Regenerative rotator cuff repair in a clinically relevant chronic disease model - ABSTRACT
Rotator cuff repair (RCR) is a common first-line surgical solution to symptomatic rotator cuff injury, with over
270,000 RCRs performed annually, and growing at a rate of 141%. Unfortunately, 30-94% of the cases are
complicated by failure and re-tear of the repaired tendon, which commonly results in a significant reduction in
activities of daily living, work, and/or sports and recreation for the patient due to pain and restricted movement.
Failed rotator cuff repairs stem from issues associated with suture retention, maintaining the correct anatomic
position of the tendon when reattached, and the lack of enduring mechanical support for the shoulder and
repaired tendon, which is necessary to allow adequate healing time after the surgical procedure. These issues
are even more problematic for severe or chronic tears where muscle atrophy, fatty infiltration, and retraction
from the anatomic insertion site complicate tendon repairs. In this project, we propose a high-performance
textile-based implant designed to address the deficiencies of current RCR. The innovation of the project is two-
fold: (1) the scaffold is designed to mimic the mechanical properties of native tendon and (2) the partially
resorbable structure and the specific utilization of resorbable and non-resorbable yarns minimizes the potential
generation of particulate debris, maintains discrete, interconnected zones to promote cell infiltration,
differentiation, and integration with both the tendon and bone tissues in their respective zones. We aim to
further the development of this high-performance scaffold by varying weaving parameters in order to maximize
the biological properties, while retaining the mechanical properties of native tendon. In Aim 1, fiber diameter
and yarn spacing will be modulated to create implants with different architectures in four combinations that will
be studied in vitro via explant culture, and assessed via histological and biomechanical analysis. In Aim 2, the
optimized scaffold will be assessed in an clinically relevant ovine model of chronic tendinopathy, which we
have shown to mimic the chronic human condition. Additionally, by attaching the implant to a completely
transected tendon, this model also tests the efficacy of the implant under a severe clinical condition of a
complete mechanical deficit. The control cohort will be repaired using advanced suture techniques only, which
is the current standard of care. At 6 months, mobility restoration, tendon and bone integration, and repair
strength will be assessed via biomechanical testing and histological analysis. The goal of this study is to further
the development of a new implant specifically tailored to meet the disparate requirements for both tendon and
bone incorporation during repair of severely torn rotator cuff tendons. We anticipate that this will lead to
improved functionality of the injured cuff in these challenging cases and ultimately improve long-term clinical
outcomes.
