Splint Bone and Proximal Sesamoid Bone Fractures Flashcards
What do splint bones provide support to?
Axial support to the carpus and tarsus
What are 2 main causes of splint bone fracture?
Hyperextension of the fetlock
External trauma **More common
How can many splint bone fractures be treated?
Rest
What condition may be a cause of persistent lameness in cases of splint bone fractures?
Suspensory desmitis
What are 3 treatments for a splint bone fracture?
Segmental ostectomy
Removal of the distal portion (midbody fx)
Conservative treatment
How would you manage a proximal splint bone fracture?
Wound management and removal of bone fragments with internal fixation.
When using internal fixation to repair a splint bone fracture, what is best?
Plates are better than screws.
How do you manage a distal splint bone fracture?
Surgical removal.
How much for the distal splint bone can you remove?
No more than 2/3 or you run a risk of collapse of proximal segment.
NOTE: Except metatarsal 4, but not guaranteed.
If you HAVE to remove more than the distal 2/3 of the splint bone, what else will be needed for proper repair?
Internal fixation
When plating a splint bone, what do you NOT want to engage?
MC III
If you DO engage the MC III while using a plate to help repair a splint bone fracture, how long can you leave the plate in for?
3-4 months
What can we see if there is a large callus formed during the healing of a fractured splint bone?
Can see chronic lameness due to impingement on the suspensory ligament causing suspensory demitis.
What is a splint exostosis?
A firm swelling due to a benign outgrowth
What horses do you see splint exostosis in?
Young horses
Which splint bone do you usually see exostosis in?
MC II
What are 2 causes of splint exostosis?
Direct trauma
Ligamentous inflammation
What clinical signs will you see with splint exostosis?
Lame initially with a firm, warm and painful swelling on palpation.
What 2 things does ligamentous injury result in?
Desmitis
Periostitis
What is a “hidden splint”?
The “bump” from a splint exostosis goes inward on the rads so they’re harder to see.
NOTE: More likely to cause impingement on the suspensory ligament.
What are 2 conservative treatments for splint exostosis?
Rest and NSAIDs
Local DMSO/infiltration with corticosteroids
What is the surgical treatment for splint exostosis, and what is required post-op?
Linear incision over side with en bloc removal. EXCELLENT bandaging is required post-op.
When performing an en bloc removal of a splint exostosis, what helps to provide better visibility?
Application of a tourniquet.
What are 3 places to get a pulse on a horse?
Facial
Transverse facial
Dorsal metatarsal artery**
NOTE: This is important to remember when performing an en bloc excision of a splint exostosis.
What are 3 lay terms for periostitis and fracture of dorsal metacarpal III?
Bucked shins
Stress fracture
Sore shins
In what horses do we see stress fractures of the dorsal cortex of MC III?
Speed horses
When do we usually see stress fractures of the dorsal cortex of MC III?
Usually in 3 year old horses that had bucked shins as a 2 year old.
What does a stress fracture of the dorsal cortex of MC III look like?
Fissure extending 60% through the cortex at a 30 degree angle.
What should you encourage trainers to do to reduce the incidence of bucked shins?
Train more at regular short distances.
What is the prognosis for a stress fracture of the dorsal cortex of MC III?
Very good
What are 4 different medical treatments for a stress fracture of the dorsal cortex of MC III?
Rest
NSAIDs
Reduced exercise
Radiographic monitoring
What is the surgical treatment for a stress fracture of the dorsal cortex of MC III?
Osteostixis (drilling holes into the bone to improve healing)
What is osteostixis?
Drilling holes into the medullary cavity to access some growth factors and vascular components.
What is the advantage of osteostixis alone when treating a stress fracture of the dorsal cortex of MC III?
Don’t have to go back to take out any screws.
What surgical treatment gives the best result for treatment of a stress fracture of the dorsal cortex of MC III?
Osteostixis with screws that are removed at 60 days.
How is osteostixis performed?
Skin staples are used as a grid to help guide the drilling. Holes are drilled perpendicular to the fracture and TOWARD the medullary cavity. 6-8 holes are drilled 10mm apart. If using a screw, it is placed unicortically across the fracture.
How many different types of sesamoid fracture are there?
6
What are the 6 different types of sesamoid fracture?
Apex Mid-body Base Abaxial Axial Comminuted
What are 2 causes of sesamoid fractures?
Excessive tension from the suspensory tendons
Trauma
What breed of horse are most affected by sesamoid fracture?
Racing breeds and those at high speed.
What type of sesamoid fracture is the most common?
Apical fractures
How is an apical sesamoid fracture treated?
Arthroscopic removal if they’re articular (up to 1/3)
If large fragment, internal fixation.
NOTE: The more you remove, the lower the prognosis for return to racing.
What is the prognosis for an apical sesamoid fracture?
Good
NOTE: Can evaluate the suspensory ligament via ultrasound if needed.
How is a mid-body sesamoid fracture repaired?
Internal fixation with either a lag screw (for TB and return to racing) or cerclage wire (for SB).
Between a lag screw and cerclage, which method is better for fixing a mid-body sesamoid fracture?
Screw fixation
What is used during recovery and shortly after post-mid-body fx repair?
External coaptation
How do you treat an intra-articular abaxial sesamoid fracture?
Arthroscopic removal of fragments
How do you treat an extra-articular abaxial sesamoid fracture?
Conservative management
What is the prognosis for abaxial sesamoid fractures?
Fair to good
Why do basilar sesamoid fractures have a poor prognosis?
Because it involves the origin of all the distal sesamoidean ligaments and lag screw fixation is challenging due to location.
