TY - JOUR
T1 - Degeneration at the insertion weakens the tensile strength of the supraspinatus tendon
T2 - A comparative mechanical and histologic study of the bone-tendon complex
AU - Sano, Hirotaka
AU - Ishii, H.
AU - Yeadon, A.
AU - Backman, D. S.
AU - Brunet, J. A.
AU - Uhthoff, H. K.
PY - 1997/9/1
Y1 - 1997/9/1
N2 - The purpose of this investigation was to determine the relationship between the degree of degeneration at the supraspinatus insertion, the tensile strength, and the site of failure of this tendon. Thirty-three fresh cadaveric shoulders (average age: 62 years; range: 39-83 years) were examined, A tensile load to failure was applied at a constant crosshead speed of 25.4 mm/min to a 10 mm wide strip of the supraspinatus tendon that remained attached to the bone. Preexisting degenerative changes at the insertion were assessed and scored histologically and compared with the ultimate tensile stress. Twenty tendons failed at the insertion (the insertion group), and 11 failed in the midsubstance (the midsubstance group). The histologic score of degeneration for the insertion group was significantly higher than that for the midsubstance group (p = 0.0026). There was a negative correlation between the ultimate tensile stress at the insertion and the degeneration score for the insertion group (r = -0.60; p = 0.013). Histologic observations revealed that disruptions of tendon fibers were located mostly in the articular half of the tendon and that they enlarged during mechanical testing in 90% of the specimens of the insertion group. It seems that degenerative changes at the supraspinatus insertion reduce the tensile strength of the tendon and constitute a primary pathogenetic factor of rotator cuff tear.
AB - The purpose of this investigation was to determine the relationship between the degree of degeneration at the supraspinatus insertion, the tensile strength, and the site of failure of this tendon. Thirty-three fresh cadaveric shoulders (average age: 62 years; range: 39-83 years) were examined, A tensile load to failure was applied at a constant crosshead speed of 25.4 mm/min to a 10 mm wide strip of the supraspinatus tendon that remained attached to the bone. Preexisting degenerative changes at the insertion were assessed and scored histologically and compared with the ultimate tensile stress. Twenty tendons failed at the insertion (the insertion group), and 11 failed in the midsubstance (the midsubstance group). The histologic score of degeneration for the insertion group was significantly higher than that for the midsubstance group (p = 0.0026). There was a negative correlation between the ultimate tensile stress at the insertion and the degeneration score for the insertion group (r = -0.60; p = 0.013). Histologic observations revealed that disruptions of tendon fibers were located mostly in the articular half of the tendon and that they enlarged during mechanical testing in 90% of the specimens of the insertion group. It seems that degenerative changes at the supraspinatus insertion reduce the tensile strength of the tendon and constitute a primary pathogenetic factor of rotator cuff tear.
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U2 - 10.1002/jor.1100150514
DO - 10.1002/jor.1100150514
M3 - Article
C2 - 9420602
AN - SCOPUS:0031229603
VL - 15
SP - 719
EP - 726
JO - Journal of Orthopaedic Research
JF - Journal of Orthopaedic Research
SN - 0736-0266
IS - 5
ER -