Orthopaedics Flashcards
Discuss the aetiopathogenesis, diagnosis of, and treatment of stress fractures in horses. (5,4,3)
Occur in young athletic animals. Recurrent percussive force from repeated submaximal loading causes microscopic damage to the bone causing pericortical remodelling which weakens the bone and allows stress fractures. Stress fractures predispose to complete fracture of the bone.
Scintigraphy, radiography (may be under too much muscle), MRI (depends on site), ultrasonography, and lameness- often acute at first but appears to quickly recover.
Conservative best, but requires prompt treatment to prevent complete fracture- box rest and Robert jones bandages with or without splints. Casting the distal limb may be an option in some cases. (external coaptation). May need to cross tie the animal to prevent lying down (eg pelvic fractures)
Discuss the aetiopathogenesis, diagnosis of, and treatment of stress fractures in horses. (5,4,3)
Occur in young athletic animals. Recurrent percussive force from repeated submaximal loading causes microscopic damage to the bone causing pericortical remodelling which weakens the bone and allows stress fractures. Stress fractures predispose to complete fracture of the bone.
Scintigraphy, radiography (may be under too much muscle), MRI (depends on site), ultrasonography, and lameness- often acute at first but appears to quickly recover.
Conservative best, but requires prompt treatment to prevent complete fracture- box rest and Robert jones bandages with or without splints. Casting the distal limb may be an option in some cases. (external coaptation). May need to cross tie the animal to prevent lying down (eg pelvic fractures)
Describe the diagnosis and treatment of supraglenoid tubercle fractures and diagnosis and treatment of carpal slab fractures (3,3,3,3)
Supraglenoid- clinical signs severe lameness, shortened cranial phase, local pain and swelling first, then muscle atrophy. Radiograph cranio-caudal and lateral if possible. If young can use internal fixation using lag screw and wire. Biceps tenotomy deceases distracting forces. Adults resect and remove fragments or if chronic/comminuted.
Carpal- clinical signs- variable degree of lameness and joint effusion on cranial carpus. Resists extension. Can be displaced or non displaced on radiograph- often need skyline view. Unless very small needs internal fixation, single 4.5mm lag screw inserted into flexed knee under athroscopic guidance.
- List the classifications of pedal bone fracture in the horse (6 marks). Outline why different treatments are required for different fractures (4 marks).
Wing non articular- conservative, hoof cast
Parasaggital- if over 18 months or displaced surgical with a lag screw
Saggital- as above
Extensor process- arthroscopy to remove small fragments large fragments candidate for internal fixation
Comminuted as above, poor prognosis
Rim/solar margin- conservative, shoeing
A horse is admitted to your clinic with a six week history of intermittent non weightbearing lameness following pricking the toe region of the sole with a nail. What are the differential diagnoses for this case and how would you confirm them (6 marks)? How would you treat this horse (4 marks)?
Subsolar abscess Pedal bone fracture Septic pedal osteitis Foot penetration Nail prick Nail bind Laminitis
Hoof testers, looking an area of pain, investigation with hoof knives, x ray if required with radio opaque marker in tract, MRI, nerve blocks
Create a drainage tract by paring out, lavage and flush, consider debriding bone (under nerve block!), put metronidazole into hole, remove any remaining debris
You are presented with a horse which has a non-weight bearing lameness. What are your likely differentials (5 marks)? Describe your approach to making a diagnosis in this case (15 marks). Choose one of your differential diagnoses and describe what your treatment plan would be in that case (10).
sub solar abscess septic pedal osteitis fractured pedal bone fracture of a long bone septic joint
History (recent trauma? sudden onset? penetrating wounds)
General clinical exam- TPR looking for generalised infection or pain.
Specific clinical exam- palpation of the limb and contralaleral limb to compare. Dont trot up. Look for pain, swelling, heat, erythema, instability. Bounding digital pulses?
You examine an 18 month old horse that has a consistently markedly broken forward foot-pastern axis and that is walking on the toe of the hoof with the heels of the hoof not making contact with the ground. What is your diagnosis (2 marks) and what treatment options are available (8 marks)?
