- Email: [email protected]
Tensile properties of the supraspinatus tendon
$28
50
.I. Shoulder Elbow Surg. March/April 1996
Abstracts
OIITCOME AFTER ACROMIOPLASTY CORRELATES W I T H BLOOD-FLOW CHANGES IN T H E R O T A T O R CUFF.
52
U. Jonsson, MD, & B. Gazelius, PhD. Depts. of Orthopaedics Danderyd Hospital and of Pharmacology, Karolinska Institutet, Stockholm, Sweden. The idea of the presem study was to see if blood flow in the supraspinatus tendon before and after acromioplasty differs between the shoulders with excellent result and those with inferior result after surgery. Methods. Sixteen shoulders ir 15 patients with suspected impingement grade II had an acromioplasty performed after at least 1 year of pain. The blood-flow was measured peroperatively in the supraspinatus tendon just anterior to the acromion both before and after anterior acfomioplasty. Laser doppler flowmetry (632.8 nm) with single fiber technique was used. All patients were examined clinically as a mean 17.5 months after surgery. Pain at rest and at activity were graded by VAS (0-10). Pain was also registrated at the impingement test and at the hand-in-neck tesU a recently described test for pain in the supraspinatus region. Results. The sum of the VASregistrations was used to grade the result. Seven shoulders were excellent with VAS sum equal or less than 2. Five shoulders were regarded fair/poor with the VAS sum equal or greater than 12. There were 4 intermediate results. All shoulders but one improved by surgery. In the group excellent, the blood flow increased as a mean 220 % after acromioplasty. The mean increase was 41% in the group fair~poor. C o n c l u s i o n . The great increase in blood flow in the supraspinatus tendon after successful acromioplasty compared to the modest increase among those with persisten! pain, implies that impingement pain may be related to impaired circulation in the rotator cuff.
5]
THE ROLE QF T ~ S U B A C R O ~ I A L B U R S A IN CUFF.TENDINOPATHIES J.A. ~ u n e t , MD, H. Ishii, MD, H.K. Uhthoff, MD, P.W. welsh, MD. Div. of Orthopedics, Univ. of Ottawa, Canada*. Div. of Orthopedics, univ. of Toronto, Canada It is assumed that the only function of the subacromial bursa is to facilitate g l i d i n g of the rotator cuff under the subacromial arch. Not surprisingly a complete bursectomy is recommended when bursal thickening interferes with smooth gliding. Is such a p r o c e d u r e always indicated, especially when the extent~ intensity and kind of bursal reactions vary from one t e n d i n o p a t h y to the other? The present study was u n d e r t a k e n to c h a r a c t e r i z e changes in the bursa in different types of rotator cuff tendinopathies. Surgical specimens were examined in a blinded fashion in 63 p a t i e n t s suffering from complete rotator cuff tears (43), impingement s y n d r o m e s (14), and calcifying tendinitis (6). Gross and h i s t o l o g i c responses were evaluated semiq u a n t i t a t i v e l y to d e t e r m i n e the p r e v a l e n c e of bursal reactions in the v i c i n i t y of and at sites distant to the cuff pathologies. M o n o c l o n a l antibodies to collagen I, If, III were used to further understand bursal changes. In the p r e s e n c e of complete tears, a localized fibrov a s c u l a r reactio~ p r e d o m i n a t e s along with m a r k e d l y increased p r o d u c t i o n of type III collagen; these changes mirror those o c c u r r i n g in the torn cuff. In impingement syndrome, a hyperemic r e a c t i o n seems the rule. In calcifying tendinitie, the bursal involvement is minimal. We feel that the entire bursa is only very rarely involved in cuff tendinopathies, the r e a c t i o n being limited to the area of tear or of inflantmation. When indicated, limited b u r s e c t o m y and bursal repair over a cuff repair may enhance cuff healing.
COMPARATIVE ANATOMY OF THE SHOULDER. Sonnabend, DH, and Jones, D. Prince of Wales Hospital, Sydney, 2031, Australia. This study reviews the skeletal shoulder anatomy of over one hundred species, and the careful dissection and histological study of the shoulders of over thirty different mammalian species. The evolution of the shoulder exemplifies anatomical adaptation to environmental requirements. In particular, the appearance of the rotator cuff, as opposed to individual tendons, correlates with the development of brachiating skills. In quadrupeds, the chest is generally flat from side to side, with the scapulae positioned vertically on the side of the thorax, almost parallel to each other. The glenoid fossae point downwards and forwards, and shoulder movement is almost purely in the sagittal plane. With the development of bipedal gait, the thorax became compressed from front to back, with the scapulae on the dorsal surface and the glenoid fossae pointing outwards. The bipedal humeral head faces inwards rather than backwards, allowing a greater range of movement, including rotation. The humeral head of terrestrial quadrupeds is generally flat and below the tuberosities. In brachiating primates, it is rounder and higher. Most animals which stand on their forelimbs have no clavicle. The clavicles of primitive quadrupedal primates are short, whilst those of brachiating and bipedal primates are relatively long. Many quadrupeds have small or posteriorly directed acromions. As primate deltoid function increases, the acromion enlarges and becomes anteriorly directed. The appearance o f a Wae rotator cuff correlates with the development of arboreal skills. It is not unique to primates. Quadrupedal primates (eg. macaque) have individual tendons, while higher primates (eg. chimpanzee, man) have rotator cuffs. So to does the tree-kangaroo, an arboreal non-primate.
