Decellularized Bovine Pericardial Patch Loaded With Mesenchymal Stromal Cells Enhance the Mechanical Strength and Biological Healing of Large-to-Massive Rotator Cuff Tear in a Rat Model

Clinical and Radiologic Outcomes of Augmented Partial Repair with Acellular Dermal Allograft and Superior Capsular Reconstruction in Massive Rotator Cuff Tears: 2-Year Follow-Up

Background/Objectives: To evaluate the clinical and radiologic outcomes of arthroscopic augmented partial repair (APR) with acellular dermal matrix versus arthroscopic superior capsular reconstruction (SCR) in massive rotator cuff tears. Methods: The study included a total of 49 patients with massive rotator cuff tears who underwent arthroscopic APR (26 patients) and SCR (23 patients) between March 2018 and June 2021. Clinical scores, visual analog scores, and range of motion were collected preoperatively and postoperatively until the last follow-up. Preoperative and postoperative simple radiographs were evaluated for arthropathic changes and acromiohumeral distances (AHDs). Magnetic resonance imaging was performed to assess the integrity of repaired structures at 12 months postoperatively. Results: The average age of patients was 63.9 years (range 53-74 years), and the mean clinical follow-up period was 2.6 years (range 2.1-2.9). The average UCLA scores improved from 18.0 to 33.2 and from 16.3 to 32.1 in APR and SCR groups at the last follow-up, respectively. For the ranges of motion, the APR group consistently showed better external rotation ranges from the postoperative 6th month until the last follow-up (p < 0.05), and the APR group revealed better ranges of motion in forward flexion, abduction, and external rotation compared to the SCR group (p < 0.05). Postoperative AHD showed better improvement in the APR group than the SCR group (p < 0.05). Re-tears were found in two patients in each group (p > 0.05). Conclusions: Both APR and SCR groups showed comparable improvement in clinical outcomes in massive rotator cuff tears, while the APR group showed statistically significant improvement in the range of motion compared to the SCR group, especially for external rotations.

Inflammation-Responsive Functional Core-Shell Micro-Hydrogels Promote Rotator Cuff Tendon-To-Bone Healing by Recruiting MSCs and Immuno-Modulating Macrophages in Rats

Rotator cuff injuries often necessitate surgical intervention, but the outcomes are often unsatisfactory. The underlying reasons can be attributed to multiple factors, with the intricate inflammatory activities and insufficient presence of stem cells being particularly significant. In this study, an innovative inflammation-responsive core-shell micro-hydrogel is designed for independent release of SDF-1 and IL-4 within a single delivery system to promote tendon-to-bone healing by recruiting MSCs and modulating M2 macrophages polarization. First, a MMP-2 responsive hydrogel loaded with IL-4 (GelMA-MMP/IL-4) is synthesized by cross-linking gelatin methacrylate (GelMA) with MMP-2 substrate peptide. Then, the resulting core particles are coated with a shell of chitosan /SDF-1/hyaluronic acid (CS/HA/SDF-1) using the layer-by-layer electrostatic deposition method to form a core-shell micro-hydrogel composite. The core-shell micro-hydrogel shows sustained release of SDF-1 and MMP-2-responsive release of IL-4 associated in situ MSCs homing and smart inflammation regulation by promoting M2 macrophages polarization. Additionally, by injecting these micro-hydrogels into a rat rotator cuff tear and repair model, notable improvements of fibrocartilage layer are observed between tendon and bone. Notably, this study presents a new and potentially powerful environment-responsive drug delivery strategy that offers valuable insights for regulating the intricate micro-environment associated with tissue regeneration.

Advances focusing on the application of decellularization methods in tendon-bone healing

BACKGROUND

The tendon or ligament is attached to the bone by a triphasic but continuous area of heterogeneous tissue called the tendon-bone interface (TBI). The rapid and functional regeneration of TBI is challenging owing to its complex composition and difficulty in self-healing. The development of new technologies, such as decellularization, has shown promise in the regeneration of TBI. Several ex vivo and in vivo studies have shown that decellularized grafts and decellularized biomaterial scaffolds achieved better efficacy in enhancing TBI healing. However further information on the type of review that is available is needed.

AIM OF THE REVIEW

In this review, we discuss the current application of decellularization biomaterials in promoting TBI healing and the possible mechanisms involved. With this work, we would like to reveal how tissues or biomaterials that have been decellularized can improve tendon-bone healing and to provide a theoretical basis for future related studies.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

Decellularization is an emerging technology that utilizes various chemical, enzymatic and/or physical strategies to remove cellular components from tissues while retaining the structure and composition of the extracellular matrix (ECM). After decellularization, the cellular components of the tissue that cause an immune response are removed, while various biologically active biofactors are retained. This review further explores how tissues or biomaterials that have been decellularized improve TBI healing.

