Technologies to Augment Rotator Cuff Repair

Augmentation of Massive Rotator Cuff Repairs Using Biceps Transposition Without Tenotomy Improves Clinical and Patient-Reported Outcomes: The Biological Superior Capsular Reconstruction Technique

PURPOSE

To evaluate the outcomes of a consecutive series of patients after transposition of the biceps without tenotomy (biological superior capsular reconstruction [bio-SCR] technique) to augment massive rotator cuff repairs.

METHODS

Thirty massive rotator cuff tears repaired and augmented using the bio-SCR technique between June 2018 and July 2021 were identified and retrospectively reviewed. American Shoulder and Elbow Surgeons (ASES) scores, visual analog scale pain scores, supraspinatus and infraspinatus strength, and range of motion were collected preoperatively and postoperatively.

RESULTS

The average age of patients undergoing bio-SCR augmentation was 67.0 years (range, 28.4-81.9 years), and the mean clinical follow-up period was 2.9 years (range, 1.8-4.5 years). The average ASES score improved from 33.2 preoperatively to 80.8 at 6 months postoperatively, 92.0 at 1 year, and 87.0 at 2 years (P < .001). The minimal clinically important difference for the ASES score was exceeded at all postoperative intervals. Active forward flexion improved from 120.6° to 156.8° (P < .001). The pain score improved from 7.1 to 0.9 (P < .001). Postoperatively, 1 complication (3.3%) occurred: a proximal biceps rupture.

CONCLUSIONS

Incorporating a transposed biceps tendon into the repair of a massive rotator cuff tear using the bio-SCR technique resulted in significant clinical improvements with a low complication rate.

LEVEL OF EVIDENCE

Level IV, case series.

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

PURPOSE

The purpose of this study was to determine whether the addition of decellularized bovine pericardial patch loaded with mesenchymal stromal cells enhanced bone-to-tendon healing and improved the biomechanical strength of large-to-massive rotator cuff tears in a small animal model.

METHODS

Adipose-derived mesenchymal stromal cells (MSCs) from rat inguinal fat were isolated, cultured, and loaded onto decellularized bovine pericardium patches. To simulate large-to-massive tears, rats were managed with free cage activity for 6 weeks after tear creation. A total of 18 rats were randomly allocated to repair-only (control), repair with pericardial patch augmentation (patch), or repair with MSC loaded pericardial patch augmentation (patch-MSC). Each group had 6 rats (one shoulder of each rat was used for histological evaluation and another for biomechanical evaluation). MSCs seeded on the pericardial patches were traced on four shoulders from 2 other rats at 4 weeks after surgery. Histological evaluation for bone-to-tendon healing and biomechanical testing was carried out at 8 weeks after repair.

RESULTS

MSCs tagged with a green fluorescent protein were observed in the repair site 4 weeks after the repair. One shoulder each in the control and patch groups showed complete discontinuity between the bone and tendon. One shoulder in the control group showed attenuation with only a tenuous connection. Fibrocartilage and tidemark formation at the bone-to-tendon interface (P = .002) and collagen fiber density (P = .040) and orientation (P = .003) were better in the patch-MSC group than in the control or patch group. Load-to-failure in the patch-MSC and patch groups was higher than that in the control group (P = .001 and .009, respectively).

CONCLUSION

Decellularized bovine pericardial patches loaded with adipose-derived and cultured mesenchymal stromal cells enhanced healing in terms of both histology and mechanical strength at 8 weeks following rotator cuff repair in a rat model.

CLINICAL RELEVANCE

Large-to-massive rotator tears need a strategy to prevent retear and enhance healing. The addition of decellularized bovine pericardial patch loaded with MSCs can enhance bone-to-tendon healing and improve biomechanical healing of large-to-massive rotator cuff tears following repair.

Bioinductive collagen implants facilitate tendon regeneration in rotator cuff tears

Purpose

To evaluate the clinical outcomes, MRI imaging and histological characteristics of biopsy samples of the tendon from patients in whom rotator cuff repair was previously performed with a bioinductive type I bovine collagen implants.

