To evaluate the effects of this graft preparation technique on histologic evidence of tenocyte mechanical damage.

A consecutive series of patients undergoing biceps tenodesis for shoulder pathology were evaluated. After suprapectoral tenodesis, 27 mm of the long head of the biceps was secured for compression into the patch. The remaining length of the residual tendon was longitudinally split, resulting in 2 equal lengths of remnant tendon from the same zone. One sample was sent to pathology with no preparation, and the other was prepared as a compressed biceps autograft patch according to the manufacturer's recommendations. Both grafts were sent to pathology for evaluation of tenocyte morphology. Records were reviewed to determine if compression resulted in mechanical damage to the tenocytes at the time of biceps augmentation.

Fifty-five shoulder procedures and 110 samples were sent for pathology analysis. Forty-two of the 55 (76%) specimens demonstrated morphologically normal tenocytes in both the compressed and noncompressed groups, and 7 (13%) cases showed evidence of tenocyte necrosis or mechanical damage in both groups. The difference in abnormal tenocyte morphology between the compressed and native groups was not statistically significant (P = .625).

Autograft biceps compression into a point-of-care patch did not result in mechanical damage to tenocyte morphology at the time of insertion for augmentation of rotator cuff pathology.

Free proximal biceps tendon compression can result in a patch that does not mechanically damage the tenocyte. The patch can be used as a biologic autograft to enhance shoulder rotator cuff repair, as well as subscapularis repair in the setting of shoulder arthroplasty.

Rotator cuff (RC) tears are common in older adults, often leading to muscle atrophy. Standard arthroscopic repair has high re-tear rates, prompting the use of biological patches for augmentation. This study assessed differences in range of motion, strength, and tendon healing using ultrasound in primary and revision RC repairs using acellular dermal allograft augmentation.

Forty-eight patients undergoing arthroscopic RC repair with dermal allograft augmentation were assessed, with 42 completing a median follow-up of 32.4 months. Twenty patients had primary repairs and 22 had revision procedures. A control group of 26 patients, matched for age, sex, BMI, and RC injury type, underwent RC repair without patch augmentation. Active range of motion, Constant-Murley socre (CS), Simple Shoulder Test (SST), Subjective Shoulder value (SSV) and isometric strength were measured. Tendon healing was assessed via dynamic US.

Both primary and revision groups showed significant improvements in clinical scores and shoulder mobility. However, the primary group had significantly higher postoperative CS, SST and SSV scores. Strength tests indicated lower values in the revision group compared to primary and control groups. Ultrasound outcomes showed reduced tendon thickness in 23 patients, with similar repair integrity across groups. Five cases of RC re-tears were noted, with higher but not significantly different re-tear rates in the revision group.

Dermal allograft augmentation in RC repair leads to significant clinical improvement in both primary and revision cases, but strength recovery is less pronounced in revision repairs. Long-term follow-up is necessary to validate these findings and assess the durability of tendon healing.

Level III, Retrospective cohort design, Treatment study.

Due to the ageing population, the number of symptomatic degenerative rotator cuff tears has increased substantially, and some are challenging to repair due to poor tendon quality with significant retraction. In order to optimize repair integrity and function, rotator cuff repair reinforcement with a superior capsule reconstruction has been proposed. This study presents the results of a technique combining cuff repair and capsular reconstruction (CRACR) using acellular dermal allograft in patients with massive rotator cuff tears and retears.

From December 2017 to July 2019, 50 consecutive patients with previous failed rotator cuff repairs or primary surgery on poor tendon quality defined as massive rotator cuff tear (full thickness rotator cuff tears with 2 or more tendons involved), were treated with the CRACR technique and enrolled prospectively. Contraindications for the CRACR procedure were Hamada stage ≥3 cuff tear arthropathy and patient's preference for reverse total shoulder arthroplasty. Patients were reviewed at 3, 6, 12, and 24 months (American Shoulder and Elbow Surgeons scores, Constant Murley Scores, Visual Analogue Scores, Oxford Shoulder Score, QuickDASH). Postoperative magnetic resonance imaging scans were requested at 6 weeks, 3 months, 6 months, 12 months, and 24 months postoperatively, to assess repair integrity.

Mean age at surgery was 58.0 years (SD 8.1, range 41-79). Of the 50 patients, 14 patients (28.0%) had previous failed rotator cuff repair. From the 36 primary cases, 28 (77.8%) had massive rotator cuff tears and one (2.8%) a perioperative irreparable tear, while 28 (77.8%) patients had a subscapularis tear. At 2 years of follow-up all scores improved significantly (Visual Analogue Scores 6.3 to 1.5; American Shoulder and Elbow Surgeons 34.0 to 79.0; Constant Murley Scores 30.9 to 68.0; OSS 23.3 to 40.1; QuickDASH 56.2 to 20.3; all P < .001). Magnetic resonance imaging scans were conducted at a mean of 14.4 months (SD 7.0, range 3-26) after surgery showing 6 isolated superior capsular reconstruction failures and 5 isolated rotator cuff retears.

In the short term, the CRACR technique is a valid option for patients with massive rotator cuff tears and retears with a high chance of a postoperative retear due to poor tendon quality. Clinical results and repair integrity are promising. Longer term follow-up is ongoing to establish the efficacy of this procedure.

Delivery of soluble allogeneic type I telocollagen (allo-telocollagen) will accelerate and improve the healing of damaged tendons. Our hypothesis draws from known mechanochemical properties of type I collagen that direct its incorporation into damaged connective tissue. We further suggest that allo-telocollagen will raise a minimal immunogenic reaction as a result of homology within species.

Seventy-eight shoulders (39 Sprague-Dawley rats) had their supraspinatus tendon surgically detached from its footprint on the humerus and repaired (72 shoulders) or left uninjured (6 shoulders). The repaired tissue was treated with an injection of 100 μL of saline, 10 mg/mL allogeneic atelocollagen (allo-atelocollagen), or 10 mg/mL allo-telocollagen at 0, 1, and 2 weeks postsurgery. At 30 and 60 days postsurgery, the tendons were assessed by mechanical testing (failure load, failure stress, stiffness, and relaxation) and by semiquantitative histologic scoring.

At 30 days postsurgery, the mechanical and histologic outcomes were not statistically different. However, at day 60, allo-telocollagen improved the failure strength of the supraspinatus (29.9 ± 4.7 N) relative to saline (20.0 ± 3.5 N, P < .001) or allo-atelocollagen (23.2 ± 1.5 N, P = .025) treated tendons, and it approached that of uninjured controls (36.9 ± 5.0 N, P = .021). Allo-telocollagen improved the failure stress of the supraspinatus (34.1 ± 9.3 MPa) relative to the saline-treated tendons (21.4 ± 6.0 MPa, P = .031, 160% improvement) and was no different than uninjured controls (33.4 ± 9.9 MPa, P = .999) or allo-atelocollagen (32.3 ± 7.4 MPa, P = .977). The stiffness of uninjured controls was far greater than any of injured or treated tendons (>200% stiffer). Histologic scoring showed that the allo-telocollagen-treated tendons produced better collagen fiber arrangement (1.55 ± 0.17) than saline (2.50 ± 0.29, P = .001) or allo-atelocollagen (2.23 ± 0.28, P = .042) treated tendons and that it did not increase markers of immunogenesis (1.10 ± 0.42) relative to either saline (1.44 ± 0.20, P = .369) or allo-atelocollagen (0.68 ± 0.41, P = .1058).

Although all 3 treatments produced similar results at 30 days, by 60 days, soluble allo-telocollagen clearly separated from the other interventions, yielding better mechanical and histologic outcomes in a torn or repaired rotator cuff rat model. Allo-telocollagen-treated tendons also approached the failure strength and matched the failure stresses of uninjured control tendons. The data suggest a new use for allo-telocollagen as a deliverable direct protein mechanotherapeutic that can improve both healing quality and speed.

Platelet-rich plasma (PRP) has been utilized as adjunctive therapy in arthroscopic rotator cuff repair. However, there is currently limited research available on the efficacy of PRP in arthroscopic repair of full-thickness rotator cuff tears.

This study aimed to perform a cross-sectional analysis of overlapping meta-analyses comparing the clinical efficacy of arthroscopic repair of full-thickness rotator cuff tears with and without PRP to assist clinicians in assessing the most reliable evidence and formulating treatment recommendations accordingly.

Systematic review; Level of evidence, 2.

