Evaluation of the subscapularis split created with passive rotation during arthroscopic dynamic anterior stabilization (DAS): A cadaveric study

Introduction. – The purpose of the present study was to analyze the ability to create a subscapularis split bypassive rotation of the arm during dynamic anterior stabilization (DAS) and to analyze the new geometryof the long head of the biceps LHB.Hypothesis. – The hypothesis was that this passive simple technique can create subscapularis split withoutadditional dissection giving rise to new position of LHB with a new stabilization function.Material and methods. – A technique of subscapularis split using the LHB was used in 12 fresh-frozenhuman cadaveric shoulders. A subscapularis split was created by passive rotation of the arm after theLHB is shuttled into the joint during DAS. The length of the subscapularis split, post-DAS position andlength of the LHB, and the angulation of the LHB relative to bicipital groove were measured after DAS andif this new geometry can give a new dynamic effect on subscapularis muscle.Results. – The mean length of the subscapular split after maximal rotation was 20.4 ± 6.0 mm (range:10–32 mm). The mean elongation of the LHB was 0.6 ± 1.4 mm (range: −1 to +3 mm). The final angle ofthe LHB relative to the bicipital groove was 45 ± 5 degrees (range: 41 to 55 degrees).Discussion. – There is no need to create a distinct split prior to DAS. Additionally, DAS maintains thelength-tension relationship of the LHB. The post-procedure medial angulation of the LHB relative to thebicipital groove may provide a lowering of the subscapularis, helping explain the anterior reinforcementof this technique.