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

          • Soft tissue

          • Nerves

          • Vessels

          • Bone ends

          • 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, Significant dehydration