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You examine an 18 month old horse that has a consistently markedly broken forward foot-pastern axis and that is walking on the toe of the hoof with the heels of the hoof not making contact with the ground. What is your diagnosis (2 marks) and what treatment options are available (8 marks)?
The clinical signs indicate contracture of either the SDFT, DDFT or both to cause a club foot. In a yearling it is more likely to be a contacture of the SDFT.
Need to assess severity (Stashak grade), looking at angle between toe and ground. Can also look at the flexibility of the joint capsule (worse prognosis if doesnt flex when extra weight applied)
Surgical- for severe contractures a tenotomy of the contracted tendon can be performed but the horse will remain lame and no chance at an athletic career.
For milder contractions a desmotomy of the accessory ligament associated (superior/inferior check) can be performed to increase the functional length of the muscuol-tendon unit. This provides a better chance at a return to function.
Hoof trimming- aim to drop the heel, so remove 2-3mm of toe everytime the heel contacts the ground.
Therapeutic shoeing or reconstruction with acrylics has the same aim, to drop the heel, can be used for toe reconstruction and to add extensions onto the toe to increase pressure on the DDFT, or with extra heel that can be gradually lowered.
You examine an 18 month old horse that has a consistently markedly broken forward foot-pastern axis and that is walking on the toe of the hoof with the heels of the hoof not making contact with the ground. What is your diagnosis (2 marks) and what treatment options are available (8 marks)?
The clinical signs indicate contracture of either the SDFT, DDFT or both to cause a club foot. In a yearling it is more likely to be a contacture of the SDFT.
Need to assess severity (Stashak grade), looking at angle between toe and ground. Can also look at the flexibility of the joint capsule (worse prognosis if doesnt flex when extra weight applied)
Surgical- for severe contractures a tenotomy of the contracted tendon can be performed but the horse will remain lame and no chance at an athletic career.
For milder contractions a desmotomy of the accessory ligament associated (superior/inferior check) can be performed to increase the functional length of the muscuol-tendon unit. This provides a better chance at a return to function.
Hoof trimming- aim to drop the heel, so remove 2-3mm of toe everytime the heel contacts the ground.
Therapeutic shoeing or reconstruction with acrylics has the same aim, to drop the heel, can be used for toe reconstruction and to add extensions onto the toe to increase pressure on the DDFT, or with extra heel that can be gradually lowered.
Initial investigation of a horse with a hind-limb lameness leads you to suspect hock region pathology. What radiographic views would you obtain to allow you to identify
a) proximal suspensory desmitis (3 marks)
b) hock osteochondrosis (3 marks)
c) a fractured calcaneus (4 marks)?
Psd- proximal metatarsus lateromedial, dorsoplantar, dlpmo dmplo.
Hock OCD- tarsus lateromedial, dorsoplantar, dlpmo, dmplo.
Fractured calcaneus- tarsus lm, dp, dmplo, dlpmo, skyline
You are presented with a 2 year old Thoroughbred colt that has hind-limb ataxia. List your differential diagnoses (5 marks) and the diagnostic approach to this case (5 marks).
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You are presented with a 2 year old Thoroughbred colt that has hind-limb ataxia. List your differential diagnoses (5 marks) and the diagnostic approach to this case (5 marks).
compression of spinal cord
-cervical vertebral malformation (wobblers)
muscle weakness
- emaciation/atrophy
- grass sickness
vestibular disease
- EHV-1
- trauma induced fractures
- temporohyoid osteodystrophy
- otitis media/interna
- cerebella abiotrophy (unlikely outside of arabs)
- ryegrass staggers (if on appropriate pasture)
if history of being outside UK
- equine protozoal myleopathy
- west nile virus
History- it is important to know vaccination history, exposure to other horses, sudden onset? progressive? other problems?
Clinical signs
-general clinical exam, concurrent respiratory disease, grade ataxia, hypermetria, mild forelimb signs?, blindfold for vestibular disease, external ear discomfort?
Radiographs of neck and skull, consider myelography, head CT/mri
- Described the clinical signs and diagnosis of a suspected pedal bone fracture. (12)
History- recent trauma, flat footed TB, sudden onset lameness. Any type of horse, not necessarily associated with competition, horses that kick the door also susceptible.
