Extract
Pain over the deltoid that is made worse by abduction against resistance is
most often diagnosed as impingement. The evaluation of a painful shoulder in
which impingement disease is suspected continues to be a challenge, and what
has been called "impingement" in the past probably represents a
clinical description of several different entities that have a similar
constellation of histories, pain patterns, and findings on physical
examination.The etiology of pain in patients with impingement has not been completely
established. The commonly accepted theory has been that the rotator cuff
tendons impinge on the acromion or the coracoacromial ligament and this
produces strain on the tendon, resulting in tears and
pain1. The surgery
traditionally recommended for this condition has been a partial acromioplasty
and a release of the coracoacromial
ligament1. However,
recent evidence suggests that an acromioplasty and a release of the
coracoacromial ligament are not necessary for a satisfactory surgical and
clinical result of a rotator cuff
repair2. In fact,
the coracoacromial ligament should not be released unless absolutely
necessary. It has been demonstrated that the coracoacromial ligament is not a
vestigial structure that can be sacrificed without possibly creating
anterior-superior shoulder
instability3,4.
These and other findings have raised questions about the role that contact of
the rotator cuff with the coracoacromial arch plays in the entity that has
been called "impingement" in clinical studies. Another theory to
explain rotator cuff wear is that it is primarily a degenerative process that
is part of
aging5,6.
Senescence of the tendon fibroblasts with resulting disruption of the tendon
architecture is a common finding in the rotator cuff with
aging7,8.
It has also been suggested that the disruption of the tendon fibers may be due
to differential stress in layers of the
tendon9. Others have
suggested that the rotator cuff tendons may fail in tension as a result of
throwing a baseball or other overhead
sports10.