Premature Closure of the Distal Physis is an orthopedic deformity of the forelimb.
Premature Closure of the Distal Physis occurs in immature dogs with open physes
(growth plates). Severe deformities can cause elbow luxation or subluxation. An affected
dog will show signs of intermittent lameness with varying degrees. Often, the limb
is deformed by moderate bowing, noticed in certain breeds of dog.
The growth plates are responsible for bone growth in immature dogs, until the
growth plates close around one year of age. The growth plates are located at the
end of each bone, and immature (open) growth plates are softer than mature bones.,
which are more susceptible to injury. The distal (towards the bottom of the bone)
growth plate is responsible for 90% of the entire bone’s growth.
Chondrodystrophic (dogs with angular limb deformities) breeds, such as the Basset
Hound, Pekingese, Bulldog, develop PCDP (premature closure of distal physis), which
is caused by asynchronous growth of the radius and ulna without apparent injury to
the growth plate. Therefore, meaning that the growth plate closes prematurely and
causes the Ulna to stop growing while the Radius continues to grow (lengthen). This
abnormal growth results in incongruity (unevenness) of the elbow joint because either
the radius or ulna is inappropriately, abnormally short in comparison to the other
bone. The incongruity causes the Radius to bow moderately. Additionally, the wrist
twists and the elbow joint is forced to luxate. This is why the deformity is often
called Elbow Dysplasia.
Studies have shown that these are inherited monogenic (singular) traits that
cause the deformities. Dogs exhibiting these deformities should be withheld from
This orthopedic issue must be resolved while the bone still has a lot more growing
to do, the sooner the better, usually before the pet is 8 months of age. Surgical
correction consists of either ulnar lengthening or ulnar shortening, but Ulnar Lengthening
is way more common. Ulnar Osteotomy (cut only) or Ulna Ostectomy (removal of small
portion) is the surgical procedure required to lengthen the Ulna. A small portion
of the Ulna is either cut or removed, either secured with or without an IM pin, and
immobilized for 6-8 weeks via bandage or K-E apparatus. This cutting or removal of
[part of the Ulna, releases the pressure on the Ulna from the Radius and allows elbow