Clinical exam and gait evaluation- general clinical exam (expect good health)
- view from afar assss stance, weight bearing
- Pedal bone fractures can present with variable amounts of lameness depending on their conformation. It can vary from non weightbearing (5/5) lameness to a more mild lameness of the single limb.
- There may be raised digital pulses implying increased blood flow in the hoof.
- there may be pain on hoof testers
- It is unlikely that there would be any abnormal soft tissue swelling of the limb.
Diagnostic local analesia- may block fully or partially to a palmar digital nerve block (covering all except the proximal thord of the hoof), though an abaxial sesamoid block may be needed for full resolution.
Radiography is indicated- lm, standing dp, dmplo, dlpmo, place into block for a dorso-proximal, palmar distal oblique (approx 60 degrees downward- sole parallel to plate), with oblique views taken as visualization of the fracture can be difficult.
If fracture suspected and not seen on radiography, MRI is appropriate.
Classification affects prognosis- non articluar wing parasaggital saggital extensor process comminuted solar rim
- Make brief notes on the diagnosis and treatment of superficial digital tendonitis in the adult horse. (12)
Diagnosis- history (sudden onset lameness, can vary in severity, worse after exercise, likely in an athletic horse, prior history, recent competition, already attempted management).
Clinical exam, visually assess from afar, clinical examination, palpate limb for heat, swelling, pain (compare to contralateral limb), “bowed tendon”.
Do not trot up/nerve block if see clinical evidence of possible lesion- may rupture and lameness doesn’t correlate with pathology.
Ultrasonography most commony used diagnostic technique. See enlargement, hypoechoic lesion in centre of cord, later see fibre formation in a haphazard manner, peritendonous oedema acutely.
Longitudinal tears very important clinically but rarely seen on ultrasound- can be diagnosed on tenoscopy (risk associated with GA and infection but allows possible aids to treatment)
Scintigraphy theoretically possible, as is MRI but unnecessary in most cases.
Phases of wound healing- inflammatory, proliferative, remodelling. The horse must be box rested until in the remodelling stage- 2-3 months.
Ice can be useful (or a game ready machine) in the first 48-72 hours with compression ideally.
Can then continue to cold hose the limb regularly but care of skin- dry throuroughly
Systemic NSAID (bute)
massage limb to improve lymphatic drainage, bandage can also be used to reduce oedema but only if good technique!
topical diclofenac (volterol) is licensed in the states, can be used off license as pain relief and antiinflammatory
topical DMSO possible free radical scavenger and antiinflammatory
intralesional IRAP (Il1 B receptor anatagonist protein) can be used in the acute phase to reduce swelling
repeat ultrasounds should be used to assess healing. Once in the remodelling phase (speckly lesion) can consider biologics (PRP, stem cells, PSGAGs- only IM)
slowly build up exercise, using ultrasound to assess lesion before every step up
other options for more intensive treatment include rigid external coaptation using a cast for 2 weeks (high associated morbidity) and tenoscopy to debride and clean lesion with associated desmotomys as appropriate.
- Described the clinical signs and diagnosis of a suspected pedal bone fracture. (12)
History- recent trauma, flat footed TB, sudden onset lameness. Any type of horse, not necessarily associated with competition, horses that kick the door also susceptible.
Clinical exam and gait evaluation- general clinical exam (expect good health)
- view from afar assss stance, weight bearing
- Pedal bone fractures can present with variable amounts of lameness depending on their conformation. It can vary from non weightbearing (5/5) lameness to a more mild lameness of the single limb.
- There may be raised digital pulses implying increased blood flow in the hoof.
- there may be pain on hoof testers
- It is unlikely that there would be any abnormal soft tissue swelling of the limb.
Diagnostic local analesia- may block fully or partially to a palmar digital nerve block (covering all except the proximal thord of the hoof), though an abaxial sesamoid block may be needed for full resolution.
Radiography is indicated- lm, standing dp, dmplo, dlpmo, place into block for a dorso-proximal, palmar distal oblique (approx 60 degrees downward- sole parallel to plate), with oblique views taken as visualization of the fracture can be difficult.
If fracture suspected and not seen on radiography, MRI is appropriate.
