Age-related degenerative functional, radiographic, and histological changes of the shoulder in nonhuman primates

Background Nonhuman primates have similar shoulder anatomy and physiology compared to humans, and may represent a previously underutilized model for shoulder research. This study sought to identify naturally occurring bony and muscular degeneration in the shoulder of nonhuman primates and to assess relationships between structural and functional aspects of the shoulder and measures of physical function of the animals. We hypothesized that age-related degenerative changes in the shoulders of nonhuman primates would resemble those observed in aging humans. Methods Middle-aged (n = 5; ages 9.4-11.8 years) and elderly (n = 6; ages 19.8-26.4 years) female vervet monkeys were studied for changes in mobility and shoulder function, and radiographic and histologic signs of age-related degeneration. Results Four out of 6 (4/6) elderly animals had degenerative changes of the glenoid compared to 0/5 of the middle-aged animals ( P = .005). Elderly animals had glenoid retroversion, decreased joint space, walked slower, and spent less time climbing and hanging than middle-aged vervets ( P