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Foot lameness
Information about Foot lameness
From The North American Veterinary Conference, Orlando, FL, Jan. 9-13, 1999.
The physical examination of the foot should include a close observation of the foot in weight-bearing posture as well as with the foot off the ground. The hoof wall and coronary band should be inspected for abnormalities of growth or injury. Evenness of length of the toe and quarters should be determined. The angle of hoof wall to pastern should be straight in most horses. Heel conformation and symmetry should be examined. With the foot out of weight bearing, the sole should be evaluated for normal concavity and frog conformation. The white line should be examined for evenness and width. Medial to lateral balance of hoof wall length should be assessed. This is an appropriate time for application of hoof testers. The best advice for hoof tester use is to establish a repeatable pattern such that each horse can be compared to itself and other horses from experience. Describing a specific diagnosis with heel pain can be a frustrating experience. It is fairly straight forward to determine that the heel region is the location of disease, injury or pain. Hoof testers across the heels and from frog to opposite heel can implicate the heel as a painful site. A palmar digital perineural block with local anesthetic can then remove region pain and the improvement in lameness demonstrates that the heel(s) is the source of lameness. It must be recalled that this does not specify the tissue(s) of origin of the problem. This may actually take further manipulation with local anesthetics or special imaging techniques.
E. M. Gaughan, DVM, Diplomate ACVS College of Veterinary Medicine Kansas State University, Manhattan, KS
448
To Dr. E. M. Gaughan, one thing that appears to be constant is that the foot of horses is the most common cause of lameness in pleasure and performance horses. He spoke to veterinarians attending the North American Veterinary Conference in January, 1999, and said, "The relationship that a veterinarian has with local farriers can also dictate success with treatment quite often, as communication of diagnostic impressions to the common need for appropriate shoeing can be vital foI an athletic horse's future." His view is that the equine foot can be considered as a total of several diagnostic regions. The toe is fairly simple in construction and is one region. The heel is more complex in construction and perhaps in diagnostic efforts as well. The distal interphalangeal or coffin joint and associated structures is a third region. It may be appropriate to consider these three regions when approaching original diagnostic efforts in the foot. There is likely a need for further delineation of specific structure involvement after the regional localization for final diagnosis of specific disease or injury. Dr. Ganghan said that there is anatomical study evidence using latex injections that the navicular bursa and the coffin joint do not have a normal communication allowing sharing of synovial fluid. He added however, that clinical experience and research experiments appear to support the concept that there may be a functional communication between these two structures. Local anesthetic placed in the coffin joint of horses with experimentally induced navicular bursitis was noted to alleviate lameness. He said another study identified residues of local anesthetic in coffin joint synovial fluid after injection of the drug into the navicular bursa. Therefore, it appears difficult to absolutely differentiate navicular from coffin joint disorders. Imaging may be the key to formulate a final diagnosis. Scintigraphy, and possible newer generations of thermography instruments, may be able to compliment radiography to more closely define the source of lameness. In many western working horses the utilization of a physical examination and palmar digital nerve block can often lead to decisions that will lead to appropriate therapeutic choices. Often heel sore horses have been either shod inappropriately or have not been trimmed to properly balance the foot. He said, "Whether or not this is what has been classically defined as navicular disease is subject for lively debate that may be circular indeed." He explained that if you are one who considers the foot as a simple structure, lameness that resolves with a palmar digital nerve block may be classified as navicular disease, navicular syndrome or heel pain syndrome. If on the other hand, you are one who desires more tissue specific diagnosis, more diagnostic efforts may be needed. It is interesting that often, regardless of one's diagnostic approach, the treatment of horses with this pattern of lameness examination is very similar." Heel pain often responds very well to appropriate trimming to balance and shoeing to provide three goals: 1) enlarge the weight bearing surface area (egg bar shoe); 2) protect the heel from concussion forces (egg bar shoe +padding); and 3) ease break-over forces (rolled
