Also referred to as windgalls, windpuffs are palpable bumps that contain fluid and form on the the lower legs of horses. [1] They most commonly present on the sides and rear of the fetlock joint. [1]

Windpuffs develop due to the accumulation of fluid within the digital sheath, which envelops and protects both the Deep Digital Flexor Tendon (DDFT) and the Superficial Digital Flexor Tendon (SDFT). [2]

Although windpuffs are not typically associated with lameness or soreness, they may develop in conjunction with an injury. [6] It is important to investigate windpuffs for underlying causes that could affect the horse’s mobility and athletic career.

Factors that contribute to the formation of windpuffs include poor conformation, hoof imbalances, and strenuous activity on hard or deep terrain. [4] Injuries to ligaments, tendons, the fetlock joint capsule, or articular cartilage within the joint can also contribute to windpuffs. [4]

Windpuffs in Horses

Windpuffs (windgalls) are palpable lumps caused by swelling on the lower legs of horses. They may be present on one or more legs and can affect both the front and hind limbs. [1]

Although they are generally considered harmless and are often seen in perfectly sound horses, it’s important to understand their causes, symptoms, and management options.

Windpuffs can be categorized into two main types:

  • Idiopathic: Windpuffs that have an unknown cause and typically don’t cause a problem other than being a cosmetic imperfection. [6]
  • Pathologic: Windpuffs that are triggered by diseases or underlying conditions. [6]

Development of Windpuffs

Windpuffs are caused by an accumulation of fluid at the rear of the fetlock joint in the Digital Flexor Tendon Sheath (DDFTS). [3]

The DDFTS is a protective structure that houses both the Deep Digital Flexor Tendon (DDFT) and the Superficial Digital Flexor Tendon (SDFT). These tendons run along the back of the horse’s lower legs.

The DDFT is positioned close to the fetlock joint, while the SDFT is slightly higher up the leg and inserts in the mid-pastern region of both the front and hind legs.

The digital sheath surrounds both of these tendons and is lined with a synovial membrane. This membrane is responsible for producing synovial fluid, which facilitates the smooth movement of the tendons over the fetlock joint. [3]

When the tendon sheath becomes damaged or inflamed, the production of synovial fluid increases, causing the tendon sheath to swell and distend outwards. [3] Swelling can extend from the mid-cannon bone to the mid-pastern region at the back of the fetlock.

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Types of Windpuffs

Accumulated synovial fluid can produce noticeable bulges (“windpuffs”) on the sides and back of the fetlock in areas where the tendon sheath is not constrained by other structures. These swellings can take on one of two forms:

  • Articular windpuff: Characterized by an enlargement of the fetlock joint capsule [3][4]
  • Non-articular windpuff: Also referred to as a tendinous windpuff, this form involves swelling of the digital flexor tendon sheath. [4][5]

Although windpuffs may not be a sign of injury, it is common for them to develop when there is a repair process occurring in the fetlock joint. [8]

Windpuffs can manifest in a single leg, both front legs, both hind legs, or all four legs. [3]

Idiopathic Windpuffs

The most common type of windpuffs is idiopathic, meaning their underlying cause is unknown. Typically, idiopathic windpuffs occur on both sides of the tendon and are symmetrical in both hind limbs. [6]

Idiopathic windpuffs often persist chronically, meaning they affect the horse for a long period of time. However, their presence can be exacerbated following exercise due to increased stress on the tendons. [9]

Some horses may have an anatomical predisposition to forming windpuffs due to their conformation. For example, horses with club feet are prone to developing windpuffs.

Idiopathic windpuffs are not associated with lameness, as this condition is unrelated to any underlying injury.

Inflammatory Windpuffs

It’s important to distinguish between windpuffs, benign soft and cool swelling around the fetlock joint, and swelling from fetlock joint inflammation. [8] Swelling can occur in both the fetlock joint and the digital sheath simultaneously.

Inflammatory windpuffs involve swelling often accompanied by heat, pain, and potential lameness. These enlarged windpuffs could indicate an underlying injury.

An inflammatory tendinous windpuff typically affects one leg more prominently than the others. It is often accompanied by some lameness, although it may be subtle. [6]

Windpuffs and lameness can develop in conjunction with tendon injuries or ligament injuries. In particular, injuries to the digital flexor tendons or nearby ligaments can lead to windpuffs. Injuries that cause adhesions within the tendon sheath can also lead to windpuffs.

Inflammatory windpuffs can also arise due to lameness in another limb, causing increased pressure on the opposing leg due to chronic hyperextension of the fetlock joint.

Signs & Symptoms

Although windpuffs are not usually painful, they can be a sign of an underlying problem or susceptibility to injury.