Classification affects prognosis- non articluar wing parasaggital saggital extensor process comminuted solar rim
- List 5 views that are routinely obtained of the carpus and, for each view, describe which anatomical feature(s) they highlight. (12)
lateromedial- the antibrachiocarpal, middle carpal and carpo-metcarpal joints are highlighted and can be assessed, the dorsal aspect of the intermediate carpal and third carpal, the distal radial transverse ridge, and the accessory carpal bone
dorsopalmar- the individual carpal bones
dmplo- lateral dorsal aspect of radius and mc3, medial palmar, accessory highlighted
dlpmo- medial dorsal, lateral palmar
flexed lateral- highlight the antibrachiocarpal and middle carpal joints, distal radius highlights the radial facets, intermediate facet and ulnar facet
skyline (dpddo) - can be used to highlight the distal radius, proximal carpals and distal carpals depending on angle used
- Write brief notes on the treatment of osteoarthritis of the distal intertarsal and tarsometatarsal joints of the hock (‘bone spavin’). (12)
Many options available as they are low motion joints and so fusion is a possibility.
Early
- rest and NSAIDs- only if acute as chronic cases do better with gentle exercise
- neutroceuticals- chondroitin and glucosamine
- corrective farriery (correct imbalances, ease breakover by raised heels and squared off toe, lateral extensions)
- joint medication using corticosteroids (risk of systemic leakage and laminitis in some animals)
- joint hyaluronic acid (more expensive but good in combination of corticosteroids, larger molecules etter but more expensive, stimulates synovial fluid secretion, biological lubricant)
- IRAP, expensive but not deleterious, possibly a waste in this joint, better if need to retain function
- PSGAGs IM can help as antiinflammatory
- cartrofen is possible systemically as antiinflammatory and promote cartilage repair
Promote ankylosis to reduce pain
- oral NSAIDs and work until joint ankylosis
- intra articular medication as above and work
- chemical- 70% ethanol as toxic to chondrocytes, synoviocytes and nerves (rapid improvement in pain), must use contrast radiography first as some horses have a communication between DIT and PIT.
- surgical- cunean tenotomy from cranial tibial muscle to relieve pressure nad pain associated with cunean bursa.
- neurectomy of the deep peroneal and partial tibial nerves is unpredictable with a poor success rate.
- surgical ankylosis- hock drilling to remove cartilage or laser ankylosis to heat cartiliage, doesnt add much to hock drilling.
- Describe the management of a) contracture of the distal interphalangeal joint in a 12 week old foal and b) an angular limb deformity arising from the distal radius in a 4 week old foal. (12)
A contracture can be of either the SDFT, DDFT or both to cause a club foot. In a foal it is more likely to be a contacture of the DDFT.
- Need to assess severity (Stashak grade), looking at angle between toe and ground. Can also look at the flexibility of the joint capsule (worse prognosis if doesnt flex when extra weight applied)
- Surgical- for severe contractures a tenotomy of the contracted tendon can be performed but the horse will remain lame and no chance at an athletic career.
- For milder contractions a desmotomy of the accessory ligament associated (superior/inferior check) can be performed to increase the functional length of the muscuol-tendon unit. This provides a better chance at a return to function.
- Hoof trimming- aim to drop the heel, so remove 2-3mm of toe everytime the heel contacts the ground.
- Therapeutic shoeing or reconstruction with acrylics has the same aim, to drop the heel, can be used for toe reconstruction and to add extensions onto the toe to increase pressure on the DDFT, or with extra heel that can be gradually lowered.
Angular limb deformity
- controlled exercise (it is likely to grown out- conservative management appropriate up to 2-3 months)
- corrective trimming
- shoeing to add a lateral extension on the correct side to alter the weight bearing axis
- casts can be applied if collateral ligament instability is suspected
- periosteal stripping is possible at this age but becomes less effective after 4 months
- transphyseal bridging approriate possibly in combination of physeal stripping, but surgery possibly unnecessary at this age
- wedge osteotomy unnecessary as growth plates open until 21 months
- Write brief notes on the treatment of osteoarthritis of the distal intertarsal and tarsometatarsal joints of the hock (‘bone spavin’). (12)
Many options available as they are low motion joints and so fusion is a possibility.
