Editorial Commentary: Dermal Allografts Are Indicated for Repair of Irreparable Rotator Cuff Tears and for Revision Surgery,and May Be Cost-Effective for Primary Repair

Improving rotator cuff repair results is the goal of all shoulder surgeons. The addition of a biologic graft may speed healing, allow accelerated rehabilitation, and increase healing rates. Recent research suggests that augmentation of rotator cuff repair using dermal allograft may be cost-effective. Indications for dermal allografts are revision rotator cuff repairs and primary cuff repairs in which a tensionless repair cannot be accomplished. Allografts act as a load-sharing device to allow tendons to heal without tension. They also serve to fill the gap in irreparable cuff tears. It is important to understand that augmentation will not compensate for advanced muscle fatty atrophy or neurapraxia. Precautions to prevent Cutibacterium acne nosocomial infection are essential. The healing time or dermal grafts is considerably longer than the repaired native cuff tendon, requiring supervised rehabilitation. Dermal allografts are a crucial tool for repair of irreparable rotator cuff tears and for revision surgery. From an economic standpoint, they now also may be considered for use in primary rotator cuff repair surgery.     

Rotator cuff repair with biological graft augmentation causes adverse tissue outcomes

Background and purpose — Biological patches can be used to augment rotator cuff tendon repair in an attempt to improve healing and reduce rates of re-rupture. However, little is known about the in vivo tissue response to these patches. We assessed native rotator cuff tissue response after surgical repair and augmentation with 2 commercially available extracellular matrix (ECM) patches.Patients and methods — Patients underwent a rotator cuff repair augmented with either GraftJacket (Wright Medical), Permacol (Zimmer Biomet), or no patch (Control), applied using an onlay technique. A sample of supraspinatus tendon was collected intraoperatively and 4 weeks post-surgery, using ultrasound-guided biopsy. Histology and immunohistochemistry were performed on all samples.Results — The Permacol group (n = 3) and GraftJacket group (n = 4) demonstrated some changes in native tendon ECM compared with the control group (n = 3). Significant disruption of the extracellular matrix of the repaired native supraspinatus, underlying both patches, was observed. The patches did not generally increase cellularity, foreign body giant cell count, or vascularity compared to the control group. 1 patient in the Permacol group had an adverse tissue immune response characterized by extensive infiltration of IRF5⁺, CD68⁺, and CD206⁺ cells, suggesting involvement of macrophages with a pro-inflammatory phenotype. No significant differences in protein expression of CD4, CD45, CD68, CD206, BMP7, IRF5, TGFß, and PDPN were observed among the groups.Interpretation — Histological and immunohistochemical analysis of native tendon tissue after patch augmentation in rotator cuff repair raises some concerns about a lack of benefit and potential for harm from these materials.

Rotator cuff tendon tears occur in 1 in 3 people aged over 60 years (Tempelhof et al. 1999). Around 17,000 rotator cuff repairs are performed in the National Health Service (NHS) in the UK each year (Digital 2016). The incidence of rotator cuff repair is increasing in the UK and the USA (Colvin et al. 2012). Numerous observational studies have attempted to describe the healing rate following cuff repair (Russell et al. 2014, Shen et al. 2014, Yang et al. 2017). Despite the evolution in technique and implants, the overall healing rate is around 60% (Carr et al. 2017). This has led surgeons to develop innovative strategies that aim to augment tendon repair and improve healing rate.One rotator cuff tendon repair augmentation strategy involves the application of a patch overlying the repair. These patches may be biological or synthetic. Biological patches are designed to become incorporated and vascularized by the native tendon, adding essential matrix proteins for healing (Zimmer 2006). Biological graft sources may be from the patient him/herself (e.g., fascia lata autograft), from cadaveric donors (e.g., dermal allograft), or from porcine tissues (e.g., dermal or small intestine submucosa, xenograft). These biological patches, sometimes called extracellular matrix (ECM) patches, are processed to remove donor cells, and sometimes chemically crosslinked, before sterilization for clinical use (Zimmer 2006, Group 2017). 2 popular biological patches, available for clinical use in rotator cuff repair, are GraftJacket (Wright Medical, Memphis, TE, USA) and Permacol (Zimmer Biomet, Warsaw, IN, USA).GraftJacket Regenerative Tissue Matrix (RTM) (manufactured by LifeCell Corporation, Branchburg, NJ, USA) is a cadaveric human dermis graft that is not crosslinked and undergoes decellularization by a proprietary process (Group 2017). Permacol (manufactured by Tissue Science Laboratories PLC, Aldershot, UK) is a porcine dermis graft that is chemical crosslinked with 4,4''-Diisocyanato-methylenedicyclohexane (HMDI), and is decellularized by a proprietary process. Both GraftJacket and Permacol patches are marketed with some supporting information from in vitro and animal studies, showing cellular infiltration and neovascularization; however, the mechanisms underpinning these observations are unclear (McQuillan and Harper 2007, Xu et al. 2009, O’Brien et al. 2011, Xu et al. 2012).The in vivo tissue response to xenograft and allograft tissue is important to consider in patch augmentation in humans. Patch augmentation in rotator cuff repair carries some additional risks. These include foreign-body reaction, sterile inflammatory response, transmission of undiagnosed malignancy, and infectious disease transmission (Hinsenkamp et al. 2012). We ascertained the tissue response of the native supraspinatus tendon to 2 biological patches at 4 weeks compared with a control (no patch), using histology and immunohistochemistry.     

