Shock Wave Therapy for Horse Leg Wounds: Can It Reduce Proud Flesh?

By Dr Duncan Houston

Lower-leg wounds in horses can be deceptively difficult.

A wound that initially looks like a straightforward cut may be close to a joint, tendon sheath, tendon, ligament or bone. Even after the serious injuries have been ruled out, wounds on the lower limb often heal slowly and may develop excessive granulation tissue, commonly called proud flesh.

Extracorporeal shock wave therapy, or ESWT, has been investigated as a way to improve the healing environment. The research suggests it may reduce proud flesh and visible inflammation in some wounds, but it is not a guaranteed way to make every wound close faster.

Quick Answer

Shock wave therapy may help reduce excessive granulation tissue and clinical inflammation in some horse lower-leg wounds. However, equine studies are very small and have produced mixed results. One found healthier-looking wounds without faster closure, while another reported a shorter overall healing time.

ESWT should be considered an adjunct to proper wound care, not a replacement for veterinary examination, cleaning, debridement, bandaging, surgical closure, infection control or skin grafting. (PubMed)

What Is Shock Wave Therapy?

Extracorporeal shock wave therapy uses acoustic pressure waves to deliver mechanical energy into tissue from outside the body. Despite the name, it does not electrically shock the horse.

Different systems generate and deliver energy in different ways. These include focused, unfocused and radial devices. The depth, energy, pulse number and distribution of the wave can vary considerably between machines.

That distinction matters because the available equine wound studies did not all use the same equipment or protocol. One study evaluated focused ESWT, while another used an unfocused electrohydraulic system. Their results should not be treated as though they came from one standardised treatment. (Experts@Minnesota)

The American Association of Equine Practitioners currently describes wound healing as an emerging ESWT application that requires cautious case selection. It recommends that shock wave treatment be performed by a licensed veterinarian, or by a licensed veterinary technician under direct veterinary supervision where legally permitted. (AAEP)

Why Are Lower-Leg Wounds So Difficult to Heal?

Wounds below the knee or hock behave differently from wounds on the horse’s body.

Research comparing limb and body wounds found consistently lower blood flow in the limb wound beds. Limb wounds also had lower glucose concentrations and higher lactate concentrations, supporting the presence of altered metabolism and relatively inadequate oxygen delivery during healing. (PubMed)

Proud flesh is not caused by one single problem. Research into naturally occurring excessive granulation tissue has found persistent inflammatory and fibrosis-associated cells, while more recent work has identified a greater proportion of immature collagen within the affected tissue. (PubMed)

Other practical problems include:

• Very little loose skin for closing wounds

• Limited soft tissue covering important structures

• Constant movement around the fetlock, pastern and hock

• Repeated contamination from soil, bedding and manure

• Ongoing irritation from an inappropriate or poorly maintained bandage

• Slow wound contraction

• Chronic inflammation

• Infection or retained foreign material

This is why a wound may look healthy for several days, then stall or begin producing a raised mound of red tissue.

What Is Proud Flesh?

Granulation tissue is a normal and necessary part of healing.

Healthy granulation tissue is usually pink to red, moist and finely textured. It fills the wound bed from the bottom upwards and provides a surface across which new skin can grow.

It becomes exuberant granulation tissue, or proud flesh, when it grows higher than the surrounding skin edges. The raised tissue interferes with normal epithelial advancement and prevents the skin from continuing across the wound.

Proud flesh often:

• Appears bright pink or red

• Has a soft, lumpy or cauliflower-like surface

• Rises above the wound edges

• Bleeds easily when touched

• Returns after previous trimming

• Develops most commonly on the lower limb

AAEP guidance describes proud flesh as a consequence of inefficient, prolonged inflammation. Infection, excessive motion and inappropriate bandaging can all contribute. (AAEP)

Not every red wound is proud flesh. Flat, healthy granulation tissue is exactly what a healing wound needs. Removing healthy tissue unnecessarily can delay recovery.

What Did the Main Shock Wave Wound Study Find?

The study most closely matching the original article was published in the American Journal of Veterinary Research in 2010.

