Fetlock MC/MT-Morton Flashcards
Categories P1 fractures
- Dorso-medial/-lateral P1 OCFs
- Proximoplantar/palmar P1 OCFs
- Diaphyseal fractures
Dorso- medial/-lateral P1 OCFs etiology
High speed hyperextension injury
Most common ‘chip’ fx TB racehorses
Dorso- medial/-lateral P1 OCFs DX
PE & LE -MCP/MTP effusion, + to flexion, mild lameness -IA analgesia resolves lameness Rads -always do both fetlocks
Dorso- medial/-lateral P1 OCFs TX
Arthroscopic removal
Screw fixation if large frag (rare)
Dorso- medial/-lateral P1 OCFs Prog
Good unless significant OA
> 80% return to athletic function after removal
Proximoplantar/palmar P1 OCFs etiology
Controversial
-Manifestation OCD
-Traumatic
Common in young STB racehorses
Proximoplantar/palmar P1 OCFs DX
PE & LE
-Effusion, +/- to flexion, rarely lame
Rads
-Incidental (PPE)
Proximoplantar/palmar P1 OCFs TX
Smaller frags
-conservative 6-12 weeks rest
Larger frags
-arthroscopic removal (Plantar approach)
Proximoplantar/palmar P1 OCFs progn
Good-63% return to prev. level racing
Diaphyseal fractures etiology
- Repetitive use injury
- Sagittal plane propagate proximally to distally most commonly (sagittal groove)
- Racehorses, and jumpers
- Often spiral fx
Diaphyseal fractures DX
Rads
Avoid blocking
Diaphyseal fractures TX
- Most require internal fixation
- Poor prognosis (barbaro)
Sesamoid fractures etiology
High speed, repetitive use
-most common type of catastrophic breakdown injury (biaxial)
Fore > hind; medial > lateral; uniaxial > biaxial
Apical > basilar > midbody
-apical/basilar=> avulsion fx
Sesamoid fractures DX
PE & LE -Sudden, acute lameness -ECP/MTP effusion if articular -fetlock drop if sig loss sups apparatus Rads Blocking-chronic
Sesamoid fractures TX
Arthroscopic removal-apical/abaxial (basilar)
-If more than 25% suspensory attachment involved removal not well tolerated
Repair-internal fixation
Sesamoid fractures Internal fixation options
- Screw in lag fashion +/- bone graft
- Tension band wire
- Arthroscopy to ensure anatomical reduction
Sesamoid fractures prognosis
Fair-excellent simple apical fx Fair for mid-body (uniaxial) fx -difficult to repair, subsequent OA -horses rested ~ 1yr Difficult to avoid sesamoiditis and damage to suspensory lig that accompanies fx
POD
Palmar/Plantar Osteochondral dz
POD etiology
- Repetitive stress injury-results in maladaptive bone remodeling
- MC3/MT3 condylar dz-subchondral bone injury (‘edema’/necrosis/sclerosis), cartilage damage, supracondylar bone remodeling (resorption)
- Leads to osteoarthrosis
- predisposes to MC3/MT3 condylar fxs
- TB racehorses most commonly affected
POD DX
- Signalment
- PE/LE + palmar/plantar metacarpal n. block
- BONE SCAN
- RADS-sclerosis, trabecular bone changes)
- MRI
- CT
POD TX
- REST (90+ days)
- continued training may lead to catastrophic failure - Pain Management
- NSAIDS
- IA medication
- ESWT
- Bisphosphonates (not young horses) - REPEAT BONE SCAN BEFORE RETURN TO TRAINING
Condylar fractures MC3/MT3 etiology
Common in racehorses-cannon sustains high loads
-Stress accumulation and micro-fx within distal palmar/plantar condyles leads to acute fx at high speeds
Vertical fxs that propagate proximally and sagittally from joint
Condylar fractures MC3/MT3 types
Lateral Condyle
-mostly short and complete, more common in MC3
-85% of forelimb condylar fxs are lateral
Medial Condyle
-Usually spiral, more common in MT3, Y shaped
-More prone to catastrophic failure (even after repair)
Condylar fractures MC3/MT3 coaptation
