Health and Disease Management
By Dr. Jack Sales, DVM
Copyright©July2003
Lesson Four
Hind Limb Lameness
Hip Disorders
Although hip disorders
are not common in the horse, if a horse is lame due to a problem in the hip, it
is usually associated with an OCD in the hip joint, or an injury from a trailer
accident or something similar. These
injuries are usually very difficult to correct and may cause permanent
lameness. The following is an outline
of some of the more common hip and thigh disorders.
A. Pelvis
B. Femur
C. Patella (knee cap)
D. Stifle Joint
E. Hock Joint
I. Fractures of the Pelvis
A. Knocked Down Hip
1. Refers to
fracture of the point of the hip which causes that point to be knocked down)
2. These horses
can be sound for some things after stall confinement healing from 3 to 6
months)
3. Identified by
the lack of a point of the hip on one side compared to the other side.
B. Fractures
within the acetabulum (fractures in the socket part of the joint are very
serious and will result in an unsound horse for life)
II. Fractures of
the Femur
A. Complete fractures are devastating
in the adult horse and usually require euthanasia.
III. Other Hip
and Thigh Injuries
A. Rupture of the round ligament
1. Toe and
stifle turn out.
2. If there is coxofemoral joint luxation, one leg is shorter than the
other.
3. In either of
these conditions future soundness is unlikely.
B. Trochanteric bursitis
1. Whorlbone lameness.
Soreness over the trochanteric bursa.
Usually causes a horse to travel like a dog would move. Inside quarter
of shoe wears more than outside quarter due to the way the horse brings the
foot down.
2. Seen most
often in standardbred trotters and pacers.
C. Fibrotic and ossifying myopathy
1. Fibrosis and
calcification of the semitendinosis and semimembranosis muscles (muscles in buttocks area below the
point of the buttocks)
2. Seen in
performance horses (reining and rodeo horses) that make sliding stops can be
prone to this lameness.
3. Butt bars on
trailers can cause this injury during hauling.
4.
Characteristic gait seen at a trot.
Horse will jerk the limb back noticeably before the foot hits the
ground. If the lameness is severe enough
to cause a problem, a surgical removal of the hardened and calcified area of
muscle is performed. If the horse is
able to perform adequately with the muscle scaring and calcification, physical
therapy procedures will partially relieve the restriction of movement and
reduce the pain.
Stifle Disorders
The Equine Stifle Joint A. Location of the Stifle Joint
The
stifle area is often injured in the horse, but luckily, because it is similar
in anatomy to our own knee, we have lots of experience and can correct
problems. Problems that can be associated
with the stifle are:
I. Upward fixation of the patella (locked up in
the stifle).
This is usually seen in the horse with
the straight up and down conformation behind. (post legged behind). The patella
(knee cap) locks in position on occasion to prevent the horse form being able
to flex his stifle or hock temporarily.
To see a horse do this is quite
startling, the horse will drag the hind leg affected with the stifle and hock
unable to bend and the toe of the hoof dragging the ground. This can happen
quite suddenly, usually when at a walk, and can pop back into normal position
just as fast.
If you are unable to get the horse to
pop back into normal position, back him up a few steps, or massage the affected
stifle and it will usually pop back into normal position.
For horses that continually have this
problem, a veterinarian can do an operation called clipping the stifle (cutting
the medial patellar ligament) and although it should be a last resort treatment
(because of future arthritic problems in the stifle caused by this surgery) it
does prevent any further locking up.
Upward Fixation of the Patella Stifle
Joint – Front View
(locked
up in the stifle) A. Patella
B. Lateral Patellar Ligament
C. Middle Patellar Ligament
D. Medial Patellar Ligament
A. Upward fixation of the Patella (summary)
1. Locked up in
the stifle (Stifled)
2. Predisposed
by post legged (straight up and down) conformation
3. May be seen
more often when a post legged horse has been fatigued in those muscles from
over work or long trailer rides.
4. Backing the
horse will often allow the stifle to pop back into normal position. If this
doesn’t work, massaging around the muscles of the stifle and attempting to
manipulate the joint might be helpful in popping it back to normal.
5. In horses
that continuously lock up, clipping the stifle will correct the condition
permanently. The vet surgically cuts the medial patellar ligament.
6. This surgery
will cause the horse to develop some level of arthritis in the stifle joint in
the future which may affect his soundness, so cutting of this ligament is not
suggested unless absolutely necessary.
II. OCD of the
stifle
A. Seen in the young horse (yearling
to 2 year old)
B. Same symptoms and signs and
treatment as when OCD was mentioned earlier.
III. Sprains,
Strains, meniscus and ligament injuries to the stifle
A. Not seen as
often as in human athletes. Horses don’t do the twisting and turning and are
four legged.
B. When this
type of injury occurs in the horse, surgery is not
very helpful. Horse will normally not be sound for future use. Pasture sound is
expected once healing is complete.
Tibia and Hock Disorders
I. Tibial
Fractures
A.Very
serious. Can be life threatening.
B. Sling may
help save a horse
C. Hairline
tibial fractures seen on some young racehorses.
D. Surgical
repair necessary on serious fractures.
II. Rupture of
the peroneus tertius
A. Caused by
rapid starts (out of starting gate or box)
B. Hock will
stay in extension when stifle flexes.
C. Horse is not
badly lame, just “goes off”
D.
E. Soundness is
expected after healing.
III. Thoroughpin
A. Inflammation
of deep flexor tendon sheath
B. Lameness is
usually not present.
C. Could be
considered a blemish.
D. Straight
hocks predispose to strain in this area
IV. Slab and
chip fractures within the hock joints.
A. Treated same
way as knee chips and slabs, with arthroscopic surgery.
Hock Joint X-ray
with Evidence of a Bone Spavin
V. Bone spavin
A. Bone spavins
are the most common cause of hind limb lameness in the horse.
B. Inflammation
of one or more of the distal 3 hock joints. (the joints that do not open much)
C. Usually
results in calcium buildup in and around these joints.
D. Spavin test
will exaggerate lameness. (Flexion test of the hock joint)
E. Manage pain
and inflammation to continue to use horse.
F. If joint
fixes in place the pain from the condition will be greatly relieved.
Flexion Test of Hock Joint
VI. Curb
A. Inflammation
of the plantar ligament.
B. Sickle and/or
cow hocks predispose to this condition.
C. Usually
causes mild lameness.
VII. Bog Spavin
A. Inflammation
of the tibiotarsal hock joint. (The joint of the hock
that moves.)
B. Fluid filled
hock.
C. Often
associated with OCD of the hock.
D. Usually
causes mild or no lameness.
VIII. Stringhalt
A. Over
exaggerated flexion of the hind leg at a walk, trot or canter. Horse is not
normally affected at a gallop or run.
B. Cause not
clearly understood, probably associated with nerve over stimulation.
C. Treatments
are not normally very successful at correcting the abnormal gait completely.
IX. Capped Hock
A. Just like a
shoe boil in the elbow, but it’s over the point of the hock.
B. A blow to the
point of the hock or kicking at a trailer gate.
C. Usually
doesn’t cause lameness, but causes blemish.
D. A vet will
normally drain and inject the area.
X. OCD of the
hock
A. Often
associated with bog spavin and has been thought to be a cause of later forming
bone spavin.
B. Previous
discussion on OCD in other joints applies here also.