Under PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, comprehensive searches of meta-analyses were performed in the PubMed, Embase, and Cochrane Library databases until June 1, 2024, and found 63 studies. The methodological quality of the included studies was evaluated using the Assessment of Multiple Systematic Reviews (AMSTAR) and Oxford Centre for Evidence-Based Medicine Levels of Evidence instruments. Data extraction from the included meta-analyses was independently performed by 2 reviewers. The Jadad decision algorithm was employed to identify meta-analyses with the most robust evidence.

This study included 5 meta-analyses. These meta-analyses had AMSTAR scores ranging from 7 to 9, with a mean of 8. The most reliable evidence, assessed by the Jadad algorithm, included 8 randomized controlled trials and involved 566 patients. It showed that the short-term (≤12 months after surgery) retear rate and visual analog scale score were significantly lower in those with PRP than in those without PRP. The short-term Constant score, short-term University of California, Los Angeles (UCLA) activity score, and long-term (>12 months after surgery) UCLA score were significantly higher in the PRP group, especially in single-row fixation.

Our study demonstrates that the most reliable evidence suggests that PRP injections can be recommended as adjunctive therapy in single-row repair for enhanced short-term outcomes. Further high-quality randomized controlled trials are imperative to increase the strength of evidence.

Arthroscopic repair is currently the gold standard for the surgical treatment of rotator cuff tears, but the retear rates remain unacceptably high. Mesenchymal stem cells (MSCs) may play a role in the local biology and enhance tendon-to-bone healing during rotator cuff repair. However, the scientific literature is still not well systematized on the effects of injection of MSCs as an augmentation tool for rotator cuff repair. Our goal was to investigate the effect of injections of MSCs to augment rotator cuff repair in patients with rotator cuff tear.

PubMed and EMBASE were searched up to June 2022 for clinical studies that applied MSCs injections to augment rotator cuff repair. Imaging, patient-reported outcomes measures, shoulder range of motion and strength were collected. Quantitative synthesis included within- and between-group mean differences with the within-group percentage of minimal clinically important difference for each study and continuous outcomes, and relative risks (RR) for retears and adverse events. Quantitative synthesis was computed with 95% confidence intervals (CIs).

We included 5 studies comprising a total of 228 individuals with a weighted mean age of 59.3 ± 1.2 years. Three studies used bone marrow MSCs and two studies applied adipose-derived MSCs. Patient-reported outcomes measures, shoulder range of motion, and strength improved significantly in all MSCs groups, with minimal clinically important differences ranging from 120% to 679% of established cut-off. When compared to rotator cuff repair alone, the MSCs groups did not result in improved outcomes. The MSCs group showed significant protective effect at the mid-term (RR = 0.52, 95% CI 0.27-0.98) and long-term (RR = 0.24, 95% CI 0.11-0.53).

There are no differences in clinical and functional outcomes between rotator cuff repair with or without augmentation with MSCs. However, there may be a protective effect against retear at the mid-term and long-term follow-up when augmenting the repair with MSCs. The literature on this topic is still preliminary and the quality and certainty of evidence is limited.

Alcohol consumption is a significant risk factor for both the occurrence and severity of rotator cuff tears. However, there is limited supporting evidence to suggest that alcohol use is associated with suboptimal outcomes after operative repair of rotator cuff tears. Rat shoulders have been demonstrated as consistent and reliable models for studying rotator cuff disease. Perioperative alcohol exposure will negatively impact the biomechanical and histologic properties of surgically repaired rotator cuffs in rats.

Rats were randomized to receive a 20% ethanol or isocaloric control solution as their primary source of drinking water. A tenotomy of the supraspinatus tendon from bone was performed surgically and then immediately repaired with a transosseous technique. After surgery, rats were continued on the same exposure solution until animals were humanely euthanized at 7, 14, or 21 days postoperatively. The surgically repaired shoulders underwent biomechanical testing to assess load to failure and failure strain. The histologic evaluation of tendon-to-bone healing was performed by a blinded pathologist using a qualitative grading system. Quantitative reverse transcription-polymerase chain reaction on total RNA from tendon-to-bone interface tissue was performed to quantify the mRNA expression of type I and III collagen, and transforming growth factor-β 1 (TGF-β 1) and 3 (TGF-β 3) at the repair site.

Biomechanical testing showed that repaired shoulder constructs in rats exposed to ethanol had significantly lower load to failure at 7 days postoperatively relative to repairs in rats exposed to a control solution. No other biomechanical parameters or time points reached statistical significance. TGF-β3 mRNA expression was found in significantly higher quantities at the repair sites of rats exposed to ethanol at 7 days postoperatively relative to control rat repair sites. No other time points or factors reached statistical significance. No significant differences were identified among time points or groups at the healing tendon-to-bone interface.

Alcohol exposure significantly decreases biomechanical load to failure of rotator cuff repairs in the early postoperative period in rat models. In the later postoperative period, alcohol exposure was not associated with a decrease in biomechanical load to failure compared with controls. In addition, rats exposed to ethanol have significantly higher TGF-β3 expression at repair sites on postoperative day 7. These data suggest that ethanol consumption does deleteriously affect rotator cuff and bone healing. Future study is needed to validate the clinical significance of these findings in humans.

Purpose: To compare the outcomes of additional biceps augmentation (ABA) and biceps superior capsule reconstruction (BSCR) in arthroscopic medium to large rotator cuff tear (RCT) repair. Hypothesis: Both ABA and BSCR yielded comparable clinical and radiological outcomes and retear rates at the 2-year follow-up in patients with medium to large RCTs. Methods: Patients undergoing ABA or BSCR for RCT repairs were included retrospectively between January 2019 and May 2020. The preoperative and postoperative Constant-Murley score (CMS), American Shoulder and Elbow Surgeons (ASES) score, subjective shoulder value (SSV), visual analog scale (VAS), and range of motion (ROM) were recorded, as well as the radiographic evaluation. Results: 67 patients (41 with ABA, 26 with BSCR) were included. There were no significant differences regarding preoperative patient demographics between groups unless forward flexion. In the ABA group, CMS, ASES, SSV, and VAS improved significantly from 33.9 ± 6.0, 37.3 ± 8.7, 24.9 ± 12.3, and 5.1 ± 1.1 to 79.3 ± 8.4, 82.7 ± 8.4, 77.5 ± 10.9, and 2.4 ± 0.6, at 2-year follow-up (all p < .001). In the BSCR group, the CMS, ASES, SSV, and VAS significantly improved from 33.9 ± 5.5, 33.5 ± 11.6, 20.8 ± 9.8, and 5.3 ± 1.5 to 72.8 ± 12.9, 79.6 ± 12.1, 73.1 ± 10.2, and 2.7 ± 0.8, at follow-up (all p < .001). All ROM improved at follow-up in both groups (all p < .001). No significant differences were found between the two groups regarding the postoperative clinical and radiological results. All patients reached minimal clinically important differences for CMS, ASES, SSV, and VAS at the final follow-up. The retear rates in the ABA and BSCR groups were 0% and 7.7%, respectively (p = .001). Conclusions: Both ABA and BSCR provided similar clinical and radiological outcomes in patients with medium to large RCTs. The BSCR group had a higher retear rate than the ABA group. Level of Evidence: Level III, Retrospective comparative therapeutic trial. Clinical Relevance: Both ABA and BSCR provided comparable clinical and radiological outcomes in patients with medium to large RCTs.

Primary repair of massive posterosuperior rotator cuff is challenging with a high rate of failure. This study details the technique and outcomes of a standard double-row cuff repair augmented with a synthetic ligament inserted in a separate adjacent location from the tendon-bone construct to off-load and de-tension the repair interface.

Eleven patients with massive rotator cuff tears involving two or more tendons with >2.5 cm of retraction were prospectively enrolled. All patients underwent arthroscopically assisted mini-open double-row repair. This was augmented by a synthetic ligament passed medially through the supraspinatus and infraspinatus musculotendinous junctions before fixation distal to the second-row anchors. This represents a third row of repair that is remote from the double-row construct and aims to minimize repair tension. The primary outcome was repair integrity according to the Sugaya classification on postoperative magnetic resonance imaging. Secondary outcomes included the Constant score, EQ-5D 3L, and Oxford Shoulder Scores.

The mean patient age was 65 with 10 males. At a mean follow-up of 13 months, 8 (73%) of the repaired tendons were intact on magnetic resonance imaging. Of the 3 retears, one occurred at the musculotendinous junction. All outcome scores were significantly improved after surgery beyond the minimal clinically important difference.