Methods

Prospective study of 30 patients with partial or complete rotator cuff tears who underwent arthroscopic repair and augmentation with a resorbable type I bovine collagen implant. Preoperatively and at 6 and 12 months after surgery, the VAS, ASES and Constant-Murley scores were evaluated and an MRI study was performed. At 6 months, biopsies of the resulting tissue were obtained and examined histologically.

Results

Patients experienced statistically significant and sustained improvement from baseline for all scores and the mean tendon thickness increased by 1.84 mm. Magnetic resonance imaging evidence of complete healing was found in 27 patients and a considerable reduction in defect size, greater than 50%, was shown in 3. In all samples obtained, the new tissue generated had the histological appearance of a tendon, and was indistinguishable from the native tendon. There was no evidence of any remaining collagen implant.

Conclusions

Biopsies of tissue formed from bioinductive type I bovine collagen implants showed, six months after surgery, the generation of a neotendon indistinguishable from the native one. Histology and MRI imaging, revealed complete integration of the implant and absence of inflammatory or foreign body reactions. The clinical parameters, thickness and MRI signal of the tendon improved significantly at 6 months, regardless of the type and size of the tear, and remained unchanged until 12 months.

Level of evidence

Level IV, case series.

Tips and Tricks for Augmenting Rotator Cuff Repair With a Bio-inductive Collagen Implant

The contemporary literature suggests that a primary feature of recurrence of rotator cuff tear after arthroscopic repair is failure of tendon healing, which can occur for multiple reasons, including compromised tissue quality. Recently, the use of augmentation implants, grafts, or scaffolds has emerged as a strategy to address the issue of deficient rotator cuff tissue. A resorbable bio-inductive collagen implant (REGENETEN; Smith & Nephew, Andover, MA) has been shown to increase tendon thickness when applied in rotator cuff repair. This article presents an experienced surgeon's tips for implanting this device. In addition, we review the current literature about this bio-inductive implant.

Combination of graphene oxide and platelet-rich plasma improves tendon-bone healing in a rabbit model of supraspinatus tendon reconstruction

The treatment of rotator cuff tear is one of the major challenges for orthopedic surgeons. The key to treatment is the reconstruction of the tendon-bone interface (TBI). Autologous platelet-rich plasma (PRP) is used as a therapeutic agent to accelerate the healing of tendons, as it contains a variety of growth factors and is easy to prepare. Graphene oxide (GO) is known to improve the physical properties of biomaterials and promote tissue repair. In this study, PRP gels containing various concentrations of GO were prepared to promote TBI healing and supraspinatus tendon reconstruction in a rabbit model. The incorporation of GO improved the ultrastructure and mechanical properties of the PRP gels. The gels containing 0.5 mg/ml GO (0.5 GO/PRP) continuously released transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF)-AB, and the released TGF-β1 and PDGF-AB were still at high concentrations, ∼1063.451 pg/ml and ∼814.217 pg/ml, respectively, on the 14th day. In vitro assays showed that the 0.5 GO/PRP gels had good biocompatibility and promoted bone marrow mesenchymal stem cells proliferation and osteogenic and chondrogenic differentiation. After 12 weeks of implantation, the magnetic resonance imaging, micro-computed tomography and histological results indicated that the newly regenerated tendons in the 0.5 GO/PRP group had a similar structure to natural tendons. Moreover, the biomechanical results showed that the newly formed tendons in the 0.5 GO/PRP group had better biomechanical properties compared to those in the other groups, and had more stable TBI tissue. Therefore, the combination of PRP and GO has the potential to be a powerful advancement in the treatment of rotator cuff injuries.

Treatment of Partial-Thickness Rotator Cuff Tears With a Resorbable Bioinductive Bovine Collagen Implant: 1-Year Results From a Prospective Multicenter Registry

Background:

Surgical treatment of partial-thickness rotator cuff tears remains challenging and controversial, with several traditional options including debridement with acromioplasty, transtendon or in situ repair, and take-down and repair. A resorbable bioinductive bovine collagen implant has shown promise as an alternative treatment option for partial-thickness tears.