JOURNAL OF EQUINE VETERINARY SCIENCE
toe). This appears to assist many horses and shoeing alone is often all that is required to return soundness. Other therapies that can help concentrate on reducing inflammation, providing some analgesia and assisting vascular perfusion of the region. Phenylbutazone often provides the antiinflammatory and analgesic properties desired. Other NSAIDs can also do this but phenylbutazone appears superior tbr muscnloskeletal injury. Local (intra-synovial) administration of sodium hyaluronate and PSGAGs can also provide antiinflammatory effects. Systemic administration has also been effective for some horses. Local corticosteroid administration into the coffin joint has provided good relief for some horses as well. Isoxsuprine has been used for some time to provide vasodilatation to the heel region of horses with heel pain. Early work demonstrated good effects on the palmar digital vessels at the pastern. Horses that are painful at the toe can usually have this alleviated with an abaxial or basisesamoid nerve block. Positive response to hoof testers usually precedes this when placed at the toe and quarters. If the sole has lost concavity, radiographs often indicate the presence of rotational laminitis. Sinking of the coffin bone within the foot is also possible. Dependant on the severity of the malpositioning of the coffin bone within the foot, some horses can return to serviceable soundness. If rotation is less than seven degrees or sinking is very minimal, horses can return to previous activity if all goes well. When into the chronic phases of care and the foot is stable, egg bar shoes with rolled toes and full pads can provide enough support and protection for a horse to comfortably train and compete. With more severe rotation or sinking the prognosis steadily decreases. Disorders of the coffin joint can be confused with navicular problems. However, tocal anesthesia and imaging may produce evidence implicating the joint. Degenerative joint disease and articular fractures of the coffin bone can appear similar clinically. Therapy of coffin joint DJD is similar to that of other joints. The coffin joint is essential for normal biomechanics of the equine limb. There is a great range of normal motion of the coffin joint and this must be preserved for soundness. Therefore, NSAIDs, HA, PSGAGs and other agents have a role in the treatment of coffin joint DJD. Coffin bone fractures can be frustrating to diagnose. Associated lameness can be marked, although acutely after injury affected horses may not be "fracture" lame. Severe distraction of fracture fragments is often apparent on radiographs of the foot. Non-displaced fractures may not be evident for 10-14 days as bone resorption occurs related to the fracture line. The prognosis for non-articular fractures is generally good. Articular fractures which result in incongruent defects of the joint surface do not fare as well. He said surgical treatment is not suggested as often as in previous years. This is because of relatively high complication rates from surgery. Utilizing the hoof wall as a natural cast can be a very effective method of treatment. This can be done by adding a version of a bar shoe to the affected foot. A "rim" Shoe, which raises a rim of steel from the bar shoe prevents hoof wall motion and indirect immobilization of the fracture site. This or a version with heavy clips can allow a favorable environment for fracture healing. Time to healing is generally protracted for the coffin bone and 6-12 months may be necessary. It is also possible that radiographs may not define good fracture healing. Volume 19, Number 7, 1999
Dr. Gaughan pointed out that recent work has questioned the bioavailability o f isoxsuprine after oral administration. And he said that further work is probably needed to complete our understanding. There are horses, however, that can return to maintainable soundness on shoeing and isoxsuprine alone. He emphasized that much more investigative work is needed to complete our understanding of "navicular disease."
Pedal osteitis can mimic laminitis and often is preceded by laminitic changes. Inflammation of the coffin bone is often difficult to diagnose with confidence, The physical examination, hoof tester exam and local anesthesia often appear like those of a horse with laminitis. Radiography and scintigraphy can help define the irregularity and inflammation of the coffin bone. Therapy then is often very similar to that for chronic, stable laminitis. Antiinflammatory agents and shoeing to reduce concussion and break-over forces appears to provide very good assistance to affected horses, allowing many to return to athletic pursuits.