Early
- rest and NSAIDs- only if acute as chronic cases do better with gentle exercise
- corrective farriery (correct imbalances, ease breakover by raised heels and squared off toe, lateral extensions)
- joint medication using corticosteroids (risk of systemic leakage and laminitis in some animals)
- joint hyaluronic acid (more expensive but good in combination of corticosteroids, larger molecules etter but more expensive, stimulates synovial fluid secretion, biological lubricant)
- IRAP, expensive but not deleterious, possibly a waste in this joint, better if need to retain function
- PSGAGs IM can help as antiinflammatory
- cartrofen is possible systemically as antiinflammatory and promote cartilage repair
Promote ankylosis to reduce pain
- oral NSAIDs and work until joint ankylosis
- intra articular medication as above and work
- chemical- 70% ethanol as toxic to chondrocytes, synoviocytes and nerves (rapid improvement in pain), must use contrast radiography first as some horses have a communication between DIT and PIT.
- surgical- cunean tenotomy from cranial tibial muscle to relieve pressure nad pain associated with cunean bursa.
- neurectomy of the deep peroneal and partial tibial nerves is unpredictable with a poor success rate.
- surgical ankylosis- hock drilling to remove cartilage or laser ankylosis to heat cartiliage, doesnt add much to hock drilling.
- Osteoarthritis is a common diagnosis in equine practice and is often treated with intra-articular medication. List the most commonly used intra-articular medications used and outline their mechanism of action. (12)
- corticosteroids- antiinflammatory by acting on glucocorticoid receptors to alter gene transcription
- hyaluronic acid- biological lubricant, stimulates synovial fluid production, quality affects effect
- IRAP- interleukin 1 receptor antagonist protein- antinflammatory
- Platelet rich plasma- aids remodelling, less useful in joints, increases wbc, no evidence.
- stem cells- aid healling and remodelling, no evidence but less marked inflammation than PRP
- ethanol 70%- only in low mobility joints to promote ankylosis and reduce pain, toxic to chondrocytes, synoviocytes and nerves.
- local anaesthetic- diagnostic test to provide analgesia acting on the sodium channels of the nerves to block them
- Describe the management of a) contracture of the distal interphalangeal joint in a 12 week old foal and b) an angular limb deformity arising from the distal radius in a 4 week old foal. (12)
A contracture can be of either the SDFT, DDFT or both to cause a club foot. In a foal it is more likely to be a contacture of the DDFT.
- Need to assess severity (Stashak grade), looking at angle between toe and ground. Can also look at the flexibility of the joint capsule (worse prognosis if doesnt flex when extra weight applied)
- Surgical- for severe contractures a tenotomy of the contracted tendon can be performed but the horse will remain lame and no chance at an athletic career.
- For milder contractions a desmotomy of the accessory ligament associated (superior/inferior check) can be performed to increase the functional length of the muscuol-tendon unit. This provides a better chance at a return to function.
- Hoof trimming- aim to drop the heel, so remove 2-3mm of toe everytime the heel contacts the ground.
- Therapeutic shoeing or reconstruction with acrylics has the same aim, to drop the heel, can be used for toe reconstruction and to add extensions onto the toe to increase pressure on the DDFT, or with extra heel that can be gradually lowered.
Angular limb deformity
- controlled exercise (it is likely to grown out- conservative management appropriate up to 2-3 months)
- corrective trimming
- shoeing to add a lateral extension on the correct side to alter the weight bearing axis
- casts can be applied if collateral ligament instability is suspected
- periosteal stripping is possible at this age but becomes less effective after 4 months
- transphyseal bridging approriate possibly in combination of physeal stripping, but surgery possibly unnecessary at this age
- wedge osteotomy unnecessary as growth plates open until 21 months
- Describe your approach to the diagnosis of a horse with suspected hindlimb proximal suspensory desmitis. (12)
History- more likely in a horse doing a lot of athletic work, often insidious inset and bilateral (owner may not realise horse is lame, association with straight hocks)
General clinical exam- systemically healthy
Specific clinical exam- horse may be painful on palpation of the suspensory ligament just distal to the tarsus and resist. Heat and swelling are rarely felt as this is a chronic injury and deep to palpate.
