Large Animal Fracture Repair Techniques

What is joint fusion for?

End stage option for treatment of lameness due to osteoarthritis, tendon/ligament rupture, articular fracture

What are the types of joint fusion?

Ankylosis

Facilitated ankylosis

Arthrodesis

When is ankylosis most successful?

Complete removal of cartilage

Complete removal of cartilage and ankylosis is most successful with what?

Alignment, compression, stabilization

Intensive pain management

What happens to the ankylosis process if cartilage is still present?

Very slow process that is most common in OA of low motion joints like pastern, lower hocks, CMC

What can you use to do facilitated ankylosis?

Alcohol injection until the joint pressurizes, do not want alcohol to leak out of the joint

Monoiodoacetate (no longer used due to pain)

What happens if you get SQ leakage of alcohol during facilitated ankylosis?

Inflammation and sloughing, this is why it is done under radiographic needle placement

How is a laser facilitated ankylosis done?

14g needle inserted with the laser going through it

Superheats and vaporizes synovial fluid leading to chondrocyte death

Why do you lead continuous lavage with cooled fluid to do a laser facilitated ankylsis?

Prevents skin burn

What is transarticular drilling?

Facilitated ankylosis technique that physically destroys and removes cartilage and allows it be filled with bone

What do you need to combine transarticular drilling with in the proximal interphalangeal joint?

Minimally invasive internal fixation

When can joint arthrodesis with internal fixation lead to athletic behavior again?

Low motion joints (PIP most common)

When is joint arthrodesis with internal fixation a salvage procedure?

High motion joints like DIP, MCP/MTP, pan-carpal, scapulohumeral

What are indications for PIP arthrodesis?

Pastern OA

P2 fracture

paster joint subluxation

What is the prognosis of PIP arthrodesis?

Very good

What are the techniques for PIP arthrodesis?

lag screw fixation

Dorsal 3 hole plate with transarticular screws

What are cons of a lag screw fixation PIP arthrodesis?

Prolonged casting required with longer duration of post-op lameness

More bony proliferation

What are the cons of a dorsal 3 hole plate with transarticular screws for PIP arthrodesis?

Most invasive and expensive, but fastest return to soundness

What are indications for fetlock arthrodesis?

Fetlock OA

Breakdown injuries

Fetlock joint luxations

What is the prognosis of a fetlock arthrodesis?

75% survival with use of a locking plate (LCP)

How do you do a fetlock arthrodesis?

10-hole LCP with transarticualr lag screw fixation or distal femoral plate

What are the indications for a tarsal arthrodesis?

Talocalcaneal OA and occasionally DIT/TMT luxation

Uncommonly done due to ankylosis techniques

What is the prognosis of a tarsal arhthrodesis?

Minimal clinical information

Reserved for severely affected limbs and luxations with a guarded prognosis for return to use

How do you do a tarsal arthrodesis?

Plate over the most unstable area

What are indications for a carpal arthrodesis?

Severe OA

Comminuted carpal fracture

Carpal luxation

What is the prognosis for carpal arthrodesis?

Guarded for return to use

Will not be able to flex entire leg so welfare concern

How do you place a carpal arthrodesis?

Multiple plates in the dorsal plane

When can you use nonsurgical management of a fracture?

Non-displaced fissure fractures

Splint stabilization for management of complete fracture

When would successful healing not guarantee a successful outcome of a fracture repair?

Horses might not be able to return to athletic use

T/F euthanasia can be the best options sometimes for fracture repair?

True

How does a transfixation pin cast work?

Similar to an external fixator, pins placed above fracture and foot, distla limb, and pins enclosed into cast

Weight comes down on bony column, cast, and across pins casing limb distal to pin float inside

What are indications for transfixation pin cast in horses?

Severely comminuted fractures not amenable to internal fixation

When is transfixation pin cast good for livestock?

Low-cost solution for many fracture configuration with a greater capacity to heal than hroses

What are some considerations for livestock fracture repairs?

Thicker skin

Better capacity to heal than horses

Limited on which antimicrobials and analgesics we use

Harder to maintain a clean environment

Can be challenging to stall confine

What are the AO principles for fracture fixation?

Anatomic fracture reduction

Rigid internal fixation

Preservation of blood supply

Early, active mobilization-based on human principles

What are the common P1 fractures?

Multiple configurations with sagittal occurring most common

How do you fix P1 fractures?

Lag screw fixation

Transfixation pin cast

What is the prognosis for a P1 fracture?

Highly dependent on fracture complexity/config

Most return to performance

What is the efficacy of using chemically-induced facilitated ankylosis in the proximal interphalangeal joint?

In normal joints experimentally, it did not work. Only 3/12 fused

In clinical cases, 50% returned to soundness but it takes a long time and multiple injections

What is the efficacy of using chemically-induced facilitated ankylosis in the distal intertarsal/tarsometatarsal joints?

Do NOT do it if the DIT communicates with the PIT

About 50% worked experimentally and 65% clinically

What is the efficacy of laser-facilitated ankylosis in the Proximal interphalangeal joint?

5/6 worked using laser with 3 parallel screws included

What is the efficacy of laser-facilitated ankylosis in the distal intertarsal/tarsometatarsal joints?