The insertion of an independent third row to off-load a standard rotator cuff repair construct resulted in favorable healing rates in patients with massive cuff tears. The technique is a simple, time-efficient method of de-tensioning the repair of massive rotator cuff tears.

The establishment of the enthesis unit remains a significant challenge due to the inability to reconstitute the native histological zones postrepair. In this study, the authors investigated the effect of 3-dimensional hyaluronan-based scaffold implanted with Wharton jelly-derived mesenchymal stem cells on enthesis healing in rat model.

Three-dimensional hyaluronan-based scaffold was seeded with mesenchymal stem cells. Bilateral supraspinatus injury model created tendon-bone interface of 48 Sprague-Dawley rats reconstructed with one of the following: group 1: sham surgery; group 2: control group; group 3: surgery, scaffold and conditioned medium; group 4: surgery, scaffold and Wharton jelly-derived mesenchymal stem cells. The rats were killed on day 30, and supraspinatus-humerus tendon to bone unit was harvested en bloc for evaluations. Histopathological, immunohistochemical, mechanical, and micro-computed tomography evaluations were performed.

Group 4 was found to be superior to the others in terms of collagen organization and density, fibroblast growth factor, collagen II, and bone morphogenetic protein 2 immunoreactivity, as well as biomechanical tensile strength (P < 0,05). Additionally, groups 3 and 4 exhibited superior bone mineral density and trabecular thickness compared with the other groups.

Wharton jelly-derived mesenchymal stem cells implanted into 3-dimensional hyaluronan-based scaffold have shown promising results in achieving a high strength enthesis unit resembling native histological zones.

Decellularized tissue refers to extracellular matrix (ECM) derived from living tissue by removing the cellular components and is used for tissue regeneration. Various decellularized tissue sheets and powders, such as the dermis, urinary bladder matrix, and small intestinal submucosa, have been clinically used as covering and prosthetic materials. Moreover, there is growing interest in the use of decellularized tissue for soft-hard interregional tissue regeneration, including in the ligament-bone, tendon-bone, and periodontal ligament-bone interfaces. The focus in these applications lies in the mechanical properties of the decellularized tissue. Decellularized ligaments and tendons have been developed using various decellularization methods, with a focus on maintaining their shape and mechanical properties, and have been applied orthotopically or ectopically to ligaments and tendons. In the ligament-bone interface, it is suggested that decellularized ligament and tendon are regenerated through the migration and rearrangement of host cells, which is referred to as "in situ tissue regeneration." It is also proposed that decellularized tissue can be used to prepare the complex structure of soft-hard interregional tissue, which consists of an ECM and cell populations with gradual change. In this case, the decellularized soft tissues of ligaments, tendons, pericardium, and others are fabricated and modified with hard tissue components to mimic the gradual structure of soft-hard interregional tissue. In this review, we present a detailed discussion of the regeneration of soft-hard interregional tissue using decellularized tissue.

This study emphasizes the clinical utility of our newly published "BicepBrace" technique by comparing its preliminary outcomes with standard treatment within the short term follow-up of 12 months following massive rotator cuff repair surgery.

A retrospective chart review of all the rotator cuff repairs by E.H.A. over a two year span was completed under institutional review board approval. Inclusion criteria included all adult patients who received primary massive rotator cuff repair within the time frame of June 15, 2021 and June 15, 2023. Exclusion criteria included non-massive rotator cuff repair, revision surgery, or rotator cuff repairs that were paired with total shoulder arthroplasty. These massive rotator cuff repairs were then evaluated for clinical failure necessitating revision surgery within 12 months of original repair. Statistical analyses were performed using t tests and chi square tests.

In total, 102 rotator cuff repairs were identified within the study timeframe. In total, 24 of these cases met criteria to be labeled as massive tears. In total, 13 of these massive tears were treated by standard technique and 11 of them were treated with our BicepBrace biceps tendon transfer technique. In total, 4 of the patients in the standard technique group were deemed clinical failures necessitating revision surgery (failure rate of 30.8%). Only one of the BicepBrace patients were deemed clinical failures (failure rate of 9.1%).

In the setting of a massive rotator cuff tear, the BicepBrace technique-utilizing the long head of the biceps tendon for superior cuff augmentation-may enhance the survivability of the repair within one year of surgery. This relatively new approach offers a promising alternative to standard techniques, particularly for certain patient populations.

Background and Objectives: Shoulder pain, mainly involving rotator cuff tears, is a common type of musculoskeletal pain that significantly impairs quality of life. Arthroscopic rotator cuff repair has become the gold standard for treating symptomatic, full-thickness rotator cuff tears. Double-row repair techniques are widely used because of their superior fixation and healing results. However, fewer implants may reduce treatment costs and raise questions about the impact on clinical outcomes and re-tear rates. This study compares the functional outcomes and re-tear rates of two transosseous-like double-row repair techniques: one anchor and one push lock (Group 1), and two anchors and two push locks (Group 2). Materials and Methods: A prospective, randomized, single-blind study was conducted on 53 patients undergoing arthroscopic repair for crescent-shaped rotator cuff tears (3-5 cm). Before surgery and 24 months after surgery, patients were evaluated for shoulder function using Constant-Murley scores and shoulder abduction angles. MRI was used to assess re-tear rates. Results: Both groups showed significant postoperative improvement in Constant scores (Group 1: 84.1; Group 2: 84.0; p > 0.05). Re-tear rates were slightly higher in Group 1 (23.1%) than in Group 2 (18.5%), but this was not statistically significant (p > 0.05). Shoulder abduction angles improved similarly between groups, with no significant difference in outcome. Despite higher costs and longer operative times, the two-anchor technique provided more stable fixation, but its functional outcomes were comparable to the single-anchor method. Conclusions: Using fewer implants in a double-row repair provides comparable functional outcomes and re-tear rates, and offers surgeons a cost-effective alternative, especially at the beginning of their learning curve. However, the two-anchor technique may be more beneficial in cases requiring improved mechanical stability. These findings provide valuable information to balance cost and effectiveness in rotator cuff repair.

Rotator cuff tears (RCTs) commonly lead to muscle atrophy, fibrosis, and fatty infiltration, complicating treatment.

To investigate the use of mitochondria isolated from bone mesenchymal stem cells (BMSC-Mito) for mitigating complications after RCT, focusing on muscle protection.

Controlled laboratory study.

RCTs were induced by transecting the tendons of the supraspinatus and infraspinatus in Sprague-Dawley rats. In vivo, 90 rats were randomized into 3 groups: sham (no intervention), RCTs treated with BMSC-Mito, and RCTs treated with phosphate-buffered saline. After 6 weeks of intramuscular injections of BMSC-Mito or phosphate-buffered saline, supraspinatus muscles were harvested for analysis. Evaluations included wet muscle weight, muscle fiber cross-sectional area, fibrosis, fatty infiltration, slow-fast myofiber types and muscle biomechanics, capillary density, mitochondria respiratory chain complex activity, adenosine triphosphate (ATP) concentration, oxidative stress, and mitochondrial ultrastructure. In vitro experiments utilized primary rat skeletal muscle cells pretreated with rhodamine 6G to induce mitochondrial dysfunction, assessing the effects of BMSC-Mito on cell viability, mitochondrial membrane potential, and oxidative stress levels.

BMSC-Mito can be effectively transplanted into muscles and integrated into the local mitochondrial network. After RCT, the supraspinatus showed significant mass loss, reduced fiber cross-sectional area, fatty infiltration, and a shift from slow to fast myofiber types, which negatively affected muscle biomechanics. These changes were reversed by BMSC-Mito. BMSC-Mito also preserved vascularity (CD31 and α-SMA) impaired by RCT. Additionally, BMSC-Mito notably improved disuse-induced mitochondrial changes, leading to increased mitochondrial number and COX IV expression; furthermore, BMSC-Mito protected mitochondria morphology and enhanced cytosolic superoxide dismutase activity. This treatment also improved mitochondria respiratory chain complex activity and ATP concentration, reducing oxidative stress. In vitro, BMSC-Mito treatment effectively maintained the mitochondrial membrane potential of skeletal muscle cells, improved cell viability, and restored its mitochondrial function and ATP levels.

These findings suggest that BMSC-Mito might play a role in preventing muscle atrophy and fatty infiltration after RCT through the protection of mitochondrial function and the promotion of angiogenesis.

BMSC-Mito present a promising therapeutic approach for addressing rotator cuff muscle degeneration.

