Biological Augmentation With Subacromial Bursa in Arthroscopic Rotator Cuff Repair

Investigation of the effects of subacromial bursal tissue preservation and microfracture procedure on healing after rotator cuff repair in a rat model

INTRODUCTION

The aim of this study is to compare the preservation of bursal tissue and microfracture techniques and to examine the effectiveness of the combination of the two methods in rotator cuff tear healing in the rat shoulder.

HYPOTHESIS

Bursal tissue preservation combined with microfracture is more effective in the rotator cuff repair.

MATERIALS AND METHODS

Twenty-three male Sprague-Dawley rats were randomly divided into two groups. The bursal tissue was preserved in group 1 (n=11) and excised in group 2 (n=12). Groups were categorized into subgroups as L (left) and R (right) based on the shoulder side receiving microfracture (L received microfracture, R did not). Histopathological examination was performed using modified Bonar Score System.

RESULTS

Cell morphology grades of group 1 were lower than group 2 (p<0.05). In terms of collagen measurements, the grade of group 1L (bursa preservation+microfracture) was lower than groups 1R, 2L, and 2R, and the grade of group 1R was lower than groups 2L and 2R. Cellularity grades of group 2 were higher than group 1 (p<0.05). Extracellular matrix grades of group 1 were lower than group 2 (p<0.05). The overall grades were lower in group 1 than in group 2 (p<0.05).

DISCUSSION

Combined treatment of bursal tissue preservation and microfracture was the most efficient method as determined by healing findings in histopathological specimens. Preservation of bursal tissue was a more effective option in tendon healing than performing only microfracture.

LEVEL OF PROOF

II, animal research.

The effect of augmenting suture material with magnesium and platelet-rich plasma on the in vitro adhesion and proliferation potential of subacromial bursa-derived progenitor cells

Background

Connective tissue subacromial bursa-derived progenitor cells (SBDCs) have been suggested as a potent biologic augment to promote healing of the repaired rotator cuff tendon. Maximizing the amount of retained progenitor cells at the tendon repair site is essential for ensuring an optimal healing environment, warranting a search for proadhesive and proliferative adjuvants. The purpose was to evaluate the effect of magnesium (Mg), platelet-rich plasma (PRP), and a combination of both adjuvants on the in vitro cellular adhesion and proliferation potential of SBDCs on suture material commonly used in rotator cuff surgery.

Methods

SBDCs were isolated from subacromial bursa samples harvested during rotator cuff repair and cultured in growth media. Commercially available collagen-coated nonabsorbable flat-braided suture was cut into 1-inch pieces, placed into 48-well culture dishes, and sterilized under ultraviolet light. Either a one-time dose of 5 mM sterile Mg, 0.2 mL of PRP, or a combination of both adjuvants was added, while a group without treatment served as a negative control. Cellular proliferation and adhesion assays on suture material were performed for each treatment condition.

Results

Augmenting the suture with Mg resulted in a significantly increased cellular adhesion (total number of attached cells) of SBDCs compared to PRP alone (31,527 ± 19,884 vs. 13,619 ± 8808; P < .001), no treatment (31,527 ± 19,884 vs. 21,643 ± 8194; P = .016), and combination of both adjuvants (31,527 ± 19,884 vs. 17,121 ± 11,935; P < .001). Further, augmentation with Mg achieved a significant increase in cellular proliferation (absorbance) of SBDCs on suture material when compared to the PRP (0.516 ± 0.207 vs. 0.424 ± 0.131; P = .001) and no treatment (0.516 ± 0.207 vs. 0.383 ± 0.094; P < .001) group. The combination of Mg and PRP showed a significantly higher proliferation potential compared to PRP alone (0.512 ± 0.194 vs. 0.424 ± 0.131; P = .001) and no treatment (0.512 ± 0.194 vs. 0.383 ± 0.094; P < .001). There were no significant differences in the remaining intergroup comparisons (P > .05, respectively).

Conclusion

Augmenting suture material with Mg resulted in a significantly increased cellular adhesion of SBDCs compared to untreated suture material, as well as augmentation with PRP alone or a combination of both adjuvants. Further, Mg with or without PRP augmentation achieved a significant increase in the cellular proliferation of SBDCs on suture material compared to untreated sutures and augmentation with PRP alone. Application of Mg may be a clinically feasible approach to optimizing the use of SBDCs as a biological augment in rotator cuff repair, while combined augmentation with PRP may harness the full potential for optimized tissue recovery due to the high concentration of PRP-derived growth factors.