53
TENSILE PROPERTIES OF T H E SUPRASPINATUS TENDON. E Itoi*, LJ Berglund, JJ Grabowski, FM Schultz, ES Gmwney, BF Money, & KN An, * Dept of Orthopedic Surgery, Akita Univ Sch of Med, Akita, Japan; Orthopedic Biomechanics Lab, Mayo Clinic, Rochester, MN, USA. This study was designed to determine the structural and material properties of the supraspinatus tendon in the anterior, middle, and posterior portions. The supraspinatus tendons obtained from 11 fresh previously-frozen cadaveric shoulders (average age 64 years) were investigated. The tendon was divided into three strips: anterior, middle, and posterior. The specimen was mounted on a material testing machine and the muscle belly was secured using a cryo-jaw. Four fluorescent markers were placed on each surface (superficial aild deep) of the tendon strip, and the position of these markers were recorded in real time using two synchronized video cameras. The specimen was pulled at a rate of 10%/see based on the initial specimen length until failure occurred. The ultimate load and strain were recorded and the stress and modulus of elasticity were calculated based on the specimen measurement. The ultimate load of the anterior strip (411.1 _+ 158.8 N) was significantly larger than those of the middle ( 152.6 + 87.5 N) and posterior strips (88.1 i 32.1 N) (p<0.0001 ). The ultimate stress was also significantly larger in the anterior strip (16.5 _+7.1 MPa) than in the middle (6.0 + 2.6 MPa) and posterior strips (4.1 _+ 1.3 MPa) (p<0.0001). The modulus of elasticity was also significantly larger in the anterior strip (superficial surface 166.8 + 34 MPa; deep surface 114.1 • 29.6 MPa) (p<0.0001), but there was no significant difference between the superficial and deep surfaces. We conclude that the anterior portion of the supraspinatus tendon is mechanically stronger than the middle and posterior portions of the tendon.
50
.I. Shoulder Elbow Surg. March/April 1996
Abstracts
OIITCOME AFTER ACROMIOPLASTY CORRELATES W I T H BLOOD-FLOW CHANGES IN T H E R O T A T O R CUFF.
52
U. Jonsson, MD, & B. Gazelius, PhD. Depts. of Orthopaedics Danderyd Hospital and of Pharmacology, Karolinska Institutet, Stockholm, Sweden. The idea of the presem study was to see if blood flow in the supraspinatus tendon before and after acromioplasty differs between the shoulders with excellent result and those with inferior result after surgery. Methods. Sixteen shoulders ir 15 patients with suspected impingement grade II had an acromioplasty performed after at least 1 year of pain. The blood-flow was measured peroperatively in the supraspinatus tendon just anterior to the acromion both before and after anterior acfomioplasty. Laser doppler flowmetry (632.8 nm) with single fiber technique was used. All patients were examined clinically as a mean 17.5 months after surgery. Pain at rest and at activity were graded by VAS (0-10). Pain was also registrated at the impingement test and at the hand-in-neck tesU a recently described test for pain in the supraspinatus region. Results. The sum of the VASregistrations was used to grade the result. Seven shoulders were excellent with VAS sum equal or less than 2. Five shoulders were regarded fair/poor with the VAS sum equal or greater than 12. There were 4 intermediate results. All shoulders but one improved by surgery. In the group excellent, the blood flow increased as a mean 220 % after acromioplasty. The mean increase was 41% in the group fair~poor. C o n c l u s i o n . The great increase in blood flow in the supraspinatus tendon after successful acromioplasty compared to the modest increase among those with persisten! pain, implies that impingement pain may be related to impaired circulation in the rotator cuff.
