Foal/Juvenile Lameness Flashcards
Distal radius growth plate closure times
24 months
Distal metacarpal growth plate closure time
6-9 months
Proximal phalanx growth plate closure time
6-12 months
Distal tibia growth plate closure time
17-24 months
Distal tibia growth plate closure time
9-12 months
Inflammation of the physis or growth complex at the end of a long bone
Physitis
Is physis active in young or old animals?
Young
When can physitis occur?
Until closure of growth plates
When does long bone growth occur?
Most of the long bone growth happens when the foals are resting rather than loadbearing
Until what age is the growth phase of the distal metacarpus?
4 months
Until what age is the growth phase of the distal radius and distal tibia?
18-20 months
Clinical signs of physitis
Heat
Pain on palpation
Possibly lameness
Joints most commonly affected by physitis
Carpus
Fetlock
Triggers of physitis
Sudden increase in feed intake or feed energy
Abrupt increase in exercise regimen
Direct trauma to the physis
Yearling physitis (often distal radius)
Diagnosis of physitis
Radiograph (soft tissue swelling and remodelling)
Treatment of physitis
Exercise restriction
Pain relief
Correction of underlying cause (angular limb deformity)
Sepsis?
Does physitis always cause lameness?
No, but will be lame if septic
Which type of Salter-Harris fracture is most frequent in foals?
Type II
Treatment options for Salter Harris fracture
Cast coaptation (<6 weeks)
Surgical correction (image shows transphyseal bridge)
Where do Salter-Harris fractures occur in foals?
Distal physis of MCIII/MTIII
Does this carpus show normal or abnormal ossification in a foal?
Normal
Bones affected by incomplete ossification in foals
Cuboidal bones (carpi, tarsi)
When does ossification occur during gestation?
Last 2-3 months of gestation (premature or dysmature foals should be radiographed to assess ossification)
Is this ossification in a foal carpi normal or abnormal?
Abnormal (incomplete ossification)
Is this ossification in a foal carpi normal or abnormal?
Abnormal (incomplete ossification)
Is this ossification in a foal tarsi normal or abnormal?
Abnormal (incomplete ossification)
Is this ossification in a foal tarsi normal or abnormal?
Abnormal (incomplete ossification)
Management for incomplete ossification in foals
Box rest until bones completely developed
What is shown in this image?
Angular limb deformity of carpi (valgus)
What is shown in this image?
Flexural limb deformity
What condition is this?
Windswept foal (black arrow: varus, white arrow: valgus)
Causes of incomplete ossification
Dysmature foal
Premature foal
Placentitis during gestation
Mare colic during gestation or heavy parasite burden (uterine lack of blood supply)
Abnormal uterine positioning
Aetiologies of angular limb deformities
Incomplete ossification
Peri-articular laxity
Acquired or congenital
Evaluation of angular limb deformities
Static (stand perpendicular to frontal plane of limb, not foal)
Dynamic
Manipulation (peri-articular laxity)
Radiography (orthogonal views, both limbs)
Can you treat angular limb deformities when peri-articular laxity is present?
No, monitor for loss of laxity before doing any interventions
Conservative treatment of angular limb deformity when there is normal ossification and peri-articular laxity
Box rest and controlled exercise
Conservative treatment of angular limb deformity when there is incomplete ossification
Box rest
When is conservative treatment of angular limb deformity acceptable?
Entire limb facing one way
How should you trim/rasp the foot with carpal valgus?
Trim lateral hoof wall
How should you trim/rasp the hoof foot with fetlock varus
Medial hoof wall
Where should a glue on shoe extension be placed with a carpal valgus?
Medial extension
Where should a glue on shoe/extension be on a foal with fetlock varus?
Lateral
When is surgical treatment indicated for angular limb deformity?
No response to treatment
One joint facing in a different direction that the one above/below
Persistent ulna/fibula
Age
What condition is shown in this radiograph?
Persistent ulna (most commonly mini horses)
What age should surgical intervention be considered for angular limb deformity?
When growth has stopped/growth plates have closed
How does this surgical intervention manage an angular limb deformity?
Stop growth on the lateral side
At what age do horses suffer from juvenile osteochondral conditions
First 2 years of life
What are the 5 juvenile osteochondral conditions?
Ligament associated OCF
Peri-articular osteocondylar fragmentation/OCF (including OCD)
Subchondral bone cyst
Osteochondral collapse
Physitis
Clinical signs of juvenile osteochondral conditions
Often silent
Joint effusion?
Lameness?
Main focus in lameness examination when investigating juvenile osteochondral conditions
Reaction to flexion tests
Which joints in young horses are more commonly associated with lameness/higher levels of lameness?
Stifle and shoulder
Causes of osteochondrosis
Multifactorial
Focal failure of endochondral ossification (epiphyseal or metaphyseal growth cartilage)
Polygenetic heritable disease
Origin of osteochondral fragmentation in fetlock that is always caused by OCD
Sagittal ridge of MCIII/MTIII
Best view to look for fragmentation due to osteochondrosis dissecans in fetlock on sagittal ridge
Flexed
What is this radiograph showing?
