Histologic and biomechanical characteristics of the supraspinatus tendon: Reference to rotator cuff tearing

T Nakajima; N Rokuuma; K Hamada; T Tomatsu; H Fukuda

doi:10.1016/S1058-2746(09)80114-6

Histologic and biomechanical characteristics of the supraspinatus tendon: Reference to rotator cuff tearing

J Shoulder Elbow Surg. 1994 Mar;3(2):79-87. doi: 10.1016/S1058-2746(09)80114-6. Epub 2009 Feb 19.

Authors

T Nakajima¹, N Rokuuma, K Hamada, T Tomatsu, H Fukuda

Affiliation

¹ From the Department of Orthopaedic Surgery, School of Medicine, Tokai University, Kanagawa, Japan; Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo Japan.

PMID: 22959646
DOI: 10.1016/S1058-2746(09)80114-6

Abstract

A bursal- or joint-side incomplete thickness tearing of the rotator cuff is clinically important, because it is known that this tearing has the potential to develop into a complete tendon disruption. Normal cadaveric supraspinatus tendons were analyzed histologically and biomechanically to clarify the differences in pathomechanical causation of bursal- and joint-side incomplete tears. Histologically, the bursal-side layer was composed of tendon bundles with a decreasing muscular component toward the insertion. The joint-side layer was a complex of tendon, ligament, and joint capsule without transitional areas. Biomechanically, the bursal-side layer had greater deformation and tensile strength. When each layer was divided into three portions of equal length, the middle segment of the bursal-side layer elongated the most, whereas the entire joint-side layer increased evenly in length. We conclude that the joint-side layer is more vulnerable to a tensile load than the bursal-side layer.