Researchers created multiple 6.25 cm² superficial wounds over the metacarpal region of both forelimbs in six healthy horses. One forelimb received ESWT and bandaging, while the opposite limb received bandaging and sham treatment.

Each treated wound received 625 pulses from an unfocused electrohydraulic shock wave generator.

The researchers assessed:

• Visible inflammation

• The amount of protruding granulation tissue

• Total wound area

• New epithelial growth

• Fibroplasia

• Blood vessel development

• Inflammatory changes

• Myofibroblast distribution

The untreated control wounds were 1.9 times as likely to appear inflamed and had significantly higher proud-flesh scores.

However, ESWT did not significantly improve:

• Total wound size

• Area of new epithelial growth

• Histological inflammation

• Fibroplasia

• Neovascularisation

• Myofibroblast findings

The researchers concluded that ESWT did not accelerate wound closure, but treated wounds developed less excessive granulation tissue and appeared clinically healthier. (PubMed)

Did Another Study Find Faster Healing?

Yes, which is why the evidence should not be simplified into “shock wave does not speed healing.”

A separate 2009 randomised study involved six healthy adult horses. Researchers created full-thickness metacarpal and metatarsal wounds that extended to the underlying periosteum.

Selected wounds received focused ESWT once weekly.

The average healing time was:

• 76 days in ESWT-treated wounds

• 90 days in untreated wounds

That was a statistically significant difference.

However, the researchers did not detect significant differences in:

• Bacterial culture results

• Area of epithelialisation

• Percentage wound contraction

• Growth-factor staining

The study therefore suggested that ESWT may shorten healing under that particular experimental protocol, but it did not identify the mechanism responsible. (Experts@Minnesota)

What Did the Growth-Factor Study Find?

A 2013 study investigated whether shock wave treatment altered growth-factor gene expression in equine skin and wounds.

The research included 14 healthy horses. Six horses had full-thickness wounds created on both forelimbs. Wounds on one limb received ESWT immediately after creation and again on days 7, 14 and 21.

ESWT-treated wounds had lower expression of transforming growth factor beta 1, or TGF-β1, throughout the study period. TGF-β1 is involved in fibroblast activity, collagen deposition and granulation tissue formation.

The researchers proposed that suppressing TGF-β1 might help reduce excessive granulation tissue. However, ESWT did not produce broad changes across all measured growth factors, and altered gene expression does not by itself prove faster or better healing in naturally occurring wounds. (PubMed)

What Does the Research Really Mean?

The most accurate conclusion is:

Shock wave therapy may improve the quality of some equine distal-limb wounds and may reduce proud flesh, but it has not been proven to make every wound heal faster.

The evidence has several important limitations:

• Each of the main wound-healing studies involved only six horses

• The wounds were surgically created

• The horses were otherwise healthy

• The injuries were controlled and standardised

• They were not naturally contaminated paddock or stable injuries

• Different shock wave devices and protocols were used

• The measured outcomes were not consistent between studies

• Large clinical trials involving naturally occurring wounds are lacking

Using the opposite limb as a control helps account for variation between horses, but it does not overcome the very small sample size or reproduce the complexity of real injuries.

In practical terms, ESWT is an interesting adjunct rather than established first-line treatment for every horse wound.

Does Shock Wave Therapy Treat Infection?

There is no good evidence that ESWT alone sterilises an equine wound or replaces appropriate infection management.

In the 2009 experimental study, bacterial culture results did not differ significantly between shock wave-treated and untreated wounds. (Experts@Minnesota)

A wound with infection may require some combination of:

• Thorough lavage

• Surgical debridement

• Removal of dead tissue

• Removal of foreign material

• Drainage

• Bacterial culture

• Local antimicrobial treatment

• Systemic antibiotics when clinically justified

• Regional limb perfusion

• Joint or tendon-sheath lavage

Applying shock waves to a wound while leaving infection, devitalised tissue or a foreign body in place is polishing the bonnet while the engine is on fire.

Which Wounds Might Be Considered for ESWT?