5]
THE ROLE QF T ~ S U B A C R O ~ I A L B U R S A IN CUFF.TENDINOPATHIES J.A. ~ u n e t , MD, H. Ishii, MD, H.K. Uhthoff, MD, P.W. welsh, MD. Div. of Orthopedics, Univ. of Ottawa, Canada*. Div. of Orthopedics, univ. of Toronto, Canada It is assumed that the only function of the subacromial bursa is to facilitate g l i d i n g of the rotator cuff under the subacromial arch. Not surprisingly a complete bursectomy is recommended when bursal thickening interferes with smooth gliding. Is such a p r o c e d u r e always indicated, especially when the extent~ intensity and kind of bursal reactions vary from one t e n d i n o p a t h y to the other? The present study was u n d e r t a k e n to c h a r a c t e r i z e changes in the bursa in different types of rotator cuff tendinopathies. Surgical specimens were examined in a blinded fashion in 63 p a t i e n t s suffering from complete rotator cuff tears (43), impingement s y n d r o m e s (14), and calcifying tendinitis (6). Gross and h i s t o l o g i c responses were evaluated semiq u a n t i t a t i v e l y to d e t e r m i n e the p r e v a l e n c e of bursal reactions in the v i c i n i t y of and at sites distant to the cuff pathologies. M o n o c l o n a l antibodies to collagen I, If, III were used to further understand bursal changes. In the p r e s e n c e of complete tears, a localized fibrov a s c u l a r reactio~ p r e d o m i n a t e s along with m a r k e d l y increased p r o d u c t i o n of type III collagen; these changes mirror those o c c u r r i n g in the torn cuff. In impingement syndrome, a hyperemic r e a c t i o n seems the rule. In calcifying tendinitie, the bursal involvement is minimal. We feel that the entire bursa is only very rarely involved in cuff tendinopathies, the r e a c t i o n being limited to the area of tear or of inflantmation. When indicated, limited b u r s e c t o m y and bursal repair over a cuff repair may enhance cuff healing.
COMPARATIVE ANATOMY OF THE SHOULDER. Sonnabend, DH, and Jones, D. Prince of Wales Hospital, Sydney, 2031, Australia. This study reviews the skeletal shoulder anatomy of over one hundred species, and the careful dissection and histological study of the shoulders of over thirty different mammalian species. The evolution of the shoulder exemplifies anatomical adaptation to environmental requirements. In particular, the appearance of the rotator cuff, as opposed to individual tendons, correlates with the development of brachiating skills. In quadrupeds, the chest is generally flat from side to side, with the scapulae positioned vertically on the side of the thorax, almost parallel to each other. The glenoid fossae point downwards and forwards, and shoulder movement is almost purely in the sagittal plane. With the development of bipedal gait, the thorax became compressed from front to back, with the scapulae on the dorsal surface and the glenoid fossae pointing outwards. The bipedal humeral head faces inwards rather than backwards, allowing a greater range of movement, including rotation. The humeral head of terrestrial quadrupeds is generally flat and below the tuberosities. In brachiating primates, it is rounder and higher. Most animals which stand on their forelimbs have no clavicle. The clavicles of primitive quadrupedal primates are short, whilst those of brachiating and bipedal primates are relatively long. Many quadrupeds have small or posteriorly directed acromions. As primate deltoid function increases, the acromion enlarges and becomes anteriorly directed. The appearance o f a Wae rotator cuff correlates with the development of arboreal skills. It is not unique to primates. Quadrupedal primates (eg. macaque) have individual tendons, while higher primates (eg. chimpanzee, man) have rotator cuffs. So to does the tree-kangaroo, an arboreal non-primate.
53
TENSILE PROPERTIES OF T H E SUPRASPINATUS TENDON. E Itoi*, LJ Berglund, JJ Grabowski, FM Schultz, ES Gmwney, BF Money, & KN An, * Dept of Orthopedic Surgery, Akita Univ Sch of Med, Akita, Japan; Orthopedic Biomechanics Lab, Mayo Clinic, Rochester, MN, USA. This study was designed to determine the structural and material properties of the supraspinatus tendon in the anterior, middle, and posterior portions. The supraspinatus tendons obtained from 11 fresh previously-frozen cadaveric shoulders (average age 64 years) were investigated. The tendon was divided into three strips: anterior, middle, and posterior. The specimen was mounted on a material testing machine and the muscle belly was secured using a cryo-jaw. Four fluorescent markers were placed on each surface (superficial aild deep) of the tendon strip, and the position of these markers were recorded in real time using two synchronized video cameras. The specimen was pulled at a rate of 10%/see based on the initial specimen length until failure occurred. The ultimate load and strain were recorded and the stress and modulus of elasticity were calculated based on the specimen measurement. The ultimate load of the anterior strip (411.1 _+ 158.8 N) was significantly larger than those of the middle ( 152.6 + 87.5 N) and posterior strips (88.1 i 32.1 N) (p<0.0001 ). The ultimate stress was also significantly larger in the anterior strip (16.5 _+7.1 MPa) than in the middle (6.0 + 2.6 MPa) and posterior strips (4.1 _+ 1.3 MPa) (p<0.0001). The modulus of elasticity was also significantly larger in the anterior strip (superficial surface 166.8 + 34 MPa; deep surface 114.1 • 29.6 MPa) (p<0.0001), but there was no significant difference between the superficial and deep surfaces. We conclude that the anterior portion of the supraspinatus tendon is mechanically stronger than the middle and posterior portions of the tendon.