If your horse has windpuffs, the swelling should be monitored for any changes in size and symmetry. Affected legs should also be monitored for the presence of heat or lameness.

Characteristics

Soft and Palpable: Windpuffs are usually soft to the touch and feel spongy like a fluid-filled sac when palpated. When gently pressed, they often yield under the pressure.

Location: Windpuffs are typically found on the backside of the fetlock joint, within the region of the digital sheath. They may extend from the mid-cannon bone down to the mid-pastern.

Bilateral Symmetry: Windpuffs often occur bilaterally, meaning they appear on both legs or all four legs.

Painless: Windpuffs are generally not painful when touched or palpated. Horses with windpuffs usually do not exhibit signs of discomfort when flexing the fetlock joint or when the windpuffs are manipulated.

Cold to the Touch: Unlike inflammatory conditions, which may be accompanied by heat and pain, windpuffs are typically cold to the touch and lack other signs associated with inflammation. [8]

Causes

Tendinous windpuffs develop from an accumulation of excessive synovial fluid within the digital flexor tendon sheath. [3] They can develop due to trauma and increased stress placed on the digital flexor tendons, often arising from the over-extension of the fetlock joint. [9]

This type of windpuff is regarded as a wear and tear injury, capable of worsening over time.

Articular windpuffs typically result from repetitive episodes of joint inflammation (synovitis), degenerative joint ailments, structural issues within the joint (such as bone chips or osteochondrosis lesions), or the stretching of the joint capsule. [3][5]

Risk Factors

Several risk factors can predispose horses to developing windpuffs. Understanding and addressing these factors is important for horse owners.

Age:

Windpuffs can manifest in horses of various ages, but anecdotal reports suggest they occur most frequently in older athletic horses. [17]

Repetitive Loading and Hyperextension:

Horses in regular training are at risk for windpuffs due to the repeated stress and hyperextension of the fetlock joint. [9] The issue is most prevalent in horses with lengthy careers in competitive sports.

Hoof Imbalance:

Windpuffs can develop due to hoof imbalance resulting from either improper trimming or shoeing. [9] An imbalanced hoof changes the way a horse bears weight, potentially leading to uneven force distribution across the joints, tendons, and ligaments of the leg.

Conformation:

Any conformation that leads to chronic hyperextension of the fetlock joint can contribute to windpuffs. Horses with the following conformations are prone to hyperextension of the fetlock joint. [9]

  • Elongated toes
  • Low heels
  • Elongated, sloping pasterns
  • Excessively straight pasterns

Diagnosis

If you suspect your horse has windpuffs, consult with your veterinarian to obtain a diagnosis. Your veterinarian will assess whether the windpuffs are idiopathic or due to an inflammatory condition.

A diagnosis may be based on the horse’s medical history, athletic career, diagnostic imaging and synovial fluid sampling.

Medical History

Make sure your veterinarian is aware of any prior injuries or medical conditions affecting your horse’s limbs. If your horse has had minor windpuffs for a long time without showing discomfort, they might not be a major concern.

However, if you observe sudden changes, such as one leg becoming worse than the other or signs of lameness, make sure to report these to your veterinarian.

If your horse starts showing signs of fluid accumulation in the region of the Deep Digital Flexor Tendon Sheath (DDFTS), take note of the following:

  • How long the swelling has been present
  • Whether there is corresponding accumulation of fluid on the opposite limb
  • Whether the horse is lame or has a history of lameness

Discussing these details with your veterinarian can help them determine whether the fluid accumulation is a result of windpuffs or an injury to the DDFTS.

Your veterinarian will also perform a flexion test on the distal limb, to assess your horse for lameness.

Ultrasound

Ultrasound is a diagnostic imaging tool used to evaluate the soft tissues and fluid and fluid in and around the DDFT sheath. [10][11] Ultrasound can guide treatment decisions and offer insight into the probable prognosis.

Ultrasound offers various diagnostic advantages:

  • It can detect fluid with heightened levels of inflammatory cells and protein, suggesting a potential infection.
  • It can identify tears in the flexor tendons and their attachments.
  • It can uncover puncture wounds that might be challenging to detect during a clinical examination and reveal foreign material within the sheath.

Foreign objects appear as bright spots on an ultrasound because the ultrasonic waves cannot pass through them and are reflected back.

X-Ray

X-ray imaging, also known as radiography, can be beneficial for examining the bones adjacent to the DDFT, including the proximal sesamoid bones, which may be involved in windpuff formation.

X-rays can help identify any associated bony changes or abnormalities around the fetlock joint that might be contributing to the development of swelling. If a horse has sustained a trauma, radiographs can reveal fractures or other injuries that might be associated with windpuffs.

Some horses might have arthritis or other joint diseases that cause changes in the bone structure, leading to fluid accumulation. X-rays can help diagnose these conditions.

