A total of 353 studies were located, and, after implementation of the exclusion criteria, 112 studies were included in the final analysis (Figure 1; 3093 subjects; 3168 elbows; 64% male; mean age, 34.9 ± 14.68 years). There was a mean of 33.4 ± 26.02 months of follow-up, and 75% of surgeries involved the dominant elbow (Table 1). Most studies were level IV evidence (94.6%), had a low MCMS (mean 28.1 ± 8.06; poor rating), and were single-center investigations (94.6%). Most studies did not report financial conflicts of interest (56.3%) (Tables 1 and 2). From 1985 through 2014, the number of publications significantly increased with time (P = .004) among all continents. The MCMS was unchanged over time (P = .247) (Figure 2A), as was the level of evidence (P = .094) (Figure 2B). Conflicts of interest significantly increased with time (P = .025) (Figure 3).
Among continents, North America published the largest number of studies (54), and had the largest number of patients (1395) and elbow surgeries (1425) (Table 1). The United States published the largest number of studies (43%). There were no significant differences between age (P = .331), length of follow-up (P = .403), MCMS (P = .123), and level of evidence (P = .288) between continents. Of the 32 studies that reported the use of preoperative MRI, studies from Asia reported significantly more MRI scans than those from other continents (P = .040); there were no other significant differences between continents in reference to preoperative imaging studies or other demographic information.
