Bit & Bridle

Equine Quittor

Other Names

  • Collateral Cartilage Infection
  • Ungual Cartilage Necrosis
  • Lateral Cartilage Suppuration

What Is Quittor in Horses?

Quittor is a chronic, suppurative (pus-producing) infection of one of the collateral (ungual) cartilages of the horse’s foot. The collateral cartilages are paired, plate-like structures attached to the wings of the pedal bone (coffin bone) on each side of the hoof, extending upward to form the “heel bulges” felt on either side of the pastern above the coronary band. When infected, the cartilage undergoes a process of necrosis — the tissue progressively dies and becomes a source of persistent purulent discharge, typically draining through one or more sinus openings at or above the coronary band.

Quittor was considerably more common in the era of working draught horses and heavy agricultural use, when persistent foot injuries and inadequate wound care allowed chronic infections to establish. While less frequently seen in modern leisure and performance horses due to improved veterinary care and wound management, it does still occur — particularly following foot injuries or deep septic processes that involve the heel region.

The condition is almost always unilateral, affecting the medial or lateral collateral cartilage of a single foot, and almost always a forelimb. Because the infection is seated within relatively avascular (poorly blood-supplied) cartilaginous tissue, it is inherently resistant to antibiotics and frequently persists despite conservative treatment, ultimately requiring surgical intervention for resolution.

Causes

Quittor develops when infection gains access to the collateral cartilage, most commonly through:

  • Traumatic wounds: Lacerations, puncture wounds, or deep bruising of the heel region, coronary band, or pastern that introduce bacteria into or adjacent to the cartilage. Injuries from wire, nails, glass, or other sharp objects are classic precipitants.
  • Infected corns or bruises: Pressure-related damage to the foot — particularly corns in the heel seat — that becomes infected and spreads to adjacent structures.
  • Foot abscesses: A subsolar abscess that tracks to the heel and breaks out near the coronary band may establish a persistent infection involving the cartilage if it communicates with or invades cartilaginous tissue.
  • Treads: Injuries caused by one foot striking the heel or coronary band of the opposite limb, or by another horse treading on the foot.
  • Spread from adjacent septic processes: Deep septic pedal osteitis, navicular bursa infection, or coffin joint sepsis may involve the collateral cartilage secondarily.

The organisms most commonly cultured from quittor lesions are mixed aerobic and anaerobic bacteria — a reflection of the soil and hoof environment. Fusobacterium, Bacteroides, staphylococcal, and streptococcal species are frequently identified.

Symptoms and Signs

The clinical presentation of quittor is relatively characteristic once the condition is established:

  • Draining sinus tracts at the coronary band: One or more openings at or just above the coronary band, typically on the medial or lateral heel, that discharge a thin, watery to moderately purulent exudate. The discharge may be intermittent — improving temporarily and then worsening again.
  • Lameness: The degree of lameness varies. In early or mild cases, lameness may be subtle. As infection deepens or spreads, lameness becomes progressively more pronounced. Horses with involvement of adjacent structures (coffin joint, navicular bursa) may be severely lame.
  • Heat and swelling: Warmth and swelling of the heel, pastern, and coronary band region on the affected side. The tissue above the draining sinus may be edematous and inflamed.
  • Fluctuant swelling: Before a sinus opens or during periods of acute exacerbation, a painful fluctuant swelling above the coronary band may be palpable as pus accumulates.
  • Failure to respond to conventional treatment: A key clinical feature of quittor is its characteristic persistence despite courses of antibiotics and routine wound management. This is attributable to the poor blood supply of the cartilaginous tissue and the presence of sequestrated (dead) tissue.

Diagnosis

Diagnosis is based on clinical signs and supported by imaging to characterise the extent of disease:

  • Clinical examination: Careful palpation of the heel, coronary band, and pastern to identify swelling, pain, and sinus openings. Probing of any sinus tracts (under sedation) helps characterise their depth and direction.
  • Radiography: X-rays of the affected foot are essential. They may reveal calcification or dystrophic change within the collateral cartilage (sidebone), or — more seriously — signs of involvement of the pedal bone (septic pedal osteitis), coffin joint, or navicular apparatus. These findings significantly influence prognosis and management planning.
  • Sinography (contrast radiography): Injection of radiographic contrast medium into the sinus tract followed by X-ray allows visualisation of the tract’s extent and its relationship to underlying structures.
  • Ultrasonography: Useful for assessing soft tissue involvement around the heel and coronary band region.
  • Culture and sensitivity: Swabs from the sinus or intraoperative samples should be submitted for culture to guide antibiotic selection.

