Pre- and Postseason Dynamic Ultrasound Evaluation of the Pitching Elbow.
OBJECTIVE
To use ultrasound imaging to document changes over time (i.e., preseason v postseason) in the pitching elbow of high school baseball pitchers.


METHODS
Twenty-two high school pitchers were prospectively followed. Pitchers were evaluated after a 2-month period of relative arm rest via preseason physical exams, dynamic ultrasound imaging of their throwing elbow, and the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) assessment. Players were reevaluated within 1 week of their last game. Dynamic ultrasound images were then randomized, blinded to testing time point, and evaluated by 2 fellowship-trained musculoskeletal radiologists.


RESULTS
Average pitcher age was 16.9 years. Average pitches thrown was 456.5, maximum velocity 77.7 mph, games pitched 7.3, and days off between starts 6.6. From preseason to postseason, there were significant increases in ulnar collateral ligament (UCL) thickness (P = .02), ulnar nerve cross-sectional area (P = .001), UCL substance heterogeneity (P = .001), and QuickDASH scores (P = .03). In addition, there was a nonsignificant increase in loaded ulnohumeral joint space (P = .10). No pitchers had loose bodies on preseason exam, while 3 demonstrated loose bodies postseason. The increase in UCL thickness was significantly associated with the number of bullpen sessions per week (P = .01). The increase in ulnar nerve cross-sectional area was significantly associated with the number of pitches (P = .04), innings pitched (P = .01), and games pitched (P = .04).


CONCLUSIONS
The stresses placed on the elbow during only one season of pitching create adaptive changes to multiple structures about the elbow including UCL heterogeneity and thickening, increased ulnohumeral joint space laxity, and enlarged ulnar nerve cross-sectional area.


METHODS
Level II prospective observational study.
Department of Orthopaedic Surgery, Henry Ford Health System, Detroit, Michigan, U.S.A.. Electronic address: robkeller23@gmail.com.
Robert A
RA
Keller
Department of Orthopaedic Surgery, Henry Ford Health System, Detroit, Michigan, U.S.A.
Nathan E
NE
Marshall
Bone and Joint Center, Henry Ford Health System, Detroit, Michigan, U.S.A.
Michael J
MJ
Bey
Department of Radiology, Henry Ford Health System, Detroit, Michigan, U.S.A.
Hafeez
H
Ahmed
Department of Radiology, Henry Ford Health System, Detroit, Michigan, U.S.A.
Courtney E
CE
Scher
Department of Radiology, Henry Ford Health System, Detroit, Michigan, U.S.A.
Marnix
M
van Holsbeeck
Department of Orthopaedic Surgery, Henry Ford Health System, Detroit, Michigan, U.S.A.
Vasilios
V
Moutzouros
D000293:Adolescent; D019412:Anatomy, Cross-Sectional; D001484:Baseball / Q000502:physiology*; D017885:Collateral Ligaments / Q000000981:diagnostic imaging; D004550:Elbow / Q000000981:diagnostic imaging*; D004551:Elbow Joint / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011897:Random Allocation; D014459:Ulnar Nerve / Q000000981:diagnostic imaging; D014463:Ultrasonography