A thorough physical examination should accompany radiographic or scintigraphic exam to determine appropriate return to exercise,
449
From The North American Veterinary Conference, Orlando, FL, Jan. 9-13, 1999.
The physical examination of the foot should include a close observation of the foot in weight-bearing posture as well as with the foot off the ground. The hoof wall and coronary band should be inspected for abnormalities of growth or injury. Evenness of length of the toe and quarters should be determined. The angle of hoof wall to pastern should be straight in most horses. Heel conformation and symmetry should be examined. With the foot out of weight bearing, the sole should be evaluated for normal concavity and frog conformation. The white line should be examined for evenness and width. Medial to lateral balance of hoof wall length should be assessed. This is an appropriate time for application of hoof testers. The best advice for hoof tester use is to establish a repeatable pattern such that each horse can be compared to itself and other horses from experience. Describing a specific diagnosis with heel pain can be a frustrating experience. It is fairly straight forward to determine that the heel region is the location of disease, injury or pain. Hoof testers across the heels and from frog to opposite heel can implicate the heel as a painful site. A palmar digital perineural block with local anesthetic can then remove region pain and the improvement in lameness demonstrates that the heel(s) is the source of lameness. It must be recalled that this does not specify the tissue(s) of origin of the problem. This may actually take further manipulation with local anesthetics or special imaging techniques.
E. M. Gaughan, DVM, Diplomate ACVS College of Veterinary Medicine Kansas State University, Manhattan, KS
448
To Dr. E. M. Gaughan, one thing that appears to be constant is that the foot of horses is the most common cause of lameness in pleasure and performance horses. He spoke to veterinarians attending the North American Veterinary Conference in January, 1999, and said, "The relationship that a veterinarian has with local farriers can also dictate success with treatment quite often, as communication of diagnostic impressions to the common need for appropriate shoeing can be vital foI an athletic horse's future." His view is that the equine foot can be considered as a total of several diagnostic regions. The toe is fairly simple in construction and is one region. The heel is more complex in construction and perhaps in diagnostic efforts as well. The distal interphalangeal or coffin joint and associated structures is a third region. It may be appropriate to consider these three regions when approaching original diagnostic efforts in the foot. There is likely a need for further delineation of specific structure involvement after the regional localization for final diagnosis of specific disease or injury. Dr. Ganghan said that there is anatomical study evidence using latex injections that the navicular bursa and the coffin joint do not have a normal communication allowing sharing of synovial fluid. He added however, that clinical experience and research experiments appear to support the concept that there may be a functional communication between these two structures. Local anesthetic placed in the coffin joint of horses with experimentally induced navicular bursitis was noted to alleviate lameness. He said another study identified residues of local anesthetic in coffin joint synovial fluid after injection of the drug into the navicular bursa. Therefore, it appears difficult to absolutely differentiate navicular from coffin joint disorders. Imaging may be the key to formulate a final diagnosis. Scintigraphy, and possible newer generations of thermography instruments, may be able to compliment radiography to more closely define the source of lameness. In many western working horses the utilization of a physical examination and palmar digital nerve block can often lead to decisions that will lead to appropriate therapeutic choices. Often heel sore horses have been either shod inappropriately or have not been trimmed to properly balance the foot. He said, "Whether or not this is what has been classically defined as navicular disease is subject for lively debate that may be circular indeed." He explained that if you are one who considers the foot as a simple structure, lameness that resolves with a palmar digital nerve block may be classified as navicular disease, navicular syndrome or heel pain syndrome. If on the other hand, you are one who desires more tissue specific diagnosis, more diagnostic efforts may be needed. It is interesting that often, regardless of one's diagnostic approach, the treatment of horses with this pattern of lameness examination is very similar." Heel pain often responds very well to appropriate trimming to balance and shoeing to provide three goals: 1) enlarge the weight bearing surface area (egg bar shoe); 2) protect the heel from concussion forces (egg bar shoe +padding); and 3) ease break-over forces (rolled
