Hock injuries can be the most difficult limb injuries to manage and enable a greyhound to return to racing without any loss of agility out of the traps or speed on the bends.
The hock is subjected to high compressive forces and twisting as a greyhound gallops around corners and then braking forces at the end of a race.
Early hock problems can occur in pups as they grow, especially in over-weight pups without adequate exercise, particularly during the winter time when they may not be able to run freely in outside yards.
We will discuss osteochondrosis and joint cartilage problems in young greyhounds in their formative year in a future article.
Injuries are also likely at the time of schooling, especially if the schooling track is not well maintained or has shifting surfaces on the corners.
Management of Hock Injuries
Sprain of the internal ligaments within the hock joint are relatively common, especially in greyhounds running on compacted, tight sand tracks.
Greyhounds with acute swelling with severe pain on flexion of a hock joint, and lameness when walking, should be taken to your vet as an X-ray to check for fracture within the hock.
This should be done before simple physiotherapy is carried out for a common sprain within the hock joint or the joint capsule.
As emphasised in Part 1 of this article, the prompt application of a support bandage and cold compression to stabilize the hock joint and reduce swelling, is the best initial form of first aid before the hock joint and surrounding area can be thoroughly examined by a vet.
The track veterinarian will normally assess the injury and apply cold and compressive support as soon as possible after the race.
Normally an ice pack applied for 7-10 minutes 2-3 times a day, combined with an elastic pressure bandage wrapped to support the joint and restrict its movement, is the best form of initial first aid.
Over the years, I have had examined greyhounds the next morning after they have pulled up well after a race, but did not perform to their expectation, only to find on careful examination sprain within the hock joint ligaments and even partial dislocation of the central tarsal bone on the right leg.
In most cases, there is internal fluid swelling due to joint irritation and soft swelling around the joint, or oedema over the sides of the injured joint.
Where the central tarsal bone has ‘popped’ on the right leg, or an internal fracture is suspected immediately after the race due to the severe pain and lameness, then compression and rest until the joint can be thoroughly examined is essential as the first form of post trauma management.
Reduction in tissue swelling and oedema by compression and ice, will allow your vet to more thoroughly examine the joint within the following few hours.
However, if the joint remains swollen and very painful when pressed over the sides, then a fracture should be suspected and prompt examination by your vet as soon as possible, is paramount for healing, especially if the central tarsal bone has been torn from its position in the right hock.
For injuries not involving fracture of the hock bones, once the degree of severity and location of any secondary injury is determined, there are normally three forms of physiotherapy that can be applied to assist rehabilitation.
Restricted Walking
It is also important to restrict flexion movement, twisting and weight bearing during the first week of rehab.
Limiting lead walking to empty out only during the first week or so, but after this time, once the hock can be flexed without resistance or pain, then walking to encourage flexion and use is helpful.
Although swimming is an exercise which is often suggested for hock injuries, the passive dragging action of the hind limbs in the typical dog paddle removes weight bearing and allows passive extension of the hocks and relaxation, rather than strengthening the hock and surrounding muscles.
Passive flexion and gentle twisting of the hock joint with the grey-hound resting on its side on a table will help to improve overall flexibility, but it must be reduced from 10 -15 movements to 4-5 movements each session if the greyhound exhibits any discomfort.
Ultrasound
If an injury involves a bony joint, such as the hock or metatarsal bones, the ultrasound beam cannot be applied directly over the bony area.
Direct ultrasound results in reflection of the ultrasound waves off the bone surface, often referred to as ‘bone bounce’ in simple terms. This results in over heating of the skin layer covering the bone with severe burn reaction and ‘cooking’ of the skin.
Therefore, ultrasound therapy is best applied under water, preferably with the limb immersed in ice cold water in a plastic bucket.
Settings of 1.5 to 2.0 watts per square cm for 5-6 minutes daily are usually effective.
Special care must be taken when using this method, so that it is best carried out by a trained physiotherapist or a skilled vet nurse.
After the first 5 days, the ultrasound frequency can be reduced to alternate days over a 10-14 day period. Consult your greyhound physiotherapist for advice.
Magnetic Field Therapy
Application of low frequency, pulsed MFT for 15-20 minutes once or twice daily for 14-21 days is especially beneficial where bone fractures or tendon injuries are present.
A cage unit, such as a Portamag 500 is ideal for treating lower limb injuries, because the affected limbs are usually at floor level if the greyhound sits up or lies down in the cage.
However, if the greyhound has difficulty in entering the cage because it is unable to flex its hock(s), then MFT may be delayed for a week or so.
Laser Therapy
Although laser therapy is useful for injuries up to 5mm deep, it often complements the application of ultrasound or MFT therapy, rather than when used alone.
Laser dwell time of 30 seconds at 10mm (1/2 inch) spacings over the affected area is often recommended.
Other Therapies
After each therapy, topical application of a warming (counter-irritant liniment) will assist in maintaining warmth and a mild anti-inflammatory affect.
The liniment is best carefully rubbed into the area after each therapy session.
Other preparations, as recommended by your vet, containing DMSO, are also suitable.
However, ensure that the appropriate times for withdrawal prior to a race if it is applied during the rehabilitation as advised by your vet, are adhered to before allowing the greyhound to return to racing.
If the injury involves nearby structures, such as the fibula bone, track leg area or Achilles tendon, then appropriate therapy for these must be provided.
Hock Support
In most cases of internal sprain within the hock , then 3 weeks of restricted exercise on the lead (not on a walking machine as the greyhound is forced to keep up with the speed of the belt), combined with rehab physiotherapy, should be adequate to allow a greyhound to return to training and then to racing within 4-6 weeks.
It is best to hand slip the greyhound in a straight gallop over 150 metres twice the first week, then increase the distance to 300 metres in a straight run (slip the greyhound onto the lure just past a bend and catch it before it corners by stopping the lure).
After another 2 weeks, a trial over 300 metres can be given, provided the greyhound has pulled up well without any discomfort or pain on flexion or gentle twisting of the hock on the table. I recommend icing after each run to reduce any swelling.
It is also a good idea to bandage the hock joint to provide support without restriction of movement.
Use only minimal stretch on a 50 mm wide elastic bandage and apply 2-3 layers to include the foot.
Tape the ends so that it remains wrapped and does not slip down as the greyhound gallops. Your vet can demonstrate how to provide a light support bandage.
In the next article, we will discuss hock fractures and their management.
