Musculoskeletal Flashcards
What additional factor may contribute to presence/development of ALD in camelid crias
Lack of Vitamin D - rickets. => hypophosphataemia
Supplementation commonplace - but care re overdose - causes maetastatic calcification in various organs (kidney) & renal dysfunction w hypercalcaemia, hyperphosphatamia
Dose vit D 1000IU/kg
Main difference in carpal physes in camelids vs the horse?
Why might this contribute to high incidence of ALD?
The ulna physis remains separate from the carial physis at the caudolateral aspect of the distal antebrachium. Delayed growth at this physis is thought to contribute to development of carpal valgus as the ulna acts as a tension band, limiting growth.
Treatment options for carpal valgus
- Conservative tx - confinement (+/- external coaptation) for mild cases < 10° deviation
- Growth accelaration - HCPTE on the distal lateral aspect of the distal radius. Needs to be combined w ulna ostectomy in those <3mo to address the lateral tension band effect of the distal ulna physis
- Growth retardation - trans-physeal bridging across the distal medial radial physis. Can also be combined w ulna ostectomy
- Radial wedge ostectomy. After period of rapid growth
Radiographic closure of the distal radial physis is approx 3 years, but minimal improvement w surgical interventions beyond 15mo
Some evidence that better outcomes seen with trans-physeal bridging vs other procedures & that they do better when operated >4mo old (could be related to severity & more severe req. earlier tx?) Overall recommendation is to combine TP bridge with PTE & UO in those w severe angulation >15°
What is arthrogryphosis?
Congenital persistent contracture with bony malformation
Uni or bilateral. Most commonly affects carpus or elbow. Cause unknow but may be related to teratogens. Affected animals are unable to stand and it is impossible to manually straighten the limb. Correction usually impossible & better to PTS
Define polydactyly & syndactyly
Polydactyly is reasonably common - usually 1-3 accessory digits on one or all limbs
Syndactyly = fusion of 2 normal digits; less common
Describe phalangeal alignment in NWCs
And OWCs
NWCs - horizontal P3 & P2, P1 45°
OWCs - horizontal P3, P2 45° & P1 vertical
List some conformational differences between llamas & alpacas
Ideal alpaca side view is 3 rectangles - body depth, neck length and leg length should be equal
Alpacas have a more vertical P1 than do llamas - alpacas more prone to hyperflexion of the fetlock
Alpacas have a short triangular face compared to llamas
Main differences between dromedary & bactrain camel
Dromedary - single hump. Also have a Dulaa (soft palate diverticulum) that protrudes from the mouth of males when in rut
Bactrain - 2 humps
Vertebral formula of camelids
C7, T12, L7, S5 Ca10-15
Only spp w 12 ribs (all others have 13 or 18)
Extra lumbar vs horse. Same sacrum
Normal synovial fluid analysis in NWCs
Similar TNC vs horses < 2.5x10’9/L
TP generally higher >38g/L considered abnormal (vs 25g/L horses)
Pigs also generally higher TP - Ave 36g/L in carpi & tarsi of normal finisher pigs (Canning AJVR 2017).
Main difference in NWCs shoulders seen in CC rads
Presence of acromian process
Features of patella luxation in camelids
Lateral and medial reported although lateral more common
Camelids have a single patella ligament, & the stifle joint has 1 compartment with broad medial and lateralpatellar retinacula that help to keep the patella within the trochlear groove
Reports of tx are uncommon - is successful report in mature male tx w trochlear wedge resection, medial imbrication (for lateral luxation) and tibial tuberosity transposition (can be done in small ruminants but not recommended for heavier cattle) done bilaterally staged. (VS 2014)
Carpal joint communications in camelids
Split into ABC, MCj & CMC as in horses.
MCj & CMC always communicate as in horses. Higher proportion also have communication w ABC - 32%
64% also have communication between carpal sheath & ABC - important WRT tx of sepsis
Unique features of the camelid tarsus
Broadly similar except T2&3 are fused instead of 1&2. Medial malleolus remains radiologically distinct into maturity
Approach to carpal valgus
When spontaneous correction does not occur or angulation is severe (>15’), surgical options should be sought.
Incl hemicircumferential periosteal elevation, ulnar ostectomy, transphyseal bridging, and wedge or step ostectomies.
- Periosteal elevation of the concave side is recommended for mild /moderate angulation (<15’).vAnecdotal evidence suggests that this should only be performed during the early phase of development (<3 months old).
- Camelids have complete ulnas that fuse distally with the radial epiphysis. Partial ulnar ostectomy has been recommended for treatment of carpal valgus. A 2-centimeter (cm) segment of ulnar is removed at a level immediately adjacent & proximal to the distal radial physis. For camelids <5 months with mild to moderate angulation of the carpus, periosteal elevation and ulnar ostectomy in combination, is recommended. However, rapid periosteal bone formation may lead to premature fusion of ulna & may complicate resolution of ALD.
- For camelids > 5 months or those w moderate to severe ALD (>15 degrees), transphyseal bridging of the convex side of the limb appears to be a better tx in plus partial ulnar ostectomy. Unicortical screws are placed on either side of & parallel to physis w figure–8 orthopedic wires between. Removal of the screws and wires should occur once the limbs have straightened. Failure to remove the screws and wires in a timely fashion may lead to overcorrection and significant carpal varus formation.
Whats the diagnosis?
Clinical features relevant to camelids?
- UFP
- Present w limb(s) extended caudally & rotated outwards, & are to be unable to flex it. ie fixed in extension same as horses
- Reported tx incl trochlea wedge resection via arthrotomy (reflect patella laterally then do medial imbrication).
What factors make camelids good candidates for fracture repair
Low weight, good tollerence for external coaptation/fixation, ability to sstain prolonged periods of recumbency
What is different about sequestra in camelids vs other spp?
Usually following trauma in other species but doesn’t seem to be the case in Camelids
Have affected appendicular skeleton and the mandible
May occur following haematogenous infection?
Rads - for dx and determine tx course
If removal will rx in instability of remaining bone may need stableisation
Remove, curettage, ABs 7d, and local management of wound/draining tract
Typical age affected by bone sequestra
Usually pre-weaned crias 2-3months old. Present w lameness. Focal area of POP with careful PE. Rads helpful. Delay sx until clear involucrum otherwise can be hard to remove
