Limb deformities in growing horses Flashcards
Types (5)
- DODs
- Septic polyarthritis & osteomyelitis
- Flexor tendon laxity
- Salter-Harris fractures
- Patella luxation
DODs (6)
• Osteochondrosis (OC) --> OCD --> Osseous cyst-like lesions • Angular limb deformities • Flexural limb deformities • Physitis • Cuboidal bone hypoplasia (incomplete ossification) • Cervical Stenotic Myelopathy/Cervical Vertebral Malformation (CSM/CVM)
Bent legs
-3 main types, causes
- Angular limb deformities: Deviation in frontal plane
- Flexural limb deformities: Deviation in sagittal plane, Acquired & congenital forms
- Flexor tendon laxity: Deviation in sagittal plane, Acquired & congenital forms
Angular limb deformities (4)
- Valgus = lateral deviation in frontal plane
- Annulus
- Varus = medial deviation
centred on fetlock, carpal or hock regions (pivot points), combinations may occur
ALD pathgenesis
- congenital (3)
- acquired (1)
Congenital
– Laxity of peri-articular tissues: collateral ligament
– Incomplete ossification of carpal bones
➢ Rounded rather than angular in shape
– Cause unknown: genetics, abnormal intra-uterine position, premature/dysmature foals
Acquired
– Asymmetrical bone growth of physis or epiphysis
➢ Uneven loading
➢ Injury to physis
ALD assessment
- observation (2)
- manipulation (4)
- radiography (8)
Observation:
– Present at birth or occurred afterwards?
– Getting worse or staying the same?
Manipulation:
– Deep pain or swelling?
– Pain in one limb so overloading in the other?
– Good front conformation?
– If able to straighten-periarticular laxity
Radiography:
– Ossification, carpal bone injury
– Physes: look for any bridging/irregularity
– OA
– Irregular physis
– Asymmetry in thickness of the cortices of the diaphysis d/t to asymmetrical loading
– Small, rounded (collapsed) cuboidal bones of carpus
– Small, rounded heads of metacarpal splint bones
•Identify pivot point & Measure angulation
- Dorsopalmer/dorsoplanter and LM
ALD Tx
- conservative (4)
- surgical
- -> strategy (3)
- -> timing (3)
Conservative:
• Box rest/limited exercise if ossification normal
• Foot trimming, foot extensions
• Dietary restriction
• Splint, brace, tube cast if marked laxity or laxity + incomplete ossification
Surgical:
Surgical treatment
• Strategy
– Growth acceleration on concave aspect of limb
– Growth retardation on convex aspect of limb
– Growth ceased → corrective ostectomy: very brave procedure
• periosteal transduction and elevation
• Timing of surgery: needs to be done when the growth plate is still open
– Fetlock increase in growth on concave aspect of limb
- Growth Retardation
- -> Bridge growth plate that’s involved with that aspect of the limb.
- -> Insert screw across the growth plate, which will stop growth on that aspect and bring into alignment.
- -> You can get overcorrection so monitor carefully - Corrective ostectomy
- -> When there is no longer any growth at plate.
- ->Take out wedges of bone and put in plate.
Flexor limb deformity
- what causes it (4)
- where
• Increased flexion of joint most frequent
–> Musculotendonous (MT) unit too short for bony components of the limb
–> “Contracted tendons”
–> Usually DDFT/SDFT unit
• DIP joint and fetlock joint most commonly affected
FLD Tx
• Stretch affected MT unit
– Physical therapy e.g. walking/hopping/ walking backwards or uphills
– Farriery
– Splint, cast
• Relax MT unit – Oxytetracycline: IV – Analgesia: NSAIDs – Splint, cast – Treat any underlying orthopaedic disease
• Transect check ligament, tendon
– Results in increase in length of tendon
Congenital flexural deformities
- aetiology
- CS (4)
- cause (4)
• Carpal, fetlock - may be secondary to rupture of common digital extensor tendon
CS:
• Usually bilateral
• DIP joint: walks on tip toes
• Fetlock: straight fetlock angle or knuckles forward
• Carpus: foot flat to ground but carpus flexed
cause: • Exposure to teratogen, e.g. locoweed, hybrid Sudan grass • Restricted foetal movement, e.g. twin • Influenza infection • Genetic predisposition
congenital flexural deformities Tx
- mild
- moderate
- severe
• Mild – able to stand & walk without knuckling
– Oxytetracycline: 20-60mg/kg iv; repeat if necessary
• Moderate – knuckling
– Splint for 24-48h, then bandage
• Severe congenital flexural deformities – Severe hyperflexion or poor response to treatment – Consider euthanasia – poor prognosis – Radiography – Cast - change after 3-4d – Farriery – Surgery
Acquired flexural deformities
- aetiology (3)
- Px (2)
- Limb pain: Pain withdrawal reflex
- Mismatch between MT unit & bone growth
- Genetic predisposition
Px:
• Treat underlying orthopaedic disease promptly
• Nutrition
Acquired flexural deformities: DIP
- CS
- Staging
- Tx (3)
DIP joint flexural deformity
- Upright, tip-toe stance initially d/t flexion of DIPJ, boxy or club foot develops due to wear at toe/no wear at heels
- box type feet
- stage one: dorsal wall < vertical
- stage two: dorsal wall > vertical
Stage 1 - treatment: 1. Farriery --> Rasp heels --> Protect and slightly extend toe Glue on shoe or acrylic to extend toe Change glue on shoe every 2 weeks, do not use for longer than 4 weeks → constricts foot
- Physiotherapy
- -> Walk on firm surface, Up slopes, Backwards, Hopping
Stage 2 (or non-responsive stage 1)– treatment:
•Transection
– Cut Inferior check ligament
– DDFT - salvage
Fetlock Flexural deformity
- age
- CS (2)
- What (2)
- Tx (3)
- 9-19mo
- Straight fetlock angle
- Knuckling forward as condition deteriorates - may be intermittent or constant
- Classically considered a contracture of superficial digital flexor tendon
- Now recognised that deep digital flexor contracture may be cause in some cases
Tx:
- farriery
- Superior or inferior check ligament desmotomy
- surgical on SDFT/DDFT
Flexor tendon laxity
- Facts (3)
- Tx (4)
- Prognosis
- Premature & dysmature foals
- Hypoflexion
- HL more commonly affected than FL
Tx: •Mild –Exercise & supportive care • Severe – Light bandaging to prevent skin trauma – Rasp heels – Extended heel shoe: protects heels & forces foot to be placed sole 1st to ground
• Usually recover