Purpose:

Data from a registry were analyzed to further establish that the implant contributes to improved patient-reported outcome (PRO) scores across a large number of patients treated for partial-thickness rotator cuff tears.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 19 centers in the United States enrolled patients >21 years old with partial-thickness tears of the rotator cuff in a comprehensive prospective multicenter registry. PRO scores were recorded preoperatively and postoperatively at 2 and 6 weeks, 3 and 6 months, and 1 year: American Shoulder and Elbow Surgeons, Single Assessment Numeric Evaluation, Veterans RAND 12-Item Health Survey (physical and mental component scores), and Western Ontario Rotator Cuff scores. Revisions were reported throughout the study.

Results:

The registry included 272 patients with partial-thickness tears (49 grade 1 tears, 101 grade 2 tears, and 122 grade 3 tears), 241 who underwent isolated bioinductive repair (IBR; collagen implant placed after bursectomy without a traditional rotator cuff repair), and 31 who had take-down and repair with bioinductive augmentation. Patients experienced statistically significant and sustained improvement from baseline for all PRO scores beginning at 3 months. Among patients with grade ≥2 tears, those with take-down and repair had significantly inferior scores at 2 and 6 weeks for most PRO scores as compared with those who underwent IBR, but the difference was no longer significant at 1 year for all but the physical component score of the Veterans RAND 12-Item Health Survey. There were 11 revisions, which occurred at a mean ± SD of 188.7 ± 88.0 days after the index surgery. There were no infections.

Conclusion:

This registry analysis further establishes across a large data set that this resorbable bioinductive bovine collagen implant improves PROs in all grades of partial-thickness tears, whether used as IBR or in conjunction with take-down and repair. IBR may offer improved early clinical outcomes (≤6 weeks) and comparable outcomes at 1 year when compared with a more invasive “take-down and repair” approach.

Current Biological Strategies to Enhance Surgical Treatment for Rotator Cuff Repair

Rotator cuff tear is one of the most common shoulder problems encountered by orthopedic surgeons. Due to the slow healing process and high retear rate, rotator cuff tear has distressed millions of people all around the world every year, especially for the elderly and active athletes. This disease significantly impairs patients' motor ability and reduces their quality of life. Besides conservative treatment, open and arthroscopic surgery contributes a lot to accelerate the healing process of rotator cuff tear. Currently, there are many emerging novel treatment methods to promote rotator cuff repair. A variety of biological stimulus has been utilized in clinical practice. Among them, platelet-rich plasma, growth factors, stem cells, and exosomes are the most popular biologics in laboratory research and clinical trials. This review will focus on the biologics of bioaugmentation methods for rotator cuff repair and tendon healing, including platelet-rich plasma, growth factors, exosomes and stem cells, etc. Relevant studies are summarized in this review and future research perspectives are introduced.

"Current concepts and expert practice report: Augmentation of rotator cuff repairs"

Rotator cuff tears are common shoulder injuries expected to increase with the growth of the aging population. Although a small subset of patients with low functional demands can be treated nonoperatively, surgical intervention is a cost-effective solution, which can restore shoulder function and help patients return to activity sooner. While multiple surgical options are available, rotator cuff repair is a highly utilized procedure with varying success. Due to a large proportion of rotator cuff repairs still failing to completely heal, this procedure requires careful planning to achieve anatomical and biomechanically stability. New technology and techniques are being explored to help increase the success of rotator cuff repairs with an increasing focus on augmentation. The current article gives a brief overview of pertinent anatomy, treatment options, and challenges in healing of rotator cuff repairs. Thereafter, the merits of different types of rotator cuff repair augmentation available will be discussed as well as the authors' experience in utilizing biologic augmentation and surgical technique.

Bionic Silk Fibroin Film Induces Morphological Changes and Differentiation of Tendon Stem/Progenitor Cells

Purpose

Tendon injuries are common musculoskeletal system disorders, but the ability for tendon regeneration is limited. Silk fibroin (SF) film may be suitable for tendon regeneration due to its excellent biocompatibility and physical properties. This study is aimed at evaluating the application value of bionic SF film in tendon regeneration.