JOURNAL OF EQUINE VETERINARY SCIENCE
toe). This appears to assist many horses and shoeing alone is often all that is required to return soundness. Other therapies that can help concentrate on reducing inflammation, providing some analgesia and assisting vascular perfusion of the region. Phenylbutazone often provides the antiinflammatory and analgesic properties desired. Other NSAIDs can also do this but phenylbutazone appears superior tbr muscnloskeletal injury. Local (intra-synovial) administration of sodium hyaluronate and PSGAGs can also provide antiinflammatory effects. Systemic administration has also been effective for some horses. Local corticosteroid administration into the coffin joint has provided good relief for some horses as well. Isoxsuprine has been used for some time to provide vasodilatation to the heel region of horses with heel pain. Early work demonstrated good effects on the palmar digital vessels at the pastern. Horses that are painful at the toe can usually have this alleviated with an abaxial or basisesamoid nerve block. Positive response to hoof testers usually precedes this when placed at the toe and quarters. If the sole has lost concavity, radiographs often indicate the presence of rotational laminitis. Sinking of the coffin bone within the foot is also possible. Dependant on the severity of the malpositioning of the coffin bone within the foot, some horses can return to serviceable soundness. If rotation is less than seven degrees or sinking is very minimal, horses can return to previous activity if all goes well. When into the chronic phases of care and the foot is stable, egg bar shoes with rolled toes and full pads can provide enough support and protection for a horse to comfortably train and compete. With more severe rotation or sinking the prognosis steadily decreases. Disorders of the coffin joint can be confused with navicular problems. However, tocal anesthesia and imaging may produce evidence implicating the joint. Degenerative joint disease and articular fractures of the coffin bone can appear similar clinically. Therapy of coffin joint DJD is similar to that of other joints. The coffin joint is essential for normal biomechanics of the equine limb. There is a great range of normal motion of the coffin joint and this must be preserved for soundness. Therefore, NSAIDs, HA, PSGAGs and other agents have a role in the treatment of coffin joint DJD. Coffin bone fractures can be frustrating to diagnose. Associated lameness can be marked, although acutely after injury affected horses may not be "fracture" lame. Severe distraction of fracture fragments is often apparent on radiographs of the foot. Non-displaced fractures may not be evident for 10-14 days as bone resorption occurs related to the fracture line. The prognosis for non-articular fractures is generally good. Articular fractures which result in incongruent defects of the joint surface do not fare as well. He said surgical treatment is not suggested as often as in previous years. This is because of relatively high complication rates from surgery. Utilizing the hoof wall as a natural cast can be a very effective method of treatment. This can be done by adding a version of a bar shoe to the affected foot. A "rim" Shoe, which raises a rim of steel from the bar shoe prevents hoof wall motion and indirect immobilization of the fracture site. This or a version with heavy clips can allow a favorable environment for fracture healing. Time to healing is generally protracted for the coffin bone and 6-12 months may be necessary. It is also possible that radiographs may not define good fracture healing. Volume 19, Number 7, 1999
Dr. Gaughan pointed out that recent work has questioned the bioavailability o f isoxsuprine after oral administration. And he said that further work is probably needed to complete our understanding. There are horses, however, that can return to maintainable soundness on shoeing and isoxsuprine alone. He emphasized that much more investigative work is needed to complete our understanding of "navicular disease."
Pedal osteitis can mimic laminitis and often is preceded by laminitic changes. Inflammation of the coffin bone is often difficult to diagnose with confidence, The physical examination, hoof tester exam and local anesthesia often appear like those of a horse with laminitis. Radiography and scintigraphy can help define the irregularity and inflammation of the coffin bone. Therapy then is often very similar to that for chronic, stable laminitis. Antiinflammatory agents and shoeing to reduce concussion and break-over forces appears to provide very good assistance to affected horses, allowing many to return to athletic pursuits.
A thorough physical examination should accompany radiographic or scintigraphic exam to determine appropriate return to exercise,
449