A 70° Arthroscope Significantly Improves Visualization of the Bicipital Groove in the Lateral Decubitus Position

Abstract

The purpose of this study was to quantify the length of the bicipital groove viewable with a 70° arthroscopeandto compare this distance visualized with use of a 30° arthroscope in both cadavers and living subjects. Diagnostic glenohumeral arthroscopy in the lateral decubitus position was performed on 10 fresh-frozen cadaveric shoulders from a posterior portal. Using 70° and 30° arthroscopes, the distalmost viewable portion of the bicipital groove was percutaneously marked. Dissection of each specimen was then performed, and the distances between the articular margins of the humeral head to each marked portion of bicipital groove were recorded. Subsequently, a similar technique was used to measure the visible length of the bicipital groove in a series of 11 patients at the time of diagnostic glenohumeral arthroscopy performed in the lateral decubitus position using 70° and 30° arthroscopes. Descriptive statistics were used for continuous data. Means were compared with a Mann-Whitney test. Statistical significance was set at P ≤ .05. The cadaveric analysis revealed a significant increase in the amount of bicipital groove visualized with the 70° arthroscope versus that visualized with the 30° arthroscope (18.0 ± 6.9mm v 11 ± 4.7mm, P= .01). In similar fashion, the results of the invivo analysis showed that the 70° arthroscope allowed for significantly more visualization of the bicipital groove than the 30° arthroscope (26.3 ± 6.2mm v 14 ± 4.7mm, P= .025). The use of a 70° arthroscope significantly increases the length of bicipital groove visualized during glenohumeral arthroscopy in the lateral decubitus position compared with that of the 30° arthroscope in both cadavers and living subjects. Routine use of a 70° arthroscope significantly improves visualization of the bicipital groove and all relevant intra-articular structures compared with that of a 30° arthroscope during diagnostic glenohumeral arthroscopy performed in the lateral decubitus position.