1961 Volume 14 Issue 3 Pages 87-91
The term of habitual suprapatellar dislocation has been used to indicate the disturbance of full extension of the thigh and leg and flexible bending of the posterior extremities occurring in young cattle and horses. This ailment was studied roentgenologically and anatomically. In addition, experiments were carried out to induce it artificially. In affected animals examined, no suprapatellar dislocation was detected at all, but the shortened medial perpendicular ligament of the patella had been displaced to the anterior surface of the trochlea of the patella on account of a strong attraction caused by the contraction of the quadriceps femoris muscle. Such being the case, it is considered reasonable to call this situation habitual vertical patellar dislocation.
The syndesmotomy of the medial perpendicular ligament of the patella has been regarded to be of great curative effect on this ailment, but has not been generally performed due to the contradictory terminology and obscure pathognomy of the ailment.
After this ligament is cut, its function is compensated by those of the lateral and intermediate perpendicular ligaments of the patella. The animal can walk immediately after operation. The cut ligament is transformed into cartilaginoid tissue in twenty to thirty days and a firm accretion occurs to it.
Since the author treated 58 limbs successfully, he is convinced that the syndesmotomy mentioned above is a radically curative plastic surgical operation causing no danger in work animals.