Introduction: 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.
Hypothesis: 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.
Material and methods: 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.
Results: 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).
Discussion: 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.
Level of evidence: Basic science study, cadaver study.
Keywords: Bankart; Hammock; Latarjet; Shoulder instability; Sling effect; Treatment.
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