Gh. Callaway et al., BIOMECHANICAL EVALUATION OF THE MEDIAL COLLATERAL LIGAMENT OF THE ELBOW, Journal of bone and joint surgery. American volume, 79A(8), 1997, pp. 1223-1231
Anatomical dissection and biomechanical testing were used to study twe
nty-eight cadaveric elbows in order to determine the role of the media
l collateral ligament under valgus loading, The medial collateral liga
ment was composed of anterior, posterior, and occasionally transverse
bundles, The anterior bundle was, in turn, composed of anterior and po
sterior bands that tightened in reciprocal fashion as the elbow was fl
exed and extended. Sequential cutting of the ligament was performed wh
ile rotation caused by valgus torque was measured, The anterior band o
f the anterior bundle was the primary restraint to valgus rotation at
30, 60, and 90 degrees of flexion and was a co-primary restraint at 12
0 degrees of flexion, The posterior band of the anterior bundle was a
co-primary restraint at 120 degrees of flexion and a secondary restrai
nt at 30 and 90 degrees of flexion, The posterior bundle was a seconda
ry restraint at 30 degrees only. The reciprocal anterior and posterior
bands have distinct biomechanical roles and theoretically may be inju
red separately, The anterior band was more vulnerable to valgus overlo
ad when the elbow was extended, whereas the posterior band was more vu
lnerable when the elbow was flexed, The posterior bundle was not vulne
rable to valgus overload unless the anterior bundle was completely dis
rupted. The intact elbows rotated a mean of 3.6 degrees between the ne
utral position and the two-newton-meter valgus torque position, Cuttin
g of the entire anterior bundle caused an additional 3.2 degrees of ro
tation at 90 degrees of flexion, where the effect was greatest. CLINIC
AL RELEVANCE: Physical findings in a patient who has an injury of the
anterior bundle may be subtle, and an examination should be performed
with the elbow in 90 degrees of flexion for greatest sensitivity, As t
he anterior bundle is the major restraint to valgus rotation, reconstr
uctive procedures should focus on anatomical reproduction of that stru
cture, Parallel limbs of tendon graft placed from the inferior aspect
of the medial epicondyle to the area of the sublimis tubercle will sim
ulate the reciprocal bands of the anterior bundle, Temporary immobiliz
ation with the elbow in flexion may relax the critically important ant
erior band of the reconstruction during healing.