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The purpose of this study was to determine change in glenohumeral joint translation after release of the coracoacromial ligament. Six fresh, frozen unpaired glenohumeral joints were tested in a neutral position and at 30 degrees internal and 30 degrees external rotation of the humerus at 0 degrees, 30 degrees, and 60 degrees of abduction on a custom glenohumeral joint translation testing apparatus. A joint compression load of 20 N was simulated; then a 15-N load was applied to the humerus in anterior, posterior, superior, and inferior directions, and translations on the glenoid were measured with an electromagnetic tracking device. The tests were then repeated after a 1.5-cm section of the coracoacromial ligament was released from the acromion. A multivariate analysis of variance was used for statistical analyses with a P value of.05 as the level of significance. At 0 degrees and 30 degrees of abduction, release of the coracoacromial ligament resulted in a significant increase in glenohumeral joint translations, in both the anterior and inferior directions. In addition, the differences in translation between before and after the release of the coracoacromial ligament decreased in all directions as glenohumeral abduction increased, and they were not significant at 60 degrees of abduction in any of the rotations. The results of this study suggest that the coracoacromial ligament has a role in static restraint of the glenohumeral joint. It provides a suspension function and may restrain anterior and inferior translations through an interaction with the coracohumeral ligament. Although this is a biomechanical study without simulation of the shoulder muscles, it indicates that the coracoacromial ligament contributes to glenohumeral stability. Caution should be exercised in the release of the coracoacromial ligament in those with rotator cuff pain associated with glenohumeral instability.

The purpose of this study was to determine whether there are changes in anterior and posterior glenohumeral translation after arthroscopic thermal capsuloplasty with a radiofrequency probe. Anteriorly directed loads of 15 N and 20 N were sequentially applied to the humerus of each of 5 cadaveric glenohumeral joints, and anterior translation on the glenoid was measured through use of a customized translation apparatus and an electromagnetic tracking device. The tests were then repeated with posteriorly directed forces, and posterior translation was measured. During testing, the glenoid was rigidly fixed and the glenohumeral joint was positioned to simulate 90 degrees of shoulder abduction and 90 degrees of external rotation. By means of the radiofrequency probe, thermal energy was then applied to the anteroinferior capsuloligamentous structures; anterior and posterior translation measurements were repeated. The results showed a significant reduction in anterior and posterior translations after thermal capsuloplasty (P.05). Anterior translation decreased from 6.8 to 4.0 mm (a 41% decrease) with the 15-N load and from 8.6 to 4.9 mm (a 42% decrease) with the 20-N load. Posterior translation decreased from 9.3 to 5.8 mm (a 36% decrease) with the 15-N load and from 10.4 to 6.5 mm (a 35% decrease) with the 20-N load. The results of this study indicate that the radiofrequency probe can be used to decrease both anterior and posterior glenohumeral translation in vitro. The biological effect on heat-treated tissues over time needs to be studied to prove that this is a satisfactory treatment for glenohumeral instability.

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The idea that mouth infections often cause serious secondary effects has, in recent years, become definitely crystallized in the minds of physician, dentist and layman. Clinical observation has been supported by careful laboratory investigations. It is now generally recognized that a chronic suppurating focus may lead to any one of a considerable group of diseases, most of which are insidious in their development and extremely chronic in their progress. The chronic focus is therefore properly considered a menace to health, and its removal is demanded. The dental profession is thus confronted with a most serious problem, so serious that the practice of dentistry must be to a considerable extent revolutionized for its solution. The chain of causes and symptoms leading up to these mouth lesions and the peculiar physiologic relationships between the tissues involved present complex problems which have been but partially solved. There are, however, certain outstanding features, the

This subject will be considered only in relation to chronic mouth infections. Ten years have elapsed since attention was prominently called to infections about the teeth as a menace to health. The clinical observations by Hunter 1 of England and the combined clinical and laboratory studies of Billings 2 and his associates in Chicago served to attract the widespread attention of both physicians and dentists. Scattered through the literature for more than a hundred years are many articles associating mouth infections with systemic disease. Benjamin Rush, in his book on the practice of medicine, published in 1818, devotes several pages to the citation of cases in which rheumatic and other ailments were relieved by the extraction of teeth. Others have made similar reports, but at no time until the past decade has a definite movement been established to eliminate this source of systemic disease. A review of the experiences of

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In a paper 1 presented before this section at the New York meeting last year there was included a tabulation covering a critical examination of 3,000 roentgenographic films of the teeth and adjacent bone of the mouths of 300 adults. During the past year these studies have been continued with results that very closely parallel the previous figures. The present tabulation, which includes that of last year, covers 600 roentgenographic mouth examinations, for each of which ten small films were made—a total of 6,000 films. 2 The object of this study is primarily to determine as nearly as possible the average percentage of chronic mouth infections, which are of two types: (1) those that begin with inflammations of the gingivae and progress along the side of the root toward the apex, destroying the peridental membrane and adjacent alveolar process—chronic suppurative pericementitis; (2) those which, subsequent to the death of the