Equine Hind limb Flashcards
What are some of the main causes of hindlimb lameness?
- Hock and stifle are most common causes of hindlimb lameness.
- Cellulitis, lymphangitis, splints
- Degenerative joint disease of the small tarsal joints
- Meniscal disease of the stifle
- Subchondral bone cysts of the stifle
- Osteochondrosis of the stifle and hock
- Proximal suspensory desmitis
- Fetlock and pastern joint disease
What are some critical conditions that cna cause hindlimb lameness?
Critical conditions:
- Joint infections (hock is very common site of synovial sepsis)
- Fractures (identify stress fracture sites from Year 1 lecture)
- Tendon ruptures (gastrocnemius and peroneus tertius rupture, SDFT luxation)
- Luxations (fetlock, hock, patella, hip)
What is the innervation of the hindlimb?
- Sciatic nerve (L6-S2)
- Branching into tibial and peroneal nerves
- Tibial nerve – supplies:
- Extensors of hock and flexors of digit
- Skin on caudomedial aspect of limb and plantar aspect of foot (+ dorsal aspect in horse)
- Peronal nerve – supplies:
- Flexors of hock and extensors of digit
- Skin on craniolateral aspect of limb and dorsal aspect of foot (not in horse)
Name the nerves in this picture of the innervation of the digit and the hoof of the hindlimb
Black, green and pink
Black: superficial peroneal nerve
Green: Deep peroneal nerve
pink: Branches of tibial nerve
Which nerve block is important in helping to diagnose proximal suspensory desmitis?
Where is it done?
High plantar nerve block: important to help diagnose proximal suspensory desmitis
Usually done with leg lifted, site is just distal to the tarsometarsal joint, axial to the 4th metatarsal bone, needle inserted to hit Metatarsal III, using a volume of 5-10ml
When is radiography a first line diagnostic for the hindlimb?
Radiography
- First line of diagnostics in
- Suspected fracture
- Suspected bone lesions
- Joint pain
- Usually first line of diagnostics after nerve blocks
- Standard views:
What is ultrasonography a first line diagnostic for?
Ultrasonography
- First line of diagnostics for suspected soft tissue lesions (e.g. tendonitis, bursal swellings)
- don’t block or trot suspected tendonitis
What should you NOT do with suspected tendonitis?
Do not block or trot with suspected tendonitis
What is gamma scintigraphy a first line diagnostic for?
First line diagnostics in suspected fractures – don’t block these cases
What is arthrocentesis a first line diagnostic for?
Suspected joint sepsis
When is MRI used?
For some difficult soft tissue injuries e.g. proximal suspensory desmitis
When is CT used for the hind limb?
Complicated fracture/bone lesions
What are the main causes of hindlimb lameness?
- Cellulitis / lymphangitis
- Degenerative joint disease of the small tarsal joints
- Meniscal disease of the stifle
- Subchondral bone cysts of the stifle
- Osteochondrosis of the stifle and hock
- Proximal suspensory desmitis
- Synovial sepsis
- Fractures
- Luxations
- Tendon ruptures
Label tarsal joints?
Tarsometatarsal and distal intertarsal usually affected –Proximal intertarsal can be affected by DJD.
What is a spavin?
Degenerative joint disease of the small tarsal joints ‘spavin’
Discuss DJD of the small tarsal joints (Spavin)?
- Lameness can be unilateral or bilateral
- Bilateral lameness can present as stiffness or gait problems (esp in canter)
- Degree of lameness can be mild or severe –Often have pain on flexion (difficult to shoe)
How is a spavin diagnose?
Diagnosis of spavin
Intra-articular anaesthesia
- TMT sometimes communicates with DIT (block seperately)
- PIT communicates with tarsocrural joint
Perineural anaesthesia
- Tibial and peroneal nerve block (images from In Practice articles by S Dyson)
How should radiography be done for the hock?
