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.