Massive,
This study aims to investigate the mechanical properties of a rotator cuff tear repaired with a polypropylene interposition graft in an ovine infraspinatus ex-vivo model. Twenty fresh shoulders from skeletally mature sheep were used in this study. A tear size of 20 mm from the tendon joint was created in the infraspinatus tendon to simulate a large tear in fifteen specimens. This was repaired with a polypropylene mesh used as an interposition graft between the ends of the tendon. Eight specimens were secured with mattress stitches while seven were secured to the remnant tendon on the greater tuberosity side by continuous stitching. Remaining five specimens with an intact tendon served as a control group. All specimens underwent cyclic loading with a universal testing machine to determine the ultimate failure load and gap distance. Gap distance increased with progressive cyclic loading through 3000 cycles for all repaired specimens. Mean gap distance after 3000 cycles for both continuous and mattress groups are 1.7 mm and 4.2 mm respectively (P = .001). Significantly higher mean ultimate failure load was also observed with 549.2 N in the continuous group, 426.6 N in the mattress group and 370 N in the intact group. The use of a polypropylene mesh as an interposition graft for large
Rotator cuff tears are common, with failure rates of up to 94% for large and massive tears. 1. For such tears, reattachment of the musculotendinous unit back to bone is problematic, and any possible tendon-bone repair heals through scar tissue rather than the specially adapted native enthesis. We aim to develop and characterise a novel soft-hard tissue connector device, specific to repairing/bridging the tendon-bone injury in significant rotator cuff tears, employing decellularised animal bone partially demineralised at one end for soft tissue continuation. Optimisation samples of 15×10×5mm. 3. , trialled as separate cancellous and cortical bone samples, were cut from porcine femoral condyles and shafts, respectively. Samples underwent 1-week progressive stepwise decellularisation and a partial demineralisation process of half wax embedding and acid bathing. Characterisations were performed histologically for the presence/absence of cellular staining in both peripheral and central tissue areas (n=3 for each cortical/cancellous, test/PBS control and peripheral/central group), and with BioDent reference point indentation (RPI) for pre- and post-processing mechanical properties. Histology revealed absent cellular staining in peripheral and central cancellous samples, whilst reduced in cortical samples compared to controls. Cancellous samples decreased in wet mass after decellularisation by 45.3% (p<0.001). RPI measurements associated with toughness (total indentation depth, indentation depth increase) and elasticity (1st cycle unloading slope) showed no consistent changes after decellularisation. X-rays confirmed half wax embedding provided predictable control of the mineralised-demineralised interface position. Initial optimisation trials show proof-of-concept of a soft-hard hybrid scaffold as an immune compatible xenograft for
Treatment of massive rotator cuff tears can be challenging. Previous studies with
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