To compare the radiographic results of bridging rotator cuff reconstruction (BRR) with dermal allograft and maximal repair for large or massive, irreparable rotator cuff tears.

This was a secondary analysis of data from a single-center, blinded-observer, randomized controlled trial that examined clinical outcomes of BRR compared with maximal repair. A sample size of 30 patients with magnetic resonance imaging (MRI)-proven large or massive (>3 cm), retracted rotator cuff tears and/or involvement of 2 or more tendons were randomly allocated to 1 of 2 groups: maximal repair or BRR using dermal allograft. MRIs were obtained preoperatively and 1 year postoperatively. The primary outcome of this study was the retear rate on MRI. Secondary outcomes included progression of muscle atrophy and fatty infiltration.

There was no difference in age or preoperative tear size between the 2 groups. Patients treated with BRR had decreased retear rate (21%) compared with patients who received maximal repair alone (87%). There was no difference in the number of patients who had progression of muscle atrophy (P = .088 for supraspinatus and P = .738 for infraspinatus) or fatty infiltration (P = .879 for supraspinatus and P = .693 for infraspinatus) between the 2 groups. A significant increase in mean postoperative supraspinatus muscle atrophy was identified in the maximal repair group (P = .034).

The results of this secondary analysis of a randomized controlled trial comparing radiographic results of maximal repair versus BRR using dermal allograft in the treatment of large or massive rotator cuff tears show that BRR results in a significantly reduced structural failure rate and a trend toward better preservation of supraspinatus muscle mass compared with maximal repair.

Level I, secondary analysis of a randomized controlled trial.

Surgical reattachment of tendon to bone is the standard therapy for rotator cuff tear (RCT), but its effectiveness is compromised by retear rates of up to 94%, primarily due to challenges in achieving successful tendon-bone enthesis regeneration under natural conditions. Biological augmentation using biomaterials has emerged as a promising approach to address this challenge. In this study, a bilayer construct incorporates polydopamine (PDA)-mediated bone morphogenetic protein 2 (BMP2) and BMP12 in separate poly(lactic-co-glycolic acid) (PLGA) fiber layers to promote osteoblast and tenocyte growth, respectively, and intermediate fibrocartilage formation, aiming to enhance the regenerative potential of tendon-bone interfaces. The lower layer, consisting of PLGA fibers with BMP2 immobilization through PDA adsorption, significantly accelerated osteoblast growth. Concurrently, the upper BMP12@PLGA-PDA fiber mat facilitated fibrocartilage formation and tendon tissue regeneration, evidenced by significantly elevated tenocyte viability and tenogenic differentiation markers. Therapeutic efficacy assessed through in vivo RCT models demonstrated that the dual-BMP construct augmentation significantly promoted the healing of tendon-bone interfaces, confirmed by biomechanical testing, cartilage immunohistochemistry analysis, and collagen I/II immunohistochemistry analysis. Overall, this combinational strategy, which combines augmentation patches with the controlled release of dual growth factors, shows great promise in improving the overall success rates of rotator cuff repairs.

Interest in biological augmentation for improving bone-tendon interface (BTI) healing after arthroscopic rotator cuff repair (ARCR) is growing. Dermal fibroblasts, known for collagen synthesis similar to tenocytes, have shown effectiveness in BTI healing in chronic rotator cuff tear (RCT) models in rabbits. However, no human clinical trials have been conducted.

To evaluate the clinical efficacy of autologous dermal fibroblasts (ADFs) for BTI healing after ARCR in patients with full-thickness RCTs >2 cm.

Randomized controlled trial; Level of evidence, 2.

A total of 86 patients were prospectively enrolled and randomized into 2 groups: an additional ADF injection between the bone and tendon during ARCR (ADF group) or ARCR alone (control group). A skin biopsy from the buttock was performed to obtain ADFs, which were cultured for approximately 4 weeks before surgery. ARCR was standardized to the double-row suture bridge technique to reduce the heterogeneity in different repair methods. The primary variable for evaluating ADF efficacy was the retear rate using magnetic resonance imaging at 6 months postoperatively. Secondary variables included range of motion, the American Shoulder and Elbow Surgeons score, the Constant score, and the Simple Shoulder Test score at baseline and at 6 and 12 months postoperatively.

Overall, 13 patients dropped out because of a subscapularis tendon tear, loss to follow-up, or the withdrawal of consent (7 in the ADF group and 6 in the control group). The retear rate was significantly lower in the ADF group (5.6% [2/36]) than in the control group (24.3% [9/37]) (P = .025). The American Shoulder and Elbow Surgeons, Constant, and Simple Shoulder Test scores showed significant improvement after surgery in both groups (all P values <.001). Functional scores and range of motion did not significantly differ between the 2 groups at 6 and 12 months (all P values >.05).

ADF application into the BTI during ARCR significantly decreased the retear rate in patients with full-thickness RCTs >2 cm. Therefore, an ADF injection could be a promising biological supplement to enhance BTI healing in these patients. However, clinical outcomes showed no significant difference between the 2 groups at 6 months and 1 year postoperatively.

The efficacy of bone marrow aspirate concentrate (BMAC) in promoting bone-tendon interface (BTI) healing without any carriers remains a subject of debate.

To evaluate BMAC effects with different carriers on tendon regeneration in a rabbit model of chronic rotator cuff tear.

Controlled laboratory study.

In vitro, the amount of growth factor and the differentiation potential of BMAC with different carriers (polydeoxyribonucleotide [PDRN] and atelocollagen [ATC]) were assessed. In vivo, 64 rabbits were randomly allocated into 4 groups. Different materials were injected into the repair site according to the allocated group: control, saline; BMAC, BMAC and saline; BMAC-PDRN, BMAC with PDRN; BMAC-ATC, BMAC with ATC (n = 16 in each). Genetic and histologic analyses were conducted at 4 and 12 weeks after repair, while biomechanical evaluations were performed at 12 weeks after repair.

In vitro, the degree of multilineage differentiation was much stronger using BMAC with ATC as compared with administration of BMAC alone or BMAC with PDRN (P < .001). In vivo, the BMAC-ATC group had the highest levels of aggrecan expression, bone morphogenetic protein 2, and collagen type I alpha 1 among all groups (all P < .001) at 4 weeks after repair. Furthermore, the BMAC-ATC group showed collagen fiber continuity, denser collagen fibers, and more mature BTI as compared with the other groups (all P < .001) at 12 weeks after repair. Concurrently, the BMAC-ATC group also demonstrated significantly higher load-to-failure versus the remaining groups (all P < .001) at 12 weeks after repair.

Local application of BMAC without appropriate carriers could not enhance BTI healing. However, BMAC with 2 different carriers effectively accelerated BTI healing, particularly in the ATC environment. Therefore, the combination of BMAC and ATC may act as a powerful biological agent to promote healing after rotator cuff repair in a chronic rotator cuff tear model using rabbits.

Local application of BMAC without appropriate carriers could not enhance BTI healing. However, the combination of BMAC and ATC may synergistically promote rotator cuff tendon healing.

Muscle degeneration is a common issue caused by rotator cuff tear (RCT) which significantly affects prognosis. Muscle stem cells (MuSCs) play a crucial role to prevent muscle degeneration after RCT. However, the pathological changes and detailed molecular mechanism underlying the myogenesis of MuSCs after RCT remain incomplete. The current study established single-cell landscape of supraspinatus muscles and found decreased expression of PIEZO1 and impaired myogenic potential of MuSCs from RCT patients. Reduced expression of PIEZO1 impaired the myogenesis of MuSCs by inhibiting the ERK/MAPK pathways. Furthermore, selective PIEZO1 agonist Yoda1 had the potential to alleviate muscle degeneration and improve shoulder function following RCT. This study emphasized the role of PIEZO1 in the myogenesis of MuSCs and suggested that activating PIEZO1 could be a potential non-surgical treatment option to reduce muscle degeneration after RCT.

