nail
- Acute onset
- Small amount of blood may be seen at the nail base
- Marked pain on manipulation of the nail
- Rarely will these heal with dressings and appropriate analgesia
- If the nail is only just hanging on a swift pull to remove it followed by dressings and analgesia
- If the nail is more strongly attached then general anaesthesia and removal of the nail and ungual process of P3 is indicated
- If one leaves these nails the dog will continue to go lame when starting to exercise as the nail becomes dislodged again from the underlying bone
How can you diagnose neoplastic conditions of the nail bed? How is it treated? What are the most common neoplasias?
- Any non healing nail bed infection or a torn nail that fails to heal after removal -always consider neoplasia
- Radiographs will show destruction of P3
- Palpate the local lymph node (prescapular or popliteal) and if enlarged aspirate
- Treatment is amputation of the digit - the majority of the weight bearing is performed by digits 3 and 4 but excision of any one digit will not affect weight bearing
- In the dog the commonest neoplasia is the squamous cell carcinoma and melanoma (highly pigmented dogs e.g. giant schnauzer)
- In the cat, particularly if several digits are involved radiograph the chest as the cat has a unique metastatic spread of the pulmonary carcinoma to the nail beds
How should pad lacerations be managed?
- Some can be managed with dressings only
- Beware the embedded foreign body
- If requires surgery perform under general anaesthesia
- The underlying pad tissue will protrude from the wound- excise this to allow easier closure
- Take deep bites of tissue.
- Although braided material is more prone to wicking infection, it is more comfortable for the animal to walk on or bury the sutures
- Dress the wound and advise re restricted exercise
- Remove the dressing after three days to allow the foot to “breathe” and avoid bandage-associated complications
What can cause pad loss? How should this be managed?
- These can occur as a result of trauma. e.g. being dragged along the road when tethered to a car
- As a result of walking on a hot surface (e.g. cat jumping onto a cooker hot plate)
- But the most common reason is loss due to the incorrect placement of a dressing or cast
Management
- If the main (metacarpal and metatarsal) pads are lost then they will require replacing
- This can be achieved by filleting out the bone from either digit 2 or 5 and using the pad as a replacement
- One should not use 3 and 4 for this surgery as these are the main weight bearing pads
Where do corns occur? How can they be treated?
- A condition common in the gazehounds
- Painful
- Mainly in forelimbs and more common in digits III and IV
- If excised they almost always recur.
- Original surgery was to section the SDF and DDF:- encouraging preliminary results. Now sectioning or removal a small segment of the SDF above the main pad is recommended
- Once the weight bearing is reduced to the digital pad the corn grows out and no further treatment is required
- This can be conducted in multiple digits without loss of function
What clues should be used to limit the differential list in the lame animal?
** Signalment**
- Breed
- Labrador retriever for elbow dysplasia
- West Highland white terrier for cruciate disease
- Age
- Osteoarthritis in the older animal
- Panosteitis in the younger animal
- Cruciate disease in the young and middle aged
History
- ask for a video
- onset
- activity
Clinical signs
* Observation in the consulting room (difficult with cats)
- stance
- head carriage (cervical disc)
- hyperextension of carpus or tarsus
- muscle atrophy
- single limb or multiple
- holding limb off the ground
- are they able to fix the stifle
- lameness or neurological deficits
* Dogs walked outside
- head nod for fore limb
- hip rise for hind limb
- neurological (catches nail on the ground and turn in tight circle to exaggerate the deficits)
- flex the limb and set off
* Full clinical examination
- systemic illness
- pyrexia
- respiratory signs
- urinary tract disease
- prostatic disease
* Lameness examination
- observe at walk and brisk trot before clinical exam
- palpate the limb (muscle atrophy, swellings)
- foot and pads (twist the nails)
- joints (effusions, instability, pain)
- ligaments and tendons (swelling, pain, heat)
- patella instability (may subluxate medially or laterally)
- cruciate rupture (cranial drawer, tibial thrust)
- bones (observe, palpate, squeeze)
- Cats
- encourage movement with treats and open basket
- video clip
- minimise handling and restraint
- make the cat face a corner
* Neurological examination
- neck or thoracolumbar pain
- palpate axilla
- rectal exam if hindlimb
- check anal and rectal tone
Response to treatment
What further investigations can you undertake in the lame animal?
Radiography
Joint taps
- single joint or multiple joints if polyarthirtis suspected
- examine in house (diff quick - neutrophilia is suggestive of sepsis)
Blood tests
CT
- elbows!!
- mineralisation of the infra and supraspinatous tendons
MRI
- soft tissue definition and stifles, shoulders, foreign bodies
- spine for nerve root tumours and lumbosacral disease
Ultrasound
- bicipital, Achilles/gastroc, patella and flexor tendons
- Also can be useful for the detection of foreign bodies
Arthroscopy
- Shoulder, elbow and stifle
- Can be both diagnostic and used to treat, e.g. FCP
- But a very steep learning curve
Biopsy?? mass or swellings
Muscle biopsies myopathy
Nerve conduction studies
Electromyography (EMG)
What serology could you run for the lame animal?
- RF for rheumatoid arthritis
- ANA/ANF for systemic lupus erythematosis
- Borrelia burgdorferi serology or PCR of joint fluid for Lymes disease
- Brucella canis serology or PCR of joint fluid for polyarthritis or discospondylitis
- Toxoplasmosis and Neospora serology if signs suggestive of neurological disease
What should you do if you can’t find anything?
If you feel that the client is still on board
* You could give non-steroidal drugs or paracetamol and reassess in two weeks or, if very lame, in two days
* Make an appointment there and then - don’t leave it up to the client
* Phone them mid way through any period of rest to enquire after their pet. Put an alarm on your phone to remind you.
But if not
- Offer them a referral (better to do this earlier than later)