It may be reasonable to discuss ESWT when a horse has:

• A distal-limb wound healing by second intention

• Recurrent excessive granulation tissue

• A wound that repeatedly becomes inflamed despite an appropriate care plan

• A clean wound bed after adequate debridement

• No untreated joint, tendon-sheath, tendon, bone or ligament injury

• No uncontrolled infection

• A wound being monitored objectively by a veterinarian

• Access to suitable equipment and an experienced operator

It may be particularly attractive when the aim is to control repeated proud-flesh formation rather than simply making the wound close as quickly as possible.

The decision should depend on wound depth, location, age, contamination, tissue quality and the structures involved. It should not depend only on whether someone nearby happens to own a shock wave machine.

When Should Shock Wave Therapy Not Be the First Priority?

Shock wave treatment should not delay investigation or definitive treatment of a fresh wound.

It is not the immediate priority when:

• The wound may still be suitable for suturing

• There is uncontrolled bleeding

• A joint or tendon sheath may have been penetrated

• Tendon, ligament or bone is exposed

• A tendon may be partially or completely lacerated

• A foreign object remains in the wound

• Necrotic tissue requires debridement

• There is a fracture

• Infection is spreading

• The horse is severely lame or non-weight-bearing

• The wound requires surgical lavage

• Skin grafting or another reconstructive procedure is more appropriate

Small wounds can still penetrate important structures. The surface appearance is a poor guide to depth, especially around joints and tendon sheaths. (University of Minnesota Extension)

Which Horses May Not Be Suitable for ESWT?

General AAEP safety guidance lists several situations in which shock wave treatment may be contraindicated or require particular caution, including:

• Pregnancy

• Bleeding disorders

• Anticoagulant treatment

• Malignant tumours in the treatment area

• Treatment directly over open growth plates in foals

Typical adverse effects are generally mild and temporary but may include local pain, redness, bruising and discomfort during treatment. (AAEP)

Open-wound treatment requires additional judgement because energy is being delivered into already damaged and inflamed tissue. The device, energy level, applicator and timing should be selected by the treating veterinarian.

How Worried Should You Be About a Lower-Leg Wound?

Lower concern

The wound is a superficial abrasion, and:

• Only the outer skin is affected

• Bleeding has stopped

• The horse is walking normally

• There is no swelling, heat or discharge

• The wound is not over a joint or other high-motion area

• The horse is bright and eating normally

Clean the wound, monitor it closely and seek veterinary advice if its depth or location is uncertain.

Moderate concern

Arrange a veterinary assessment when:

• The skin edges have separated

• The wound is below the knee or hock

• Tissue beneath the skin is visible

• The wound is over a high-motion area

• Mild lameness or swelling is present

• The wound repeatedly becomes contaminated

• Healing appears to have stalled

• Granulation tissue is approaching the level of the skin edges

Early assessment may preserve the option of closure and prevent a simple wound from turning into a three-month hobby nobody asked for.

High concern

Obtain urgent veterinary care when:

• Proud flesh is clearly above the skin margins

• The wound repeatedly bleeds

• Discharge, odour, heat or pain is increasing

• Swelling is spreading up the limb

• The horse is becoming more lame

• Tendon, ligament or bone may be exposed

• The wound is not objectively becoming smaller

• There is a puncture near a joint or tendon sheath

• The horse has a fever or reduced appetite

Critical

Treat the situation as an emergency when:

• The horse will not bear weight

• Bleeding is heavy or persistent

• Clear, sticky fluid is coming from the wound

• A foreign object remains embedded

• The leg is unstable or abnormally positioned

• A tendon appears divided

• Bone or a joint surface is visible

• The wound is directly over a joint and the horse is severely lame

• The horse is weak, distressed or deteriorating rapidly

University of Minnesota equine first-aid guidance recommends immediate veterinary contact for wounds deeper than the skin, heavy bleeding, clear sticky discharge, wounds over structures that bend and wounds on the back of the lower limb. (University of Minnesota Extension)

When Is a Horse Leg Wound an Emergency?

The most dangerous wound is not necessarily the largest one.

A tiny puncture can enter a joint or tendon sheath and introduce bacteria into a closed synovial space. Early lameness may initially be mild, then become severe as infection develops.

