Effect of an anterior glenoid defect on anterior shoulder stability: a cadaveric study.
BACKGROUND
There have been few biomechanical studies to clarify which size of a glenoid defect is critical. However, those studies have assumed that the defect occurred anteroinferiorly. Recent studies have reported that the defect is located anteriorly rather than anteroinferiorly. Therefore, the effect of the anterior, not anteroinferior, glenoid defect on shoulder stability needs to be investigated.


OBJECTIVE
The anterior glenoid defect would have a similar effect on anterior shoulder stability as that of the anteroinferior glenoid defect.


METHODS
Controlled laboratory study.


METHODS
Eight fresh-frozen cadaveric shoulders were used (mean age, 74 years). The specimen was attached to a shoulder-testing device with the arm in abduction and external rotation. An osseous defect was created stepwise with a 2-mm increment of the defect width. The stability ratio was used to evaluate joint stability. With a 50-N axial force, the translational force applied to the humeral head was measured by a force transducer.


RESULTS
The stability ratio without a defect (32% +/- 6%) significantly decreased after creating a 6-mm defect (17% +/- 5%; P = .0001), which was equivalent to 20% of the glenoid length.


CONCLUSIONS
An osseous defect at 3 o'clock with a width that was equal to or greater than 20% of the glenoid length significantly decreased anterior stability.


CONCLUSIONS
The results suggest that reconstruction of the glenoid concavity might be necessary in shoulders with an anterior glenoid defect of at least 20% of the glenoid length.
Yamamoto
Nobuyuki
N
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
Itoi
Eiji
E
Abe
Hidekazu
H
Kikuchi
Kazuma
K
Seki
Nobutoshi
N
Minagawa
Hiroshi
H
Tuoheti
Yilihamu
Y
D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D016059:Range of Motion, Articular; D012783:Shoulder Dislocation / Q000503:physiopathology*; D012785:Shoulder Joint / Q000503:physiopathology*