VERY IMPORTANT
-half/full limb dorsal splint, cast, kimzey splint
Condylar fractures MC3/MT3 DX
- PE: acute, marked lameness
- Rads: RADIOGRAPH BEFORE BLOCKING
- Nuclear Scint
- CT-surgical planning
Condylar fractures MC3/MT3 TX
- Lag screw fixation
- Arthroscopy to confirm reduction, clean up frags
- Plating-needs to be removed before return to high speed
Condylar fractures MC3/MT3 aftercare
3 month lay-off; mean return to start time 9 months
Condylar fractures MC3/MT3 Prognosis
Directly related to severity of injury
Soundness depends on perfect reconstruction of joint
65% return to racing
Bucked shins
Dorsal metacarpal disease (DMD)
-maladaptive remodeling of MC3
Common in young TB racehorses
Predisposes to dorsal cortical fractures
DMD DX
- PE
- Heat, swelling, pain on palpation
- Acute onset lameness after high speed workout - Rads
- thickened dorsal cortex/periosteal rxn
- may be bilateral - Nuclear Scintigraphy
DMD TX
- Prevention-training
- rest
- NSAIDS
- appropriate training modifications
- counter irritants (pin firing historically, maybe don’t do)
DMD prognosis
Very good
Risk for dorsal cortical stress fxs
Dorsal cortical fx MC3 etiology
Progression maladaptive bone remodeling
Usually incomplete
Saucer fx - complete
DX-similar to DMD
Dorsal cortical fx MC3 TX
- Rest
- stall rest with gradual return to exercise
- frequent, short breezes once back into full training - Soundess to asses healing
- Extracorporal shockwave therapy
- Surgery
- Osteostixis (cortical drilling): improv vascularization
- 3.5 mm unicortical screw-must remove
Dorsal cortical fx MC3 prognosis
- Good (85 and 97% return to racing after cortical drilling/ cortical drilling + screw)
- Reccurence of fx more common after cortical drilling alone compared to drilling + screw
- Recurrence rate higher w/o surgery (anectodally)
Splints etiology
Proliferative periostitis of small MCs/MTs
Primarily young horses
Cyclic strains during exercise
Trauma resulting in subperiosteal hemorrhage and lifting of periosteum
Splints DX
- PE/LE
- local firm swelling +/- painful to palp
- may block to low or high 4-point/6-point - Rads
- Nuclear scintigraphy
- U/S TO EVAL CONCURRENT SUSPENSORY PATHOLOGY
Splints TX
- Most respond to conservative tx
- rest until not sensitive to palpation
- bandaging
- NSAIDS, cold, topical diclofenac, local steroid inj
- ESWT - Splint ostectomy for chronic/nonresponsive cases/impinging on suspensory ligament
- Treatment of any concurrent suspensory desmitis
Splints prognosis
Good to excellent
Splint fractures etiology
- Direct trauma-kick
- Exercise-cyclic strain, strain on suspensory and inter-osseous ligament
- fx usually distal 1/3
- 67-81% distal splint fractures have concurrent suspensory desmitis
Splint fractures DX
- PE/LE
- typically acute lameness - Rads
- U/S
- concurrent suspensory desmitis
Splint fractures TX
- Closed fx-conservative
- Stall rest, bandage, cold therapy, NSAIDS, surpass
- healing accompanied by large exostosis-impingement ofsuspensory ligament - Excessive callous ush needs to be removed
- Open fx
- often form sequestrum
- remove and debride
Splint removal
Up to 2/3 distal aspect MC/MT II or MC/MT IV
-probs can’t actually remove whole MT IV
Splint internal fixation
Req’d for proximal unstable fractures
Splint bone fractures prognosis
- Distal 2/3 fractures good prognosis
- depends on concurrent SL desmitis - Proximal fractures-good unless residual instability of CMC/TMT joint +/- OA, infection into adjacent synovial structures