Matthew D. Sandusky

Glenohumeral Joint Translation after Arthroscopic, Nonablative, Thermal Capsuloplasty with a Laser

The purpose of this study was to determine whether there are changes in anterior and posterior glenohumeral translation after arthroscopic, nonablative, thermal capsuloplasty with a laser. Two anteriorly and two posteriorly directed loads were sequentially applied to the humerus of nine cadaveric glenohumeral joints, and anterior and posterior translation of the humerus on the glenoid was measured. The glenoid was rigidly fixed, and the glenohumeral joint was positioned simulating 90° of shoulder abduction and 90° of external rotation. Using the holmium:yttrium-aluminum-garnet laser, thermal energy was then applied to the anterior capsuloligamentous structures and anterior and posterior translation measurements were then repeated. The results showed a significant reduction in anterior and posterior translation after laser anterior capsuloplasty. Anterior translation decreased from 10.9 2.0 mm (mean SEM) to 6.4 1.5 mm with the 15-N load; and from 13.4 2.1 mm to 8.9 1.8 mm with the 20-N load. Posterior translation decreased from 7.2 1.2 mm to 4.4 0.6 mm with the 15-N load and from 10.4 1.4 mm to 6.5 0.9 mm with the 20-N load. These results indicate that the holmium:yttrium-aluminum-garnet laser can be used to decrease glenohumeral joint translation and may be an effective treatment for glenohumeral joint instability.

Age related biomechanical properties of the glenoid–anterior band of the inferior glenohumeral ligament–humerus complex

OBJECTIVE To quantify the biomechanical properties of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex for the two age groups. DESIGN In vitro human cadaver study evaluating the biomechanical properties of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex for a younger group (n=5, mean age 38.5, SD 0.5 years) and an older group (n=7, mean age 74.8, SD 5.3 years). BACKGROUND Glenohumeral instability is more of a problem in younger than in older individuals, primarily because recurrence is much more common at a young age. METHODS Tensile testing was performed on the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex in the shoulder apprehension position using a custom jig, Instron machine and a video digitizing system. RESULTS In the younger individuals disruption of the complex most often occurred at the glenoid-labrum region of the glenoid insertion site. In the older individual, disruption most often occurred at the midsubstance region. The load and the stress at failure of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex showed that the older group was only 61% and 46% of the younger group, respectively. CONCLUSIONS The structural properties of the glenoid-anterior band of the inferior glenohumeral ligament-humerus complex and the material characteristics of the anterior band of the inferior glenohumeral ligament for the younger group were significantly superior than the older group. RELEVANCE A stronger and more extensive repair, such as the traditional open technique, may be necessary for younger individuals with glenohumeral instability whereas in older individuals, a different repair technique, such as an arthroscopic technique, may be sufficient.

The anterior band of the inferior glenohumeral ligament : Assessment of its permanent deformation and the anatomy of its glenoid attachment

Surgical treatment for traumatic, anterior glenohumeral instability requires repair of the anterior band of the inferior glenohumeral ligament, usually at the site of glenoid insertion, often combined with capsuloligamentous plication. In this study, we determined the mechanical properties of this ligament and the precise anatomy of its insertion into the glenoid in fresh-frozen glenohumeral joints of cadavers. Strength was measured by tensile testing of the glenoid-soft-tissue-humerus (G-ST-H) complex. Two other specimens of the complex were frozen in the position of apprehension, serially sectioned perpendicular to the plane containing the anterior and posterior rims of the glenoid, and stained with Toluidine Blue. On tensile testing, eight G-ST-H complexes failed at the site of the glenoid insertion, representing a Bankart lesion, two at the insertion into the humerus, and two at the midsubstance. For those which failed at the glenoid attachment the mean yield load was 491.0 N and the mean ultimate load, 585.0 N. At the glenoid region, stress at yield was 7.8 +/- 1.3 MPa and stress at failure, 9.2 +/- 1.5 MPa. The permanent deformation, defined as the difference between yield and ultimate deformation, was only 2.3 +/- 0.8 mm. The strain at yield was 13.0 +/- 0.7% and at failure, 15.4 +/- 1.2%; therefore permanent strain was only 2.4 +/- 1.1%. Histological examination showed that there were two attachments of the anterior band of the inferior glenohumeral ligament at the site of the glenoid insertion. In one, poorly organised collagen fibres inserted into the labrum. In the other, dense collagen fibres were attached to the front of the neck of the glenoid.

The anterior band of the inferior glenohumeral ligament

Surgical treatment for traumatic, anterior glenohumeral instability requires repair of the anterior band of the inferior glenohumeral ligament, usually at the site of glenoid insertion, often combined with capsuloligamentous plication. In this study, we determined the mechanical properties of this ligament and the precise anatomy of its insertion into the glenoid in fresh-frozen glenohumeral joints of cadavers. Strength was measured by tensile testing of the glenoid-soft-tissue-humerus (G-ST-H) complex. Two other specimens of the complex were frozen in the position of apprehension, serially sectioned perpendicular to the plane containing the anterior and posterior rims of the glenoid, and stained with Toluidine Blue. On tensile testing, eight G-ST-H complexes failed at the site of the glenoid insertion, representing a Bankart lesion, two at the insertion into the humerus, and two at the midsubstance. For those which failed at the glenoid attachment the mean yield load was 491.0 N and the mean ultimate load, 585.0 N. At the glenoid region, stress at yield was 7.8 +/- 1.3 MPa and stress at failure, 9.2 +/- 1.5 MPa. The permanent deformation, defined as the difference between yield and ultimate deformation, was only 2.3 +/- 0.8 mm. The strain at yield was 13.0 +/- 0.7% and at failure, 15.4 +/- 1.2%; therefore permanent strain was only 2.4 +/- 1.1%. Histological examination showed that there were two attachments of the anterior band of the inferior glenohumeral ligament at the site of the glenoid insertion. In one, poorly organised collagen fibres inserted into the labrum. In the other, dense collagen fibres were attached to the front of the neck of the glenoid.