Gait evaluation- walk and trot the horse in straight lines- expect a mild/moderate, often bilateral, hindlimb lameness. Would expect a negative flexion test result unless associated DJD of DIT, TMT. Working the horse on the lunge normally highlights the lamness and anecdotally suspensory injuries can appear worse on soft surfaces and when the more affected limb is on the inside.
Diagnostic local analgesia. Negative responses up to and including the low 6 point block, may see a mild worsening of lameness as hoof proprioception and compensation lost. Expect positive result to sub tarsal block but may only be partial if concurrent DJD of TMT/DIT. Should block the TMT separately after the blocks have worn off to compare improvement.
Ultrasonography- Commonly see swelling of the proximal suspensory and altered fibre pattern. Important to compare both sides.
Radiography- can see the attachment of the suspensory in the proximal metatarsus on x ray and may see osteophyte formation and scleosis.
May see positives on MRI and scintigraphy
- DESCRIBE the clinical signs of annular ligament desmitis in the horse (5 marks) and BRIEFLY OUTLINE the treatment recommended for this condition (5 marks).
- causes restriction within the fetlock tunnel and irritation of the SDFT especially.
- persistant mild/moderate lameness
- notched appearence to palmar/plantar fetlock pathognomic
- swelling of palmar/plantar fetlock
- may be able to palpate a thickened annular ligament
- diagnostic local analgesia, ultrasound, MRI
- surgery to perform an annular ligament desmotomy is effective as it releases the tension on the structures of the DFTS. Done via tenoscopy and curved scalpel blade incises the ligament longitudinally. Can start gentle walking exercise as soon as incisions well closed to prevent adhesion formation. Intrasynovial HA improves function via lubrication. Good prognosis unless adhesions, sepsis or tendonitis concurrently
- conservative box rest and NSAID less rewarding than surgery
- Describe your approach to the diagnosis of a horse with suspected hindlimb proximal suspensory desmitis. (12)
History- more likely in a horse doing a lot of athletic work, often insidious inset and bilateral (owner may not realise horse is lame)
General clinical exam- systemically healthy
Specific clinical exam- horse may be painful on palpation of the suspensory ligament just distal to the tarsus and resist. Heat and swelling are rarely felt as this is a chronic injury and deep to palpate.
Gait evaluation- walk and trot the horse in straight lines- expect a mild/moderate, often bilateral, hindlimb lameness. Would expect a negative flexion test result unless associated DJD of DIT, TMT. Working the horse on the lunge normally highlights the lamness and anecdotally suspensory injuries can appear worse on soft surfaces and when the more affected limb is on the inside.
Diagnostic local analgesia. Negative responses up to and including the low 6 point block, may see a mild worsening of lameness as hoof proprioception and compensation lost. Expect positive result to sub tarsal block but may only be partial if concurrent DJD of TMT/DIT. Should block the TMT separately after the blocks have worn off to compare improvement.
Ultrasonography- Commonly see swelling of the proximal suspensory and altered fibre pattern. Important to compare both sides.
Radiography- can see the attachment of the suspensory in the proximal metatarsus on x ray and may see osteophyte formation.
May see positives on MRI and scintigraphy
- You are called to a horse in a field that has a wound over the palmar aspect of the fetlock joint and which is lame. Briefly describe your approach to such a case, your differential diagnoses and the first aid measures you would apply. (30).
Assess the tetanus vaccination of the horse. If any doubt provide tetanus antitoxin and tetanus toxoid vaccine at opposite ends of the horse.
The horse needs to stand still to be examined- it needs adequate restraint (headcollar) and should be moved from the field if possible to a mud free area on hard standing for cleaning and assessment. If necessary, sedation can be used to allow a full examination.
The horse should be watched moving at walk to see if it is very lame as expected with a synovial sepsis (5/5) and visual examination from afar should give an indication of weight bearing. The horse could have synovial sepsis and still be relatively sound if the joint capsule remains open and the excess fluid can drain.
A history from the owner is necessary to see if they know when the injury is likely to have occurred and the likely degree of contamination
A general clinical exam should be performed to assess degree of pain and systemic infection.