Arthroscopic Biological Augmentation With Subacromial Bursa for Bursal-Sided Partial-Thickness Rotator Cuff Tears

Background

Augmentation with subacromial bursa has not been fully established in bursal-sided partial-thickness rotator cuff tears (PT-RCTs).

Purpose

To compare the results of acromioplasty + arthroscopic debridement versus acromioplasty + augmentation with subacromial bursa for Ellman type 2 PT-RCTs involving 25% to 50% of the tendon surface area.

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 40 patients (mean age, 47.8 years) with Ellman type 2 PT-RCTs whose symptoms did not regress despite 3 months of nonoperative treatment. The patients underwent either acromioplasty + debridement (group A; n = 18) or acromioplasty + augmentation (group B; n = 22). Outcome scores (visual analog scale [VAS] pain score, Constant-Murley score [CMS], and American Shoulder and Elbow Surgeons [ASES] score) were obtained preoperatively and at 6, 12, and 18 months postoperatively. Magnetic resonance imaging (MRI) scans performed at 6 months postoperatively were used to determine the integrity and state of healing.

Results

There were no significant differences between groups A and B in preoperative VAS, CMS, or ASES scores, and patients in both groups saw significant improvement at each follow-up time point on all 3 outcome scores (P = .001 for all). Scores on all 3 outcome measures were significantly better in group B than group A at each postoperative time point (P < .05 for all). Postoperative MRI scans revealed persistent partial tears in 5 of 18 patients in group A compared with 2 of 22 patients in group B (P < .05). Conversion to full-thickness tear (3/18 patients) was seen only in group A.

Conclusion

Patients who underwent biological augmentation of their PT-RCTs had improved outcome scores compared with those treated with acromioplasty and debridement alone.

Current Understanding and New Advances in the Surgical Management of Reparable Rotator Cuff Tears: A Scoping Review

Rotator cuff (RC) tears are among the most common musculoskeletal disorders and can be associated with pain, weakness, and shoulder dysfunction. In recent years, there have been significant advances with regard to the understanding of rotator cuff disease and its management. With technological improvements and advanced diagnostic modalities, there has been much progress as to improved understanding of the pathology. Similarly, with advanced implant designs and instrumentation, operative techniques have evolved. Furthermore, refinements in postoperative rehabilitation protocols have improved patient outcomes. In this scoping review, we aim to provide an overview of the current knowledge on the treatment of rotator cuff disorders and to highlight recent advances in its management.

Rotator Cuff Repair Using a Needle Arthroscope Through a Dual-Lumen Flexible Cannula

The advent of arthroscopy in shoulder surgery has allowed for the development of minimally invasive techniques for the treatment of shoulder pathology. Further developments in needle arthroscopy have continued this trend toward less invasive shoulder surgery, allowing for decreased pain using smaller portals and decreased fluid irrigation through the shoulder joint during surgery. This technique describes a minimally invasive rotator cuff repair using a dual-lumen cannula that provides both direct visualization and direct instrument access to the pathology. This new cannula has the potential to further refine and to simplify needle arthroscopic techniques about the shoulder. With judicious patient selection, needle arthroscopy is a viable option for the treatment of common shoulder pathology.

Effects of leukocyte-rich platelet-rich plasma and leukocyte-poor platelet-rich plasma on the healing of bone-tendon interface of rotator cuff in a mice model