The biological factors that affect healing after rotator cuff repair (RCR) are not well understood. Genetic variants in the extracellular matrix protein Tenascin C (TNC) are associated with impaired tendon healing and it is expressed in rotator cuff tendon tissue after injury, suggesting it may have a role in the repair process. The purpose of the current study was to determine the role of TNC on tendon healing after RCR in a murine model. The supraspinatus tendon was transected and repaired on the left shoulder of wild-type (WT-RCR), Tenascin C null (Tnc--RCR) and Tnc heterozygous (Tnc+/--RCR) mice. Controls included the unoperated, contralateral shoulder of WT-RCR, Tnc-RCR, Tnc+/--RCR mice and unoperated shoulders from age and genotype matched controls. We performed histologic, activity testing, bulk RNA-seq, and biomechanical analyses. At 8-weeks post-RCR, Tnc- and Tnc+/- mice had severe bone and tendon defects following RCR. Tnc--RCR mice had reduced activity after RCR including reduced wheel rotations, wheel duration, and wheel episode average velocity compared with WT-RCR. Loss of Tnc following RCR altered gene expression in the shoulder, including upregulation of sex hormone and WNT pathways and a downregulation of inflammation and cell cycle pathways. Tnc- mice had similar biomechanical properties after repair as WT. Further research is required to evaluate tissue specific alterations of Tnc, the interactions of Tnc and sex hormone and inflammation pathways as well as possible adjuvants to improve enthesis healing in the setting of reduced TNC function.

Information about outcomes after revision rotator cuff repair (RCR) is limited. A more thorough investigation of pain, range of motion (ROM), strength, and functional outcomes is needed. Comparing outcomes between primary and revision rotator cuff repair patients can help surgeons guide patient expectations of the revision procedure. The aim of this study was to compare the outcomes of a revision repair group to a control group of primary RCR patients. We expect revision RCR patients to have worse clinical outcomes than primary RCR patients.

A retrospective review of patients who underwent primary or revision RCR between 2012 and 2020 was performed. The case group included 104 revision patients, and the control group included 414 primary RCR patients. Patient visual analog score for pain, ROM, strength, Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES), and Constant-Murley scores were collected at baseline, 12 months, 24 months, and final follow-up.

The average final follow-up was 43.9 months for primary patients and 63.8 months for revision patients. Three hundred fifty-two primary patients and 55 revision patients had a final follow-up of 2 or more years. By the final follow-up, primary patients had less pain than revision patients (Δ of 2.11, P < .0001), but both groups improved overall. Primary patients had significant improvements in forward flexion, external rotation, internal rotation, and abduction at 2 years that were lost by final follow-up, but revision patients did not experience any long-term improvement in ROM. These differences in ROM between groups were not significant. Supraspinatus strength in the revision group did not improve nor decline by final follow-up. By final follow-up, both primary and revision patients had improved SST and ASES scores from baseline. Primary patient ASES scores were 17.9 points higher (P < .0001) than revision patients by final follow-up, and there was no difference between groups in SST scores at this time.

Revision RCR significantly improves patient pain, SST score, and ASES score at 4 years. Revision patients should not expect to see the improvements in ROM that may occur after primary repair.

The challenge of achieving effective tendon-to-bone healing remains a significant concern in sports medicine, necessitating further exploration. Biomimetic electrospun nanomaterials present promising avenues for improving this critical healing process.

To investigate the biological efficacy of a novel aligned-to-random PLGA/Col1-PLGA/nHA bilayer electrospun nanofiber membrane in facilitating tendon-to-bone healing.

Controlled laboratory study.

The bilayer membrane's composition, combining PLGA/Col1 for tendon attachment and PLGA/nHA for bone integration, was examined using scanning electron microscopy, Fourier transform infrared spectroscopy, and mechanical testing. Positioned between the Achilles tendon and bone, its design aimed for harmonious integration with both types of tissue. In vitro, biocompatibility, cell adhesion, and proliferation of the biomaterial were evaluated using live/dead staining and the CCK-8 assay. Collagen secretion and mineralization were measured for 2 cell types. In vivo, tendon-to-bone insertion samples harvested from mice were analyzed: micro-computed tomography assessed bone formation; histological staining evaluated chondrogenesis, tendinogenesis, and the 4-layer structure of the insertion; and biomechanical testing measured insertion strength. Real-time polymerase chain reaction identified genes involved in tendon-to-bone healing, and transcriptome analysis elucidated the underlying cellular and molecular mechanisms.

The optimal composition was determined as 10% 3:1 for aligned PLGA/Col1 and 9% 5:1 for PLGA/nHA. Coculture showed minimal cell death, firm cell adherence, and steady proliferation, with PLGA/Col1 enhancing collagen secretion. In vivo, the material promoted bone and cartilage formation and improved tendon-to-bone interface strength. Transcriptome analysis indicated links to TNF and NF-κB pathways and to genes IL-1β, ADAM8, and EGR2.

The novel aligned-to-random PLGA/Col1-PLGA/nHA bilayer nanofiber membrane outperformed other materials in both in vitro and in vivo evaluations, significantly enhancing tendon-to-bone healing. It notably improved cartilage and bone formation, tendon maturation, and biomechanical strength at the surgical interface. These effects may be associated with the TNF and NF-κB pathways and with the genes IL-1β, ADAM8, and EGR2.

This study introduces a biomimetic nanofiber membrane enhancing tendon-to-bone healing, which is crucial for sports medicine. Its efficacy in improving healing outcomes, including bone and cartilage formation and biomechanical strength, could significantly lower failure rates in surgical procedures such as rotator cuff repair and anterior cruciate ligament reconstruction. This advancement offers promising implications for patient recovery and the effectiveness of surgical interventions in tendon-to-bone injuries.

Preoperative assessment of fatty degeneration is important for managing rotator cuff tears. The Goutallier classification is semiquantitative and observer dependent. Discrepancies among surgeons can be prominent. A quantitative method may improve accuracy and reliability in evaluating the exact percentage of fatty infiltration (Fat%).

This study aimed to investigate the correlation between the new quantitative method and the Goutallier classification in assessing fatty infiltration (FI) of the supraspinatus muscle and to explore the use of this method in predicting retear after rotator cuff repair. It was hypothesized that the new method would significantly correlate with the Goutallier classification and be more sensitive to retear.

Cohort study (diagnosis); Level of evidence; 3.

This study included 105 patients who underwent arthroscopic rotator cuff repair for large to massive tears. All patients underwent routine preoperative and 1-year postoperative magnetic resonance imaging and were divided into 2 groups according to tendon healing. Preoperative quantitative Fat% of the supraspinatus muscle was evaluated based on the signal intensity (SI) of the T1-weighted sequence. The Fat% was calculated using the following equation: SIsupraspinatus = SIfat× Fat% + SImuscle× (1 - Fat%). The correlation between the Fat% and the Goutallier grade was determined. Univariate and multivariate analyses were performed to identify the independent risk factors for retear.

The mean preoperative Fat% of the supraspinatus muscle was 23.77 ± 15.96. A significant correlation was found between the Fat% and the Goutallier grade of the supraspinatus muscle (R = 0.655; P < .001). The overall retear rate was 21.9%; however, functional status significantly improved regardless of cuff healing. Multivariate analysis identified the Fat% (P = .005) and the modified Patte classification (P = .003) as independent risk factors of retear. The receiver operating characteristic curves showed that the cutoff value of Fat% for predicting retear was 33.2%. Fat% >33.2% possessed superior diagnostic accuracy (79.0%), Youden index (0.513), and positive and negative predictive values (51.6% and 90.5%, respectively) compared with the Goutallier grades.

Although the quantitative method for assessing Fat% of the supraspinatus muscle significantly correlated with the Goutallier classification, the quantitative method is more clinically relevant to retear. Fat% of the supraspinatus muscle >33.2% possessed higher diagnostic value than the Goutallier grades in predicting retear.

Infusion catheters facilitate a controlled infusion of local anesthetic (LA) for pain control after surgery. However, their potential effects on healing fibroblasts are unspecified.

Rat synovial fibroblasts were cultured in 12-well plates. Dilutions were prepared in a solution containing reduced-serum media and 0.9% sodium chloride in 1:1 concentration. Each well was treated with 500 μl of the appropriate LA dilution or normal saline for 15- or 30-min. LA dilutions included: 0.5% ropivacaine HCl, 0.2% ropivacaine HCl, 1% lidocaine HCl and epinephrine 1:100,000, 1% lidocaine HCl, 0.5% bupivacaine HCl and epinephrine 1:200,000, and 0.5% bupivacaine HCl. This was replicated three times. Dilution of each LA whereby 50% of the cells were unviable (Lethal dose 50 [LD50]) was analyzed.

LD50 was reached for lidocaine and bupivacaine, but not ropivacaine. Lidocaine 1% with epinephrine is toxic at 30-min at 1/4 and 1/2 sample dilutions. Bupivacaine 0.5% was found to be toxic at 30-min at 1/2 sample dilution. Bupivacaine 0.5% with epinephrine was found to be toxic at 15- and 30-min at 1/4 sample dilution. Lidocaine 1% was found to be toxic at 15- and 30-min at 1/2 sample dilution. Ropivacaine 0.2% and 0.5% remained below LD50 at all time-points and concentrations, with 0.2% demonstrating the least cell death.

