Save Your Dog’s Hock!
Protect your Greyhound from being one of 700 that fracture their hocks every year in Australia
By Dr Peter Yore, Dr John Katakasi & Dr David Larratt
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Hock fractures are not just random and spontaneous. Loss of bone density has been confirmed as a cause of weakness, explaining why serious fracture may occur after only mild racing interference.
The right hock is affected 95% of the time and early loss of bone density may cause subtle and short-lived pain.
Beware of giving your dog anti-inflammatory medication straight after a run as it can mask underlying bone damage.
WAIT and allow your dog to fully cool down. A veterinary physical examination can follow the guidelines in this booklet.
Early signs of loss of bone density in the right hock:
Slowing or running wide on the corners
Palpable pain on the forward-facing side of the hock
Over-stretched soft tissues.
Detection of pre-fracture bone lesions on X-rays.
Examination
Guidelines for examining your dog’s hock:
Perform Hock Compression Test.
Perform the Front of Hock Palpation Test as this is where early bone damage occurs.
Perform Metatarsal & Tarsal Torsion Tests to check contraction or over-stretching of damaged soft tissues.
Hock Compression Test
For the right hock, the left hand pushes down on the stifle whilst the right hand pushes up on the foot.
Pain may indicate a problem in calf muscle, Achilles tendon, plantar ligaments of hock or a crack in a bone (fibula, hock, metatarsal).
Front of Hock Palpation Test
Most of the early bone damage (occurring before fracture) is on the inside front of the hock.
Use the thumb to walk up each metatarsal onto the hock bones, applying even pressure.
If painful, follow up with X-Rays.
Metatarsal Torsion Test
Used to assess contraction in the plantar ligaments (Katakasi, 2023).
Use left hand to support the bent hock.
Right hand holds the metatarsals, rotating them to assess stiffness and pain.
If painful, anti-inflammatory injection can be useful.
Note: white dot marks the lower end of the hock
Tarsal Torsion Test
Assess laxity in the soft tissues at the front of the hock (Yore, 1990).
Use left hand to support the hock in full extension.
Right hand holds the skin over the hock to assess excess movement of the soft tissues beneath the skin on rotation. Commonly, the presence of laxity is detected on internal rotation of the right hock.
This test can be performed on the wrist joints to assess laxity and required direction of strapping.
Strapping
Why is strapping helpful?
Hocks are naturally turned out at 25 degrees. This prevents the back legs from striking the front legs when a dog runs.
As a dog runs anti-clockwise around the corner, the right hock has to twist inwards, causing the soft tissues to stretch. The soft tissues have to be tight to compress and support the bones. This cannot happen when they are over-stretched and damaged.
Normal Hock Angle
Red arrow highlights the angle of the hock which is normally turned out at 25 degrees from the mid-line.
Twisting on the Corner
When cornering, the right hock twists in by at least 25 degrees. This may lead to over-stretching of soft tissues (tendons, ligaments and joint capsular sleeve) which can leave the underlying bones vulnerable to injury.
Laxity Assessment of Soft Tissues
This is an example of a dog with laxity of the supportive soft tissues of the front of the hock.
This photo shows the neutral position where the white dot marks the mid-point of the hock and red line shows alignment with outside toe.
Laxity Assessment of Soft Tissues
The soft tissue laxity of this right hock allows anticlockwise stretching by 15-20 mm. By comparison, the stretch in the left hock was only 5mm.
Laxity is reflected by the amount of movement of the white dot and the shifting alignment of the red vertical line to the middle toes.
This dog gets strapped for every run which prevents bone damage on the inside of the hock and reduces the risk of fracture.
Strapping to Counter Laxity
To counteract the common internal laxity of the right hock, strapping needs to circle in the opposite direction.
A firm grip is achieved with 7.5cm Elastoplast as the standard.
Small bitches may only require 5cm tape.
Wrists may also require Strapping.
Over-stretching damage to the soft tissues surrounding the wrists may also occur, leading to loss of support for the underlying bones. Perform torsion testing to detect the direction of laxity and then strap to counteract.
Testing the Strapping
Once strapped, check that the internal laxity has been corrected by repeating the tarsal torsion test.