Radiolucency is a fragment on sagital ridge or MCIII (always caused by OCD)
Fragments in the fetlock with an unclear origin (may be caused by/mistaken for OCD)
Palmar/plantar P1 fragment (arrow, usually avulsion fragmentation by distal and oblique sesamoid ligaments)
Dorsal margin of proximal P1 (trauma)
Types of fragmentation in fetlock joint and their common causes
Sagittal ridge (OCD)
Palmar/plantar P1 (avulsion, black circles)
Dorsal margin of proximal P1 (trauma, white circles)
Age dependent top differential of subchondral lucencies on radiograph
<2y, OCD
>2y, trauma-induced
Diagnosis of OCD
Lameness examination
4 orthogonal views (Fragments? Soft tissue swelling?)
Challenges with diagnosis of tarsus OCD
Many foals have lesions at 1 month then many heal by 1 year (healing potential better in distal aspect trochlear ridge)
(Few lesions originate/resolve after age of 5 months)
Challenges related to diagnosis of stifle OCD
Very dynamic process
2 treatment options (dependent on clinical signs)
Leave it
Remove (usually GA, occasionally standing sedation)
Considerations when making treatment recommendations
Intended purpose of horse (high speed = remove all)
Ownership (Future sale? Genomic breeding value?)
Finance, risks (GA) and prognosis
Typical treatment recommendation for loose fragments in joint
Removal
Typical treatment recommendation for osteochondrosis flattening in joint
Monitor and see
When does osceochondrosis become osteochondrosis dissecans?
When pathology progresses from flattening to osteochondral fragmentation
What does this radiograph show?
Palmar P1 defect, most likely due to cartilage so not visible on radiograph
Aetiology that could cause palmar P1 defect (controversial)
Osteochondrosis
Trauma
Aetiology of fragment of dorsoproximal P1 fragment in racehorses
Trauma from overextension of fetlock at high speed in racehorses
(Unclear in non racehorses)
Most common presenting complaint in osteochondral conditions
Joint effusion
What is 1 on this tarsus?
Distal intermediate ridge of tibia (DIRT lesion)
DMPLO view
What is 2 on this tarsus?
Lateral trochlear ridge of talus
DMPLO view
What is 3 on this tarsus?
Medial malleolous of the tibia (concern with OCD is intra-articular aspect)
Top 3 sites for hock OCD
Distal intermediate ridge of tibia (DIRT)
Lateral trochlear ridge of talus
Medial malleolus of the tibia (intra-articular aspect)
What is this site of osteochondrosis in the fetlock?
Sagittal ridge of distal metacarpal
Main site of OCD lesions in stifle joint
Lateral trochlear ridge of femur (lateral trochlear ridge is shorter than the medial trochlear ridge)
Which anatomical structure contains a cyst like structure on this radiograph?
Medial femoral condyle
What does this image show? (2 year old)
Effusion of femoropatellar joint
Fetlock radiograph views for OCD
DP
LM
+/- Flex lateral
DMPLO
DLPMO
Where is the fragment in this DMPLO view of the fetlock?
Palmaro/plantaromedial
Special view to look for palmar/plantar fragmentation in fetlock
Dorsal 30 proximal 70 lateral-palmarodistal medial oblique
View to look for tarsus fragmentation
DP* (dorsal 15 degree lateral-plantarmedial oblique)
LM
DMPLO* (5 degrees disto-proximal)
DLPMO
Stifle radiograph views to diagnose OCD
Lateromedial
Caudocranial
Caudo(60)lateral-craniomedial oblique
Which structure for OCD diagnosis is highlighted in the stifle caudocranial view?
Femoral condyles
Which structure for OCD diagnosis is highlighted in the stifle caudolateral-craniomedial view?
Femoral condyles
Lateral trochlear ridge
Conservative management options for osteochondrosis
Box rest/small paddock
Joint injection with corticosteroids
What condition might a horse suffer from if fragments are not removed in the tarsus and stifle?
Osteochondrosis
Clinical signs of subchondral cyst-like/SCL lesions
Lameness (more likely than in OCD)
Joint effusion
Positive response to flexion
Bone containing subchondral lucency in E
P2
Bone containing subchondral lucency in G
P1
Aetiologies of sub-chondral cyst like lesions
Osteochondrosis
Trauma to articular cartilage/subchondral bone
Most common sites of subchondral cyst-like lesions (there are many)
Medial femoral condyle
Phalanges
Metacarpus/metatarsus
Radius
Scapula
Tibia
Carpal bones
Cervical vertebrae
Most ‘telling’ diagnostic sign during lameness examination of subchondral cyst-like lesions
Improvement with joint block
Treatment options for subchondral cystic lesions
Intra-lesional injection with corticosteroids (SCL which communicate with joint, arthroscopic guidance)
Mesenchymal stem cells within joint (no arthroscopy, under GA with ultrasound guidance)
Arthroscopic debridement (remove unsupported cartilage)
Transcondylar bone screw (GA, standard cortical screw or absorbable screw)
Conservative (acceptable if no lameness, needs monitoring)