Though pain pumps are generally efficacious, LAs may inhibit fibroblasts, including perineural fibroblast and endoneurial fibroblast-like cells, which may contribute to persistent nerve deficits, delayed neurogenic pain, and negatively impact healing. Should a continuous infusion be used, our data supports ropivacaine 0.2%.

Basic Science Study; Animal model.

The purpose of this study was to evaluate the safety and efficacy of a bioinductive patch augmentation following arthroscopic rotator cuff repair (RCR) in terms of patient-reported outcomes, motion, and complications stratified by tear size.

A retrospective review of patients undergoing primary RCR with and without bioinductive bovine collagen patch augmentation for supraspinatus/infraspinatus tears from 2014 to 2022 at two centers was performed. Exclusion criteria included: age <18 years, revisions, or lack of 6-month postoperative follow-up. Patients were propensity-score matched 2:1 to patch-augmented patients based on age, sex, BMI, and tear size. Outcomes were compared between the patch and control groups after being stratified by tear size.

A total of 125 patients patch augmented RCRs were matched to 250 controls. No significant differences in demographics or comorbidities between groups. Following stratification by tear size, VAS for partial and small/medium tears in the patch cohorts were lower (p = 0.02) at 3 months. Functional scores were not statistically different. Patch-augmented partial and small/medium tears showed increased forward elevation (p < 0.05) at 1-year follow-up. Retear rates were statistically similar.

Bioinductive patch augmentation demonstrates equivalent outcomes for pain and function, retear rate, but is associated with improved forward elevation up to 1-year for partial and small/medium tears.

Level III, retrospective cohort study.

Failure of healing or retear after surgical repair of the rotator cuff tendons are still a problem and can cause ongoing shoulder pain and dysfunction. Compromised microcirculation as seen in regular alcohol consumption may lead to poor healing.

To compare the clinical outcomes and tendon integrity of patients after rotator cuff repair with and without regular alcohol intake.

Case control matched cohort study; Level of evidence, 3.

Patients who underwent arthroscopic rotator cuff repair (ARCR), had regular alcohol intake (according to world health organization (WHO) definition of harmful alcohol consumption) and were at least 2 years postoperative were included, and matched according to age, sex, involved tendon, and tear size with patients who underwent ARCR without regular alcohol intake. Patient-reported outcome (PRO) scores were collected at final follow-up including the Constant Murley Score (CMS), Western Ontario Rotator Cuff Score (WORC), Simple Shoulder Test (SST), and visual analog scale (VAS). Tendon integrity (maintained continuity: yes/no = full thickness) was assessed by ultrasound examination at final follow-up. Complications and revision surgeries are reported.

Twenty-two patients (versus twenty-two matched-controls) were available for follow-up. There were two female (9%) and twenty male (91%) patients with a mean age of 66.6 years (standard deviation, 36-85 years). The mean follow-up was 4 years (standard deviation, 2-5 years) in the alcohol group and 5 years (standard deviation, 2-10 years) in the non-alcohol group. No differences in mean PRO scores between alcohol and non-alcohol groups were seen except VAS (0.5 (standard deviation, 0-5) vs. 1.6 (standard deviation, 0-8), (P = 0.049*) respectively). Intact tendon insertion was seen in 77% (17/22) for the alcohol group and 100% (22/22) for non-alcohol group, (P = 0.021*). One patient underwent revision surgery (5%) in the alcohol group due to a retear, no further peri- or postoperative complications were noticed.

Patients with torn rotator cuff tendons benefited similarly from ARCR independently of their alcohol use concerning clinical presentation. However, significantly higher retear rates were recorded in the alcohol group.

To investigate the efficacy of exosomes derived from dermal fibroblasts (DF-Ex) on bone-to-tendon interface (BTI) healing in a chronic rotator cuff tear (RCT) model of rabbit.

After extraction of DF-Ex, the characterization of DF-Ex was identified in the in vitro study. In the in vivo experiment, 48 rabbits were randomly allocated into 3 groups. To create chronic RCT models, transected tendons were left untreated for 6 weeks and then were repaired in a transosseous manner. Different materials were injected into repair site according to the allocated group (group A: saline, group B: fibrin glue only, group C: DF-Ex with fibrin glue; n = 16 for each). Genetic and immunofluorescence analyses were conducted at 4 weeks post-surgery. Furthermore, genetic, histologic, and biomechanical analyses were conducted at 12 weeks post-surgery.

In vitro analyses revealed the exosomal marker proteins CD9, CD63, and ALIX were positively expressed in DF-Ex, whereas negative control Calnexin was nearly absent. In vivo analyses showed that group C had the highest mRNA expression levels of COL1A1, COL3A1, and ACAN among all groups (P < .001, P = .007, and P = .002, respectively) at 4 weeks postsurgery. Meanwhile, there were more preliminary fibrocartilaginous matrix (aggrecan+/collagen II+) formation in group C. At 12 weeks postsurgery, group C had better collagen fiber continuity and orientation, denser collagen fibers, more mature bone-to-tendon junction, and greater fibrocartilage layer formation compared with the other groups (all P < .05). Moreover, group C also had greater load-to-failure value (53.3 ± 6.1 N/kg, P < .001).

Topical DF-Ex administration effectively promoted BTI healing by upregulating the COL1A1, COL3A1, and ACAN mRNA expression levels at an early stage and enhancing the structural and biomechanical properties at 12 weeks after surgical repair of a chronic RCT model of rabbit.

The study could be a transitional study to investigate the efficacy of DF-Ex on BTI healing for surgical repair of chronic RCTs as a powerful biological agent in humans.

This study aimed to investigate changes in gene expression related to matrix synthesis in individuals with full-thickness rotator cuff tears (RCTs) and normal tendon tissues. The study also aimed to examine the differences in gene expression according to 4 distinct tear sizes.

A total of 12 patients with full-thickness RCTs were included in the study, all of whom underwent arthroscopic rotator cuff repair. The RCTs were stratified by size into small, medium, large, and massive. Tendon samples were harvested from the midpoint between the lateral end of the torn tendon and the musculotendinous junction. Subsequent analysis of the tissue samples revealed the mRNA expression levels of 11 collagen types, 6 proteoglycans, and 8 glycoproteins through real-time polymerase chain reaction techniques. For control purposes, supraspinatus tendon tissue was sourced from 3 patients who had proximal humerus fractures but did not present with RCTs.

Among the 11 collagens and 14 non-collagenous protein (NCP) genes examined in this study, COL3A1 and COL10A1 showed a significant increase, whereas COL4A1 and COL14A1 showed a tendency to decrease compared to those in the normal group. ACAN significantly increased by 8.92-fold (p < 0.001) compared to that in the normal group, whereas DCN and LUM showed a tendency to decrease. FN1 and TNC increased significantly by 3.47-fold (p = 0.003) and 5.38-fold (p = 0.005), respectively, and the genes ELN, LAMA2, and THBS1 were all significantly reduced compared to those in the normal group. In the NCPs, almost all the genes with increased expression levels had the highest level in small size RCTs, and gene expression decreased as the size increased. The 3 proteoglycans (ACAN, BGN, and FMOD) showed the highest levels of expression in small size RCTs compared to those in the normal group, and 5 glycoproteins (COMP, FBN1, FN1, HAPLN1, and TNC) also showed the highest expression in small size RCTs.

We confirmed that most of the detected extracellular matrix gene expression changes were related to the size of the full-thickness RCTs. In NCPs, gene expression was increased in small-size tears, and gene expression levels were significantly reduced when the size increased.

This review offers a comprehensive discussion of magnetic resonance imaging (MRI) for the assessment of rotator cuff tendon repair and joint-preserving surgical options for patients with irreparable rotator cuff tears. Deciding to proceed with arthroscopic repair of a rotator cuff tendon tear is impacted both by clinical factors and morphological imaging features. Preoperative clinical and imaging features also predict the likelihood of success of a rotator cuff tendon repair and are important to recognize. In patients with irreparable rotator cuff tears and relatively preserved glenohumeral cartilage, various joint-preserving surgical options are available and seen increasingly in clinical practice.The acceptable range of postoperative imaging findings correlating with a functionally intact rotator cuff repaired tendon, and MRI findings that are either suggestive of or definitive for rotator cuff tendon repair failure are discussed in detail, with attention to the Sugaya classification. Ancillary features, such as progressive retraction of the myotendinous junction and the degree of muscle fatty atrophy, can be used as problem-solving tools in cases equivocal for rotator cuff retear. Finally, this review discusses in detail the most common joint-preserving treatment options for patients with irreparable rotator cuff tears, including an in-depth focus on superior capsular reconstruction.

