Louis U. Bigliani

Inferior glenohumeral ligament: Geometric and strain-rate dependent properties

The inferior glenohumeral ligament (IGHL) is an important structure for maintaining shoulder stability. This study was aimed at determining the geometric and anatomic characteristics of the IGHL and its tensile properties at a higher strain rate than previously tested. Eight fresh-frozen human cadaver shoulders (average age 69 years, age range 62 to 73 years) from four female and four male cadavers were used to harvest bone-ligament-bone specimens from the three regions of the IGHL (superior band, anterior axillary pouch, and posterior axillary pouch). Uniaxial tensile tests were performed at the moderately high strain rate of approximately 10% per second with a servo-hydraulic testing machine. This represented a strain rate that was approximately 100 to 1000 times faster than that previously reported. During tensile testing, bone-ligament-bone strains were calculated from grip-to-grip motion on the testing machine, and mid-substance strains were determined by a video dimensional analyzer. Although all regions of the IGHL had similar lengths (averaging 43.4 mm), their thickness varied by region and by proximal-to-distal location. The superior band was the thickest (2.23 +/- 0.38 mm) of the three regions. Of the remaining two regions the anterior axillary pouch (1.94 +/- 0.38 mm) was thicker than the posterior axillary pouch (1.59 +/- 0.64 mm). By proximal-to-distal location the IGHL was thicker for all three regions near the glenoid (2.30 +/- 0.57 mm) than near the humerus (1.61 +/- 0.52 mm). The superior band had a greater stiffness (62.63 +/- 9.78 MPa) than either the anterior axillary pouch (47.75 +/- 17.89 MPa) or the posterior axillary pouch (39.97 +/- 13.29 MPa). Tensile stress at failure was greater in the superior band (8.4 +/- 2.2 MPa) and the anterior axillary pouch (7.8 +/- 3.1 MPa) than the posterior axillary pouch (5.9 +/- 1.7 MPa). The anterior axillary pouch demonstrated greater bone-to-bone and mid-substance strains (30.4% +/- 4.3% and 10.8% +/- 2.4%, respectively) before failure than the other two regions (superior band: 20.8% +/- 3.8% and 9.1% +/- 2.8%, respectively; posterior axillary pouch: 25.2% +/- 5.8% and 7.8% +/- 2.6%, respectively). Bone-to-bone strain was always greater than mid-substance strain, indicating that when the IGHL is stretched, the tissue near the insertion sites will experience much greater strain than the tissue in the mid-substance. insertion failures were more likely at slower strain rates, and ligamentous failures were predominant at the fast strain rate. When compared with other tensile studies of the IGHL at slower strain rates (0.01% per second and 0.1% per second), the superior band and the anterior axillary pouch demonstrated the viscoelastic effects of increased stiffness and failure stress. This superior band and anterior axillary pouch pouch viscoelastic stiffening effect suggests that these two regions may function to restrain the humeral head from rapid abnormal anterior displacement in the clinically vulnerable position of abduction and external rotation.

Fractures of the shoulder girdle

Classification of Proximal Humeral fractures percutaneous pinning of PH fractures ORIF greater tub/lesser tub fractures ORIF surgical neck fractures ORIF 3 pt fractures ORIF 4 pt fractures HHR 4 pt fractures arthroscopic assisted ORIF prox hum/clavicle nonunion ORIF PH malunion locked fx-dislocation classification/ORIF scapula glenoid fx classification/ORIF AC/clavicle fx classification/ORIF SC fx humeral shaft fx-surgical approaches.

3-Fragmentfrakturen des proximalen Humerus: Ender-Nagelung

Proximale Humerusfrakturen sind insbesondere bei Alteren recht haufig (Lind et al. 1989). Bei jungeren Patienten kommen sie zwar ebenfalls vor, sind jedoch meist auf starke Gewalteinwirkung zuruckzufuhren. Ungefahr 80–85% aller proximalen Humerusfrakturen sind nicht disloziert und lassen sich mit gutem Ergebnis konservativ behandeln (Neer 1970a). Bei dislozierten Trummerfrakturen des proximalen Humerus sind konservative Masnahmen weniger erfolgversprechend (Neer 1970a), da es hier haufig zur Verheilung in Fehlstellung oder als Pseudarthrose mit Schmerzen und Bewegungseinschrankung kommt (Bloom und Obata 1967, Neer 1970a, Sturzenegger et al. 1982, Bigliani 1991). Wird eine Therapie der 3-Fragmentfraktur des proximalen Humerus erwogen, empfiehlt sich zur Wiederherstellung anatomiegerechter Verhaltnisse und Ermoglichung einer fruhzeitigen Rehabilitation ein operativer Eingriff.