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Equine tendinitis
EQUINE TENDINITIS Alicia L. Bertone, DVM, PhD
Editor's note: This paper was presented at the 1995 World Equine Veterinary Association Meeting held at Yokohama, Japan, in conjunction with the World Veterinary Association and is published here at the request of the World Equine Veterinary Association.
Superficial digital flexor tendinitis (bowed tendon) occurs in high performance horses in the middle third of the tendon. Injury is due to excessive tensile forces causing hemorrhage, edema +/- fiber damage (tearing). Diagnosis is by exam (lameness, soreness to palpation of the tendon, heat, swelling, edema), and tendon ultrasound to determine fiber damage. If fiber damage exists, healing time wil! be a minimum of 5-6 months. Treatment consists of aggressive physical therapy including support wraps, hydrotherapy, topical sweats, phenylbutazone, and adjustment of heel angle. In acute tendinitis, superior check desmotomy may assist healing (the mechanism is not known). If core lesions (isolated central fiber damage) exist, tendon splitting will assist healing. Peri- or intra-lesional injections of hyaluronate and systemic administration of PSGAG probably assist with healing. Alternate therapies, such as laser application in the healing phase, may assist healing, but more research is necessary to prove effectiveness. Prognosis for return to racing at least 2 races is 60% in Thoroughbreds and to at least 3 races is 75% in Standardbreds. The average time until racing after injury is 11 months. Low bows (tendinitis in the distal 1/3 of the superficial or deep digital flexor) may need annular ligament resection to relieve constriction pressure around the fetlock area. Deep digital flexor tendinitis is unusual, but may be combined with SDF tendinitis. If deep digital tendinitis is present in the digital sheath, effusion and adhesions in the sheath may complicate healing and affect outcome. Treatment is similar to that outlined above except surgery (distal check desmotomy) has not gained popularity. Tenoscopy Author'saddress:Department of Veterinary Clinical Sciences, College of Veterinary Medicine, 601 Tharp St, The Ohio State University, Columbus, OH 43210, USA.
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of the tendon sheath allows synovectomy and adhesion removal as a method of therapy. Resection of the annular ligament may be necessary to relieve intrathecal pressure. Intrathecal hyaluronate is indicated if adhesions are present or expected. Long rest periods and slow return to exercise (1 yr total) is necessary to prevent re-injury. Palmar/plantar annular ligament constriction can occur as a complication of deep digital flexor tendinitis. The annular ligament is a band that extends from the collateral ligaments of the fetlock around the flexor surface of the joint. The function is to contain the flexor tendons in the sesmoidean groove. The digital sheath encases the tendons as they progress through the groove. If tendinitis or synovitis of the sheath enlarges the structures that must pass through this limited canal, a bulge will develop proximal and distal to the annular ligament causing pain. Treatment is addressed at reducing inflammation of the enlarged structures (medical treatment of tendinitis and synovitis) and in releasing the annular constriction. Transection of the annular ligament can be performed through an incision or small stab incision.
T R E A T M E N T OF T E N D I N I T I S INJURIES Bruises, Contusions, O v e r u s e (Tendinitis)
Clinical Signs: Swelling, heat, pitting edema, pain on palpation, lameness or gait abnormality. Seromas may develop. Diagnostic tests: Physical examination, Centesis, Ultrasound, Thermography, Nuclear Scintigraphy Physical Therapy : Acute injury (0-48 hrs) - Control inflammatory response. 1. Ice: 1/2 -1 hr, 3-4 X/day for analgesia, hemorJOURNAL OF EQUINE VETERINARY SCIENCE
rhage control, vessel constriction, and reducing effects of inflammatory mediators. 2. Bandaging: Constant, firm and uniform pressure to collapse tissue planes, reduce tissue fluid. 3. Rest: Stall rest to prevent further damage and aggravating inflammation. 4. Shoes: Removed, trim feet to minimize low, 9underslung heel.
Subacute injury ( 2-28 days) - Reduce inflammatory response and start repair process. 1. Alternate cold~warm - Warm interval 3X cold for vasoconstriction and rapid vasodilation and increased lymphatic flow. Help clear inflammatory products. After 4-6 days warm water only. 2. Rubefacients - Topical medications that stimulate circulation. Often used as "sweat" bandages (topical rubefacient, occlusive bandage, support bandage). 3. Pressure bandage - Counteract swelling. 4. Hydromassage - Stimulates blood and tissue fluid circulation. Turbulator boot, pressure hose, water treadmill, whirlpool. 5. Mild, noninjuring exercise Usually only walking (controlled). Movement stimulates circulation of tissue fluids, maintains tissue flexibility, aids structural repai r if not excessive. In tendons, passive motion or intermittent active motion (mild) will aid tendon repair alignment and strength, and decrease adhesion formation.
palpation, irregularity in structure contour, greater and more persistent lameness. Diagnostics: Physical examination (may include altered function), ultrasound, thermography. The ultrasound may allow assessment of the amount of fiber damage and therefore prognosis and convalescent time. Physical Therapy: Acute Injury - Same as above. Subacute Injury - Same as above. Amount of exercise will be species, type and severity of injury dependent and must be tailored to each case. Chronic Injury - (> 28 days).
