Toxina botulínica associada à denervação acetabular para tratamento da displasia coxofemoral em cães

Abstract

Hip dysplasia (HD) is one of the main causes of pelvic limb lameness in dogs, with a multifactorial etiology. The diagnosis is based on the clinical-orthopedic examination associated with the standardized radiographic examination. The acetabular denervation (AD) technique is based on mechanical deperiostization of the dorsal acetabular border, sectioning the fibers that innervate the joint capsule, while botulinum toxin (BT) promotes chemical denervation by inhibiting acetylcholine release at the neuromuscular junction. This study aimed to evaluate the response of dogs with HD to surgical treatment with isolated AD or associated with intra-articular use of BT. Fifteen dogs of different breeds, ages, and sexes, weighing over 20 kg, were included. In each dog, the hip joint considered most affected received, in addition to the AD surgery, treatment with intra-articular application of BT at a dose of 50 IU, and this was the Botulinum Toxin Group (BTG). The contralateral hip joint served as a control and was subjected to AD surgery and intra-articular application of physiological saline solution, and this was the Physiological Solution Group (PSG). The dogs were evaluated for a period of one year based on clinical variables related to limb support, muscle mass, joint range of motion, lameness, and pain, as well as radiographic evaluations. The results showed a transient superiority of the BTG in relation to the parameters observed in the preoperative period, with an earlier favorable evolution compared to PSG. From the evaluation of 180 days, it was noted that the effect of BT no longer had an influence on the variables, and the favorable results were maintained in both groups by the AD surgery. In both groups, throughout the study, there was an improvement in variables such as thigh perimeter, degree of pain, degree of lameness, extension angle, and flexion angle. Some variables showed an important correlation with each other, such as degree of pain versus degree of lameness and thigh perimeter versus pelvic limb support. In conclusion, the AD surgery is efficient in improving clinical variables such as pain and lameness, as well as providing functional improvement due to aspects such as increased muscle mass and greater joint range of motion. The association of AD surgery with intra- articular BT application promotes synergism in the clinical and functional improvement of the hip joint, providing earlier and transiently superior favorable results when compared to isolated surgical treatment.