LA 13: Simple Eq Fractures Flashcards
Common Fx
Metacarpal/metatarsal II and IV fx - splint bone fx
Distal phalanx (P3) fractures
Splint Fx - Facts
Splint bones = head, body, button
FL>HL
2 Mechanisms - internal, external
Internal Splint Fx
“Pressure” DT concurrent suspensory desmitis
–splint bones aren’t very WB but intimately related to suspensory
Possible prox sesamoid damage
External Splint Fx
Skin/SQ IFX
Sequestration
Tendon, suspensory damage
Dx Splint Fx
Palp, nerve blocks, RADS
Suspensory ligament US
Tx Splint Fx
If distal 1/3 to 50% then can surgically remove distal fragment
If proximal 1/3 req internal fixation
Splint Fx: Proximal Fx req Stabilization
Absence of IFX - just need plates or screws to stabilize IFX
If have an IFX, need to wait and treat the IFX first
Why don’t screws need to engage both cortices in a splint fx?
For most equine long bone fx, DO want to engage both cortices
Splint bone fx provides some support but not a major WB bone –> unicortical provides enough stability
Splint Fx: callus formation
Reasonable to give horse a chance to heal on it’s own
- -need to warn O that callus formation can cause lameness that req surgery later on
- -ex: can have a fracture that doesn’t start causing lameness until the callus starts to impinge on the suspensory
P3 Fx Dx
Hoof testers
Nerve blocks
RADS
P3 Fx Healing - foals vs adults
Foals will heal and look radiographically normal
Adults - coffin bones heal with fibrous union, never appear radiographically normal
EXAMwhich P3 fractures are articular?
III - sagittal II - articular wing fracture IV - extensor process fx V (maybe) - comminuted VII *foals*
P3 fx: I
Non-articular wing fx
P3 fx: II
Articular wing fx
P3 Fx: III
sagittal fx - articular. Fixation improves progressions
P3 fx: IV
Extensor process fx
Causes lameness but not severe lameness
Can cause major coffin jt OA
P3 fx V
Comminuted fx
Maybe articular
P3 Fx VI
Solar margin fx
Not articular
Caused by seedy toe, hx of laminitis
Prognosis for healing good but usually assoc with underlying pathology - complicates things
P3 fx 7
Foals
Incidental
Can be articular
Don’t usually see lameness
P3 Fx Tx - Non-articular
Rest
Shoeing
Neurectomy
Good prog if not complicated by other factors
P3 Fx Tx - extensor process (IV)
Bigger they are, prog goes down
Small-medium fragment can be removed arthroscopically as long as don’t have preexisting coffin jt OA
Fixation rarely needed
Good prognosis
P3 Fx Tx - other articular fx
Fixation (screw)
Shoeing
Neurectomy (maybe)
Fair to poor prognosis
Common Racehorse Fx
Metacarpal/Metatarsal Fx --Stress Fx 'Saucer fx' --Distal MC3/MT3 'Condylar fx' Osteochondral fx --carpal --prox phalanx P1 Prox sesamoid bone (PSB) fx
Metacarpal Stress Fx
Bucked shin complex - shin splints Saucer fx Fatigue failure --inappropriate training methods --microfx
Early Phases MC Stress Fx
Sensitive palp, heat, swelling, lame
RADS - no fx, sub-periosteal callus, endosteal thickening
Mostly front limb
Dorsal MC3 Fx
Sensitive to palpation, lame
RADS: dorsolateral cortical fx, endosteal thickening
Tx Metacarpal Stress Fx
Drilling 5-7 holes around the fx to increase blood supply, osteoblasts, encourage healing, MSC/open bone marrow
NOT A LAG SCREW - just a placement screw
–will undergo some bending
–More effective than osteosticks
Unicortical
Recruit additional healing factor
Not all need to be repaired sx - if very prox or very distal, generally heal well on their own
If in the middle, don’t heal well - best to do sx
Distal MC3/MT3
Condylar fx
CS - lame by the time off track work/race, effusion, very sore to flexion
Dx - beware of medial fx - can spiral up cannon bone
Lateral condylar fx RARELY spiral
Medial condylar WILL spiral
Distal MC3/MT3 Fx - Repair
Don’t have to repair if $$$ is an issue
Displaced = more sore than non-displaced
–non-displaced can progress to displaced quickly
Alignment with jt most important!!! - arthroscopy
Be as close to jt surface as possible
Most done under GA but can done standing w/ good sedation and nerve blocks
Osteochondral Fx
IA fx
- -recurrent synovitis
- -osteoarthritis
- -shortened athletic career
Carpal Osteochondral Fragments
Knee chips Etiology: trauma = hyperextension of carpus --distal radiocarpal bone --distal intermediate carpal bone --prox third carpal bone
Carpal Osteochondral Fragments CS
Effusion/lameness after calling out --typically subside within 24-48 hrs --both recur with exercise RADS --4-6 views, both carpi --> lat, flex lateral, D-P, DMPLO, DLPMO, skyline of C3 (flexed separates inner carpal and radiocarpal)
Carpal Osteochondral Fragments Tx
Arthroscopic sx
Fragment removal
Debridement
Carpal Osteochondral Fragments Prognosis
If acute (no OA), and less than 30% cartilage loss, then good for race performance Prog also depends on how quickly address and whether there's pre-existing dz
Slab Fx
usually involve middle carpal and CMC
Chip Fx
Just corners off the cuboidal bones
Dorsal, proximal P1 fx
Hyperextension fx
RF medial eminence P1
–bilat RADS
Lameness, tx, prog as for carpal OC fragments
Proximal Sesamoid Bone Fx
6 basic types
- -prog decreases as fx becomes more distal (or axial)
- -Assess concurrent suspensory desmitis
PSB CS
Jt effusion
Heat on palp
Lameness
PSB Tx
Arthroscopic removal
Repair: lag screw fixation > circumferential wiring
Nothing: retire
Prog varies by location –> worse prox to distal
Which PSB fx have a good prog?
Apical
Abaxial
Which PSB have a poor prog?
Axial
Comminuted
Esp poor prog if combined with condylar fx
Medial and lateral (biaxial) PSB fx
Biaxial fx lead to loss of suspensory apparatus