Platelet-rich plasma (PRP) is widely used clinically to treat tendon injuries, and often contains leukocytes. However, the debate regarding the concentration of leukocytes in PRP is still ongoing. This study aimed to evaluate the therapeutic effects of leukocyte-rich platelet-rich plasma (LR-PRP) and leukocyte-poor platelet-rich plasma (LP-PRP) on the healing of the bone-tendon interface (BTI) of the rotator cuff. A total of 102 C57BL/6 mice were used. Thirty mice were used to prepare the PRP, while 72 underwent acute supraspinatus tendon injury repair. The animals were then randomly assigned to three groups: LR-PRP, LP-PRP and control groups. The mice were euthanized at 4 and 8 weeks postoperatively, and histological, immunological and biomechanical analyses were performed. The histological results showed that the fusion effect at the bone-tendon interface at 4 and 8 weeks after surgery was greater in the PRP groups and significantly increased at 4 weeks; however, at 8 weeks, the area of the fibrocartilage layer in the LP-PRP group increased significantly. M2 macrophages were observed at the repaired insertion for all the groups at 4 weeks. At 8 weeks, M2 macrophages withdrew back to the tendon in the control group, but some M2 macrophages were retained at the repaired site in the LR-PRP and LP-PRP groups. Enzyme-linked immunoassay results showed that the concentrations of IL-1β and TNF-α in the LR-PRP group were significantly higher than those in the other groups at 4 and 8 weeks, while the concentrations of IL-1β and TNF-α in the LP-PRP group were significantly lower than those in the control group. The biomechanical properties of the BTI were significantly improved in the PRP group. Significantly higher failure load and ultimate strength were seen in the LR-PRP and LP-PRP groups than in the control group at 4 and 8 weeks postoperatively. Thus, LR-RPR can effectively enhance the early stage of bone-tendon interface healing after rotator cuff repair, and LP-PRP could enhance the later stages of healing after rotator cuff injury.

Subacromial Bursa: A Neglected Tissue Is Gaining More and More Attention in Clinical and Experimental Research

The subacromial bursa has long been demolded as friction-reducing tissue, which is often linked to shoulder pain and, therefore, partially removed during shoulder surgery. Currently, the discovery of the stem cell potential of resident bursa-derived cells shed a new light on the subacromial bursa. In the meanwhile, this neglected tissue is gaining more attention as to how it can augment the regenerative properties of adjacent tissues such as rotator cuff tendons. Specifically, the tight fibrovascular network, a high growth factor content, and the large progenitor potential of bursa-derived cells could complement the deficits that a nearby rotator cuff injury might experience due to the fact of its low endogenous regeneration potential. This review deals with the question of whether bursal inflammation is only a pain generator or could also be an initiator of healing. Furthermore, several experimental models highlight potential therapeutic targets to overcome bursal inflammation and, thus, pain. More evidence is needed to fully elucidate a direct interplay between subacromial bursa and rotator cuff tendons. Increasing attention to tendon repair will help to guide future research and answer open questions such that novel treatment strategies could harvest the subacromial bursa's potential to support healing of nearby rotator cuff injuries.

Histological and molecular features of the subacromial bursa of rotator cuff tears compared to non-tendon defects: a pilot study

Background

The role of the subacromial bursa in the development or healing of shoulder pathologies is unclear. Due to this limited knowledge, we aimed to understand specific reactions of the subacromial bursa according to rotator cuff (RC) pathologies compared to non-tendon defects of the shoulder. We hypothesized that the tissue composition and inflammatory status of the bursa are likely to vary between shoulder pathologies depending on the presence and the extent of RC lesion.

Method

Bursa samples from patients with either 1) shoulder instability with intact RC (healthy bursa, control), 2) osteochondral pathology with intact RC, 3) partial supraspinatus (SSP) tendon tear, or 4) full-thickness SSP tear were investigated histologically and on gene expression level.

Result

Bursae from SSP tears differed from non-tendon pathologies by exhibiting increased chondral metaplasia and TGFβ1 expression. MMP1 was not expressed in healthy bursa controls, but strongly increased with full-thickness SSP tears. Additionally, the expression of the inflammatory mediators IL1β, IL6, and COX2 increased with the extent of SSP tear as shown by correlation analysis. In contrast, increased angiogenesis and nerve fibers as well as significantly upregulated IL6 and COX2 expression were features of bursae from patients with osteochondral pathology. Using immunohistochemistry, CD45+ leukocytes were observed in all examined groups, which were identified in particular as CD68+ monocytes/macrophages.

Conclusion

In summary, besides the strong increase in MMP1 expression with SSP tear, molecular changes were minor between the investigated groups. However, expression of pro-inflammatory cytokines correlated with the severity of the SSP tear. Most pronounced tissue alterations occurred for the osteochondral pathology and full-thickness SSP tear group, which demonstrates that the bursal reaction is not exclusively dependent on the occurrence of an SSP tear rather than longstanding degenerative changes. The present bursa characterization contributes to the understanding of specific tissue alterations related to RC tears or non-tendon shoulder pathologies. This pilot study provides the basis for future studies elucidating the role of the subacromial bursa in the development or healing of shoulder pathologies.