Call your veterinarian immediately when a wound:

• Is over or close to a joint

• Is close to a tendon sheath

• Is on the back of the cannon or pastern

• Releases clear or pale-yellow sticky fluid

• Causes severe or increasing lameness

• Contains an embedded object

• Exposes tendon, ligament or bone

• Is associated with rapidly increasing swelling

• Continues bleeding through firm pressure

• Causes loss of normal limb movement

Do not wait for pus, fever or severe swelling before acting. Synovial infection is much easier to treat before bacteria and inflammatory material have significantly damaged the joint or tendon sheath.

What Should You Do Immediately After Finding the Wound?

1. Keep the horse still

Move the horse only when it can do so safely.

If fracture, tendon injury or severe instability is possible, unnecessary walking can worsen the damage. Place the horse in a safe area and wait for veterinary instructions.

2. Control bleeding

Apply firm, continuous pressure with a clean dressing or folded cloth.

Do not repeatedly remove the dressing to check whether the bleeding has stopped. Add further absorbent material over the original layer if blood begins soaking through.

3. Do not remove an embedded object

An object may be limiting bleeding or showing the precise direction and depth of penetration.

Photograph its location and contact your veterinarian before removing it. Puncture size does not reliably indicate severity. (University of Minnesota Extension)

4. Rinse superficial contamination

Tap water or sterile saline can be used to flush dirt from a wound while waiting for veterinary advice.

Avoid forceful scrubbing of exposed healthy tissue. Do not fill the wound with random powders, harsh antiseptics or multiple ointments before it has been properly assessed.

University of Minnesota guidance recommends cleaning dirty wounds with tap water or sterile saline, covering them with a clean dry bandage and avoiding ointments unless directed by a veterinarian. (University of Minnesota Extension)

5. Cover the wound

A clean non-stick dressing and appropriately padded bandage can reduce further contamination.

An incorrectly applied lower-leg bandage can cause pressure injury, tendon swelling or additional tissue damage. Obtain help when you are not confident applying one.

6. Check tetanus protection

Tetanus vaccination status should be reviewed after every wound.

AAEP guidance recommends that a previously vaccinated adult horse receive a tetanus toxoid booster at the time of injury when at least six months have passed since the previous booster. Horses with an unknown or incomplete vaccination history may require a different protocol, including consideration of tetanus antitoxin. (AAEP)

7. Take photographs

Take a clear photograph before extensive cleaning when doing so will not delay urgent treatment.

Include a ruler or another consistent scale in later photographs. Record:

• Date

• Wound length and width

• Depth where safely assessable

• Amount and colour of discharge

• Granulation-tissue height

• Limb swelling

• Lameness

• Current dressing and medications

Objective records are far more useful than trying to remember whether it looked “roughly a bit better” last Tuesday.

How Will a Veterinarian Assess the Wound?

The examination may include:

• Clipping and cleaning the surrounding area

• Careful exploration under sedation and local anaesthesia

• Assessment of skin viability

• Evaluation of tendons and ligaments

• Testing for joint or tendon-sheath communication

• Radiographs for fractures, foreign material or bone damage

• Ultrasound examination

• Synovial fluid sampling

• Bacterial culture

• Surgical debridement

• Evaluation for primary closure, delayed closure or skin grafting

The correct treatment order is usually:

1. Identify the damaged structures.

2. Control contamination and infection.

3. Remove dead or foreign material.

4. Establish a healthy wound bed.

5. Control motion and protect the wound.

6. Decide whether an adjunct such as ESWT adds meaningful value.

Starting at step six because the technology looks impressive is how expensive detours are born.

How Is Existing Proud Flesh Usually Treated?

Established proud flesh frequently needs to be reduced to the level of the surrounding skin.

Veterinary treatment may include:

• Sharp surgical debridement

• Correction of infection or excessive movement

• Changes to the bandaging protocol

• Carefully selected topical corticosteroid treatment

• Skin grafting for large or refractory wounds

• Repeated measurement and reassessment

Granulation tissue itself has few nerve endings, so trimming the raised portion can often be performed in a standing sedated horse. However, the surrounding skin, wound margins and deeper tissues remain sensitive, and excessive removal can cause significant bleeding or expose important structures.

