A Knitted PET Patch Enhances the Maturation of Regenerated Tendons in Bridging Reconstruction of Massive Rotator Cuff Tears in a Rabbit Model

Abstract

Background: Although nondegradable synthetic grafts for bridging reconstruction of massive rotator cuff tears (MRCTs) have shown satisfactory clinical outcomes, their function and details on graft-tendon healing and enthesis regeneration have not been fully studied. Hypothesis: The knitted polyethylene terephthalate (PET) patch as a nondegradable synthetic graft could provide sustained mechanical support, facilitating enthesis and tendon regeneration in the treatment of MRCTs. Study Design: Controlled laboratory study. Methods: A knitted PET patch was fabricated for bridging reconstruction (PET group) in a New Zealand White rabbit model of MRCTs (negative control group), and an autologous Achilles tendon was used as a control (autograft group). The animals were sacrificed, and tissue samples were harvested for gross observation as well as histological and biomechanical analyses at 4, 8, and 12 weeks postoperatively. Results: Histological analysis showed no significant difference in the graft-bone interface score between the PET and autograft groups at 4, 8, and 12 weeks postoperatively. Interestingly, in the PET group, Sharpey-like fibers were observed at 8 weeks, while fibrocartilage formation and the ingrowth of chondrocytes were recognized at 12 weeks. Meanwhile, the tendon maturing score was significantly higher in the PET group than in the autograft group (19.7 ± 1.5 vs 15.3 ± 1.2, respectively; P = .008) at 12 weeks, with parallel-oriented collagen fibers around the knitted PET patch. Moreover, the ultimate failure load of the PET group was similar to that of a healthy rabbit tendon at 8 weeks (125.6 ± 13.6 vs 130.8 ± 28.6 N, respectively; P > .05) and no different from that of the autograft group at 4, 8, and 12 weeks. Conclusion: The knitted PET patch could not only immediately reconstruct the mechanical support for the torn tendon postoperatively in the rabbit model of MRCTs but also enhanced maturation of the regenerated tendon by fibrocartilage formation and improved the organization of collagen fibers. Herein, the knitted PET patch could be a promising candidate graft adopted in bridging reconstruction of MRCTs. Clinical Relevance: A nondegradable knitted PET patch can safely bridge MRCTs with satisfactory mechanical strength and the promotion of tissue regeneration.

Engineering an extracellular matrix-functionalized, load-bearing tendon substitute for effective repair of large-to-massive tendon defects

“…However, we did not observe any breakage or ruptures in our scaffolds, suggesting that before collagen fibers fully mature, the elastomer core with its excellent biomechanical strength, suture retention value, could sufficiently and permanently support the dynamic loading strain during the tendon healing phase and prevent early tendon retear or scaffold failure after surgery. It is worth noting that in a clinical setting, nondegradable devices, including PET patch (nondegradable synthetic graft), suture anchors ( e.g ., polyether ether ketone; PEEK) and sutures ( e.g ., high molecular weight polyethylene or FiberWire®), are routinely used and not removed after surgery [ 23 , 65 , 66 ]. However, even though they can reinforce the mechanical properties, their application is limited due to the poor tenogenic-bioactivity [ 38 ].…”

“…Consequently, various tendon substitute/scaffolds have been developed to provide mechanical augmentation for tendon repair [ 22 ]. These include degradable biomaterials such as polycaprolactone (PCL), polylactic acid (PLA), and poly( l -lactide) (PLLA), as well as nondegradable materials like polyethylene terephthalate (PET) patch [ 23 , 24 ]. Despite these diverse approaches, a singular approach has yet to achieve complete functional repair and regeneration.…”

Application of Nondegradable Synthetic Materials for Tendon and Ligament Injury

“…Zhong et al investigated the potential of a knitted PET patch as a nondegradable synthetic graft for bridging reconstruction of MRCTs in a rabbit model (Figure 3B,C). [59] The knitted PET patch was compared to an autologous Achilles tendon graft in terms of graft-bone interface scores, tendon maturation, and biomechanical properties at various postoperative time points. Histological analysis revealed that the PET patch promoted fibrocartilage formation, chondrocyte ingrowth, and Sharpey-like fiber formation at 12 weeks.…”

“…Reproduced with permission. [ 59 ] Copyright 2023, SAGE. D) Preparation for a 3‐layer fascia latae‐ligament‐fascia lata graft: the sandwich graft.…”

Ultrasound-Controlled Delivery of Growth Factor-Loaded Cerasomes Combined with Polycaprolactone Scaffolds Seeded with Bone Marrow Mesenchymal Stem Cells for Biomimetic Tendon-to-Bone Interface Engineering

“…Tissue engineering approaches have been explored to enhance the repair of RCT, with a particular focus on the appropriate formation of different tissue zones. − Synthetic biomaterials, including polycaprolactone (PCL), polyethylene terephthalate and polyurethane, have been extensively utilized in animal models of RCT. , Biomaterial scaffolds created by three-dimensional (3D) printing have often been cocultured with mesenchymal stem cells (MSCs), treated with growth factors (GFs), and then transplanted into the rotator cuff to promote tendon-to-bone healing . MSCs or MSC-derived constructs with scaffolds have also been applied for tendon-to-bone healing. − …”