A close visual examination of the affected limb to assess the presence of synovial fluid, swelling and contamination. The position of the wound can indicate some of the structures likely to be involved
- fetlock joint
-DFTS
-DDFT
-SDFT
-annular ligament
-suspensory (and possibly lateral branches)
-metacarpal 3
-manica flexoria
-distal sesamoidian ligaments
-sesamoid bones
-p1
The wound should be flushed thoroughly ideally using saline, but tap water would be adequate to start with. High volumes are needed and pressure created by using a needle can be handy.
Once visibly clean, digital palpation using a clean hand and sterile gloves is appropriate to try and assess the depth of the wound. The main differential diagnosis of concern is that of synovial sepsis- if the tendons are visible on palpation or there is yellow synovial fluid the horse should be referred for arthroscopy/tenoscopy.
After digital palpation a sterile probe could be used if there are any areas of concern.
Sterile arthrocentesis of the fetlock joint and digital flexor tendon sheath can be performed for cytology (more useful) and culture (rarely gives results) if necessary and the joint can then be distended with saline to see evidence of communication with the wound.
DDX- sesamoidian fracture, synovial sepsis of fetlock of DFTS, trauma to tendons/ligaments, fracture of mc3/p1, flesh wound
Once satisfied the wound doesnt communicate with a synovial structure, the wound can be cleaned superficially using chlorhexidine and bandaged with a honey or silver dressing. If synovial sepsis is suspected a joint flush is required (or IVRA, intrajoint abs). The horse should be provided with broad spectrum antibiosis (IV then an oral course) and pain relief (NSAID)
- Osteoarthritis is a common diagnosis in equine practice and is often treated with intra-articular medication. List the most commonly used intra-articular medications used and outline their mechanism of action. (12)
- corticosteroids- antiinflammatory by acting on glucocorticoid receptors to alter gene transcription
- hyaluronic acid- biological lubricant, stimulates synovial fluid production, quality affects effect
- IRAP- interleukin 1 receptor antagonist protein- antinflammatory
- Platelet rich plasma- aids remodelling, less useful in joints, increases wbc, no evidence.
- stem cells- aid healling and remodelling, no evidence but less marked inflammation than PRP
- ethanol 70%- only in low mobility joints to promote ankylosis and reduce pain, toxic to chondrocytes, synoviocytes and nerves.
- DISCUSS the management (6 marks) and surgical approach (4 marks) to the treatment of carpal valgal angular limb deformities in foals. (10 marks).
Management
often self corrects in young foals as weight bearing forces control remodelling. In premature foals, ossification of the carpal bones may not be complete and thus the foal should be encouraged not to weight bear until they have ossified.
-controlled exercise
-corrective trimming- gradually rasping down the lateral aspect of the hoof sole by a few mms to alter weight bearing axis
-shoeing to add a lateral extension on the medial side to alter the weight bearing axis
-casts can be applied if collateral ligament instability is suspected
Surgical
- periosteal stripping is possible at this age but becomes less effective after 4 months
- transphyseal bridging approriate possibly in combination of physeal stripping, but surgery possibly unnecessary at this age
- wedge osteotomy unnecessary as growth plates open until 21 months
- DESCRIBE the aetiopathogenesis of stress fractures in horses (6 marks) and LIST 4 sites at which stress fractures occur in the horse (4 marks).
Occur in young athletic animals. Recurrent percussive force from repeated submaximal loading causes microscopic damage to the bone causing pericortical remodelling which weakens the bone and allows stress fractures as they do not have time to heal. Stress fractures predispose to complete fracture of the bone.
Proximal phalynx, metacarpal, metatarsal, humerus, scapula, tibia, pelvis and vertebrae
- LIST 5 treatment options for superficial digital flexor tendinitis in an Event horse and briefly explain the mechanism of action of each treatment. (10 marks).
Conservative- aims to reduce inflammation, prevent further damage and relatively immobilise to aid healing
Phases of wound healing- inflammatory, proliferative, remodelling. The horse must be box rested until in the remodelling stage- 2-3 months.
Ice can be useful (or a game ready machine) in the first 48-72 hours with compression ideally.
