A Comparison of Two Surgical Approaches to the Scapulohumeral Joint in Dogs

Abstract
Two scapulohumeral arthrotomy techniques were evaluated and compared in 10 normal, young adult greyhounds. A caudolateral approach with craniodorsal retraction of the teres minor muscle (no-tenotomy) and a craniolateral approach with tenotomy of the infraspinatus tendon were each performed unilaterally in 5 dogs. The dogs were evaluated using force plate gait analysis, lameness evaluation, radiography, and goniometry for 5 weeks and then euthanatized. Tenotomy sites and sections of the humeral articular cartilage were collected from shoulder joints that had been operated on and examined microscopically. The same surgical approach has then performed on the contralateral shoulder in the cadavers and exposure of the humeral articular cartilage was measured using planimetry. Peak vertical force applied to the operated limbs in the tenotomy group was significantly less than preoperative leads on day 3 and significantly less than the no-tenotomy group on days 21 and 28. The peak vertical force applied to the operated limbs in the no-tenotomy group was not significantly different from preoperative levels during the study. Scapulohumeral arthrotomy by tenotomy of the infraspinatus resulted in decreased range-of-motion and joint extension compared with joints operated on without tenotomies, but provided significantly greater exposure to the articular surface. Scapulohumeral arthrotomy with craniodorsal retraction of the teres minor muscle did not significantly alter goniometric measurements compared with unoperated joints. Both techniques resulted in similar subjective lameness scores and caused no gross microscopic or radiographic evidence of articular cartilage damage.