Changes

Also know as: '''''Contracted tendons'''''

Also know as: '''''Contracted Tendons'''''

==Introduction==

==Introduction==

Flexural limb deformities applies to those in which the limb '''deviates from the normal vertical alignement''' in the sagittal plane.

Flexural limb deformities term applies to those in which the limb '''deviates from the normal vertical alignement''' in the sagittal plane.

The primary problem involves the soft tissues that support the various joints of the limb. Depending on the defect and on its severity and chronicity, the problem may involve one or more of the flexor muscles and the associated ligaments and fascia, or it may also involved the ligaments, fascia, joint capsule and synovial structures of the joints involved.

The primary problem involves the soft tissues that support the various joints of the limb. Depending on the defect and on its severity and chronicity, the problem may involve one or more of the flexor muscles and the associated ligaments and fascia, or it may also involved the ligaments, fascia, joint capsule and synovial structures of the joints involved.

Flexural limb deformities are divided into two broad categories:

Flexural limb deformities are divided into two broad categories:

 

:'''Flexor laxity''': in which the joints are hyperextended due to loose supporting structures.

'''Flexor laxity''': in which the joints are hyperextended due to loose supporting structures.

:'''Flexor contracture''': normal extension of joints is limited and the joints are permanently flexed due to tight supporting structures.

 

'''Flexor contracture''': normal extension of joints is limited and the joints are permanently flexed due to tight supporting structures.

As for the aetiology of flexural limb deformities, the two categories are:

As for the aetiology of flexural limb deformities, the two categories are:

 

:'''Congenital''': the deformity is present at birth. Causes include: genetic predisposition, intrauterine malpositioning, teratogens.

'''Congenital''': the deformity is present at birth. Causes include: genetic predisposition, intrauterine malpositioning, teratogens.

::The deformities commonly observed are: digital hyperextension and contractural deformities.

 

::Congenital flexural deformities are common causes of [[Dystocia - Horse|dystocia in the mare]].

The deformities commonly observed are: digital hyperextension and contractural deformities.

:'''Acquired''': excessive intake and abrupt changes in quality and quantity of feed can lead to accelerated growth in foals. The longitudinal growth rate of the bones exceeds the ability of the tendons to extend passively, pulling the respective joint into flexion. Polyarthritis and trauma are painful conditions and can lead to a flexion reflex resulting in an acquired contractural deformity.

 

Congenital flexural deformities are common causes of dystocia in the mare.

 

'''Acquired''': excessive intake and abrupt changes in quality and quantity of feed can lead to accelerated growth in foals. The longitudinal growth rate of the bones exceeds the ability of the tendons to extend passively, pulling the respective joint into flexion. Polyarthritis and trauma are painful conditions and can lead to a flexion reflex resulting in an acquired contractural deformity.

Joints involved include: distal interphalangeal joint, metacarpophalangeal joint, metatarsophalangeal joint and carpus.

Joints involved include: distal interphalangeal joint, metacarpophalangeal joint, metatarsophalangeal joint and carpus.

==Clinical signs==

==Clinical Signs==

'''Congenital digital hyperextension''': toes lift off the ground due to flaccidity of the flexor tendons and the foot may rock back on the heel. More severe cases result with the foal walking on the palmar/plantar surface of the phalanges resulting in skin abrasions of the pastern and fetlock. It is more common in the hindlimbs.

:'''Congenital digital hyperextension''': toes lift off the ground due to flaccidity of the flexor tendons and the foot may rock back on the heel. More severe cases result with the foal walking on the palmar/plantar surface of the phalanges resulting in skin abrasions of the pastern and fetlock. It is more common in the hindlimbs.

'''Congenital contractural deformities''': no voluntary extension of the affected limbs.  

:'''Congenital contractural deformities''': no voluntary extension of the affected limbs.  

''Distal interphalangeal joint contracture'': the foal walks on its toes. The dorsal hoof wall is often concave in appearance with increased heel length (club foot)

:''Distal interphalangeal joint contracture'': the foal walks on its toes. The dorsal hoof wall is often concave in appearance with increased heel length (club foot)

''Metacarpophalangeal joint contracture'': the foal will have difficulty standing and knuckle over at the fetlock.

:''Metacarpophalangeal joint contracture'': the foal will have difficulty standing and knuckle over at the fetlock.

''Carpal contracture'': foal observed buckling forward.

:''Carpal contracture'': foal observed buckling forward.

'''Acquired contractural deformities:'''

'''Acquired contractural deformities:'''

''Distal interphalangeal joint contracture'': short toe and steep dorsal hoof wall angle. Boxy appearance over time. Stage I: angle of the dorsal hoof wall is less than 90°. Stage II: angle of the dorsal hoof wall is more than 90°.

:''Distal interphalangeal joint contracture'': short toe and steep dorsal hoof wall angle. Boxy appearance over time. Stage I: angle of the dorsal hoof wall is less than 90°. Stage II: angle of the dorsal hoof wall is more than 90°.

''Metacarpophalangeal/metatarsophalangeal joint contracture'': straight angle to knuckled-over appearance at the fetlock. More common in the forelimbs.

:''Metacarpophalangeal/metatarsophalangeal joint contracture'': straight angle to knuckled-over appearance at the fetlock. More common in the forelimbs.