Can then continue to cold hose the limb regularly but care of skin- dry throuroughly
Systemic NSAID (bute)
massage limb to improve lymphatic drainage, bandage can also be used to reduce oedema but only if good technique!
topical diclofenac (volterol) is licensed in the states, can be used off license as pain relief and antiinflammatory
topical DMSO possible free radical scavenger and
anti-inflammatory biologics intralesional IRAP (Il1 B receptor anatagonist protein) can be used in the acute phase to reduce swelling
Once in the remodelling phase (speckly lesion) can consider biologics
- PRP- platelets and growth factors intended to help in healing and remodelling phase
- stem cells- thought to be stimulated to become tenocytes and aid healing
- PSGAGs- IM only or causes aseptic flare, anti-inflammatory
rigid external coaptation using a cast for 2 weeks (high associated morbidity) but immobilisation improves healing as it allows proliferation and reduces any further damage
tenoscopy- to debride and clean lesion with associated desmotomys as appropriate. allows uninterrupted healing, could combine with biologics. GA risk
- DESCRIBE the clinical signs of annular ligament desmitis in the horse (5 marks) and BRIEFLY OUTLINE the treatment recommended for this condition (5 marks).
- causes restriction within the fetlock tunnel and irritation of the SDFT especially.
- persistant mild/moderate lameness
- notched appearence to palmar/plantar fetlock pathognomic
- swelling of palmar/plantar fetlock
- may be able to palpate a thickened annular ligament
- diagnostic local analgesia, ultrasound, MRI
- surgery to perform an annular ligament desmotomy is effective as it releases the tension on the structures of the DFTS. Done via tenoscopy and curved scalpel blade incises the ligament longitudinally. Can start gentle walking exercise as soon as incisions well closed to prevent adhesion formation. Intrasynovial HA improves function via lubrication. Good prognosis unless adhesions, sepsis or tendonitis concurrently
- conservative box rest and NSAID less rewarding than surgery
- DESCRIBE how you would diagnose a fractured pedal bone in the horse (5 marks) and LIST the different types of recognised pedal bone fractures in the horse (5 marks).
History- recent trauma, flat footed TB, sudden onset lameness. Any type of horse, not necessarily associated with competition, horses that kick the door also susceptible.
Clinical exam and gait evaluation- general clinical exam (expect good health)
- view from afar assss stance, weight bearing
- Pedal bone fractures can present with variable amounts of lameness depending on their conformation. It can vary from non weightbearing (5/5) lameness to a more mild lameness of the single limb.
- There may be raised digital pulses implying increased blood flow in the hoof.
- there may be pain on hoof testers
- It is unlikely that there would be any abnormal soft tissue swelling of the limb.
Diagnostic local analesia- may block fully or partially to a palmar digital nerve block (covering all except the proximal thord of the hoof), though an abaxial sesamoid block may be needed for full resolution.
Radiography is indicated- lm, standing dp, dmplo, dlpmo, place into block for a dorso-proximal, palmar distal oblique (approx 60 degrees downward- sole parallel to plate), with oblique views taken as visualization of the fracture can be difficult.
If fracture suspected and not seen on radiography, MRI is appropriate.
Classification affects prognosis- non articluar wing parasaggital saggital extensor process comminuted solar rim
- DESCRIBE the clinical signs of annular ligament desmitis in the horse (5 marks) and BRIEFLY OUTLINE the treatment recommended for this condition (5 marks).
- causes restriction within the fetlock tunnel and irritation of the SDFT especially.
- persistant mild/moderate lameness
- notched appearence to palmar/plantar fetlock pathognomic
- swelling of palmar/plantar fetlock
- may be able to palpate a thickened annular ligament
- diagnostic local analgesia, ultrasound, MRI
- surgery to perform an annular ligament desmotomy is effective as it releases the tension on the structures of the DFTS. Done via tenoscopy and curved scalpel blade incises the ligament longitudinally. Can start gentle walking exercise as soon as incisions well closed to prevent adhesion formation. Intrasynovial HA improves function via lubrication. Good prognosis unless adhesions, sepsis or tendonitis concurrently
- conservative box rest and NSAID less rewarding than surgery
