Abstract
Background
Long term success of any shoulder joint reconstruction procedure involving subscapularis attachment take down is dictated by the way one chooses to release and repair/reconstruct the subscapularis insertion. There are several methods that were reported in the literature without any preset guidelines which are easily reproducible.
Methods
5 specimens of fresh cadaver shoulder joints dissected and the subscapularis footprint insertion involving the tendon and muscle exposed. We intend to preserve subscapularis tendon footprint along with the lesser tuberosity by performing the footprint osteotomy fashioned step wise in the following manner.
Results
It has two vertical components (sagittal and coronal plane osteotomies) and one horizontal component (distal osteotomy at musculo tendinous junction level).
Figure 1: demonstrating the three step cuts in the dry bone of proximal humerus with three different ostetomes to mark the plain of osteotomies in the lesser tuberosity
Step-1: Medial wall ridge of the inter-tubercular sulcus serves as landmark for sagittal component. The depth of sagittal component is just 5 – 10mm and its length extending from articular margin proximally and distally up to musculo tendinous junction, measuring approximately 15–20mm.
Step-2: Coronal plane osteotomy is in line with and parallel to undersurface of subscapularis tendon adjacent to the articular margin and connecting sagittal component and measured 10–15mm approximately.
Figure 2: demonstrating the two cuts / osteotomies to mark the sagittal and coronal components of the subscapularis foot print osteotomy in the lesser tuberosity of a fresh cadaver.
Step-3: The horizontal component (distal osteotomy at musculo tendinous junction level is 5–10 mm in width, connects the two vertical components, thus completing the footprint osteotomy.
Discussion
Subscapularis reattachment plays a pivotal role in the shoulder joint reconstruction procedures especially total joint arthroplasty. Subscapularis take down either by tenotomy or by periosteal elevation from lesser tuberosity followed by repair carries a risk of retraction and poor healing and early failure. Footprint osteotomy as a thin sliver of cortical bone instead of these above described three steps with the attached tendon carries a risk of fragmentation of the bone sliver along with lack of rotation control on the repair. The necessity for doing such a three step osteotomy procedure which results in a wedge shaped bone tendon foot print construct, we believe is of paramount importance for a successful reconstruction.
Figure 3: demonstrating the marking sutures passed into the bone tendon construct comprising of lesser tuberosity and subscapularis for effective foot print reconstruction in a fresh cadaver.
Conclusions
This three step footprint osteotomy of the Subscapularis tendon offers a stable construct which is easy to reproduce with better healing potential
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