Technique: Lateromedial and DP
Describe technique for radiography of the hock?
Technique: D45 o LPM and P45 o LDM obliques
What are the radiographic changes seen in DJD (Spavin)?
Radiographic signs of joint disease
- Narrowing of joint space
- Peri-articular osteophyte formation
- Subchondral bone sclerosis –bone re model (white)
- Subchondral bone lucency (can look like lytic, destructive disease) –eroded down (black)
Severity of radiographic signs may not relate to severity of lameness
- Can see horses with radiographic signs and no clinical signs
- Need diagnostic anaesthesia to confirm diagnosis
Describe the radiographic changes seen in this image?
- DLPMO view
- Loss of distal intertarsal joint space
- lysis and sclerosis on dorsal aspect of DIT joint
- Light blue =Tarso crural joint
- Lost joint space DIJ
- Dark blue= Looks lytic –OA
Describe this radiograph?
- DMPLO
- Lytic and sclerotic changes, and osteophyte formation between 2 nd metatarsal and 2 nd tarsal bones
- Osteophyte formation dorsal aspect of TMT (light blue) and DIT
- Lysis
- Scleoris
- Remodelling
- Osteophyte on the dorsal aspect of tarso-metotarsal
Describe these radiographic images?
- LM and DMPLO
- New bone bridging dorsal aspect of distal intertarsal joint
- Not a good radiograph –angled
What is the treatment for a bone spavin?
Treatment of spavin:
No radiographic changes:
- intra-articular medication
Once radiographic changes present, joints will continue to degenerate
Options:
- Pain relief and work horse
- Arthrodese joint (low motion joint so can fuse)
DO NOT REST THESE HORSES
Discuss treatment of the spavin?
1. Pain relief
- Intra-articular steroids (lasts 1-3 months)
- Systemic NSAIDs
2. Arthrodese joint
- Chemical arthrodesis
- 60-80% sound long term with MIA or ethanol 1,2 (case selection and contrast studies essential)
- Surgical arthrodesis (60-80% sound long term)
- Requires up to 12 months
Common causes of tarsal lameness?
Tarsal lameness
- OCD common site
- Synovitis of tarsocrural joint
- OA of tarsocrural joint (high motion joint -> poor prognosis)
- Intra-articular fragments
- Luxations and collateral ligament injuries
- Remember sepsis of this joint secondary to kick wounds / trauma is common
Discuss synovial sepsis?
Synovial sepsis
- Tarsocrural joint common site
- Small tarsal joints can be affected
- Difficult to flush
- Treated by use of intra-articular antibiotics impregnated beads
- Don’t forget other synovial structures:
- Tarsal sheath
- Calcaneal bursa
Label the joints and bursa of the tarsus?
What are the main causes of stifle lameness?
- DJD
- OCD
- Bone cysts
- Fractures
- Joint effusion
- Septic arthritis
- Meniscal injuries
- Cruciate injuries
- Collateral ligament injuries
- Patellar ligament injuries
Clinical signs of stifle lameness?
- Proximal limb lameness tend to exacerbated by soft ground
- Can show abduction (trying to avoid flexion of the joint)
- Reduced range of movement
- Pain on flexion
- Remember reciprocal apparatus means hock and stifle flex together, so flexion tests cannot distinguish between hock and stifle, and many of the signs of lameness are the same
- cant separate the joints out like you can in the FL
What has happened here?
Shouldn’t be able to flex stifle and the hock be extended.
Damage to perineal tersius muscle (runsdown over front of stifle (over hock))
When it is rupturede you can flex the stifle and extend hock.
What are the clinical signs of stifle lameness?
Clinical signs of stifle lameness
- Joint effusion
- Pain on palpation (e.g. Meniscus)
- Crepitus from fractures (patella, tibial crest)
Label this!!!!
The femoropatellar joint usually communicates with?
