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. 3 to 4 month healing time.

 

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.

 

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