Arthroscopic Biological Augmentation for Massive Rotator Cuff Tears: The Biceps-Cuff-Bursa Composite Repair

Surgical repair of massive and chronic rotator cuff tears is difficult due to tendon retraction and severe atrophy, and the resultant retear rate in the structurally weak tendons is high. Commercially available patches and bioinductive scaffolds have been used to provide strength and superior healing environment in partial and complete rotator cuff tears. Biological biceps autograft has been used for superior capsular reconstruction, and the subacromial bursa has been shown to have significant pluripotent stem cell potency for tendon healing. We describe our technique for combined use of the long biceps tendon (LBT) and vasculature-preserved subacromial bursa as autografts in rotator cuff repair augmentation. The technique involves obtaining a LBT graft of sufficient length using a "traction and tenodesis" technique. The subacromial bursa is mobilized as a continuous layer (vascular bursal duvet) by maintaining its medial and lateral vascularity. All-suture anchors are used to minimize the insertion apertures (3 mm) in tuberosity. The bursa is advanced laterally, and the mobilized cuff is repaired together as a biceps-cuff-bursa composite unit. Combined use of the biceps and bursa as biological autografts has the advantage of structural and regenerative augmentation, and the autografts are easily accessible without added cost.

Analysis of Patient Factors Affecting In Vitro Characteristics of Subacromial Bursal Connective Tissue Progenitor Cells during Rotator Cuff Repair

Unsatisfactory failure rates following rotator cuff (RC) repair have led orthopaedic surgeons to explore biological augmentation of the healing enthesis. The subacromial bursa (SB) contains abundant connective tissue progenitor cells (CTPs) that may aid in this process. The purpose of the study was to investigate the influence of patient demographics and tear characteristics on the number of colony-forming units (CFUs) and nucleated cell count (NCC) of SB-derived CTPs. In this study, we harvested SB tissue over the supraspinatus tendon and muscle in 19 patients during arthroscopic RC repair. NCC of each sample was analyzed on the day of the procedure. After 14 days, CFUs were evaluated under a microscope. Spearman’s rank correlation coefficient was then used to determine the relationship between CFUs or NCC and patient demographics or tear characteristics. The study found no significant correlation between patient demographics and the number of CFUs or NCC of CTPs derived from the SB (p > 0.05). The study did significantly observe that increased tear size was negatively correlated with the number of CFUs (p < 0.05). These results indicated that increased tear size, but not patient demographics, may influence the viability of CTPs and should be considered when augmenting RCrepairs with SB.

The interaction between human rotator cuff tendon and subacromial bursal tissue in co-culture

BACKGROUND

The role of subacromial bursa in rotator cuff pathology is unclear. Along with recognized inflammatory potential, current data demonstrate the presence of mesenchymal stem cells and potential regenerative properties of the bursa. The purpose of this study was to (1) approximate an in vitro co-culture model that represents interaction between torn rotator cuff tendon and subacromial bursa, (2) quantify the cellular activity of tendon and bursa and their interactions, (3) use this model to induce a state of inflammation present with rotator cuff pathology.

METHODS

In part 1, tendon and bursa samples were obtained from 6 patients undergoing rotator cuff repair. Tendon and bursa were cultured alone and together in co-culture wells for 21 days. Markers specific for tenocyte gene expression (tenascin C, decorin, etc) were measured in both tendon and bursa alone and compared to co-culture models. In part 2 of the study, an inflammatory state was induced with interleukin-1β treatment, and markers of inflammation were measured via protein assay at 0 and 21 days in samples from 7 additional patients.

RESULTS

There was an increase in tendon and bursa markers in nearly all groups as evidenced by increased gene expression of known tendon and bursa markers. There was a significant increase in gene expression when torn tendon was co-cultured with bursa compared with culturing alone. Additionally, a state of inflammation was induced as evidenced by increased markers of inflammation, inflammatory protein concentration, and inflammatory cells and disruption of histologic morphology.

