Premature ulnar joint closure
The premature Ulnafugenschluss is the leading cause of limb deformities of the forelimb in the domestic dog . This is coming through a trauma to a premature end of the distal epiphysis of the ulna ( ulna ) and then to a curvature of the spoke .
Emergence
The distal ulnar joint has a conical shape. For this reason, transverse forces are more likely to lead to joint trauma with premature closure of the growth plate than to epiphysiolysis . While the two growth plates of the radius each contribute about half to the longitudinal growth of the bone, the lower (distal) ulnar plate contributes over 80% to the longitudinal growth of the ulna. Since both forearm bones are firmly connected to one another by the interossea antebrachial membrane , the ulna that remains in the growth spans the growing radius similar to an arch. There is a forward bending of the spoke and a deviation of the pastern joint to the outside ( valgus position ).
A special form is the retained ulna cone , which occurs mainly in large dog breeds such as the Great Dane . The primary problem here is a disorder of the enchondral ossification , which, however, also leads to reduced growth of the ulna.
Symptoms and Diagnosis
The premature ulnar joint closure manifests itself in alternating lameness of the affected limb. If it persists for a long time, the deformation of the spoke described above (bending forward and carpus valgus) occurs.
In the x-ray the ulnar joint is more closed than that of the spoke. When the ulnar cone is retained, the affected metaphysis becomes bright in the shape of a flame.
treatment
The treatment depends on the extent of the deformation and the age of the animal and thus the expected growth in length. If the animal is still growing, the ulna is surgically severed ( osteotomy ) and possibly stabilized in the medullary cavity with a nail. If the valgus is over 25 °, a corrective osteotomy of the radius must be performed.
literature
Christine Pepper and Martin Kramer: Selected orthopedic diseases during the growth phase in dogs and cats. In: Kleintierpraxis 58 (2013), pp. 306-320.