''Proximal interphalangeal joint contracture'': dorsal subluxation with an audible click as the foal walks. Occurs bilaterally.

:''Proximal interphalangeal joint contracture'': dorsal subluxation with an audible click as the foal walks. Occurs bilaterally.

==Diagnosis==

==Diagnosis==

A thorough '''history''' including nutritional management should be taken.

A thorough '''history''' including nutritional management should be taken.

'''Radiography''' might reveal bony abnormalities such as osteochondrosis and degenerative joint disease.

'''Radiography''' might reveal bony abnormalities such as [[osteochondrosis]] and [[Degenerative Joint Disease|degenerative joint disease]].

The foal should be '''observed standing and walking'''. Its limbs should be '''manipulated and palpated''' in weight-bearing and non-weight bearing positions.

The foal should be '''observed standing and walking'''. Its limbs should be '''manipulated and palpated''' in weight-bearing and non-weight bearing positions.

'''Congenital deformities''':

'''Congenital deformities''':

 

:''Digital hyperextension'': Moderate exercise. Light bandaging to protect the phalanges. Heel-extension shoes.

''Digital hyperextension'': Moderate exercise. Light bandaging to protect the phalanges. Heel-extension shoes.

:''Contracture deformities'': encourage weight-bearing exercise or manipulate the limbs of a foal if it is recumbent

 

:Oxytetracycline intravenously chelates calcium ions and is thought to aid in tendon relaxation. The foal's nutrition should also be corrected.

''Contracture deformities'': encourage weight-bearing exercise or manipulate the limbs of a foal if it is recumbent

:Toe extensions can be applied and splints and casts can be used to relax the muscle-tendon unit.

 

Oxytetracycline intravenously chelates calcium ions and is thought to aid in tendon relaxation. The foal's nutrition should also be corrected.

 

Toe extensions can be applied and splints and casts can be used to relax the muscle-tendon unit.

'''Acquired deformities''':  

'''Acquired deformities''':  

 

:''Distal interphalangeal joint'': balanced nutrition and exercise are important, and non-steroidal anti-inflammatories can be used to help the foal continue to exercise during the painful stretching of the tendons. Toe-extensions and casts have also been used to correct the deformity.

''Distal interphalangeal joint'': balanced nutrition and exercise are important, and non-steroidal anti-inflammatories can be used to help the foal continue to exercise during the painful stretching of the tendons. Toe-extensions and casts have also been used to correct the deformity.

:''Metacarpophalangeal joint'': a combination of a balanced diet, physical therapy, [[NSAIDs]] can be used. Corrective shoeing including wedges to raise the heel to bring the fetlock into a more normal position.

 

:''Carpal joint'': use of physical therapy and splints

''Metacarpophalangeal joint'': a combination of a balanced diet, physical therapy, NSAIDs can be used. Corrective shoeing including wedges to raise the heel to bring the fetlock into a more normal position.

:''Proximal interphalangeal joint'': trimming of the hoof.

 

''Carpal joint'': use of physical therapy and splints

 

''Proximal interphalangeal joint'': trimming of the hoof.

 

'''Surgical therapy''' is an option for acquired contractures or severe congenital deformities, and includes:

'''Surgical therapy''' is an option for acquired contractures or severe congenital deformities, and includes:

 

:''Distal interphalangeal joint contracture'': desmotomy of the superior or inferior check ligament, depending on if the deep or the superficial digital flexor palpates tighter.

''Distal interphalangeal joint contracture'': desmotomy of the superior or inferior check ligament, depending on if the Deep of the Superficial digital flexor palpates tighter.

:Tenotomy of the deep digital flexor tendon can be considered as a salvage procedure in stage II deformities.

 

:''Metacarpophalangeal joint contracture'': desmotomy of the superior or inferior check ligament as above. Additional transection of the suspensory ligament might be necessary in severe cases, however the prognosis for athleticism is poor.

Tenotomy of the deep digital flexor tendon can be considered as a salvage procedure in stage II deformities.

:''Carpal joint contracture'': tenotomy of the ulnaris lateralis and flexor carpi ulnaris tendons

 

:''Proximal interphalangeal joint'': transection of the inferior check ligament. If subluxation of the pastern is not reducible, surgical arthrodesis may be necessary.

''Metacarpophalangeal joint contracture'': desmotomy of the superior or inferior check ligament as above. Additional transection of the suspensory ligament might be necessary in severe cases, however the prognosis for athleticism is poor.

 

''Carpal joint contracture'': tenotomy of the ulnaris lateralis and flexor carpi ulnaris tendons

 

''Proximal interphalangeal joint'': transection of the inferior check ligament. If subluxation of the pastern is not reducible, surgical arthrodesis may be necessary.

==Prognosis==

==Prognosis==

Lavoie, J-P. (2009) '''Blackwell's Five-Minute Veterinary Consult: Equine''' ''John Wiley and Sons''

Lavoie, J-P. (2009) '''Blackwell's Five-Minute Veterinary Consult: Equine''' ''John Wiley and Sons''

[[Category:To Do - Helen]]

 

[[Category:To Do - Review]]

[[Category:Musculoskeletal Diseases - Horse]]

[[Category:Expert Review - Horse]]