Bioinductive patch as an augmentation for rotator cuff repair, a systematic review and meta-analysis

BACKGROUND

Rotator cuff tears are a prevalent cause of shoulder pain and dysfunction. For those who fail initial conservative treatment, operative intervention can be pursued. A significant and common complication after rotator cuff repair (RCR) is retearing or nonhealing. Numerous augmentations to traditional suture RCR have been studied. Of these, the Smith + Nephew Regeneten bioinductive collagen patch has had promising initial results; however, analytic data for its use are lacking, and there is no meta-analysis comparing the available data to historical RCR outcomes.

METHODS

A PRISMA-guided literature search was conducted using Ovid MEDLINE, PubMED, Cochrane, and ClinicalTrials.gov. Thirteen studies met inclusion and exclusion criteria. Only clinical trials on full and partial-thickness tears were included. American Shoulder and Elbow Surgeon score, Constant-Murley Score, the visual analog scale for pain, the minimal clinically important difference (MCID), tendon thickness, and complication rates were primary outcomes of interest. A meta-analysis was performed to determine the overall complication and retear rate from the included studies.

RESULTS

American Shoulder and Elbow Surgeon score, Constant-Murley Score, and visual analog scale for pain improved significantly in all studies that reported them, and most patients achieved MCID. Patient-reported outcome measure improvements were similar to historical improvements in standard RCR, and a similar proportion of patients achieved MCID after standard repair. Tendon thickness improved significantly and to a similar degree as standard RCR. Overall retear rate after full thickness RCR augmented with the bioinductive patch was 8.3%. For partial thickness RCR, total retear rate was of 1.1% across all patients. The overall complication rate with the bioinductive patch was 15.5% across all full-thickness RCR studies and 16.2% in partial thickness RCR. We found overall retear rate to be lower after augmentation with the bioinductive patch compared to traditional repair; however, the overall complication rate was similar for full-thickness tears and higher for partial-thickness tears. Lastly, adverse reactions to the bioinductive patch were noted at 0.2%.

CONCLUSIONS

The bioinductive collagen patch appears to be a safe augmentation for rotator cuff repair. Patients are likely to experience significant subjective improvement in patient-reported outcome measures and significant increases in tendon thickness. Retear rate has been a concern after RCR for decades, and the bioinductive patch may help mitigate this risk. There is lack of case-control studies comparing the bioinductive patch to traditional suture RCR. Such data are needed to better determine the role of the bioinductive patch in the treatment of full and partial-thickness rotator cuff repairs.

Decellularized biological matrices for the repair of rotator cuff lesions: a systematic review of preclinical in vivo studies

Background: Rotator cuff tears (RCTs), resulting from degeneration or trauma of the shoulder tendons, are one of the main causes of shoulder pain. In particular, massive RCTs represent 40% of all injuries, require surgical treatment, and are characterized by poor clinical outcomes and a high rate of failure. In recent years, the use of biological decellularized patches for augmentation procedures has received great interest owing to their excellent self-integration properties, improving healing and, thus, presenting an innovative therapeutic option. However, the findings from clinical studies have emerged with conflicting viewpoints regarding the benefits of this procedure, as an excessive tension load might compromise the integrity of the tendon-to-bone connection when the patch exhibits low elasticity or insufficient strength. This could prevent the healing process, leading to unpredictable results in clinical practice. Methods: This systematic review was conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines across three databases (PubMed, Scopus, and Web of Knowledge) to underline the results obtained in preclinical studies involving animal models of RCT surgeries that utilized the biological decellularized matrix augmentation technique in the last 5 years. Results: Thirteen articles were included after the screening, and the SYRCLE tools were applied to assess the risk of bias in in vivo studies. Open-surgery techniques were conducted to create tendon defects or detachment in different animal models: rat (31%), rabbit (46%), dog (15%), and sheep (8%). Patches decellularized with non-standardized protocols were used in 77% of studies, while commercially available matrices were used in 15%. Of the studies, 31% used allogenic patches, 61% used xenogenic patches, and 8% utilized both xenogenic and autologous patches. Conclusion: Overall, this review provides a comprehensive overview of the use of acellular patches and their effective therapeutic potential in rotator cuff (RC) repair at the preclinical level with the aim of expanding the strategies and matrices available for surgeons. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42023468716.

Compressed Biceps Autograft Augmentation of Arthroscopic Rotator Cuff Repair

Rotator cuff repair failure rates continue to be a challenging problem. Various methods of biological and structural augmentation of the rotator cuff have been explored to improve tendon healing after repair. We describe a technique in which biceps tendon autograft is harvested after tenodesis. The biceps tendon is then compressed into a patch that is placed over the repaired rotator cuff tendon. Repurposing the portion of the tendon that is otherwise discarded offers several advantages over other augmentations that have been used, including the biological potential of live autograft tenocytes in the patch, lower cost, and no donor-site morbidity.