Post by IH Health on Jul 30, 2009 13:55:06 GMT 1
Navicular Syndrome
What is it?
Navicular is a progressive and degenerative syndrome that affects the navicular bones of both front feet (the navicular bones sit at the back of the pedal bone). It takes time for the condition to show itself rather than being “occurring overnight”. The bone becomes diseased and slowly breaks down. It normally becomes apparent between the ages of 7 and 12 years.
Causes
The exact causes of navicular are unknown however; TBs and TB crosses are more prone to it, especially males. Reported causes include: passive venous congestion (clogging up of the arteries) causing reduced blood flow to the navicular bone (ischemia) and thus essential nutrients and oxygen. PVC can be caused by enforced rest. The bone starts to ulcerate and pit, meaning lesions appear on the tendon that runs over the navicular bone causing trauma and pain. Navicular is also thought to be caused by incorrect trimming where the pastern/foot axis is allowed to slope too much, exerting extra pressure on the deep digital flexor tendon, causing damage to the navicular bone, through repeated heavy compression through the legs and through hereditary defects such as poor conformation (boxy feet, excessively sloping pasterns, collapsed heels etc). Sidebone can also be a predecessor to navicular due to it reducing elasticity and circulation in the foot.
Symptoms
• Navicular slowly develops so to begin with there may be just short periods of undiagnosed or intermittent lameness that wears off with exercise. The lameness may return up to 30 minutes after exercise.
• The stride may become shorter
• The horse will move toe first, attempting to place all weight there before transferring its weight choppily to the heel causing a jarring action. The toe may show signs of excessive wear. This shuffling gait can sometimes lead to an incorrect diagnosis of a shoulder problem.
• Periods of lameness increases in frequency and stumbling may be more pronounced.
• The horse may attempt to dig in its stable bed or in mud, pointing its toe downwards, attempting to alleviate pressure on the heels
• Heat in the foot
• Shuffling of weight
• Pain in the area of the navicular bones
• Heels contract, causing hoof to become more upright or boxy.
Diagnosis
Diagnosis of navicular is through a vet and selective x-rays and nerve blocking. The hoof can be examined for changes in angle and during flexion of the fetlock and pastern joints the horse may show pain. Nerve blocks can be introduced to test to pinpoint the lameness and x-rays may show a degradation of the navicular bone (the foramina or opening in the tissue) will be larger in number, size and shape).
Treatment
Navicular cannot be cured, it can only be managed to the best of the owners ability. Once the damage is done, there is no reversing it. Management can include therapeutic shoeing with oval shaped, egg bar shoes or pads and wedges to raise the heels and relieve pressure and concussion forces is sometimes used, along with drugs such as vasodilators such as lsoxsuprine hydrochloride (widens blood vessels), bute to relieve pain, cortisone injections and anticoagulants such as warfin (things the blood). Warfin needs very careful dosing and treatment as the therapeutic dose is near fatal.
Neurectomy procedures are sometimes undertaken to cut the nerves in the foot, which will relieve pain for a few months and should be considered a last resort. Care is needed afterwards because the horse will not feel any foot injuries and the nerves will grow back in time or form painful nerve mass endings. Because of the way the nerves grow back the operation cannot be repeated in normal circumstances.
Desmotomy is a relatively new procedure in which the suspensory ligaments of the navicular bone are cut under a general anaesthetic, relieving stress on the navicular bone.
Websites (click on title for link)
Coping with Navicular
Previous discussions (click on title for link)
Navicular/deep flexor tendonitis
Navicular?
Navicular shoeing
+ much more in the search section!
Please post below any information you have on this subject or of your experiences in diagnosis/treatment/aftercare. All information given is for reference only and does not constitute or should replace qualified veterinarian advice.
What is it?
Navicular is a progressive and degenerative syndrome that affects the navicular bones of both front feet (the navicular bones sit at the back of the pedal bone). It takes time for the condition to show itself rather than being “occurring overnight”. The bone becomes diseased and slowly breaks down. It normally becomes apparent between the ages of 7 and 12 years.
Causes
The exact causes of navicular are unknown however; TBs and TB crosses are more prone to it, especially males. Reported causes include: passive venous congestion (clogging up of the arteries) causing reduced blood flow to the navicular bone (ischemia) and thus essential nutrients and oxygen. PVC can be caused by enforced rest. The bone starts to ulcerate and pit, meaning lesions appear on the tendon that runs over the navicular bone causing trauma and pain. Navicular is also thought to be caused by incorrect trimming where the pastern/foot axis is allowed to slope too much, exerting extra pressure on the deep digital flexor tendon, causing damage to the navicular bone, through repeated heavy compression through the legs and through hereditary defects such as poor conformation (boxy feet, excessively sloping pasterns, collapsed heels etc). Sidebone can also be a predecessor to navicular due to it reducing elasticity and circulation in the foot.
Symptoms
• Navicular slowly develops so to begin with there may be just short periods of undiagnosed or intermittent lameness that wears off with exercise. The lameness may return up to 30 minutes after exercise.
• The stride may become shorter
• The horse will move toe first, attempting to place all weight there before transferring its weight choppily to the heel causing a jarring action. The toe may show signs of excessive wear. This shuffling gait can sometimes lead to an incorrect diagnosis of a shoulder problem.
• Periods of lameness increases in frequency and stumbling may be more pronounced.
• The horse may attempt to dig in its stable bed or in mud, pointing its toe downwards, attempting to alleviate pressure on the heels
• Heat in the foot
• Shuffling of weight
• Pain in the area of the navicular bones
• Heels contract, causing hoof to become more upright or boxy.
Diagnosis
Diagnosis of navicular is through a vet and selective x-rays and nerve blocking. The hoof can be examined for changes in angle and during flexion of the fetlock and pastern joints the horse may show pain. Nerve blocks can be introduced to test to pinpoint the lameness and x-rays may show a degradation of the navicular bone (the foramina or opening in the tissue) will be larger in number, size and shape).
Treatment
Navicular cannot be cured, it can only be managed to the best of the owners ability. Once the damage is done, there is no reversing it. Management can include therapeutic shoeing with oval shaped, egg bar shoes or pads and wedges to raise the heels and relieve pressure and concussion forces is sometimes used, along with drugs such as vasodilators such as lsoxsuprine hydrochloride (widens blood vessels), bute to relieve pain, cortisone injections and anticoagulants such as warfin (things the blood). Warfin needs very careful dosing and treatment as the therapeutic dose is near fatal.
Neurectomy procedures are sometimes undertaken to cut the nerves in the foot, which will relieve pain for a few months and should be considered a last resort. Care is needed afterwards because the horse will not feel any foot injuries and the nerves will grow back in time or form painful nerve mass endings. Because of the way the nerves grow back the operation cannot be repeated in normal circumstances.
Desmotomy is a relatively new procedure in which the suspensory ligaments of the navicular bone are cut under a general anaesthetic, relieving stress on the navicular bone.
Websites (click on title for link)
Coping with Navicular
Previous discussions (click on title for link)
Navicular/deep flexor tendonitis
Navicular?
Navicular shoeing
+ much more in the search section!
Please post below any information you have on this subject or of your experiences in diagnosis/treatment/aftercare. All information given is for reference only and does not constitute or should replace qualified veterinarian advice.
