Equine musculoskeletal trauma: Assessment and stabilization (Proceedings)

Types of musculoskeletal trauma

• Wounds and lacerations

• Skin

• Deep structures (tendon, ligament, joint, bone)

• Vascular injury

• Nerve injury

• Fracture

Patient assessment

• Horses may be frantic and distressed following trauma

• Use appropriate restraint to keep you and your patient safe during assessment

• Use sedation

o Most equine sedatives also provide analgesia as well as provide chemical restraint

o Will decrease horse's anxiety for thorough assessment

• Anatomy

o Knowledge of anatomy is critical to appropriate assessment

o Appropriate identification of affected structures

o Determines necessity of immediate treatment

o Will dictate method of stabilization for transport

o Anatomic relationships very important

• Integument

• Muscle

• Vascular and nerve

• Tendon/ligament

• Synovial structures: joints, tendon sheaths, bursa

• Bone

o Location, location, location

• Small wounds in the wrong location can be life-threatening

• Based on location some fractures cannot be repaired

Integument

• Lacerations and wounds

o When involving only the skin, subcutaneous tissue and fascia they usually will heal well

o Some may require extensive wound care management long term

• Burns

o As in human burn patients these require extensive management locally and systemically

Muscle

• Muscle damage is confined to the areas above the carpus and tarsus

• Not necessarily life or performance threatening unless extensive

• Myositis can be a bigger concern than direct trauma

o Clostridial Myositis

Vascular injury

• Laceration of large vessels can result in exsanguination

• Damage to major blood supply to the limb can result in loss of the limb – either by transection or blunt trauma

Nerve injury

• Loss of sensation

o Can return over time

• Loss of function

o Can lose function of a limb which is life-threatening

• Examples: suprascapular, radial, or femoral nerve paralysis

Tendons and ligaments

• Major supporting structures of the lower limb

• Injury can be life and performance threatening

• Transection of the major tendons and ligaments can have a diagnostic stance when weight bearing

o Deep digital flexor tendon

• Toe flips up

o Superficial digital flexor tendon

• Fetlock drops slightly or can appear normal

o Suspensory ligament

• Fetlock drops

o Extensor tendons

• Cannot extend the digit

• Catches toe and "knuckles over" at the fetlock

• Transection results in loss of stability of joints and other soft tissue structures

o Severe injury can result in joint dislocation

o They can look like horses with a fracture

Synovial structures

• Contamination of synovial structures can be life threatening

• Sepsis can be refractory to treatment

o Causes severe lameness due to synovitis and infection

• Many synovial structures are superficial and easily penetrated

Bone

• Fracture

o Complete or incomplete

o Stress fracture

o Greenstick fracture

o Open or closed

o Simple, slab, or comminuted

• Disruption of periosteum

o Risk of sequestrum formation

Injury assessment

• Palpation

o Identify damaged structures

o Feel for

• Crepitus

• Bone fragments

• Synovial structure involvement

• Tendon / ligament involvement

• Joint instability

o Always clean and lavage wounds prior to palpation

o Clip if possible

• Radiographs

o Bone damage

o Fractures

o Luxation / dislocation

o Can be used to assess soft tissue injury

• Contrast studies

• Position of probe in relation to other structures

• Presence of gas in synovial structures

• Synovial centesis and joint distention if wound is over a joint

o Used to evaluate if a joint is involved

o You don't need to have a lab to assess joint fluid

o Fluid appearance:

• Pale yellow

• Viscous

• Clear with no turbidity

o Abnormal fluid indicates inflammation or sepsis

o Procedure:

• Sterile prep of the synovial structure at a site distant from the wound

• Insert needle into synovial cavity and aspirate fluid

• Depending on structure you may not get fluid back

• Distend synovial structure with sterile fluids (20-60 ml)

• Watch wound to see if fluid comes out the wound

• Fluid escape = synovial involvement

• Can now do a limited lavage of synovial cavity

• Inject antibiotics before removing needle.

• Ultrasound

o Used to evaluate damage to soft tissue structures

o May identify foreign body

o Evaluate synovial and other body cavity fluid for signs of inflammation or sepsis

Stabilization of musculoskeletal injuries

• Don't forget to assess the whole animal – not just the most obvious issue

o Systemic issues such as shock and dehydration may need to be addressed before stabilization of musculoskeletal trauma

o Address the most life-threatening injuries first

• Severe hemorrhage

• Compression bandage

o Unstable fractures or soft tissue injuries

• Splinting

• Compression bandage

o Very important component of musculoskeletal stabilization

o Used to:

• Stop hemorrhage

• Decrease or minimize swelling

• Protect wounds

• Stabilize fractures and severe soft tissue injury

o Components

• Non-stick pad (Telfa, Release, Adaptec)

• Gauze sponges

• Kling roll (soft white cotton roll)

• Heavy padded bandage

• Brown gauze

• Vetrap

• Elastikon

o Preparation

• Clean any wounds

• If heavily contaminated place a wet-to-dry until transported for repair

• Wear gloves until wound is covered

• Especially important if open synovial structure or open fracture

Immobilization

• Immobilization objectives

• Prevent further damage

o Soft tissue

o Nerves

o Vessels

o Bone ends

o If closed fracture – to prevent it from becoming open

o Decrease contamination

o Stabilizing limb decreases horse's anxiety

• Splint materials

o Wood boards

o PVC pipe

o Metal

o Casting material

o Be creative!!!

o Essentials:

• Must be stiff and long enough for appropriate use

• Always place over padded bandage (e.g. Robert-Jones)

• Immobilization Principles

o ALWAYS incorporate the joint above and below the fracture in splint

o NEVER end a splint at the fracture site

• Dorsal splint

o Used in front limb

o Fractures and soft tissue injuries distal to the fetlock

o Want to keep metacarpus and phalanges in dorsal alignment to prevent further disruption of the fracture

o Examples: P1 and P2 fractures, DDFT transection in pastern region

• Full limb lateral splint (front limb)

o Used in front limb

o Fractures of carpus and distal radius

o Use in proximal radius fractures in controversial

• Plantar splint

o Same principles as dorsal front limb splint

o Fractures and soft tissue injuries distal to the fetlock

o Want to keep metacarpus and phalanges in dorsal alignment to prevent further disruption of the fracture

• Full limb lateral splint – hind limb

o Used in tibia fractures

o Combine with plantar splint for fractures / dislocations of the tarsus

• Kimzey splint

o Manufactured by Kimzey Welding Works

o Used for:

• Fractures of distal cannon bone and distal limb

• Severe soft tissue trauma resulting in instability

o Keeps limb in appropriate alignment

• Casting material splint

• PVC splint

o Use 6 – 8" diameter pipe

o Cut into 3 – 4 "wide strips of appropriate length

o Can be bent with heat

Additional treatments

• Analgesia

• NSAIDS

• Low doses of sedation can also be given

o Be careful not to give too much as it may make them unstable on their feet

• Antibiotics (systemic)

o Severely contaminated wounds

o Synovial structure involvement

o Fracture

o Burns

• IV Fluids

o If in shock

o Significant blood loss

o Significant dehydration