Synovial Fluid Sample

Taking a sample of synovial fluid from the tendon sheath can also provide valuable diagnostic information. [12] This procedure is also known as joint fluid aspiration or arthrocentesis.

By analyzing the synovial fluid, veterinarians can check for elevated levels of inflammatory cells. An increase in these cells suggests an active inflammatory process, which could indicate an injury or disease within the joint or tendon sheath.

Synovial fluid can also be evaluated for signs of infection. The presence of bacteria or an increased white blood cell count in the synovial fluid might indicate a septic (infected) joint or tendon sheath.

Elevated protein levels in the fluid can also indicate inflammation or potential injury within the joint or tendon sheath.

Differential Diagnosis

Differential diagnosis refers to the process by which a veterinarian determines which disease or condition explains your horse’s symptoms. It involves ruling out other conditions that can present with similar clinical signs.

Your veterinarian will distinguish windpuffs from other conditions by assessing your horse’s physical condition and conducting various diagnostic tests.

Your horse’s evaluation may include a tendon sheath block using an anesthetic, ultrasound, magnetic resonance imaging (MRI), or tenoscopy, which involves a visual examination of the inside of the tendon sheath using a fiberoptic camera.

Other conditions to rule out in the diagnosis of windpuffs include stocking up, tenosynovitis and proximal annular ligament desmitis.

Stocking Up

It is important to distinguish between windpuffs and stagnation edema (stocking up), which is swelling due to inactivity. Some horses experience leg swelling when they remain stationary for long periods, especially after vigorous exercise.

Although this swelling resembles windpuffs, stocking up result from poor circulation. This swelling is transient (short-lived) and subsides when the horse starts moving or exercising again.

Tenosynovitis

Tenosynovitis is a condition characterized by increased fluid accumulation in the Deep Digital Flexor Tendon Sheath (DDFTS), which can mimic the appearance of windpuffs. [7] It involves the inflammation of the synovial membrane surrounding the tendon sheath.

Tenosynovitis can be distinguished from windpuffs because this condition involves acute swelling, pain upon palpation of the affected area, and lameness. [15]

Proximal Annular Ligament (PAL) Desmitis

Proximal Annular Ligament (PAL) Desmitis involves inflammation of the annular ligament located at the top (proximal) part of the digital flexor tendon sheath.

This ligament stabilizes and hold the digital flexor tendons close to the back of the fetlock joint, ensuring smooth movement and preventing excessive tendon displacement.

PAL Desmitis can lead to pain, swelling, and restricted movement of the associated tendons within the sheath. There may be a noticeable bulge of swelling above and below the ligament. [6][7]

Prognosis

The prognosis for windpuffs in horses is generally favorable. These benign, fluid-filled swellings are often cosmetic concerns and usually do not indicate a severe underlying issue. However, chronic windpuffs are challenging to completely eliminate.

Therapeutic treatments, including draining the fluid and administering steroids, hyaluronic acid, or various regenerative medications, may temporarily reduce fluid accumulation. But the swelling often returns over time.

Treatment

Consult with your veterinarian to determine an appropriate treatment plan for windpuffs in your horse. Treatment will depend upon your horse’s symptoms, athletic career, and the underlying cause of fluid accumulation.

Rest

If windpuffs arise from over-training, reducing the horse’s exercise load or allowing rest can help alleviate the swelling. In some cases, your veterinarian may recommend stall rest with restricted turn out to prevent excessive movement and control inflammation.

In most cases, once inflammation in the digital tendon sheath subsides, it is possible to resume riding the horse. If there is an underlying tendon injury, the repair and remodelling process can take several weeks to months. [16]

Medications

Your veterinarian may prescribe anti-inflammatory medications as part of the treatment plan.

Intramuscular injections of polysulfated glycosaminoglycan (PSGAG), such as Adequan®, can also be administered.

For more severe cases, your veterinarian may consider additional interventions, such as steroids, injections, and fluid drainage.

Hoof Care

Proper hoof care plays an important role in the treatment and prevention of windpuffs in horses. Foot balance is critical for reducing strain on the tendons and ligaments.

Work with a qualified farrier to evaluate and correct any imbalances in your horse’s hooves through trimming and shoeing.

Supportive Therapies

Cold therapy, supportive wrapping (bandaging), and poultices may help resolve minor strains or sprains that can contribute to windpuff formation.

Sweating the limb, a method involving the application of an ointment like furacin beneath a wrap, can also help reduce swelling.

Long-Term Management

For older horses with chronic windpuffs, ongoing monitoring is crucial to safeguard against progression or enlargement of tendon sheath distension. However, in most chronic cases, windpuffs are considered cosmetic blemishes and do not significantly impact the horse’s performance or quality of life.

