Abstract
Objective: The high incidence of retear following primary rotator cuff tendon (RCT) repair necessitates new strategies for tendon footprint augmentation. This study’s objective was to evaluate the SeriCuff™, a non-mammalian derived silk-based long-term bioresorbable implant, for RCT footprint reinforcement. The study aimed to characterize the device when overlaid on the infraspinatus tendon footprint of sheep in a RCT repair model. The technique was not targeted for the repair of massive RCT defects but advocated as a preventive measure to cuff reruptures in mid-to-large cuff tears, avoiding the need for surgical revision.
Methods: Bilateral surgeries were performed on each of 10 sheep during a single surgical session. The right shoulder of each animal was implanted with SeriCuff and the left shoulder was used as an operated control. The superficial layer of the infraspinatus tendon was removed and feathered for a distance of 1 cm. The remaining footprint was bluntly dissected from the humeral head with the exception of a thin band of the superior portion of the infraspinatus tendon. The footprint was approximated, 3 suture anchors placed equi-distantly along the edge of the full thickness region of the tendon and the tendon sutured to the anchors with a modified Mason-Allen stitch. Two additional anchors were placed along the lateral edge of the tendon in the right shoulder. The SeriCuff device was positioned over the 5 anchors and sutured in place using a single suture at each location (Fig 1B). In the left shoulder, no device was implanted and a second row of anchors was not used. Animals were allowed to ambulate immediately post-op with unrestrained motion for the duration of the study. All animals were necropsied at 3 mos and evaluated histologically (N=4) and mechanically (N=6). Samples designated for mechanical analysis were dissected leaving only the infraspinatus tendon and muscle attached to the humorous. The tendon was pulled to failure at a rate of 500 mm/min with the sample positioned such that the longitudinal axis of the tendon was collinear with the applied load.
Results: The animals were able to ambulate following surgery with return to normal gait at an average of 6 days post-operatively. Pain scores diminished with time throughout the first two weeks. Mechanical analysis indicated an average 42% increase in repair strength of the SeriCuff reinforced repair as compared to the contralateral control at 3 months. The SeriCuff device supported the formation of Sharpy’s fibers in the remodeling tendon tissue.
Conclusions: The addition of SeriCuff helped to reestablish the tendon footprint resulting in significantly increased repair strength 3 most post-op and therefore may have applications in reducing the high incidence of primary repair failure.
Correspondence should be addressed to Mr Carlos A. Wigderowitz, Senior Lecturer, University Dept of Orthopaedic and Trauma Surgery, Ninewells Hospital and Medical School, Dundee DD1 9SY