Treatment

Conservative medical management alone rarely resolves established quittor because the infected, necrotic cartilage acts as a persistent source of infection that antibiotics cannot penetrate adequately. Effective treatment almost always requires surgery:

  • Surgical debridement and cartilage excision: The definitive treatment for quittor is surgical removal of all infected and necrotic cartilage. Under general anaesthesia or, in some cases, standing sedation with regional anaesthesia, the surgeon removes the affected cartilage, debrides the surrounding tissue, and ensures adequate drainage. The wound is typically left open or partially open for drainage and granulation.
  • Perioperative antibiotics: Systemic antibiotics are administered perioperatively and for a period post-surgery. Regional limb perfusion — delivering high concentrations of antibiotic directly to the foot via the digital vasculature — may be used to supplement systemic treatment.
  • Post-operative wound management: Regular bandage changes, wound lavage, and careful monitoring for signs of secondary infection are essential during the healing phase.
  • Therapeutic shoeing: Once healing progresses, a skilled farrier should provide supportive shoeing to protect the healing heel and facilitate hoof wall regrowth over the surgical site.

Referral to an equine surgical specialist is advisable for all but the most superficial cases. The BEVA maintains guidance on referral pathways for horses with complex foot disease. For related foot conditions, see our articles on Equine Canker and Equine Navicular Disease.

Prevention

  • Attend promptly to all foot and heel wounds — clean, assess for depth, and seek veterinary attention for puncture wounds or lacerations in the heel or coronary band region.
  • Maintain good farriery including correct foot balance. Poorly balanced feet with excessive heel pressure predispose to corns and bruising that can become infected.
  • Address subsolar abscesses promptly and ensure adequate drainage — an abscess that is left to track for weeks has more opportunity to involve cartilaginous structures.
  • Protect horses in work on hard surfaces with appropriate shoeing to reduce the risk of tread injuries and heel trauma.

Prognosis

Prognosis for quittor is fair to good when surgery is performed promptly and completely, and when underlying structures (coffin joint, navicular apparatus, pedal bone) are not involved. Cases limited to the collateral cartilage with no deep spread carry a reasonable prospect of return to work following surgical resolution and appropriate post-operative management.

Cases with involvement of the coffin joint, navicular bursa, or pedal bone have a significantly more guarded prognosis, as these structures are much more difficult to decontaminate and can sustain permanent damage. Chronic, long-standing cases that have been repeatedly treated without surgery carry a more guarded outlook due to established tissue destruction and the risk of extensive cartilage involvement.

When to Call the Vet

Seek veterinary assessment urgently if you notice:

  • Any draining sinus at or above the coronary band, particularly in the heel region
  • Lameness alongside heat and swelling in the heel and pastern area
  • A painful, fluctuant swelling developing near the coronary band following a known foot injury
  • A wound in the heel region that fails to heal despite several weeks of treatment
  • Signs of serious deterioration — marked lameness, significant swelling extending up the pastern or cannon region — following any heel injury

Frequently Asked Questions

Can quittor heal on its own without surgery?

In the vast majority of established cases, quittor will not resolve without surgical removal of the infected cartilage. Antibiotics can reduce acute inflammation and temporarily improve signs, but they cannot eliminate the infection seated within poorly vascularised necrotic cartilage. Surgery is the definitive treatment, and delaying it allows infection to spread and worsens the prognosis.

How long is recovery after quittor surgery?

Recovery typically takes several months depending on the extent of surgery and the size of the wound created. The surgical site heals by secondary intention (granulation and re-epithelialisation) in most cases, and the hoof wall above the surgical site must regrow — a process that takes months. Horses require careful wound management throughout this period and may need supportive shoeing for an extended time. Return to full work is possible but should be guided by your vet based on healing progress.

Is quittor common in modern horses?

Quittor is considerably less common than it was in the era of heavy working horses. Improved standards of wound care, veterinary availability, and reduced use of horses for heavy draught work have all contributed to its decline. It does still occur, however, particularly following deep penetrating wounds to the heel or poorly managed foot abscesses in horses where veterinary care was delayed or inadequate.

Which foot is most commonly affected?

Quittor almost exclusively affects the forelimbs, and the medial collateral cartilage is more commonly involved than the lateral in some studies, possibly reflecting the greater exposure of the medial heel to tread injuries. Hindlimb involvement is rare. Bilateral cases are unusual.