Effect of posterior capsule tightness on glenohumeral translation in the late-cocking phase of pitching.
BACKGROUND
Throwing injuries.


OBJECTIVE
To study the effects of posterior capsule tightness on humeral head position in late cocking simulation.


METHODS
Eight fresh frozen shoulders were placed in position of "late cocking," 90 degrees abduction, and 10 degrees adduction and maximal external rotation. 3D measurements of humeral head relationship to the glenoid were taken with an infrared motion sensor, both before and after suture plication of the posterior capsule. Plications of 20% posterior/inferior capsule and 20% entire posterior capsule were performed, followed by plications of 40% of the posterior/inferior capsule and 40% entire posterior capsule.


METHODS
Cadaver Lab.


METHODS
Posterior capsular placation.


METHODS
Humeral head position.


RESULTS
40%, but not 20%, posterior/inferior and posterior plications demonstrated a trend to increased posterior-superior humeral head translation relative to controls.


CONCLUSIONS
Surgically created posterior capsular tightness of the glenohumeral joint demonstrated a nonsignificant trend to increased posterior/superior humeral head translation in the late cocking position of throwing.
Clabbers
Kim M
KM
Bucks Orthopedic Surgery Associates, Levittown, PA, USA.
Kelly
John D
JD
Bader
Dov
D
Eager
Mathew
M
Imhauser
Carl
C
Siegler
Sorin
S
Moyer
Ray A
RA
D001484:Baseball / Q000502:physiology*; D002102:Cadaver; D006801:Humans; D017746:Joint Capsule / Q000502:physiology* / Q000601:surgery; D009068:Movement / Q000502:physiology*; D012399:Rotation; D012785:Shoulder Joint / Q000502:physiology*