We describe an arthroscopic technique for irreparable rotator cuff tears using patch bridging reconstruction with fascia lata autograft. Compared with conventional rotator cuff repair, this technique reconstitutes the rotator cuff as a dynamic structure, preserves the rotator cuff remnant, reduces excessive tension of the rotator cuff, and preserves the shoulder joint. The fascia lata patch itself is low cost and avoids risks of transmission of blood-borne infectious diseases and rejection. Although the bridging reconstruction is a complex operation with a long learning curve, we believe patch bridging using fascia lata is a highly effective and reproducible surgical protocol for appropriate irreparable rotator cuff tear patients.

Arthroscopic repair with the biceps rerouting (BR) technique has been determined to lead to promising clinical and biomechanical outcomes for treating large-to-massive rotator cuff tears (LMRCTs). However, the in vivo effects of BR on glenohumeral kinematics during functional shoulder movements have not been fully elucidated.

To investigate whether BR provides a better restoration of shoulder kinematics compared with conventional rotator cuff repair (RCR).

Controlled laboratory study.

Patients who underwent either repair with the BR technique (BR group) or RCR alone (RCR group) for treating LMRCTs between January 2021 and May 2022 were enrolled. They underwent a 1-year postoperative kinematic evaluation of bilateral shoulders by performing scapular-plane abduction with a dual fluoroscopic imaging system. Glenohumeral translation in the superior-inferior (S-I) and anterior-posterior (A-P) directions was assessed in shoulder abduction at 10° increments. Moreover, the mean, maximum, minimum, and range of glenohumeral translation were calculated throughout the entire movement.

A total of 9 patients were enrolled in each group for final analysis, and baseline characteristics were comparable between the groups. In the RCR group, compared with contralateral shoulders, the operative shoulders showed increased superior humeral head translation during lower abduction angles of 30° to 50° (all P≤ .004), with a greater maximum (P = .014) and a larger range (P = .002) for S-I translation throughout the entire movement. In the BR group, no significant differences between operative and contralateral shoulders were detected in any kinematic variables for S-I translation (all P≥ .132); however, the operative shoulders exhibited a larger maximum (P = .031), a smaller minimum (P = .008), and a larger range (P < .001) for A-P translation throughout the entire movement compared with the contralateral shoulders.

BR successfully reduced residual superior humeral head translation compared with conventional RCR and restored normal S-I glenohumeral kinematics in the treatment of LMRCTs. However, A-P glenohumeral kinematics was not fully restored after BR, and its effect on long-term clinical outcomes requires further investigation.

BR can be a promising technique to treat LMRCTs. However, its potential adverse effects on A-P glenohumeral kinematics should not be ignored, requiring further clinical evidence to determine long-term outcomes.

The natural history of rotator cuff tears often involves progressive pain development, tear enlargement, and advancing muscle fatty degeneration. Both surgery and conservative management have proven to be effective treatments. Our study purpose was to compare the short- to mid-term effects of rotator cuff repair on shoulder function, progression of tear size, and muscle degeneration compared to controls with asymptomatic tears that developed pain and were managed nonoperatively.

This comparative study consists of 2 separate longitudinal study arms. The control group consisted of asymptomatic degenerative cuff tears followed until pain development and then managed nonoperatively with continued surveillance. The surgical group consisted of subjects with degenerative tears that failed nonoperative treatment and underwent surgical intervention with a minimum of 2 years follow-up. Outcomes included visual analog scale pain, American Shoulder and Elbow Surgeons, active range of motion, strength, and ultrasonography.

There were 83 controls and 65 surgical shoulders. The surgical group was younger at enrollment (58.9 ± 5.3 yr vs. 61.2 ± 7.8 yr, P = .04). The median follow-up for control subjects after pain development was 5.1 years (interquartile range [IQR] 3.6) and the median postoperative follow-up for the surgical group was 3.0 years (IQR 0.2). Baseline tear widths (median 14 mm, IQR 9 vs. 13 mm, IQR 8; P = .45) and tear lengths (median 14 mm, IQR 13 vs. median 11 mm, IQR 8; P = .06) were similar between the surgical group and controls. There were no differences in the baseline prevalence of fatty degeneration of the supraspinatus or infraspinatus muscles between groups (P = .43 and P = .58, respectively). At final follow-up, the surgical group demonstrated significantly lower visual analog scale pain (0 [IQR 2] vs. 3.5 [IQR 4], P = .0002), higher composite American Shoulder and Elbow Surgeons (95 [IQR 13] vs. 65.8 [IQR 32], P = .0002), and activities of daily living scores (29 [IQR 4] vs. 22 [IQR 8], P = .0002), greater abduction strength (69.6 N [standard deviation {SD} 29] vs. 35.9 N [SD 29], P = .0002), greater active forward elevation (155° [SD 8] vs. 142° [SD 28], P = .002), greater active external rotation in abduction (mean 98.5°, SD 12 vs. mean 78.2°, SD 20; P = .0002) compared to controls. Additionally, the prevalence of fatty muscle degeneration was lower in the surgical group for the supraspinatus and infraspinatus (25% vs. 41%, P = .05; 17% vs. 34%, P = .03; respectively).

This prospective longitudinal study comparing a surgical cohort undergoing rotator cuff repair with a control group treated nonoperatively supports the notion that surgical intervention has the potential to alter the early natural history of degenerative rotator cuff disease. Patients in the surgical group demonstrated clinically relevant differences in pain and functional outcomes. Surgical intervention was protective against progressive muscle degeneration compared to nonoperative treatment.

To compare side-to-side superior capsular reconstruction (SCR) with over-the-top SCR in terms of functional outcomes, pain relief and allograft survival rates.

Patients who had undergone arthroscopic dermal allograft SCR for massive irreparable rotator cuff tears and clinical follow-up for ≥2 years were recruited. All patients underwent postoperative assessment with routine radiographic analysis for acromiohumeral distances, ultrasound imaging 1 and 3 months after SCR and magnetic resonance imaging (MRI) at least 12 months after SCR. The outcome measures were visual analogue scale (VAS), American Shoulder and Elbow Surgeons (ASES), Constant and Single Assessment Numeric Evaluation (SANE) scores.

SCR was performed in 56 patients including side-to-side SCR in 32 and over-the-top SCR in 24. Postoperative MRI showed that the grafts were intact in 46 patients (82.1%; 26 who underwent side-to-side SCR and 20 who underwent over-the-top SCR). The proportion of nonhealing grafts in the over-the-top group was significantly higher with concomitant subscapularis tears (60% vs. 5.3%; p = 0.02). VAS scores and functional outcomes improved postoperatively in both groups and postoperative VAS (1.4 vs. 1.7; n.s.), Constant (74.8 vs. 76.0; n.s.), mean ASES (87.4 vs. 89.1; n.s.) and mean SANE (81.7 vs. 84.3; n.s.) scores did not differ significantly.

For massive rotator cuff tears, over-the-top and side-to-side SCR achieve similar pain relief and functional improvement, and the rate of healing allografts is high. However, over-the-top SCR is not recommended for massive posterosuperior rotator cuff tears with repairable subscapularis tendon tears due to a higher nonhealing rate.

Level III.

A high prevalence of rotator cuff tears presents a major clinical challenge. A better understanding of the molecular mechanisms underlying enthesis development and healing is needed for developing treatments. We recently identified hedgehog (Hh)-lineage cells critical for enthesis development and repair. This study revealed cell-cell communication within the Hh-lineage cell population. To further characterize the role of Hh signaling, we used mouse models to activate and inactivate the Hh pathway in enthesis progenitors. Activation of Hh target genes during enthesis development increased its mineralization and mechanical properties. Activation of Hh signaling at the injured mature enthesis promoted fibrocartilage formation, enhanced mineralization, and increased expression of chondrogenic and osteogenic markers, which implies that Hh signaling drives cell differentiation to regenerate the damaged enthesis. Conversely, deletion of Hh target genes impaired enthesis healing. In summary, this study revealed a new strategy for enthesis repair via activation of Hh signaling in endogenous cells.