Methods

Tendon stem/progenitor cells (TSPCs) were isolated from rat Achilles tendon and characterized based on their surface marker expression and multilineage differentiation potential. SF films with smooth or bionic microstructure surfaces (5, 10, 15, 20 μm) were prepared. The morphology and mechanical properties of natural tendons and SF films were characterized. TSPCs were used as the seed cells, and the cell viability and cell adhesion morphology were analyzed. The tendongenesis-related gene expression of TSPCs was also evaluated using quantitative polymerase chain reaction.

Results

Compared to the native tendon, only the 10, 15, and 20 μm SF film groups had comparable maximum loading and ultimate stress, with the exception of the breaking elongation rate. The 10 μm SF film group had the highest percentage of oriented cells and the most significant changes in cell morphology. The most significant upregulations in the expression of COL1A1, TNC, TNMD, and SCX were also observed in the 10 μm SF film group.

Conclusion

SF film with a bionic microstructure can serve as a tissue engineering scaffold and provide biophysical cues for the use of TSPCs to achieve proper cellular adherence arrangement and morphology as well as promote the tenogenic differentiation of TSPCs, making it a valuable customizable biomaterial for future applications in tendon repair.

The 3D-Printed PLGA Scaffolds Loaded with Bone Marrow-Derived Mesenchymal Stem Cells Augment the Healing of Rotator Cuff Repair in the Rabbits

The healing of tendon-bone in the rotator cuff is featured by the formation of the scar tissues in the interface after repair. This study aimed to determine if the 3D-printed poly lactic-co-glycolic acid (PLGA) scaffolds loaded with bone marrow-derived mesenchymal stem cells (BMSCs) could augment the rotator cuff repair in the rabbits. PLGA scaffolds were generated by the 3D-printed technology; Cell Counting Kit-8 assay evaluated the proliferation of BMSCs; the mRNA and protein expression levels were assessed by quantitative real-time polymerase chain reaction and western blot, respectively; immunohistology evaluated the rotator cuff repair; biomechanical characteristics of the repaired tissues were also assessed. 3D-printed PLGA scaffolds showed good biocompatibility without affecting the proliferative ability of BMSCs. BMSCs-PLGA scaffolds implantation enhanced the cell infiltration into the tendon-bone injunction at 4 weeks after implantation and improved the histology score in the tendon tissues after implantation. The mRNA expression levels of collagen I, III, tenascin, and biglycan were significantly higher in the scaffolds + BMSCs group at 4 weeks post-implantation than that in the scaffolds group. At 8 and 12 weeks after implantation, the biglycan mRNA expression level in the BMSCs-PLGA scaffolds group was significantly lower than that in the scaffolds group. BMSCs-PLGA scaffolds implantation enhanced collagen formation and increased collagen dimeter in the tendon-bone interface. The biomechanical analysis showed that BMSCs-PLGA scaffolds implantation improved the biomechanical properties of the regenerated tendon. The combination of 3D-printed PLGA scaffolds with BMSCs can augment the tendon-bone healing in the rabbit rotator cuff repair model.

Bionic Silk Fibroin Film Promotes Tenogenic Differentiation of Tendon Stem/Progenitor Cells by Activating Focal Adhesion Kinase

Background

Tendon injuries are common musculoskeletal disorders in clinic. Due to the limited regeneration ability of tendons, tissue engineering technology is often used as an effective approach to treat tendon injuries. Silk fibroin (SF) films have excellent biological activities and physical properties, which is suitable for tendon regeneration. The present study is aimed at preparing a SF film with a bionic microstructure and investigating its biological effects.

Methods

A SF film with a smooth surface or bionic microstructure was prepared. After seeding tendon stem/progenitor cells (TSPCs) on the surface, the cell morphology, the expression level of tenogenic genes and proteins, and the focal adhesion kinase (FAK) activation were measured to evaluate the biological effect of SF films.

Results

The TSPCs on SF films with a bionic microstructure exhibited a slender cell morphology, promoted the expression of tenogenic genes and proteins, such as SCX, TNC, TNMD, and COLIA1, and activated FAK. FAK inhibitors blocked the enhanced expression of tenogenic genes and proteins.

Conclusion

SF films with a bionic microstructure may serve as a scaffold, provide biophysical cues to alter the cellular adherence arrangement and cell morphology, and enhance the tenogenic gene and protein expression in TSPCs. FAK activation plays a key role during this biological response process.