AAEP guidance describes surgical trimming to skin level as a common treatment and warns that topical corticosteroids must be used carefully because excessive application can delay healing. (AAEP)

ESWT should not be viewed as a non-surgical eraser for a large mass of existing proud flesh. Its more plausible role is helping control the wound environment and reducing repeated overproduction after appropriate wound preparation.

Does Bandaging Prevent or Cause Proud Flesh?

Bandaging can do both, depending on the wound and how the bandage is managed.

A bandage may:

• Protect the wound from contamination

• Absorb discharge

• Reduce movement

• Maintain an appropriate wound environment

• Protect delicate new tissue

However, excessive moisture, pressure, inflammation or prolonged occlusion can encourage granulation tissue.

In one controlled experimental study, all bandaged distal-limb wounds developed excessive granulation tissue, while none of the unbandaged wounds did. Healing time did not significantly differ once the excessive tissue was surgically removed. (PubMed)

That does not mean every lower-leg wound should be left uncovered. Many wounds require bandaging for protection and motion control.

It means the bandage should be treated as an active part of the medical plan. Dressing type, pressure, moisture, frequency of change and the stage of healing should be reassessed rather than continued automatically for weeks.

Shock wave therapy cannot compensate for a wet, slipping, contaminated or excessively tight bandage.

Can Shock Wave Therapy Hide Pain?

Yes, temporary pain reduction is one of the important safety considerations.

Experimental equine studies have found reduced sensory nerve conduction after ESWT and changes consistent with a temporary analgesic effect. (PubMed)

A horse appearing more comfortable after treatment does not prove that:

• The wound has closed

• The tendon is stronger

• Infection has resolved

• The horse is ready to exercise

• Deeper structures are safe

Return to exercise should be based on wound examination, lameness assessment and structural healing, not simply on the horse looking less painful after ESWT.

The AAEP specifically warns that pain masking may contribute to reinjury of compromised tissues. (AAEP)

How Many Shock Wave Treatments Are Needed?

There is no validated universal protocol for horse wounds.

The experimental studies used different:

• Devices

• Energy settings

• Pulse numbers

• Treatment intervals

• Wound depths

• Wound locations

Some research protocols applied ESWT weekly, with repeated treatments during the first several weeks. That does not create a standard prescription for every clinical wound. (Experts@Minnesota)

A sensible clinical plan should define:

• Why ESWT is being used

• What objective improvement is expected

• How wound area will be measured

• How proud-flesh height will be recorded

• When the response will be reassessed

• When treatment will be discontinued

Do not continue repeated sessions indefinitely because the wound appears vaguely “healthier.” There should be measurable progress.

What Else Can Look Like Proud Flesh?

A non-healing, raised or repeatedly bleeding wound is not always simple excessive granulation tissue.

Possible alternatives or contributing problems include:

Infection or biofilm

Persistent infection can maintain inflammation and prevent normal epithelialisation.

The wound may develop increasing discharge, odour, pain, heat or fragile granulation tissue. Deep infection can be present without dramatic surface pus.

Retained foreign material

Wood, wire fragments, dirt, hair and dead tissue may remain within a wound and continually stimulate drainage or inflammation.

Bone sequestrum

A piece of devitalised bone may separate after trauma and create a persistent draining wound. Radiographs or ultrasound may be needed.

Joint or tendon-sheath infection

A small wound near a synovial structure may continue draining or become increasingly painful. This is an emergency rather than a proud-flesh problem.

Excessive movement

Wounds around the fetlock, pastern and hock may repeatedly split or remain inflamed because of constant motion.

Habronema or summer sores

Habronema larvae deposited in damaged skin can cause intensely inflammatory, non-healing lesions with proud-flesh formation. The wounds may be itchy and may contain small gritty yellow nodules. (Center for Equine Health)

An abnormal skin mass

An unusual, recurrent or irregular lesion may require biopsy rather than repeated empirical proud-flesh treatment. Shock wave therapy should not be applied to a possible tumour without diagnosis, and AAEP guidance lists malignant tumours in the treatment area as a contraindication. (AAEP)

Common Mistakes With Horse Leg Wounds

Assuming every red tissue bed is proud flesh

Flat red granulation tissue is usually part of normal healing. Proud flesh rises above the skin margins.