Treatment of Massive rotator cuff tears (MRCT) is difficult, with high rates of retears. Using biological augmentation in the form of the highly vascular subacromial bursa, was used to improve tendon healing. This work aimed to evaluate the results of arthroscopic guided mini-open transosseous repair with bursal augmentation in the treatment of MRCTs in a five-step approach. Forty-eight patients, with a mean age of 63.15 years, were treated with this technique. The patients were evaluated with the constant, UCLA and VAS scores. Plain X-rays were performed to evaluate the CSA and MRI was done to confirm the diagnosis of MRCT and determine the degree of fatty degeneration. Ultrasound was done at 1 year post-operative to determine any retears. The mean follow-up period was 29 months ± 4.95. The Constant and UCLA mean scores improved from (52.52) to (89) and (13.2) to (30.5) respectively (p < 0.0001). The post-operative active flexion and abduction improved from a mean of (112° to 170°) and (136.2° to 167°) respectively, while ER improved from (62.8° to 70°) with their p values (p < 0.0001). Pain improved from a mean VAS of (5.85) to (0.5) (p < 0.0001). No deterioration of function was noted throughout the follow-up period, and no retears occurred on post-operative ultrasound evaluation. Mini-open transosseous repair with bursal augmentation in the treatment of MRCT is an effective and low-cost method that achieves satisfactory results with no retears.

Rotator cuff injury (RCI), characterized by shoulder pain and restricted mobility, represents a subset of tendon-bone insertion injuries (TBI). In the majority of cases, surgical reconstruction of the affected tendons or ligaments is required to address the damage. However, numerous clinical failures have underscored the suboptimal outcomes associated with such procedures. Further investigations have revealed that these failures are largely attributable to delayed healing at the tendon-bone interface, excessive formation of vascularized scar tissue, and inadequate integration of tendon grafts within bone tunnels. As a result, the healing process of rotator cuff injuries faces significant challenges.Bone marrow-derived mesenchymal stem cell exosomes (BMSC-exos) have emerged as a prominent focus of research within the field of bioengineering, owing to their remarkable potential to regulate cellular proliferation and differentiation, modulate immune responses, and facilitate tissue repair and regeneration following cellular damage. In this review, we explore the anti-inflammatory, angiogenic, anti-scarring, and bone metabolism-modulating effects of BMSC-exos in the context of rotator cuff injury. Additionally, we address the limitations and ongoing challenges within current research, offering insights that could guide the clinical application of BMSC-exos in the treatment of rotator cuff injuries in the future.

Rotator cuff tears are common among physically active individuals and often require surgical intervention owing to their limited self-healing capacity. This study proposes a new bioprinting approach using bone- and tendon tissue-specific bioinks derived from decellularized extracellular matrix, supplemented with hydroxyapatite and TGF-β/poly(vinyl alcohol) to fabricate engineered tendon-to-bone complex tissue. To achieve this goal, a core-shell nozzle system attached to a bioprinter enables the effective and simultaneous fabrication of aligned tendon tissue, a gradient tendon-bone interface (TBI), and a mechanically improved bone region, mimicking the native tendon-to-bone structure. In vitro evaluation demonstrated the well-directed differentiation of human adipose stem cells towards osteogenic and tenogenic lineages in the bone and tendon constructs. In the graded TBI structure, further facilitated fibrocartilage formation and enhanced the integration of tendon-to-bone tissues compared to non-graded structures in vitro. Furthermore, using a rabbit rotator cuff tear model, implantation of the biologically graded constructs significantly promoted the rapid regeneration of full-thickness tendon-to-bone tissue, including the formation of a high-quality TBI in vivo. This bioprinting approach not only improved mechanical properties and tissue integration but also enhanced angiogenesis and extracellular matrix (ECM) formation, demonstrating its potential as a promising platform for the regeneration of tendon-to-bone complex tissues.

Rotator cuff repair surgeries often face high failure rates, particularly in cases involving tendon degeneration. Traditional repair techniques and devices frequently fail to adequately restore a healthy native enthesis and strong tendon-bone integration. This study investigates the efficacy of a novel, fully synthetic, bioresorbable nanofiber scaffold in restoring the native enthesis and enhancing the biomechanical properties and overall success of rotator cuff repairs, particularly in the context of chronically degenerated tendons.

This study used an ovine model to simulate chronic tendon degeneration with subsequent rotator cuff transection and repair. All repairs were performed using the standard double-row configuration with suture tape; half of the repairs were augmented with the bioresorbable nanofiber scaffold. Nondestructive biomechanical testing was conducted to assess the strength of the repair constructs, followed by histological analysis of all tendon samples to evaluate tissue regeneration and integration at the repair site.

Results demonstrated that the scaffold group achieved significantly improved biomechanical properties (peak force, peak stress, equilibrium force, and equilibrium stress) compared to the suture only group, indicating enhanced repair strength and native enthesis restoration. Scaffold samples exhibited significantly decreased cross-sectional areas (ie, less fibrosis) which were similar to healthy tendons. Histological findings indicated the scaffold did not impede re-establishment of Sharpey-like fibers at the tendon insertion.

This study provides compelling evidence that the use of a fully synthetic, bioresorbable nanofiber scaffold in rotator cuff repair significantly improves biomechanical outcomes and enthesis regeneration. These improvements were achieved while retaining close to native tendon thickness. The findings suggest that this scaffold represents a significant advancement in rotator cuff repair technology, offering a promising solution to enhance repair strength and quality of bone-tendon integration, especially in challenging cases of tendon degeneration.

Although a certain degree of tension in bridging sutures is required for proper tendon healing following suture-bridge rotator cuff repair, excessive suture tension may be detrimental to tendon healing. This study aimed to investigate the effects of bridging suture tension on clinical outcomes and tendon healing. We hypothesized that fixed, low tension of the bridging sutures would improve the tendon healing rate and clinical outcomes compared with maximum manual tensioning.

A group of 39 patients with a rotator cuff tear were treated with arthroscopic suture-bridge rotator cuff repair, in which the bridging sutures were uniformly tensioned to 20 N (group A). A separate group of 37 patients was treated with the same suture construct, but the sutures were tensioned by maximum manual pulling (mean tension, 36.1 N; group B). The visual analog scale (VAS) score for pain, active anterior elevation, external and internal rotation, and Constant score were compared between the groups preoperatively and at 1, 3, and 6 months and 1 and 2 years postoperatively. Anatomical healing was evaluated using magnetic resonance imaging (MRI) at 1 year after surgery.

At 6 months postoperatively, all clinical values had improved in both groups. The Constant score (p < 0.001), VAS pain score (p < 0.001), and anterior elevation (p = 0.004) were significantly better in group A than in group B. Two years postoperatively, there was no significant difference between groups A and B in the Constant score (p = 0.847), VAS pain score (p = 0.991), and anterior elevation (p = 0.855). Group A demonstrated a significantly lower retear rate (3 of 39, 7.7%) than group B (9 of 37, 24.3%) (p = 0.0467).

Double-row suture-bridge repairs with fixed, low tension led to superior clinical outcomes at 6 months and a superior tendon healing rate at 1 year compared with repairs with higher suture tension. However, the clinical outcomes did not differ significantly at 2 years between the 2 tensioning methods.

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

To use a finite element method to construct a patch-bridge repair model for massive rotator cuff tears (MRCTs) and investigate the effects of different suture methods and knot numbers on postoperative biomechanics.

A finite element model based on intact glenohumeral joint data was used for a biomechanical study. A full-thickness defect and retraction model of the supraspinatus tendon simulated MRCTs. Patch, suture, and anchor models were constructed, and the Marlow method was used to assign the material properties. Three suturing models were established: 1-knot simple, 1-knot mattress, and 2-knot mattress. The ultimate failure load, failure mode, stress distribution of each structure, and other biomechanical results of the different models were calculated and compared.

The ultimate failure load of the 1-knot mattress suture (71.3 N) was 5.6 % greater than that of the 1-knot simple suture (67.5 N), while that (81.5 N) of the 2-knot mattress was 14.3 % greater than that of the 1-knot mattress. The stress distribution on the patch and supraspinatus tendon was concentrated on suture perforation. Failure of the bridging reconstruction mainly occurred at the suture perforation of the patch, and the damage forms included cutting-through and isthmus pull-out.

A finite element model for the patch-bridging reconstruction of MRCTs was established, and patch-bridging restored the mechanical integrity of the rotator cuff. The 2-knot mattress suture was optimal for patch-bridging reconstruction of MRCTs.