Mechanical characterization and biocompatibility of a novel reinforced fascia patch for rotator cuff repair

Abstract

To provide mechanical augmentation for rotator cuff repair, it is necessary (though perhaps not sufficient) that scaffolds have tendon-like material and suture retention properties, be applied to the repair in a surgically appropriate manner, and maintain their mechanical properties for an acceptable period of time following surgery. While allograft fascia lata has material, structural, and biochemical properties similar to tendon tissue, its poor suture retention properties abrogates its potential as an augmentation device. The goal of this work was to design a novel reinforced fascia patch with suture retention and stiffness properties adequate to provide mechanical augmentation for rotator cuff repair. Fascia was reinforced by stitching with PLLA or PLLA/PGA polymer braids. Reinforced fascia patches had a maximum construct load greater than (or equal to) the suture retention properties of human rotator cuff tendon (∼250N) at time zero and after in vivo implantation for 12 weeks in a rat subcutaneous model. The patches were able to withstand the 2500 loading cycles projected for the early post-operative period. The patches also demonstrated biocompatibility with the host using a rat abdominal wall defect model. These studies suggest the potential use of reinforced fascia patches to provide mechanical augmentation, minimize tendon retraction and possibly reduce the incidence of rotator cuff repair failure.

Does Augmentation with a Reinforced Fascia Patch Improve Rotator Cuff Repair Outcomes?

“…Our group has developed a polymer-reinforced fascia ECM patch and demonstrated its biomechanical properties and utility, as well as initial biocompatibility, through a series of bench, cadaveric, and small-animal investigations [3,23]. The current study builds on our previous work by investigating the biomechanical utility and biocompatibility of this patch in the context of large-animal rotator cuff repair healing.…”

“…Third, there were anatomic and size dissimilarities compared to the human rotator cuff condition [14]. As a consequence, the fascia patch used in this canine study was scaled down from its well-characterized and optimum design for human application [3,23]. Fourth, bone anchors were needed to secure the patch superiorly and inferiorly over the repair because dogs lack the soft tissue anatomy of a human rotator cuff.…”

“…We prepared reinforced fascia patches by stitching lyophilized human fascia lata from the iliotibial tract of three human donors aged 18 to 55 years (Musculoskeletal Transplant Foundation, Edison, NJ, USA), with custom 100% PLLA fiber as described [3]. However, given the size constraints of the canine shoulder, we scaled down the patches to 18 9 34 mm, from our previously described 50 9 50 mm [3,23].…”

“…However, given the size constraints of the canine shoulder, we scaled down the patches to 18 9 34 mm, from our previously described 50 9 50 mm [3,23]. The use of smaller and rectangular-shaped patches required the stitch pattern to be modified as well.…”

“…However, native fascia lata has poor suture retention properties (* 10 N) [3], which limits its usefulness as a tendonlike scaffold for rotator cuff repair augmentation. We recently reinforced fascia ECM with PLLA polymer braids to engineer the suture retention properties of fascia to meet the needs of musculoskeletal applications [3]. We found the reinforced fascia patch has and maintains its suture retention properties on the order of human rotator cuff tendon before and after implantation in a rat subcutaneous model.…”