Tendons and Ligaments

Ligaments

-connect two bones or cartilages or hold together a joint

-role is to maintain bones in alignment and provide support to a joint

-usually located on either side of a joint

Tendons

-a flexible cord of strong fibrous collagen tissue attaching a muscle to a bone

-flexors: on the back surface of the leg and function in flexing the leg, absorbing the forces applied to the leg in motion, assisting in the support of the leg when weight bearing, and assisting in locomotion

-extensor: on the front surface of the leg and function in extending the leg and bearing weighr

Tendon and Ligament Injuries

-can occur through direct trauma and abnormal/excessive forces placed on joints

-severity of lameness ranges from mild to severe

-with injuries there is often heat, pain, and swelling in the region of injury

Suspensory ligament

-serves to cushion impact and prevent extreme overextension of the fetlock joint; runs from the back of the cannon bone and attaches to the back of the upper third of the long pastern bone.

Treatment of tendon and ligament injury

-stall rest

-ice or cold hosing

-bandaging to immobilize the limb

-anti-inflammatories to aid in reduction of swelling and provide pain relief

-slow rehabilitation plan

Degenerative Suspensory Ligament Disease (DSLD)

-subtle onset; affects more than one limb and is usually bilateral

-usually appears in the later years of a horse’s life

-diagnosis:

• full lameness exam w/ an ultrasound (will show visible changes to the suspensory ligament)

• severe lameness on affected limbs after a fetlock flexion test

• suspensory will feel harder and thicker than normal, area may be hot or swollen

-treatment:

• no cure, focus on making horse comfortable

• stall rest, controlled exercise, pain relief with NSAIDs/anti-inflammatories, supportive boots or wraps, and corrective shoeing

• stem cell injection, PRP injection, shockwave therapy, laser therapy, magnetic therapy, acupuncture, chiropractic care

Extensors and flexors

-5 extensors; main one is the common digital extensor tendon

-2 flexors: superficial digital flexor and the deep digital flexor

Flexor/Extensor

-common digital extensor tendon: extends toe

-lateral digital extensor tendon: extends pastern

-superficial flexor tendon: flexes pastern

-deep digital flexor tendon: flexes toe

-suspensory ligament: stabilizes fetlock joint

Check apparatus

-allows the horse to sleep standing on its feet by locking the lower legs without much muscular effort

-braces the entire joint system; the fibrous bands take over the muscles’ job of straightening the various joints; act as drawstrings uniting all the joints together

Tendon sheath

-a balloon like structure that encloses and lubricated the flexor tendons slightly above and below the fetlock joint

-distension of the lower digital flexor tendon sheath is typically a wind puff

• the remnant of an old injury, it occurs when inflammation stretches a tendon sheath or joint capsule and then subsides; the structure remains stretched and fills with fluid

Tendon sheath sepsis

-an infected tendon sheath usually results from a wound that has penetrated into the sheath

• bacteria is introduced into the sheath and proliferates, and a massive inflammatory process follows

-once the wound heals closed, the tendon sheath becomes a closed abscess and the horse is severely lame

-signs: swelling, severe lameness

-standard treatment: arthroscopy (flushing out the infected tissue) & antibiotics

Tendon injury

-can occur from external trauma or mechanical overload

-a repetitive low grade injury characterized by inflammation, with the presence of heat, pain, and swelling

-results from excessive stress on the tendon that stretches and ruptures the tendon fiber bundles

-treatment:

• control the inflammation

• cold therapy

• support bandages

• anti-inflammatory drugs

• 6-12+ month of rest

Bowed tendon (tendonitis)

-damage of individual fibers or entire tendon; a pocket forms behind the tendon from blood and fluid collection

-collection signs:

• swelling

• throbbing

• heat

• lameness

• commonly found in the middle of the cannon bone

Tendonitis prevention and treatment

-prevention: fatigue is often a factor when tendon and ligament injuries occur; easiest prevention is appropriate training and conditioning program

-treatment:

• therapy, rest, and rehab

• reduce inflammation, maintain blood flow, and decrease the formation of scar tissue within the tendon

Platelet rich plasma (PRP)

-platelets are little blood cells responsible for clotting blood; they contain many growth factors

-when injected into a tendon the growth factors encourage new cells to grow into the injury site and more normal tendon fibers to develop

-treats tendon injuries and suspensory ligament injuries

Stem cell therapy

-stem cells can be found in both bone marrow and fat

• stem cells have the ability to grow into many different types of tissue

-bone marrow can be taken from the horse’s pelvis or sternum and sent to a specialist lab to culture more stem cells

Extracorporeal shockwave therapy (ESWT)

-involves the delivery of high impact short duration physical ‘shock waves’ to an area of damaged or inflamed tissue

• deliverance of a series of shocks focused on the site of tissue damage which is repeated at 7-10 day intervals for up to 4 occasions

• there is evidence that it can improve and increase blood flow to the area, reduce pain by suppression of nerve ending activity (numbing of nerves) and increase tendon, ligament, and bone regeneration

Pin Firing/Thermocautery

-a therapy that uses a small, red-hot probe to caused cauterization of tissue in horses with chronic injuries to produce a stronger inflammatory process

-used commonly in race horses to treat splints or chronic tendonitis

-makes chronic inflammations acute and allows them to heal

-after care: horse must have 6 months-year off