Shoulder and elbow evaluation of pitchers in National High School Baseball Invitational Tournaments and National High School Baseball Championships from 1993 to 2016 in Japan.

Abstract

Shoulder and elbow examinations for pitchers have been performed in Japan's National High School Baseball Invitational Tournaments (NHSBITs) and National High School Baseball Championships (NHSBCs) since 1993. However, for years the results have not been analyzed. The purpose of this study was to evaluate changes in the condition of shoulders and/or elbows of pitchers from 1993 to 2016. Pitchers in NHSBITs and NHSBCs, 1994-2016, were examined together with those who received a trial examination (Trial) in the NHSBC 1993. Shoulder and elbow symptoms were comprehensively graded into five categories; none, mild, moderate, severe and dysfunction. Standard plain radiographs of the shoulder and elbow were obtained. Average Annual Percent Changes (AAPCs) in the percentages of pitchers with symptoms and positive radiographic findings were analyzed. The percentages of pitchers with moderate or worse symptoms in the shoulder or elbow were 14.6% and 13.8%, respectively, in the Trial, 1.1% and 1.1% in NHSBITs and 1.3% and 2.0% in NHSBCs. The AAPC of pitchers with a symptomatic shoulder in NHSBITs was reduced over the study period, at -3.36% (P < 0.05), but that in NHSBCs was unchanged at -1.01%. The AAPCs of pitchers with a symptomatic elbow in NHSBITs and in NHSBCs decreased, at -3.13% and -3.33%, respectively (P < 0.05), while that of pitchers with residual apophyseal fragmentation at the ulnar collateral ligament insertion increased at +2.79% (P < 0.05). The decreased percentages of symptomatic pitchers suggest that joint condition is well controlled in high school days; however, the increased frequency of radiographic findings suggests the necessity of protection against overuse in younger players. The percentages of pitchers with symptomatic shoulders and elbows in NHSBITs and those with symptomatic elbows in NHSBCs have decreased over the 23 years. However, the increased frequency of residual medial humeral epicondyle apophyseopathy should be noted.