A prospective study comparing tendon-to-bone interface healing using an interposition bioresorbable scaffold with a vented anchor for primary rotator cuff repair in sheep

Abstract

Background: The purpose of this study was to evaluate the biomechanical and histologic properties of rotator cuff repairs using a vented anchor attached to a bioresorbable interpositional scaffold composed of aligned PLGA (poly(L-lactide-co-glycoside)) microfibers in an animal model compared to standard anchors in an ovine model. Methods: Fifty-six (n ¼ 56) skeletally mature sheep were randomly assigned to a repair of an acute infraspinatus tendon detachment using a innovative anchor-PLGA scaffold device (Treatment) or a similar anchor without the scaffold (Control). Animals were humanely euthanized at 7 and 12 weeks post repair. Histologic and biomechanical properties of the repairs were evaluated and compared. Results: The Treatment group had a significantly higher fibroblast count at 7 weeks compared to the Control group. The tendon bone repair distance, percentage perpendicular fibers, new bone formation at the tendon-bone interface, and collagen type III deposition was significantly greater for the Treatment

Partial Infraspinatus Tendon Transection as a Means for the Development of a Translational Ovine Chronic Rotator Cuff Disease Model

“…A boardcertified veterinary pathologist unblinded to species but blinded to tendon/muscle section (medial vs. lateral) performed the histopathological analysis on all samples. The pathologist who performed the analysis of the specimens in this study utilized samples from previous studies 3,18,21,26,27,31 to generate and calibrate to a baseline of uninjured ovine tendons before performing the analysis on the specimens in this study.…”

Enthesis trauma as a means for the development of translatable chronic rotator cuff degeneration in an ovine model

“…Three cross-sectional area (CSA) measurements of all tendons were taken proximal to the insertion using previously validated techniques in which an area micrometer that applied 0.12 MPa of pressure parallel to the cross section of the tendon (23,(35)(36)(37). The minimum of these CSA measurements was used to transform force to stress, resulting in values that indicate the highest level of stress in each tendon.…”

“…For purposes of reporting tendon overall CSA, these measurements were averaged. The humeri were subsequently mounted in polyvinyl chloride (PVC) sleeves using a strong two-part hard casting resin (SmoothCast 321, Smooth-On, Macungie, PA) and mounted in a custom fixture attached to a servo-hydraulic load frame (Model 805, MTS Corp., Eden Prairie, MN) which allowed anatomically accurate loading of the tendon (Figure 1) (23,25). Prior to biomechanical testing, tendons underwent a pre-loading phase to normalize viscoelastic effects in which a static preload of 5N was applied for a duration of two minutes (37)(38)(39)(40)(41)(42).…”

“…Furthermore, the inherently small size of some of these animal models (i.e., 'small animals') precludes the assessment of physiologicallyrelevant sized devices or comparable dosages of cellular therapies intended for use in humans. This has led some researchers to propose the use of ewes as a translational model for rotator cuff injury (21)(22)(23). One of the first ovine models used as a means to generate degenerative changes to tendons in the rotator cuff involved a full transection of the infraspinatus tendon with a delayed repair (24).…”

Mucoadhesive Electrospun Fibre-Based Technologies for Oral Medicine

“…Electrospinning uses a high voltage (5–30 kV) to produce polymer fibres, with diameters ranging from two nanometres up to several micrometres from a polymer solution or melt [ 22 ]. So far, at least 12 electrospun medical devices are in late stages of regulatory or market approval, with the majority being used as surgical grafts or for tissue regeneration [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. The technique is particularly promising for drug delivery because of its versatility and the high surface area of the resulting nanofibre mesh, which allows an active compound to be incorporated and released at a controlled rate by either diffusion or degradation of the nanofibres [ 3 ].…”