Arthroscopic Treatment of Partial Rotator Cuff Tears
William B. Stetson, MD,* Richard K.N. Ryu, MD,
and Edward S. Bittar, MD, PhD
Partial rotator cuff tears can be a natural consequence of aging or can be caused by
anatomic impingement or trauma. These tears can be asymptomatic or a potential source
of shoulder dysfunction. We know very little about their natural history and whether they
progress to full-thickness tears. With the advent of magnetic resonance imaging and
shoulder arthroscopy, a more precise characterization of these tears is now possible. At the
present time, there is no accepted classiﬁcation system of partial-thickness rotator cuff
tears. The optimal clinical approach to treating these tears is also controversial and ranges
from simple debridement to open repair. The purpose of this article is to review partial-
thickness rotator cuff tears, including the pathogenesis, diagnosis, nonoperative, and
operative treatment options, and to create a rational treatment algorithm.
Oper Tech Sports Med 12:135-148 © 2004 Elsevier Inc. All rights reserved.
KEYWORDS partial rotator cuff tear, shoulder arthroscopy
artial-thickness tears of the rotator cuff may involve ei-
ther the articular surface, bursal surface, or both sides of
the rotator cuff. They may be asymptomatic or a potential
source of shoulder dysfunction.
With the advent of magnetic
resonance imaging (MRI) and shoulder arthroscopy, more
tears are being recognized. The optimal clinical approach to
these tears has not been completely deﬁned.
To gain a better
understanding of these tears, we must ﬁrst understand the
anatomy and pathogenesis of these tears and then agree on a
classiﬁcation system to develop a rational approach to their
The suprascapular artery is the primary vascular supply to
the supraspinatus tendon. The vascular studies of Rathbun
have shown that the articular side of the rotator
cuff is hypovascular as compared with the bursal side. This
ﬁnding has been suggested as a factor in the tendency for
partial tears to occur on the articular surface of the cuff
Collagen bundles located near the articular surface of the
cuff are thinner and less uniform than the thick parallel bun-
dles found closer to the bursal surface. The articular surface
of the cuff has an ultimate failing stress only half as high as the
This lack of uniformity of the collagen bun-
dles along with the hypovascularity of the articular surface of
the cuff are contriebuting factors for partial tears to occur
more commonly on the articular surface.
The anatomic footprint of the rotator cuff is an important
landmark for recognizing the degree of partial tearing of the
articular surface of the rotator cuff.
In a cadaveric study,
studied the anatomic insertions of the rotator cuff
musculature. He found the supraspinatus had a rectangular
insertion from approximately the 11:30 position to 1 o’clock
position with an average length of 23 mm (range 18-33 mm)
and a width of 17 mm (range 12-24 mm) (Fig. 2). The in-
fraspinatus wraps and interdigitates with the supraspinatus
tendon. The infraspinatus frames the bare spot of the hu-
meral head, has an average length of 28 mm (range 20-45
mm), and has a width of 18 mm (range 12-24 mm).
The pathogenesis of partial rotator cuff tears are multifacto-
rial and may be classiﬁed as intrinsic, extrinsic, traumatic, or
a combination of all of these. Intrinsic changes in the cuff are
related to intrinsic tendinopathy with failure of collagen ﬁ-
bers within the cuff. This may be caused by a lack of unifor-
mity of the collagen bundles especially on the articular side
causing partial tearing on the articular side. The lack of cuff
vascularity also contributes to weakness of the cuff on the
articular side leading to degenerative tears associated with the
aging process. These degenerative tears are often associated
with extensive delamination or can remain entirely intraten-
Extrinsic impingement because of narrowing of the su-
praspinatus outlet caused by coracoacromial arch abnormal-
ities can result in cuff irritation and may play a major role in
many partial cuff tears.
Histological changes have been
found on the undersurface of cadaveric acromion specimens
*From the Department of Orthopedic Surgery, Arthritis, Orthopedic, and
Sports Medicine, University of Southern California, Glendale, CA.
†Private Practice, Santa Barbara, CA.
Address reprint requests to Richard K.N. Ryu, MD, 533 E. Micheltorena
Street, Ste 204, Santa Barbara, CA 91103. E-mail: FamRyu5@aol.com
1060-1872/04/$-see front matter © 2004 Elsevier Inc. All rights reserved.