Weird and wonderful
There are no end to these but I will highlight some of the more common other causes
of lameness or perceived lameness in foals.
New-born foals with wind swept or excessive limb laxity or flexural limb deformities
may appear lame due to limb weakness or knuckling over. These presentations are
transient and will self-correct with time and correct management as the foal matures.
A secondary lameness as a result of acquired lesions from pressure on the heel
bulbs in slack foals or knuckling over at the fetlocks or excessive pressure at the
point of the toe may develop in contracted foals. It is important to prevent the foal
from injuring itself with appropriate bandaging of extremities exposed to abnormal
ground contact and confinement with controlled exercise until the foal strengthens.
Rupture of the common and lateral digital extensor tendon is fairly common in foals
with flexural limb deformities and results in the foal knuckling over at the knee and
the fetlock. These cases have a characteristic swelling on the lateral aspect just
below the carpus and can be differentiated from contracted foals by the way the limb
can be manually pulled forward and placed in the correct anatomical position. Care
must be taken to protect the limb from damages as a result of knuckling forward, with
bandaging and in some cases intermittent splinting until the foal learns to walk
without knuckling forward by swinging the limb forward. These cases have a very
good prognosis with conservative management.
Incomplete ossification and collapse or fracture of the cuboidal bones in immature
and dysmature foals results in juvenile osteoarthritis. Early recognition and
radiographs of the carpi and tarsi of the foals enables correct management and
enforced confinement until the bones have ossified sufficiently.
Traumatic fracture of cuboidal bones (especially carpus) has a poor prognosis for
future athletic soundness as there is normally significant soft tissue damage and joint
instability.
Developmental orthopaedic disease (OCD subchondral cysts) may also result in
lameness, more typically in weanlings and yearlings, but is beyond the scope of this
presentation.
Radial nerve paralysis is normally a result of a “shoulder on shoulder” collision
between two foals (two lame foals will sometimes present simultaneously as a
result). Typical presentation is a dropped shoulder and dragging of the toe as it is
unable to advance the limb or load the limb. One must rule out fracture of the
scapula and humerus with radiographs. Treatment consisting of corticosteroids nonsteroidal anti-inflammatories should result in improvement within 3-5 days for a good
prognosis.
I have seen a case where improvement occurred only very gradually with lots of
supportive care and rehabilitation over 3 months that went on to have a normal
athletic career.
Proceedings
of
the
South
African
Equine
Veterinary
Association
Congress
2016
236