Orthopaedic disease Flashcards
Indications for imaging of orthopaedic disease without blocking first
Heat, pain on palpation
Conformational changes
Joint effusions
Logical approach to lameness diagnosis
History
Clinical exam
Diagnostic anaesthesia
Imaging
Diagnosis and treatment
Foot radiography views
Lateromedial view
Dorsopalmar view
Dorsoproximal palmarodistal oblique (pedal) or ‘upright pedal’
Dorsoproxima palmarodistal oblique (navicular) or ‘upright navicular’
Palmaroproxmial palmarodistal oblique (navicular) or ‘skyline navicular’
Lateromedial view of equine foot
Good for: distal interphalangeal joint, foot balance, laminitis
Poor for: most navicular bone changes
Pay close attention to dorsal margins
Dorsopalmar view of equine foot
Good for: distal interphalangeal joint, foot balance, proximal interphalangeal joint, collateral cartilages
Poor for: navicular bone
Dorsoproximal palmarodistal oblique view (pedal) of equine foot
Pedal or Upright pedal view
Good for: pedal bone diseases – fracture, osteitis, keratoma
Poor for: navicular bone, distal interphalangeal joints
Dorsoproximal palmarodistal oblique view (navicular) of equine foot
Navicular or upright navicular view
Good for: navicular bone (especially distal border)
Poor for: everything else!
Palmaroproximal palmardistal oblique view of equine foot
Navicular or skyline navicular view
Good for: navicular bone
Poor for: everything else!
Radiographs to take after an abaxial sesamoid nerve block
A full foot series
Dorsopalmar view of the metacarpo/tarsophalangeal joint
+/- orthogonal views of the proximal interphalangeal joint
Standing low field MRI
Gold standard for distal limb imaging, can be used if nothing is showing on radiographs
Expensive (~£1300)
Soft tissue pathology
Prognostication
If not an option, then back to blocking!
§ Can return to block other more specific structures
Plan following a four point nerve block
Investigation of digital flexor tendon sheath (DFTS)
- U/S
- Contrast tenography
- MRI?
- Tenoscopy
Fetlock radiography, four orthogonal views
- lateromedial
- dorsopalmar
- Dorsomedial palmarolateral oblique
- Dorsolateral palmomedial oblique
Lameness localised with a deep branch of the lateral plantar nerve block
○ Limb is held flexed and rested on the vets knee
○ The flexor tendons are pulled medially to open up injection site
○ Needle is advanced along the axial surface of the lateral splint bone
○ 3ml of local anaesthetic solution is injected (resistance should be low)
○ The horse is re-examined after 10 minutes
Then Proximal suspensory ultrasonography
Lameness localised with a lateral palmar nerve block
○ Horse is weightbearing
○ Needle is introduced on the medial side of the accessory carpal bone
○ Injection resistance is high – injecting into tight fascia. Worry if the resistance is low!
○ 3ml of local anaesthetic solution is injected
○ The horse is re-examined after 10 minutes
then Proximal suspensory ultrasonography
Proximal suspensory ultrasonography
○ Longitudinal
○ Transverse
○ Weight-bearing
○ Non-weightbearing
Challenging – believe your blocks!
Lameness localised to tarsus
Tarsal radiogrograhy
- Lateromedial (LM)
- Dorsopalmar (DP)
- Dorsomedial Palmarolateral oblique (DMPLO)
- Dorsolateral Palmaromedial oblique (DLPMO)
Lameness located to the carpus
Carpal radiography
- Lateromedial (LM)
- Dorsopalmar (DP)
- Dorsomedial Palmarolateral oblique (DMPLO)
- Dorsolateral Palmaromedial oblique (DLPMO)
- flexed lateromedial
- proximal and distal row (skyline)
Lameness localised to the stifle
(Can’t get orthogonal views)
Stifle radiography
- Lateromedial (LM)
- Caudolateral craniomedial oblique (CaLCrMO)
- Caudocranial (CaCr)
- Flexed lateromedial
Stifle ultrasonography
- patellar ligaments
- collateral ligaments
- medial and lateral menisci
- cartilage of the trochlear ridges
- meniscotibial ligaments
Common angular limb deformities (horses)
Carpal valgus
Fetlock varus
Tarsal valgus
Aetiology of angular limb deformities - congenital
Incomplete ossification of the cuboidal bones
□ Cuboidal bones ossify in late gestation
□ Carpus and tarsus
Diagnosis:
§ ALWAYS RADIOGRAPH PREMATURE FOALS
Treatment:
§ limiting weight bearing and activity
§ Strict stall rest 2 weeks; re-xray to monitor until able to do more activity
§ Depending on severity, casts
Prognosis: Guarded for athletic activity
Soft tissue laxity
§ Carpus most affected
Aetiology of angular limb deformities - developmental
Asynchronal growth
□ Dysplasia of the metaphysis or epiphysis
□ Common cause of ALD
Nutritional imbalance
□ Fast growth
Trauma/infection
□ Leads to early closure and asynchronal growth
Growth plate closure times in horses
Growth plates determine bone length
Closure time varies between breeds (lighter close earlier)
Most rapid growth 1st 10 weeks
Correct fetlock deformities within 70 days
Treatment of angular limb deformities in horses
Conservative
- most correct within 2 weeks
- restrict exercise
- Hoof correction
- Nutritional management
Surgical
- Periosteal transection and stripping
- Transphyseal bridging/implants
- corrective ostectomy
Periosteal Transection and Stripping
Growth Acceleration via inhibited growth with “release” of periosteum
Performed on short aspect of limb
- Varus: Performed medial
- Valgus: Performed lateral
good cosmetic result, no overcorrection possible
Transphyseal bridging/implants
Growth reduction via tension across the growth plate
Performed on mild-severe ALD
Performed on the long aspect of the limb
- Varus: Lateral
- Valgus: Medial
All techniques carry a risk of possible implant infection
Over correction can occur!