Analysis of Time to Form Colony Units for Connective Tissue Progenitor Cells (Stem Cells) Harvested From Concentrated Bone Marrow Aspirate and Subacromial Bursa Tissue in Patients Undergoing Rotator Cuff Repair

Purpose

To evaluate the time required for colonies to develop from concentrated bone marrow aspirate (cBMA) and subacromial bursal tissue samples.

Methods

Samples of cBMA and subacromial bursa tissue were harvested from patients undergoing rotator cuff repair surgery between November 2014 and December 2019. Samples were analyzed for time to form colonies and number of colonies formed. The impact of age, sex, and cellularity (cBMA only) was analyzed. Samples were cultured and evaluated daily for colony formation in accordance with the guidelines of the International Society for Cellular Therapy. Demographic factors were analyzed for impact on time to form colonies and number of colonies formed.

Results

Samples of cBMA were obtained from 92 patients. Subacromial bursa tissue was obtained from 54 patients. For cBMA, older age was associated with more days to form colonies (P = .003), but sex (P = .955) and cellularity (P = .623) were not. For bursa, increased age was associated with longer time to form colonies (P = .002) but not sex (P = .804). Conclusions: Increased age (in cBMA and subacromial bursa tissue) and lower initial cellularity (in cBMA) are associated with longer time to form colonies in culture.

Clinical Relevance

Although connective tissue progenitor cells are widely used in orthopaedic practice, there are few metrics to determine their efficacy. Time to form colonies may serve as an important measurement for determining connective tissue progenitor cell viability for augmentation of rotator cuff repair. Subacromial bursa tissue may represent a viable alternative to cBMA for augmentation of rotator cuff repair, capable of forming colonies expediently in vivo.

Effect of atelocollagen on the healing status after medial meniscal root repair using the modified Mason-Allen stitch

INTRODUCTION

Addition of collagen during medial meniscal root repair (MMRR) may improve meniscal root healing minimising fibrous scar tissue formation. The purpose of this study was to verify the effect of atelocollagen on MMRR using the modified Mason-Allen stitch when compared with that of the conventional pullout repair by assessing the clinical and radiological outcomes.

HYPOTHESIS

It was hypothesised that atelocollagen would enhance the healing effect on the meniscal root following MMRR. Moreover, we presumed that MMRR with atelocollagen application might reduce meniscal extrusion by promoting healing.

MATERIALS AND METHODS

A total of 47 patients who underwent MMRR using the modified Mason-Allen stitch between 2015 and 2016 were included, and they were divided into group A (atelocollagen application; n=25) and group R (MMRR without atelocollagen application; n=22). The postoperative clinical outcomes, radiological outcomes, and meniscal root healing and medial compartment cartilage status on follow-up magnetic resonance imaging (MRI) were compared between the two groups.

RESULTS

Mean follow-up duration was 26.4±4.8 months in group A and 27.1±5.2 months in group R (p=0.598). Mean duration from surgery to follow-up MRI was 12.5±1.4 months in group A and 12.7±1.2 months in group R (p=0.604). The subjective knee scores improved significantly in both groups at the last follow-up (all, p<0.001). The Kellgren-Lawrence (K-L) grade progressed in 16% and 22.7% in group A and group R, respectively (p=0.351). Follow-up MRI showed progression of cartilage loss in the medial compartment in 28% and 40.9% in group A and group R, respectively (p=0.355). In terms of meniscal root healing, 18 (72%) and 12 (54.5%) patients had complete healing, and 6 (24%) and 8 (36.4%) patients had partial healing in groups A and R, respectively. The mean value of the intra-meniscal signal intensity (IMSI) of the meniscal root based on MRI in group A was significantly lower than that in group R (p<0.001). The medial meniscal extrusion in groups A and R decreased by 0.2±0.1mm and 0.1±0.3mm following MMRR without significant differences (p=0.056 and p=0.229, respectively). The IMSI presented significant negative correlations with the root healing status and significant positive correlations with K-L grade progression (p<0.05).