Exercise rehabilitation program 1. The goal is to increase use of structure at a rate just below that which will cause physical damage. This is very site, species and use dependent. In horses with tendon injuries, this often includes swimming, underwater treadmills, jogging or ponying. Support bandages (if properly applied) can decrease tendon load in the rehabilitation of tendon injuries. 2. Many other therapeutic modalities are on the market for use in this healing phase, but none have yet been proven beneficial or the effective delivered dosages determined. These include: Blisters, firing (cautery iron, freeze firing), Injectable irritants (iodine), electromagnetic fields, direct electrical stimulation, and laser application.
Pharmacologic therapy: Pharmocologic therapy: 1. NSAIDs reduce inflammation and pain. The choice of medication is species and injury dependent. In horses, phenylbutazone or flunixin meglumine would be used. 2. Topical DMSO reduces inflammation and pain. Often used in horses in conjunction with sweat bandages. 3. Other: Steroids are not recommended, although they are potent anti-inflammatory drugs, because they may impair healing (fibroplasia). Intra- or peri-lesional sodium hyaluronate may assist healing, but is expensive and has not been proven to be of benefit. Methysulfmethoxine (MSM) is a byproduct of DMSO that is given orally, but it has not been proven to be effective. 4. Sodium Hyaluronate: Intra- or peri-lesional hyaluronate injections into significant fiber damage areas may assist with healing and matrix organization. Intrathecal administration has been shown to weaken adhesion formation that may form following tendon injury in the sheath. 5. Polysul~ated glycosaminoglycan: intralesional or systemic (intramuscular) administration of PSGAG may assist with matrix production by tenocytes and promote early matrix replacement and organization.
See Bruises, Contusions, Overuse
Surgical Therapy Acute injury No surgery should be done in the -
first 48 hours unless a foreign body or infection exists, in which case foreign bodies should be removed, and the wound cleansed and drained. Subacute injury - Applies to tendon injuries in horses. Desmotomy of the accessory ligament of the superficial digital flexor (SDF) tendon superior check ligament desmotomy has been clinically successful in improving tendon cosmetics and racing performance of horses with SDF tendinitis. Longitudinal tendon splitting is indicated in tendons with central (core) lesions to aid healing. Chronic injury - The above surgeries can be done in this phase, but may be less effective.
Strains (fiber damage) Clinical Signs: Swelling, heat, edema, more pain on
Volume 16, Number 1, 1996
17
Editor's note: This paper was presented at the 1995 World Equine Veterinary Association Meeting held at Yokohama, Japan, in conjunction with the World Veterinary Association and is published here at the request of the World Equine Veterinary Association.
Superficial digital flexor tendinitis (bowed tendon) occurs in high performance horses in the middle third of the tendon. Injury is due to excessive tensile forces causing hemorrhage, edema +/- fiber damage (tearing). Diagnosis is by exam (lameness, soreness to palpation of the tendon, heat, swelling, edema), and tendon ultrasound to determine fiber damage. If fiber damage exists, healing time wil! be a minimum of 5-6 months. Treatment consists of aggressive physical therapy including support wraps, hydrotherapy, topical sweats, phenylbutazone, and adjustment of heel angle. In acute tendinitis, superior check desmotomy may assist healing (the mechanism is not known). If core lesions (isolated central fiber damage) exist, tendon splitting will assist healing. Peri- or intra-lesional injections of hyaluronate and systemic administration of PSGAG probably assist with healing. Alternate therapies, such as laser application in the healing phase, may assist healing, but more research is necessary to prove effectiveness. Prognosis for return to racing at least 2 races is 60% in Thoroughbreds and to at least 3 races is 75% in Standardbreds. The average time until racing after injury is 11 months. Low bows (tendinitis in the distal 1/3 of the superficial or deep digital flexor) may need annular ligament resection to relieve constriction pressure around the fetlock area. Deep digital flexor tendinitis is unusual, but may be combined with SDF tendinitis. If deep digital tendinitis is present in the digital sheath, effusion and adhesions in the sheath may complicate healing and affect outcome. Treatment is similar to that outlined above except surgery (distal check desmotomy) has not gained popularity. Tenoscopy Author'saddress:Department of Veterinary Clinical Sciences, College of Veterinary Medicine, 601 Tharp St, The Ohio State University, Columbus, OH 43210, USA.
16
of the tendon sheath allows synovectomy and adhesion removal as a method of therapy. Resection of the annular ligament may be necessary to relieve intrathecal pressure. Intrathecal hyaluronate is indicated if adhesions are present or expected. Long rest periods and slow return to exercise (1 yr total) is necessary to prevent re-injury. Palmar/plantar annular ligament constriction can occur as a complication of deep digital flexor tendinitis. The annular ligament is a band that extends from the collateral ligaments of the fetlock around the flexor surface of the joint. The function is to contain the flexor tendons in the sesmoidean groove. The digital sheath encases the tendons as they progress through the groove. If tendinitis or synovitis of the sheath enlarges the structures that must pass through this limited canal, a bulge will develop proximal and distal to the annular ligament causing pain. Treatment is addressed at reducing inflammation of the enlarged structures (medical treatment of tendinitis and synovitis) and in releasing the annular constriction. Transection of the annular ligament can be performed through an incision or small stab incision.