- Medial femorotibial joint, and communicates with the lateral femorotibial joint in 20-25% horses
- The femorotibial joints do not communicate
- Need to block all 3 joints separately
How can you localise site of hock pain?
Localising site of pain
- Intra-articular anaesthesia
- Need to block each individual joint
- No peri-neural anaesthesia
Summarise stifle injuries?
- 50% of stifle lameness are due to soft tissue injuries
- Medial meniscal injuries most common
- +/-radiographic changes
- Medial femorotibial +/-femoropatella effusion
- Other associated injuries –medial collateral ligament, cranial cruciate and cartilage lesions
- Once you have radiograph changes –irreversible joint disease in high motion joint and so intra articular injections are no good –want to just control pain
What is the diagnostic approach to stifle lameness in terms of radiography?
- Remember many are soft tissue injuries
- Radiographic signs of DJD associated with poor prognosis for return to athletic function
- Bony lesion- OCD, subchondral bone cysts, DJD, fractures
Discuss diagnostic approach to stifle lameness with regards to ultrasonography
- Good diagnostic tool for soft tissue injuries
- High incidence of soft tissue injuries means that most cases warrant an ultrasound exam
- Can evaluate lateral and medial meniscus, collateral ligaments, patella ligaments, and components of cruciate ligament
- Horse stifle IS TOO BIG TO MRI
Discuss these 2 meniscal ultrasounds?
Normal – should be flush with or just under the bone and homogeneous.
On the right pic; black is shadows and the meniscus itself is fine.
Discuss these 2 meniscal ultrasounds?
Meniscal injury
Margins irregular. Changes in echogenicty
Look at: size, shape and echogenicity
What can be seen here?
Medial meniscal injury
What can be seen here?
lateral femoral condyle erosion
Describe diagnostic approach to stifle lameness with regards to arthroscopy?
- Good diagnostic tool to evaluate soft tissues and cartilage
- Diagnosis and treatment can be combined
Disadvantage: Cost and requirement for general anaesthesia
Allows for a full evaluation –owner needs to be aware this wont cure them
Note –menisci and cruciate ligaments cannot be completely evaluated by either ultrasonography or arthroscopy
What are treatments for meniscal injuries?
Treatment options:
- Rest and NSAIDs
- Arthroscopic debridement
Discuss prognosis of meniscal injury treatment?
- Prognosis 50-60%
- Arthroscopy useful as a diagnostic and prognostic tool
- Presence of radiographic changes -> poor prognosis
- Degree of lameness reflects prognosis
- Older horses have poorer prognosis
Discuss cruciate injuries?
- Cruciate injuries
- Predominantly cranial cruciate
- Associated pathology –menisci, collateral ligs and articular cartilage
- Arthroscopy as a diagnostic and surgical tool
- Prognosis –depends on severity and presence of radiographic changes
What can be seen here?
Lateral meniscus and cranial cruciate damage. Haemhorrage and tearing in meniscus –as it was so young was euthanised
How are collateral ligaments and patella ligament injuries usually damaged?
Collateral ligament injuries
- Predominantly medial collateral
- Look for other pathology
Patellar ligament injuries
- Uncommon
- Seen in jumping horses
- Patella fractures or pathology
What can be seen here?
Patella ligament disease seen 3 day eventer with lateral patella ligament pathology
Ultrasound – change in echogenicity
Discuss subchondral bone cysts?
Subchondral bone cysts
- Aetiology unclear
- may be developmental, but some may also be traumatic in origin
- Have been induced experimentally by creating damage in predilection site
- Mainly seen on medial femoral condyle
- Diagnosed on radiography
What are the treatment and outcomes for subchondral bone cysts?
Treatment and outcomes
Surgical debridement of cyst
Arthroscopic injection of steroid into cyst cavity
Prognosis approx 60% sound
Older horses have worse prognosis
- 0-3 year olds prognosis 64%
- > 3 year olds prognosis 34%**
Radiographic changes of DJD have worse prognosis
