Hiroshi Hattori1, Kiyokazu Akasaka2, Takahiro Otsudo3, Toby Hall4, Katsuya Amemiya5, Yoshihisa Mori5. 1. Department of Physical Therapy, Saitama Medical University Graduate School of Medicine, Moroyama, Saitama, Japan; Department of Rehabilitation, Kawagoe Clinic, Saitama Medical University, Kawagoe, Saitama, Japan. 2. Department of Physical Therapy, Saitama Medical University Graduate School of Medicine, Moroyama, Saitama, Japan; School of Physical Therapy, Saitama Medical University, Moroyama, Saitama, Japan. Electronic address: akasaka-smc@umin.ac.jp. 3. Department of Physical Therapy, Saitama Medical University Graduate School of Medicine, Moroyama, Saitama, Japan; School of Physical Therapy, Saitama Medical University, Moroyama, Saitama, Japan. 4. School of Physiotherapy and Exercise Science, Curtin University, Perth, WA, Australia; Manual Concept, Perth, WA, Australia. 5. Department of Rehabilitation, Kawagoe Clinic, Saitama Medical University, Kawagoe, Saitama, Japan.
Abstract
BACKGROUND: To prevent elbow injury in baseball players, various methods have been used to measure medial elbow joint stability with valgus stress. However, no studies have investigated higher levels of elbow valgus stress. This study investigated medial elbow joint space gapping measured ultrasonically resulting from a 30 N valgus stress vs. gravitational valgus stress after a repetitive throwing task. METHODS: The study included 25 high school baseball players. Each subject pitched 100 times. The ulnohumeral joint space was measured ultrasonographically, before pitching and after each successive block of 20 pitches, with gravity stress or 30 N valgus stress. Two-way repeated measures analysis of variance and Pearson correlation coefficient analysis were used. RESULTS: The 30 N valgus stress produced significantly greater ulnohumeral joint space gapping than gravity stress before pitching and at each successive 20-pitch block (P < .01). For the 2 stress methods, ulnohumeral joint space gapping increased significantly from baseline after 60 pitches (P < .01). Strong significant correlations were found between the 2 methods for measurement of medial elbow joint space gapping (r = 0.727-0.859, P < .01). CONCLUSIONS: Gravity stress and 30 N valgus stress may produce different effects with respect to medial elbow joint space gapping before pitching; however, 30 N valgus stress appears to induce greater mechanical stress, which may be preferable when assessing joint instability but also has the potential to be more aggressive. The present results may indicate that constraining factors to medial elbow joint valgus stress matched typical viscoelastic properties of cyclic creep.
BACKGROUND: To prevent elbow injury in baseball players, various methods have been used to measure medial elbow joint stability with valgus stress. However, no studies have investigated higher levels of elbow valgus stress. This study investigated medial elbow joint space gapping measured ultrasonically resulting from a 30 N valgus stress vs. gravitational valgus stress after a repetitive throwing task. METHODS: The study included 25 high school baseball players. Each subject pitched 100 times. The ulnohumeral joint space was measured ultrasonographically, before pitching and after each successive block of 20 pitches, with gravity stress or 30 N valgus stress. Two-way repeated measures analysis of variance and Pearson correlation coefficient analysis were used. RESULTS: The 30 N valgus stress produced significantly greater ulnohumeral joint space gapping than gravity stress before pitching and at each successive 20-pitch block (P < .01). For the 2 stress methods, ulnohumeral joint space gapping increased significantly from baseline after 60 pitches (P < .01). Strong significant correlations were found between the 2 methods for measurement of medial elbow joint space gapping (r = 0.727-0.859, P < .01). CONCLUSIONS: Gravity stress and 30 N valgus stress may produce different effects with respect to medial elbow joint space gapping before pitching; however, 30 N valgus stress appears to induce greater mechanical stress, which may be preferable when assessing joint instability but also has the potential to be more aggressive. The present results may indicate that constraining factors to medial elbow joint valgus stress matched typical viscoelastic properties of cyclic creep.
Authors: Grant H Garcia; Anirudh K Gowd; Brandon C Cabarcas; Joseph N Liu; John R Meyer; Gregory M White; Anthony A Romeo; Nikhil N Verma Journal: Orthop J Sports Med Date: 2019-01-29
Authors: Lafi S Khalil; Toufic R Jildeh; Muhammad J Abbas; Chad L Klochko; Courtney Scher; Marnix Van Holsbeeck; Stephanie J Muh; Eric C Makhni; Vasilios Moutzouros; Kelechi R Okoroha Journal: Arthrosc Sports Med Rehabil Date: 2021-10-09