UCD VMTH Fact Sheet Superficial Digital Flexor Tendinitis 2010

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Large Animal Ultrasound Service - Fact Sheet
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.
C L I N I C A L SI G N S
Ultrasound & Superficial Digital Flexor Tendon Injuries
Subtle to severe tendon swelling
Heat & pain on palpation
SDF injuries are readily diagnosed with ultrasound. The classic
Mild to no lameness
“core lesion” appearance is a hypoechoic or dark area in the
middle of the tendon. Ultrasonography allows measurement of
I N I T I A L T R E AT M E N T
the degree of tendon enlargement and the size of the injured
Reduce inflammation:
portion. From these measurements, injury severity can be
Cold hosing or icing
determined based on the percent of tendon damage.
Anti-inflammatories
Ultrasound can also rule out other causes of swelling such as
Bandaging
inflammation around the tendon. This can occur with trauma
Stall rest
(interference), slipped bandages or bandages that are placed
Handwalking as recommended by
too tightly. This is commonly referred to as a “bandage” bow.
your veterinarian.
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
Ultrasound images from
3 horses with mild,
moderate and severe
SDFT injuries
visit. Ultrasound is also important to detect evidence of reinjury
as the horse returns to a full workload.
Fact Sheet written and designed by Dr. Mary Beth Whitcomb, UCD VMTH LA Ultrasound Service
Superficial Digital Flexor Tendonitis
Large Animal Ultrasound Service - Fact Sheet
Treatment Options for SDF Tendonitis
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).
P R O G N O SI S
Mild Injury – good for most
athletic purposes
Moderate – good for some
athletic purposes
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.
Severe – good/fair for pasture
soundness, fair/poor for athletic
purposes
REHABILITATION
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.
Prognosis & Rehabilitation
8-16 months - depends on
Prognosis depends on injury severity and intended use of your horse (see left margin). It also depends upon
severity of injury
tolerance of the rehabilitation protocol. This is especially true in the early months when confined horses can
Stall rest + controlled exercise
may include walking under saddle or small paddock confinement.
be difficult or even dangerous during walks. Recommendations should be adjusted for your safety needs and
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
Rehabilitation Schedule for Mild-Moderate SDFT Injury
Month
Walk
0-2
30-45
Trot
Canter Jumping
Turnout
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
10
20
20
10-15
Low
Yes
11
20
20
10-15
Normal
Yes
12
Yes
Competition
Yes
*All in minutes per day
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.
For more information on our
services, please visit us at:
www.vetmed.ucdavis.edu/vmth/
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.
One Shields Avenue
Davis, CA 95616
Phone 530-752-0290
Fax 530-752-9815