CONCLUSION

There is a clear interaction between rotator cuff tendon and the milieu produced by the subacromial bursa in this in vitro co-culture system that is significantly different when compared to an isolated culture of tendon and bursa. This system was successfully used to induce a state of inflammation that may represent in vivo inflammation. This in vitro model of rotator cuff pathology can aid investigators in testing effects of agents proposed to improve rotator cuff healing. This can lead to further knowledge regarding effective treatment options.

Arthroscopic Bursa-Augmented Rotator Cuff Repair: A Vasculature-preserving Technique for Subacromial Bursal Harvest and Tendon Augmentation

Rotator cuff repairs are associated with suboptimal outcomes and possibly greater incidence of retears if the biological healing environment is compromised. Strategies to optimize tendon-bone healing include the use of bioinductive scaffolds and regenerative stem cell therapy. The subacromial bursa has been shown to have significant pluripotent stem cell potency for tendon healing and has the advantage of easy accessibility and no added cost. However, a reproducible surgical technique for bursal mobilization, harvest, and vascularity preservation has not been described. We describe our technique for vasculature-preserving bursal mobilization and harvest of the entire posterosuperior and lateral subacromial bursa, and its use in rotator cuff repair augmentation is presented. The technique involves mobilization of the bursa as a continuous layer by maintain its medial and lateral vascularity. The bursa is advanced laterally, and the "vascular bursal duvet" and cuff tendons are repaired together as a tendon-bursa unit.

Surgical Technique for Arthroscopic Rotator Cuff Augmentation With Human Acellular Dermal Matrix

Arthroscopic repair is probably the gold standard for treating large rotator cuff tears. Although positive, the results of this type of intervention depend on many factors such as the size of the tear, the age of the patient, and the number of previous surgeries. To decrease the rate of recurrence, we propose a surgical technique for augmenting the repair using an acellular dermal matrix (ArthroFlex, LifeNet Health). Our technique allows the surgeon to initially suture the tear in a regular fashion without visual interference. Once the tear is repaired, the augmentation is performed in a simple, all-arthroscopic, reproducible, and safe way. Also, we do not use extra implants for the fixation of the graft, so it does not increase the cost of the procedure (leaving aside the cost of the matrix itself).

Biologic Augmentation of Arthroscopic Rotator Cuff Repair Using Minced Autologous Subacromial Bursa

Failure of rotator cuff repair surgery can be attributed to a variety of factors, including insufficient biologic environment to support healing. The subacromial bursal tissue has been shown to have a reservoir of mesenchymal stem cells and is a potential source for biologic augmentation during rotator cuff repair. We have developed a technique to capture the subacromial bursal tissue during subacromial bursectomy and then reimplant the tissue on the bursal surface of the rotator cuff tendon after rotator cuff repair. Our goal is to describe our technique of subacromial tissue collection and reimplantation that obviates the need of suturing a whole sleeve of bursal tissue while improving cell yield for rotator cuff healing.

Local Autologous Stem Cells Application in Rotator Cuff Repairs: "LASCA" Technique

Rotator cuff tears are among the most common orthopaedic conditions, with a very high social impact. A major concern is failure rates. To reduce these rates, recent years have seen increased attention to the biological augmentation of rotator cuff tears repairs, with a special focus on the application of mesenchymal stem cells (MSCs). Among the many tissues recognized as a source of MSCs, subacromial bursa recently has emerged. Another promising cell source was found to be the long head of the biceps tendon. Both those local MSC sources, unfortunately, are commonly considered discharge material. The purpose of this paper is to describe a simple yet fast arthroscopic technique of biological augmentation for rotator cuff repairs by mechanical harvesting and deployment of local MSCs sources, called LASCA (local autologous stem cells application), a feasible technique accessible to every shoulder surgeon and adaptable to many different techniques.

Single-Incision Rotator Cuff Repair With a Needle Arthroscope

Arthroscopy frequently has been used to treat a variety of shoulder conditions, including rotator cuff tears. Arthroscopic techniques, when compared with open techniques, are associated with less morbidity, leading to lower complication rates, easier recovery, and improved outcomes. As technology improves, we continue to develop less-invasive surgical techniques to treat rotator cuff pathology. With the development of the NanoScope (Arthrex, Naples, FL), we have the opportunity to view through a small cannula without making a standard viewing portal. This technique combines this small viewing portal with standard repair techniques through only a single lateral incision to provide a less-invasive rotator cuff repair technique.