Tendinitis
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Tendinitis is injury and inflammation within a tendon, most commonly the superficial or deep digital flexor tendon. The superficial digital flexor tendon is a high-load elastic structure that stores and releases energy at speed; fatigue and overstrain can tear fibre bundles, creating the characteristic bowed forelimb tendon. Deep digital flexor injury occurs at several levels, including within the hoof where it passes over the navicular bone.
Acute superficial injury produces heat, swelling, pain and variable lameness along the back of the cannon. A core lesion may be present even when the horse becomes more comfortable within days. Deep injuries inside the foot usually lack visible swelling and present as persistent lameness. Tendon healing fills the defect with scar tissue that is less organised and elastic than the original, leaving a lifelong reinjury risk.
Fast work, fatigue, inadequate conditioning, poor surface, limb and hoof mechanics, and continuing through subtle inflammation all influence risk. One dramatic “bow” can follow cumulative microscopic damage rather than a single bad step. Not every thick tendon is active tendinitis: old scar, tendon-sheath fluid and nearby ligament injury require distinction.
Prognosis depends on tendon, lesion size, fibre disruption and desired athletic level. Small injuries in lower-speed disciplines fare better than major superficial flexor tears in racehorses. Cosmetic reduction in swelling is not proof of mechanical strength. Collagen remodelling takes many months, so a rushed return after apparent clinical recovery is a common reason for recurrence.
Tendon injury ranges from microscopic fibre disruption to a core lesion or complete rupture. Heat and swelling may fade before collagen regains organised strength, explaining the high reinjury risk during premature return. The superficial digital flexor tendon is commonly injured in galloping horses, while other tendons and insertion sites have different loading and prognosis.
Screening & Early Detection
Both limbs are palpated systematically for heat, pain, thickening and loss of normal tendon edges before and after exercise. Lameness examination and diagnostic analgesia localise deep or subtle lesions. Acute severe injury may be stabilised before extensive movement, while a wound near a tendon sheath requires urgent assessment for synovial penetration.
Ultrasound is the main tool for superficial and mid-limb tendons, documenting cross-sectional area, fibre alignment and core lesions at standard levels. Very early scans can underestimate the final lesion as damage evolves, so repeat imaging after several days and during rehabilitation is valuable. MRI is preferred for deep digital flexor injury within the hoof and other regions hidden by bone.
Serial scans are compared at the same levels and machine settings, but exercise progression also considers lameness and palpation. A tendon that looks smaller can remain poorly organised. Baseline screening of athletes can identify change from the horse’s normal, yet ultrasound abnormalities without pain or functional change should not automatically be injected or rested without clinical interpretation.
Treatment & Management
Acute care limits additional fibre disruption and controls inflammation. Exercise stops; cold therapy, a correctly applied compression bandage, NSAIDs and appropriate support are used under veterinary direction. Severe breakdown may need splinting. Intratendinous corticosteroid is contraindicated because it impairs repair. The horse is not repeatedly trotted to see whether swelling has settled.
After the acute phase, controlled loading is the central treatment. Hand walking begins at a lesion-specific time and progresses through walk, trot and canter over many months using lameness and serial ultrasound. Complete inactivity for the entire healing period produces weak disorganised tissue, while premature speed overloads immature scar. Hoof balance and shoeing reduce abnormal tendon strain.
Platelet-rich plasma, stem-cell products, shockwave or other regenerative approaches may be considered for selected lesions; evidence and product quality vary, and none replaces rehabilitation. Surgery is reserved for particular tendon-sheath adhesions, constriction or selected chronic problems. Return to competition is gradual, and some horses require a lower-impact discipline. Prognosis is guarded for large core lesions and high-speed racing because repaired tendon never regains identical structure and reinjury remains common.
Hoof balance and shoeing are reviewed so rehabilitation does not repeatedly overload the healing tendon.
Breeds or species affected
Akhal-Teke
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Anglo-Arabian
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Arabian
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Barb
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Caspian
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Kathiawari
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Marwari
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Shagya Arabian
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Thoroughbred
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American Quarter Horse
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American Paint Horse
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Appaloosa
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Australian Stock Horse
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Brumby
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Waler
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Morgan
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Standardbred
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American Saddlebred
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Tennessee Walking Horse
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Missouri Fox Trotter
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Rocky Mountain Horse
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Peruvian Paso
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Criollo
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Mustang
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Canadian Horse
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Andalusian
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Lusitano
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Lipizzaner
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Friesian
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Dutch Warmblood
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Hanoverian
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Holsteiner
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Oldenburg
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Westphalian
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Trakehner
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Selle Français
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Belgian Warmblood
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Danish Warmblood
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Swedish Warmblood
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Swiss Warmblood
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Australian Warmblood
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Irish Sport Horse
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Cleveland Bay
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Württemberger
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Zangersheide
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Knabstrupper
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Orlov Trotter
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Camargue
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Icelandic Horse
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Pony of the Americas
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Quarter Pony
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Miniature Horse
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Clydesdale
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Shire
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Percheron
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Belgian Draft
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Suffolk Punch
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American Cream Draft
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Ardennes
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Breton
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Boulonnais
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Comtois
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Dutch Draft
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North Swedish Horse
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Norwegian Fjord
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Haflinger
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Gypsy Cob
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Irish Draught
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Welsh Pony and Cob
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Connemara Pony
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New Forest Pony
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Dartmoor Pony
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Exmoor Pony
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Shetland Pony
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Highland Pony
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Fell Pony
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Dales Pony
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Australian Pony
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Finnhorse
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Black Forest Horse
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