83% improved lameness and 64% returned to normal

25% needed additional intervention

What can happen in facilitated ankylosis of any technique?

Persistent articular cartilage and potential for residual lameness

Summarize ethyl alcohol facilitated ankylosis?

Low cost and minimally invasive

Less predictable in mildly affected joints due to amount of tissue left to destroy

Summarizelaser facilitated ankylosis?

Not good for PIP without internal fixation

Lower hocks are pretty good but less likely for radiographic fusion

Summarize drilling facilitated ankylosis?

Overdrilling can lead to instability

Lower hocks are less predictable

Carpus is good

PIP needs to be paired with an internal fixation and is less predictable

How do you treat non-displaced fissure fractures?

Strict stall rest, tied for 8 weeks

Consider a sling

Can be used on the radius, tibia, deltoid tubercle, nonarticular patella, scapular spine

How do you do ao splint stabilization for management of a complete fracture?

Possible for non-weight bearing or non-articular fractures that are well reduced and stable

Stall rest for 8-12 weeks

Reset splint and bandage every 3-4 days

How do you do a external coaptation like casts for farctures?

Most common for P3 nonarticular fractures

Fiberglass material

Needs diligent monitoring and first change at 3-4 days once swelling subsides then every 10-14 days for foals and 5-6 weeks for adults

Complications will occur

Often thought to be more economic but costs add up over time

How do you use splints for fracture manageement?

Very rare, need to reset splint every 3-4 days and rest for 8-12 weeks

What are Schroeder-Thomas splints used for?

Livestock only on closed fractures distal to the elbow or stifle

What are velpeau slings used for?

Samelids with shoulder luxations

Why are transfixation pin casts best on severely comminuted fractures?

Strain is distributed across all fragments

When is pin stiffness proportional to?

Pin radius but diameter must be <20% of total bone diameter

How much should pins diverge for a transfixation pin cast?

10 degrees each for 30 total degrees

What size pins do you use for a transfixation pin cast in adults?

2 or 3 4-6.3mm positive profile threaded pins

Place in metaphyseal region proximal to fracture

How often do you need to change the cast with a transfixation pin cast?

every 10-14 days for 8 weeks (very long time)

What is a transfixation pin cast a race between?

Fracture healing and pin loosening

What are the complications of transfixation pin casts?

Pin loosening

Pathologic fracture

How do you know if a pin loosened with a transfixaiton pin cast?

Pin movement becomes painful and should be removed

Can place a more proximal pin

What can cause a pathologic fracture duringa transfixation pin cast?

Bone weakened by osteomyelitis

Ring sequestration

Stress riser

What are some challenges with equine fracture repair?

Horses are large animals with thin skin and no redundant tissue

Must bear weight on all 4 limbs right after

Very little room for error

Implant failure and and infection are common

Lots of soft tissue trauma

Limited blood supply to distal limbs

What is anatomic fracture reduction important?

IMportant for stable fracture repair and implant strength

Why do you want rigid internal fixation?

Motion at the fracture site delays healing and cycles the implants leading to failure

How does P2 usually fracture?

Uni or bi-axial palmar eminence

COmminuted

How can you repair P2 fractures?

PIP arthrodesis with single plate and bi-axial lag screws

PIP arthrodesis with double plate fixation

Transfixation pin cast

What is the prognosis of P2 fractures?

Much worse in the front than rear

Rarely return to performance but comminuted is worse

What fracture do racehorses tend to get?

MC/MTIII

How do you repair a MC/MTIII condylar fracture?

If lateral: lag screw fixation

If medial spiral: plate fixation

Describe what commonly happens with MC/MTIII condylar fractures

Lateral more common than medial but medial more likely to spiral

What is the prognosis for a MC/MTIII condylar fracture?

Pretty good, about 40-70% can go back to racing

What are the configurations of MC/MTIII diaphyseal fractures?

Transverse (common in foals)

Short oblique with butterfly fragment

Comminuted

How do you fix MC/MTIII diaphyseal fractures?

Double plate fixation

Transfixation pin cast

What is the prognosis of MC/MTIII diaphyseal fractures?

Dependent on severity of fracture and stability of repair

Poor if comminuted and guarded if simple in adults

Fair in foals

What causes MCIII dorsal cortical stress fractures?

Bucked shins and incomplete remodeling response to accumulating microdamage to the dorsal cortex during race training

Can curve dorsally and become a saucer fracture

How do you treat MCIII dorsal cortical stress fractures?

COnservative with rest

Osteostyxis drilling holes perpendicular to fracture

Lag screw fixation

Prognosis is good

Where do carpal chip fractures occur?

Radial carpal bone in MC joint

Intermediate carpal bone in ABC joint

What is the prognosis of a carpal chip fracture?

Depends on the degree of cartilage damage

What commonly gets carpal slab fractures?

Racehorses at the radial and 3rd carpal bones

How do you treat carpal slab fractures?

Slab removal if <1cm thick

Lag screw fixation if larger

What gets olecranon fractures?

from a kick presenting with a dropped elbow

How do you treat olecranon fractures?

Plating

Describe proximal limb fractures in radius, tibia, femur, and scapula

Hard because it is hard to get to the bones

Should stabilize, radiograph, consult with surgeon