X-ray
X-rays can be helpful to prevent fracture
It makes sense to X-Ray your dog’s hocks if there is reduced performance on the corners without any other obvious injury. Note: it can be common for dogs with low grade hock pain to have muscle soreness in other areas of the hind leg especially in the groin or gracilis muscles.
Radiology of the hock has progressed beyond the two standard views and the interpretation of X-Rays has also advanced.
X-Rays can detect several early bone changes that exist prior to hock fracture and include:
A black hole which is the starting point of the common vertical fracture of the front of the Central Tarsal Bone (CTB),
Calcification of soft tissue at the back of the hock indicates hardening and contraction in response to over-stretching damage. However, calcified ligaments are now more prone to rupture.
PRE-FRACTURE
New OBLIQUE angle X-Ray to investigate hocks
Green spot on Central Tarsal Bone (CTB).
Red arrow points to a black hole indicating loss of bone at the base of the CTB.
This can be a starting point for a vertical fracture.
This is an OBLIQUE view taken at a
30-degree angle away from the standard Lateral X-Ray. It is called the Plantaromedial-dorsolateral view.
Ask your vet about using this view to assess your racing greyhound.
FRACTURE
Standard Lateral View X-Ray
Green spot on fractured CTB.
Red arrows point to the common fracture line that occurs at the front of the CTB. This is called the Dorsal fracture line and is found in almost all hock fractures.
There was also another fracture line in this hock and the white screw was used to stabilize the structure.
(A) PRE-FRACTURE
Lateral X-Ray of hock (Before)
Yellow arrow points to calcification in the plantar ligaments. The laying down of calcium in soft tissues happens in response to over-stretching however structural flexibility is now reduced.
Red outline on the talus which is the bone that pounds down onto the CTB - the common fracture site.
This dog raced successfully for 4 months before rupture of the calcified plantar ligament seen in the X-Ray above.
(B) FRACTURE
Lateral X-Ray of collapsed hock (After)
Yellow arrow points to the tight and calcified plantar ligaments which have ruptured and causing the hock to collapse forward.
Red outline on the talus shows how it has rocked back and crushed the underlying CTB.
The hock was repaired but the dog’s racing career is now over.
X-ray (A) and (B) are from the same dog.
The Authors:
Dr Peter Yore BVSc, IVAS
Belmont Veterinary Hospital, NSW
Dr John Katakasi BVSc (Hons), CVA, CVCHM
Adelaide Plains Veterinary Surgery, SA.
Dr David Larratt BVSc, IVAS
The Lake Veterinary Hospitals, NSW
The authors have devoted their veterinary careers to the diagnosis, treatment and prevention of the many complex injuries that occur with racing greyhounds.
Without doubt, hock fracture continues to be the most common and serious injury leading to premature retirement from racing.
We are driven to share our collective experience to prevent this injury, by educating trainers and veterinarians.
Radiology can be useful for detecting the early bone lesions preceding fracture and to assess how much spelling is required to allow healing.
At the recent greyhound veterinary conference (AGWSDV 2023) an agreed spelling-time for small lesions in bones is 6 weeks. Repeat X-Ray at this stage will confirm if healing is complete.
Some hock injuries will benefit from further investigation using CT imaging. However, the initial first investigative step of X-Ray is cheaper, easier to access and the dog usually does not have to be sedated.
VETERINARY ADVICE DISCLAIMER
DISCLAIMER: THIS BOOKLET AND ASSOCIATED WEBSITE DOES NOT PROVIDE VETERINARY ADVICE
This information, including but not limited to, text, images, graphics and other material contained in this booklet and/or associated website are for informational purposes only. This information is intended to benefit the welfare and wellbeing of racing greyhounds. No material in this booklet and/or associated website is intended to be a substitute for professional veterinary advice, diagnosis or treatment. Always seek the advice of your veterinarian with any questions regarding a veterinary condition or treatment and before undertaking a new diagnostic and/or treatment regime, and never disregard professional veterinary advice or delay in seeking it because of something you have read in this booklet and/or associated website.
THE AUTHORS, (DR PETER YORE, DR JOHN KATAKASI and DR DAVID LARRATT), ARE NOT RESPONSIBLE, NOR LIABLE FOR ANY ADVICE, DIAGNOSIS, COURSE OF TREATMENT OR ANY OTHER INFORMATION THAT YOU OBTAIN FROM THIS BOOKLET AND/OR ASSOCIATED WEBSITE.
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