T R E A T M E N T OF T E N D I N I T I S INJURIES Bruises, Contusions, O v e r u s e (Tendinitis)
Clinical Signs: Swelling, heat, pitting edema, pain on palpation, lameness or gait abnormality. Seromas may develop. Diagnostic tests: Physical examination, Centesis, Ultrasound, Thermography, Nuclear Scintigraphy Physical Therapy : Acute injury (0-48 hrs) - Control inflammatory response. 1. Ice: 1/2 -1 hr, 3-4 X/day for analgesia, hemorJOURNAL OF EQUINE VETERINARY SCIENCE
rhage control, vessel constriction, and reducing effects of inflammatory mediators. 2. Bandaging: Constant, firm and uniform pressure to collapse tissue planes, reduce tissue fluid. 3. Rest: Stall rest to prevent further damage and aggravating inflammation. 4. Shoes: Removed, trim feet to minimize low, 9underslung heel.
Subacute injury ( 2-28 days) - Reduce inflammatory response and start repair process. 1. Alternate cold~warm - Warm interval 3X cold for vasoconstriction and rapid vasodilation and increased lymphatic flow. Help clear inflammatory products. After 4-6 days warm water only. 2. Rubefacients - Topical medications that stimulate circulation. Often used as "sweat" bandages (topical rubefacient, occlusive bandage, support bandage). 3. Pressure bandage - Counteract swelling. 4. Hydromassage - Stimulates blood and tissue fluid circulation. Turbulator boot, pressure hose, water treadmill, whirlpool. 5. Mild, noninjuring exercise Usually only walking (controlled). Movement stimulates circulation of tissue fluids, maintains tissue flexibility, aids structural repai r if not excessive. In tendons, passive motion or intermittent active motion (mild) will aid tendon repair alignment and strength, and decrease adhesion formation.
palpation, irregularity in structure contour, greater and more persistent lameness. Diagnostics: Physical examination (may include altered function), ultrasound, thermography. The ultrasound may allow assessment of the amount of fiber damage and therefore prognosis and convalescent time. Physical Therapy: Acute Injury - Same as above. Subacute Injury - Same as above. Amount of exercise will be species, type and severity of injury dependent and must be tailored to each case. Chronic Injury - (> 28 days).
Exercise rehabilitation program 1. The goal is to increase use of structure at a rate just below that which will cause physical damage. This is very site, species and use dependent. In horses with tendon injuries, this often includes swimming, underwater treadmills, jogging or ponying. Support bandages (if properly applied) can decrease tendon load in the rehabilitation of tendon injuries. 2. Many other therapeutic modalities are on the market for use in this healing phase, but none have yet been proven beneficial or the effective delivered dosages determined. These include: Blisters, firing (cautery iron, freeze firing), Injectable irritants (iodine), electromagnetic fields, direct electrical stimulation, and laser application.
Pharmacologic therapy: Pharmocologic therapy: 1. NSAIDs reduce inflammation and pain. The choice of medication is species and injury dependent. In horses, phenylbutazone or flunixin meglumine would be used. 2. Topical DMSO reduces inflammation and pain. Often used in horses in conjunction with sweat bandages. 3. Other: Steroids are not recommended, although they are potent anti-inflammatory drugs, because they may impair healing (fibroplasia). Intra- or peri-lesional sodium hyaluronate may assist healing, but is expensive and has not been proven to be of benefit. Methysulfmethoxine (MSM) is a byproduct of DMSO that is given orally, but it has not been proven to be effective. 4. Sodium Hyaluronate: Intra- or peri-lesional hyaluronate injections into significant fiber damage areas may assist with healing and matrix organization. Intrathecal administration has been shown to weaken adhesion formation that may form following tendon injury in the sheath. 5. Polysul~ated glycosaminoglycan: intralesional or systemic (intramuscular) administration of PSGAG may assist with matrix production by tenocytes and promote early matrix replacement and organization.
See Bruises, Contusions, Overuse
Surgical Therapy Acute injury No surgery should be done in the -
first 48 hours unless a foreign body or infection exists, in which case foreign bodies should be removed, and the wound cleansed and drained. Subacute injury - Applies to tendon injuries in horses. Desmotomy of the accessory ligament of the superficial digital flexor (SDF) tendon superior check ligament desmotomy has been clinically successful in improving tendon cosmetics and racing performance of horses with SDF tendinitis. Longitudinal tendon splitting is indicated in tendons with central (core) lesions to aid healing. Chronic injury - The above surgeries can be done in this phase, but may be less effective.
Strains (fiber damage) Clinical Signs: Swelling, heat, edema, more pain on
Volume 16, Number 1, 1996
17