Difference of Medial Elbow Joint Space According to Load and External Rotation Angle

The purpose of this study is to assess changes to the medial elbow joint space(MEJS) depending on grip contraction, valgus force and the angle of the glenohumeral joint external rotation(GHER).

Ultrasonography was used to investigate the spatial variation of MEJS according to the angle of GHER, valgus force and grip contraction. In this condition, each variable was set to grip and non-grip; GHER 90 and maximum; valgus force 0 lb, 1 lb and 2 lb. One-way repeated ANOVA was used to see change with weight, and independent-samples T-test was used to see changes with the angle of the GHER and valgus force.

The MEJS was the narrowest at GHER 90° x grip contraction x 0lb and the MEJS was the largest at GHER maximum x non-grip contraction x 2lb. There was no significant difference between GHER 90° and the GHER maximum, and it was significant between the grip contraction and non-grip contraction. GHER 90° × grip contraction and GHER 90° × non-grip contraction showed significant difference between 0lb and 2lb according to the weight and there was no significant difference in the rest. In the GHER maximum x non-grip contraction, there was a significant difference between the 0lb and 2lb and the 1lb and 2lb and there was no significant difference in the rest. There was no significant difference in GHER maximum x grip contraction.

According to the results of this study, the prevention of ulnar collateral ligament(UCL) damage and the guidelines for exercise during overthrowing can be applied.