Waiting because the wound is small

A small puncture over a joint or tendon sheath can be more dangerous than a much larger superficial skin wound.

Starting advanced therapy before diagnosing the injury

Shock wave treatment should never delay investigation of deeper structures, contamination or infection.

Copying a research protocol from the internet

Pulse number and energy cannot be transferred safely between different devices and wound types.

Treating pain relief as proof of healing

ESWT may temporarily reduce pain perception. Comfort alone is not evidence that tissue strength has returned.

Trimming proud flesh at home

The tissue can bleed heavily, and important structures may lie immediately underneath it. Debridement should be planned and performed by a veterinarian.

Applying multiple powders and ointments

Products can damage healthy epithelial cells, trap contamination or make the wound impossible to assess accurately.

Leaving the same bandaging plan unchanged

A dressing appropriate during the first inflammatory stage may be unsuitable once the wound has developed healthy granulation tissue.

Ignoring tetanus status

Even relatively superficial wounds can provide an entry point for tetanus. (AAEP)

How Can Proud Flesh Be Prevented?

Not every case can be prevented, but the risk can be reduced.

Obtain early veterinary assessment

Early examination identifies wounds that can be sutured, require surgical treatment or involve important structures.

Control contamination

Flush wounds appropriately, maintain clean dressings and keep the horse in a clean, dry environment.

Remove dead or foreign material

Devitalised tissue and retained debris prolong inflammation.

Control movement

Movement across the wound repeatedly disrupts fragile tissue and may stimulate excessive granulation.

Reassess bandaging

Bandages should be changed and adjusted according to wound stage, drainage and tissue response.

Measure the wound

Weekly measurements and consistent photographs reveal whether the wound is actually shrinking.

Control flies

Fly management reduces irritation and the risk of Habronema-associated summer sores. (Center for Equine Health)

Maintain tetanus vaccination

Keep routine tetanus protection current and discuss post-wound boosting with your veterinarian. (AAEP)

Treat proud flesh early

A small amount of tissue above the wound edge is generally easier to control than a large chronic mass.

Frequently Asked Questions

Does shock wave therapy remove existing proud flesh?

Not directly. It may help reduce further excessive granulation in selected wounds, but established proud flesh often requires veterinary debridement to bring the tissue back to skin level. (PubMed)

Does shock wave therapy make horse wounds heal faster?

The evidence is mixed. One six-horse study found less inflammation and proud flesh without faster closure. Another six-horse study reported average healing at 76 days with ESWT compared with 90 days without it. (PubMed)

Is ESWT safe to use directly around a wound?

It can be used under veterinary supervision in selected cases, but wound-specific evidence remains limited. General side effects may include short-lived pain, redness, bruising and treatment discomfort. Patient selection, equipment and energy settings matter. (AAEP)

How many ESWT sessions does a wound need?

There is no standard number. Research protocols commonly involved repeated weekly treatment, but they used different devices and wound models. The treating veterinarian should set an individual protocol and objective reassessment point.

Can my horse compete after shock wave therapy?

Competition and racing rules vary. The AAEP recommends a minimum withdrawal period of 72 hours, but the applicable discipline or jurisdiction may require a longer period. Always confirm the specific rules before competition. (AAEP)

Final Thoughts

Shock wave therapy is a genuinely interesting option for difficult equine lower-leg wounds, particularly when excessive granulation tissue keeps returning.

The strongest available finding is not that ESWT magically closes wounds. It is that treated wounds in one controlled model appeared less inflamed and produced less proud flesh. Another small study reported faster complete healing, but the total evidence remains too limited to guarantee the same result in naturally occurring injuries.

The fundamentals still matter most: identify the structures involved, control contamination, remove dead tissue, manage infection, use the correct dressing and monitor the wound objectively.

Once those pieces are in place, ESWT may be worth considering as part of a veterinarian-directed plan. It is a supporting actor, not the entire cast.

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Use ASK A VET™ to organise wound photographs, measurements, treatment dates, bandage changes and veterinary instructions. If a wound is worsening, becoming painful or developing excessive tissue, direct examination by your regular veterinarian remains essential.