Horses with chronic windpuffs should be provided ample turnout on pasture to promote circulation and alleviate swelling.

Address Underlying Conditions

If windpuffs arise due to an underlying condition, work with your veterinarian to address the root cause. If left untreated, windpuffs may progress and result in mild to severe lameness.

For example, windpuffs may be associated with damage to the digital flexor tendons, resulting in the formation of adhesions within the digital sheath. This can lead to thickening of the palmar/plantar annular ligament. The fetlock joint of affected limbs might also show resistance during a flexion test.

Resolving these underlying conditions is key to preventing lameness.

Prevention

Windpuffs in horses cannot always be prevented. However, there are management practices that you can implement to reduce the risk of this condition.

Follow these tips to prevent the formation of windpuffs in your horse:

  • Hoof Trimming: Maintain proper hoof balance through regular trimming and shoeing from a qualified farrier.
  • Veterinary Checks: Regular examinations can help detect lameness and address any early signs of joint issues.
  • Exercise Warm-Up: Implement thorough warm-up and cool-down routines before and after exercise to reduce the risk of injury.
  • Prevent Overexertion: Develop an appropriate training and exercise regimen to reduce strain on the tendons and ligament of the legs.
  • Turnout Time: Provide sufficient turnout time on an appropriate pasture to support healthy circulation.
  • Identify Lameness: Be vigilant for early signs of discomfort or lameness and seek veterinary advice promptly.

Nutrition

Feeding your horse a balanced diet can also help reduce the risk of windpuffs and support healthy regulation of inflammation.

Provide your horse with a forage-based diet and avoid grain-based complete feeds with high levels of sugar and starch. Also, ensure your horse gets adequate levels of key anti-inflammatory nutrients, including:

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Summary

  • Windpuffs in horses can emerge due to fluid accumulation within the digital sheath enveloping the DDFT and SDFT tendons.
  • Most of the time, windpuffs are not harmful or painful to the horse and are merely a cosmetic issue.
  • Some cases of windpuffs are idiopathic, with unknown origins, but others arise due to inflammatory conditions resulting from injury.
  • Windpuffs can present in the fetlock joint or along the deep digital flexor tendon near the fetlock joint.
  • Consult with a veterinarian to determine if there is an underlying cause for windpuffs in your horse that requires treatment.

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References

  1. Carver, J. A Treatise on the Veterinary Pathology of the Different Lamenesses to Which the Horse Is Subject. Farriers Mag. 1818.
  2. Singer, E. An approach to diagnosing lameness in equine patients. Vet Times. 2015. Accessed Oct 3, 2023.
  3. Pilliner, S. and Davies, Z. Equine Science 5th Edition. John Wiley & Sons. 2013.
  4. Dyson, S. Forelimb Lameness in the horse 1 An approach to diagnosis. In Practice. 1986.
  5. Devereux, S. The Veterinary Care of the Horse: 3rd Edition. Crowood Press. 2019.
  6. L. A. Fortier, Indications and techniques for tenoscopic surgery of the digital flexor tendon sheath. Equine Vet Educ. 2005.
  7. Brokken, M.T. Digital Sheath Tenosynovitis in Horses – Musculoskeletal System. Merck Veterinary Manual. Accessed: Sep. 18, 2023.
  8. Ivers, T. The Bowed Tendon Book. The Russell Meerdink Company Ltd., 2006.
  9. Schramme, M.C. Treatment of deep digital flexor tendonitis in the foot. Equine Vet Educ. 2008.
  10. Kent, A.V. et al. Improved diagnostic criteria for digital flexor tendon sheath pathology using contrast tenography. Equine Vet J. 2020. View Summary
  11. McDiarmid, A. Ultrasonography of the palmar metacarpus and pastern in the horse. In Practice. 1995.
  12. Schnabel, L.V. et al. Tendon sheath masses – What are the differential diagnoses and what diagnostics are needed? Equine Vet Educ. 2023.
  13. Maranon, G. et al. The effect of methyl sulphonyl methane supplementation on biomarkers of oxidative stress in sport horses following jumping exercise. Acta Vet Scand. 2008. View Summary
  14. Jess, T. and Ross-Jones, T. Omega-3 fatty acid supplementation in horses. R Bras Zootec. 2014.
  15. Ross, M.W. Chapter 8 – Manipulation. IN: Diagnosis and Management of Lameness in the Horse. 2nd Edition. Saunders. 2011.
  16. Dakin, S.G. et al. Resolving an inflammatory concept: The importance of inflammation and resolution in tendinopathy. Vet Immunol Immunopathol. 2014. View Summary
  17. Varney, C. Should You Be Concerned About Equine Windpuffs?. Dressage Today. Accessed Oct 3, 2023.