DISCUSSION

Atelocollagen application during MMRR yielded lower IMSIs, suggesting better healing, than did conventional pullout root repair. However, this technique could not demonstrate beneficial effects on meniscal extrusion.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Microcurrent and adipose-derived stem cells modulate genes expression involved in the structural recovery of transected tendon of rats

Tendon injuries are common and have a high incidence of re-rupture that can cause loss of functionality. Therapies with adipose-derived stem cells (ASC) and the microcurrent (low-intensity electrical stimulation) application present promising effects on the tissue repair. We analyzed the expression of genes and the participation of some molecules potentially involved in the structural recovery of the Achilles tendon of rats, in response to the application of both therapies, isolated and combined. The tendons were distributed in five groups: normal (N), transected (T), transected and ASC (C) or microcurrent (M) or with ASC, and microcurrent (MC). Microcurrent therapy was beneficial for tendon repair, as it was observed a statistically significant increase in the organization of the collagen fibers, with involvement of the TNC, CTGF, FN, FMDO, and COL3A1 genes as well as PCNA, IL-10, and TNF-α. ASC therapy significantly increased the TNC and FMDO genes expression with no changes in the molecular organization of collagen. With the association of therapies, a significant greater collagen fibers organization was observed with involvement of the FMOD gene. The therapies did not affect the expression of COL1A1, SMAD2, SMAD3, MKX, and EGR1 genes, nor did they influence the amount of collagen I and III, caspase-3, tenomodulin (Tnmd), and hydroxyproline. In conclusion, the application of the microcurrent isolated or associated with ASC increased the organization of the collagen fibers, which can result in a greater biomechanical resistance in relation to the tendons treated only with ASC. Future studies will be needed to demonstrate the biological effects of these therapies on the functional recovery of injured tendons.

No healing improvement after rotator cuff reconstruction augmented with an autologous periosteal flap

PURPOSE

To show descriptive clinical and magnetic resonance (MR) imaging results after an additional periosteal flap augmentation in mini-open rotator cuff reconstruction and to evaluate potential healing improvement at long-term follow-up.

METHODS

Twenty-three patients with degenerative rotator cuff tears were followed after receiving a mini-open single-row repair with a subtendinous periosteal flap augmentation. Data were collected preoperatively, after 12 months and after 11 years. Clinical examination, simple shoulder test (SST), Constant-Murley Score (CS), ultrasonography examination and 3T MR imaging were performed.

RESULTS

Out of 23 patients, 20 were available for short-term and 19 for final follow-up at a median of 11.5 years (range 10.4-13.0). Questions answered with "yes" in SST improved from baseline 5.0 (range 1.0-8.0) to short 10.5 (range 8.0-12.0) and final follow-up 12.0 (range 7.0-12.0). CS improved from 53.5 (range 25.0-66.0) to 80.8 (range 75.9-89.3) and finally to 79.8 points (range 42.3-95.4). Improvement was highly significant (p < 0.05). Severe retears were found in 9/19 patients. Ossifications along the refixed tendon were noticed in 8/19 cases. Ossifications did not correlate with clinical outcome. At final follow-up, patients with retears seemed likely to have lower strength values in CS (mean ± SD) than patients without retears (7.3 ± 4.1 vs. 12.8 ± 5.3; p < 0.05).

CONCLUSION

No positive effect on improving healing response in rotator cuff refixation with a periosteal flap augmentation could be found. Retear rate is comparable to that of conventional rotator cuff refixation in the published literature. Ossifications along the tendon, without negatively affecting the clinical outcome, were seen. This invasive technique cannot be advised and should not be used anymore.

LEVEL OF EVIDENCE

IV.

Editorial Commentary: New Kid on the Block: Rotator Cuff Patch Augmentation Requires Rigorous Scrutiny

There is still plenty of room for improvement in surgical rotator cuff repair healing as well as in nonsurgical cases. Adding an implant or patch to improve results has been a subject of much discussion for a couple of decades. The main problem has been that the surgical procedures are so difficult, with added time and its effect, and therefore are controversial. Many surgeons are reluctant to go the surgical route. As we have advanced technically, we are at a turning point, with newer implants that can be easily augmented. Therefore, recently many surgeons have been using implants, and preliminary reports seem promising. New implants must withstand vigorous challenges, and future extensive and long-term studies can enable improved implants using human tissue.