Evaluation of the subscapularis split created with passive rotation during arthroscopic dynamic anterior...

The purpose of the present study was to analyze the ability to create a subscapularis split by passive rotation of the arm during dynamic anterior stabilization (DAS) and to analyze the new geometry of the long head of the biceps LHB.

The hypothesis was that this passive simple technique can create subscapularis split without additional dissection giving rise to new position of LHB with a new stabilization function.

A technique of subscapularis split using the LHB was used in 12 fresh-frozen human cadaveric shoulders. A subscapularis split was created by passive rotation of the arm after the LHB is shuttled into the joint during DAS. The length of the subscapularis split, post-DAS position and length of the LHB, and the angulation of the LHB relative to bicipital groove were measured after DAS and if this new geometry can give a new dynamic effect on subscapularis muscle.

The mean length of the subscapular split after maximal rotation was 20.4±6.0mm (range: 10-32mm). The mean elongation of the LHB was 0.6±1.4mm (range: -1 to +3mm). The final angle of the LHB relative to the bicipital groove was 45±5 degrees (range: 41 to 55 degrees).

There is no need to create a distinct split prior to DAS. Additionally, DAS maintains the length-tension relationship of the LHB. The post-procedure medial angulation of the LHB relative to the bicipital groove may provide a lowering of the subscapularis, helping explain the anterior reinforcement of this technique.

Basic science study, cadaver study.