Foals monitored on a daily basis to ensure this doesn’t occur
Implants removed between 6-8 weeks (when the leg is straight)
Corrective ostectomy
Reconstruction
Foals with closed growth plates or severe diaphyseal deformities
Very rarely done
Flexural limb deformities
Abnormal angulation of the limb in the sagittal plane (flexed or extended)
Primarily soft tissue vs. ALD primarily bone
Forelimbs most often affected
Can be in one or more limbs
Contracture flexural limb deformities
Persistent hyperflexion
Can have tendon contracture as a result of scarring from tendon injury—seen in adults and rare in foals
Hyperextension flexural limb deformities
Elongation of tendinous unit in relation to bone
Congenital
· Birth up to 1 month
· Carpus or MCPJ most commonly
· Teratogenic
· Intrauterine positioning
· Genetics
Acquired
· 1-6 months
· DIPJ and MCPJ most commonly
· Nutrition
· Trauma
· Infections
Causes of contracture
Mostly multifactorial and difficult to explain
Intrauterine malpositioning with large foals
Diseases acquired by the mare in pregnancy:
□ Locoweed/hybrid sudan grass
□ Gene mutation in sire
□ Influenza
□ Defects in cross linking of elastin and collagen
□ Glycogen branching enzyme deficiency (QH foals)
Prognosis of contracture
Good prognosis if can straighten and no osseous changes—guarded if not
Treatment of contracture
Rads: helps rule out any bony abnormalities
Conservative:
□ Mild cases usually resolve with limited exercise
□ Need further treatment if don’t improve or unable to stand
® Splints/casts
® Toe extensions – be careful!
® Analgesics
® IV Oxytetracycline:
◊ Popular treatment to relax tendons (Possibly via Inhibition of collagen gel contraction by myofibroblasts)
◊ Very useful in mild to moderate cases—not as rewarding with severe cases
Digital hyperextension
Fetlock dropped and toe may rise; severe if plantar/palmar region on the ground
Can range from mild to severe
Caused by flaccid flexor muscles
Corrects often within a few weeks with increased muscle tone
Treatment of digital hyperextension
If needed
protect skin
place heel extensions
mild exercise
Acquired flexural limb deformities
DIPJ - distal interphalangeal joint
MC/MT - metacarpa/metatarsal
DIPJ flexural limb deformity
Due to DDFT
Stage 1: wall not passed vertical plane
Stage 2: wall passed vertical; worse prognosis
Treatment of DIPJ flexural limb deformity
Controlled exercise with Physiotherapy
Analgesics—address underlying cause of pain
Elevate heel to ease DDFT tension; Toe extension may be useful or cause more pain
Surgery:
□ ALDDFT desmotomy if unresponsive to medical treatment
□ DDFT tenotomy if very bad or doesn’t respond to all other treatments first
MC/MT flexural limb deformities
May be due to DDFT or SDFT (palpate which under tension—difficult)
Treatment of MC/MT flexural limb deformities
Controlled exercise with Physiotherapy
Analgesics—address underlying cause of pain
Elevate heel to ease DDFT tension; Toe extension may be useful or cause more pain
+/- splints with caution (can cause sores)
Surgery:
□ If no response to medical treatment or >180*
□ ALDDFT desmotomy and/or AL SDFT
Clinical signs of physitis
Enlarged physis
Usually painful on palpation
Variable lameness; may be reluctant to stand
Diagnosis of physitis
Clinical signs
Radiographs of physitis
Irreguar/wide growth plate; may see sclerosis