SDFT injuries are common in event and Thoroughbred racehorses but can occur in horses of many

uses, including hunter/jumpers, dressage and western performance horses. Injuries in athletic

horses are most likely due to repetitive microtrauma rather than a one time “bad step” incident.

The mid-metacarpal (mid cannon bone) region is most commonly affected.

Horses with mild injuries may show no lameness or only mild short-lived lameness.

In such cases, slight focal swelling of the tendon or pain on palpation may be the

only evidence of mild injury.

Moderate injuries typically result in the classic “bowed tendon” appearance but may

not cause noticeable lameness, leading owners to believe the horse is unaffected.

Severe injuries cause moderate to severe lameness and obvious tendon swelling.

Hind limb injuries are relatively rare and are more likely to occur due to blunt

trauma such as from a kick.

SDF injuries are readily diagnosed with ultrasound. The classic

“core lesion” appearance is a hypoechoic or dark area in the

middle of the tendon. Ultrasonography allows measurement of

the degree of tendon enlargement and the size of the injured

portion. From these measurements, injury severity can be

determined based on the percent of tendon damage.

Ultrasound can also rule out other causes of swelling such as

inflammation around the tendon. This can occur with trauma

(interference), slipped bandages or bandages that are placed

too tightly. This is commonly referred to as a “bandage” bow.

Recheck ultrasound exams are recommended every two months

during the rehabilitation process. Most SDFT injuries show an

improved brightness (echogenicity) and fiber pattern at each

visit. Ultrasound is also important to detect evidence of reinjury

as the horse returns to a full workload.

Information Technology Solutions

CLINICAL SIGNS

Subtle to severe tendon swelling

Heat & pain on palpation

Mild to no lameness

INITIAL TREATMENT

Reduce inflammation:

Cold hosing or icing

Anti-inflammatories

Bandaging

Stall rest

Handwalking as recommended by

your veterinarian.

Ultrasound & Superficial Digital Flexor Tendon Injuries

Superficial Digital Flexor Tendonitis Large Animal Ultrasound Service - Fact Sheet

Ultrasound images from 3 horses with mild, moderate and severe SDFT injuries

Fact Sheet written and designed by Dr. Mary Beth Whitcomb, UCD VMTH LA Ultrasound Service

Initial treatment goals are to reduce inflammation with cold hosing, ice, bandaging and anti-inflammatories

as recommended by your veterinarian. Your horse should also be stall confined until ultrasound can be

performed (ideally 3-5 days after the onset of swelling).

Once ultrasound confirms injury, various treatment options are available (see below). All include rest and a

controlled exercise program to maximize treatment success. It is important to be aware that treatments are

thought to improve healing quality and do not reduce the rehabilitation period. Long term success rates

have not been proven for individual treatment options, and some studies offer conflicting information.

Most SDFT injuries show gradual improvement on ultrasound throughout rehabilitation.

In the images above, the injury is less apparent at 60 days and is difficult to

detect at 8 months post injury. Ultrasound rechecks are important until

your horse returns to competition to help to reduce the risk of reinjury.

Cross-sectional area measurements are critical to monitor healing and to

detect subtle evidence of new tendon damage.

This rehabilitation schedule should serve as a guideline for a horse with mild-moderate SDFT injury

and is not recommended for severe injuries. The objective is to encourage the best repair possible by

gradually loading the tendon. Each increase in exercise should only occur if the horse is sound and

ultrasound shows no regression in healing. Deviations from this schedule are often necessary.

Prognosis & Rehabilitation Prognosis depends on injury severity and intended use of your horse (see left margin). It also depends upon

tolerance of the rehabilitation protocol. This is especially true in the early months when confined horses can

be difficult or even dangerous during walks. Recommendations should be adjusted for your safety needs and

may include walking under saddle or small paddock confinement.

PROGNOSIS

Mild Injury – good for most

athletic purposes

Moderate – good for some

athletic purposes

Severe – good/fair for pasture

soundness, fair/poor for athletic

purposes

REHABILITATION

8-16 months - depends on

severity of injury

Stall rest + controlled exercise

program

Increases in exercise depend on

soundness & stable/improved

ultrasound findings

** Horses usually become sound

before healing is complete

LA ULTRASOUND

FACULTY

Mary Beth Whitcomb, DVM

Betsy Vaughan, DVM

For more information on our

services, please visit us at:

www.vetmed.ucdavis.edu/vmth/

Treatment Options for SDF Tendonitis

Month Walk Trot Canter Jumping Turnout

0-2 30-45 None

3 30-45 5 None

4-5 30 10-15 None

6-7 30 20-25 Supervised

8 30 20 5 Supervised

9 30 20 10 Yes

10 20 20 10-15 Low Yes

11 20 20 10-15 Normal Yes

12 Competition Yes

*All in minutes per day

One Shields Avenue Davis, CA 95616 Phone 530-752-0290 Fax 530-752-9815

Superficial Digital Flexor Tendonitis Large Animal Ultrasound Service - Fact Sheet

Rehabilitation Schedule for Mild-Moderate SDFT Injury

Intralesional Injections – performed under ultrasound guidance to assure placement into the injured area. Several products are available, including bone marrow, platelet rich plasma and stem cells.

Tendon Splitting – a needle or blade is inserted into the core lesion to decompress the injured area. Acoustic Shock Wave Therapy – performed in the standing horse, may stimulate healing.