NEUROGENIC ACCELERATION OF OSTEOARTHROSIS - THE EFFECTS OF PREVIOUS NEURECTOMY OF THE ARTICULAR NERVES ON THE DEVELOPMENT OF OSTEOARTHROSIS AFTER TRANSECTION OF THE ANTERIOR CRUCIATE LIGAMENT IN DOGS

The development of osteoarthrosis in unstable knee joints of dogs after transection of the anterior cruciate ligament is greatly accelerated when the afferent nerve fibers from the ipsilateral hindlimb have been interrupted by dorsal root ganglionectomy before transection. The purpose of the current study was to determine whether partial loss of the afferent fibers from the knee joints of dogs, accomplished by neurectomy of the primary articular nerves before transection of the ligament, also accelerates the development of osteoarthrosis. Osteoarthrosis did not develop in dogs that had had transection of the medial, posterior, and lateral articular nerves to the left knee joint but had an intact anterior cruciate ligament. Osteoarthrosis developed in all dogs that had had transection of the anterior cruciate ligament. However, the osteoarthrotic lesions, as guaged by histological and macroscopic criteria, were more frequent and severe in dogs that had had neurectomy before transection than in those that had intact sensory nerves and an unstable joint (p less-than-or-equal-to 0.05). A subchondral fracture occurred in three dogs that had had neurectomy and had an unstable joint but in none of the dogs that had intact sensory nerves and an unstable joint. CLINICAL RELEVANCE: Osteoarthrosis develops in the knee joint in dogs when the joint has been rendered unstable due to transection of the anterior cruciate ligament but not in a stable joint that has had interruption of the sensory nerve supply. The severity of the ensuing osteoarthrosis in unstable joints is increased by resection of the ipsilateral articular nerves; that is, the rate at which osteoarthrosis develops, and its severity, are decreased in joints in which the fibers of the sensory nerves are intact. These findings suggest that an underlying neurological disorder or damage to small articular nerves during an operation could adversely affect the outcome in joints in which the articular cartilage is damaged by osteoarthrosis or other factors.