Biologic and pharmacologic augmentation of rotator cuff repairs

As rotator cuff repair techniques have improved, failure of the tendon to heal to the proximal humerus is less likely to occur from weak tendon-to-bone fixation. More likely causes of failure include biologic factors such as intrinsic tendon degeneration, fatty atrophy, fatty infiltration of muscle, and lack of vascularity of the tendons. High failure rates have led to the investigation of biologic augmentation to potentially enhance the healing response. Histologic studies have shown that restoration of the rotator cuff footprint during repair can help reestablish the enthesis. In animal models, growth factors and their delivery scaffolds as well as tissue engineering have shown promise in decreasing scar tissue while maintaining biomechanical strength. Platelet-rich plasma may be a safe adjuvant to rotator cuff repair, but it has not been shown to improve healing or function. Many of these strategies need to be further defined to permit understanding of, and to optimize, the biologic environment; in addition, techniques need to be refined for clinical use.     

Pathologic evidence of degeneration as a primary cause of rotator cuff tear

Histopathologic, histochemical, and morphometric studies were done on 80 medial stumps of torn rotator cuff tendons to clarify the cause of tears. A high prevalence and diffuse distribution of degenerative changes were observed in the rotator cuff tendons including thinning and disorientation of collagen fibers, myxoid degeneration, hyaline degeneration, chondroid metaplasia, calcification, vascularproliferation, and fatty infiltration. No distinct inflammatory reaction was observed. Thinning and disorientation of collagen fibers, myxoid degeneration, and hyaline degeneration were seen in all cases. All changes except vascular proliferation and fatty infiltration were more pronounced in the middle to deep layers of the tendons than in the superficial layer. The collagen fibers were disoriented in the deep layer of the tendons, shown by microscopic image analysis. The frequency and distribution of thinning and disorientation of collagen fibers, myxoid degeneration, and hyaline degeneration suggest that these are early degenerative processes. Chondroid metaplasia and calcification may be chronic pathologic changes that occur after tearing regardless of the type of tear. Preexisting degenerative change in the middle and deep layers of the tendon in association with microtrauma seems to be the main cause of rotator cuff tears.     

Graft Augmentation of Repairable Rotator Cuff Tears: An Algorithmic Approach Based on Healing Rates

We provide our algorithm for tissue augmentation of rotator cuff repairs based on the current available evidence regarding rotator cuff healing. A variety of factors are associated with healing following rotator cuff repair. Increasing tear size and retraction as well as severe fatty degeneration have been associated with worsening rates of tendon healing. Given the correlation between tendon healing and postoperative outcomes, it is important to identify patients at high risk for failure and to modify their treatment accordingly to minimize the risk of early biomechanical failure and maximize the potential for structural healing. One approach that may be used to improve healing is tissue augmentation. Tissue augmentation is the use of tissue patches and scaffolds to provide rotator cuff reinforcement. Surgical management for rotator cuff tears (RCTs) continues to be a challenging task in orthopaedic surgery today. Appropriate treatment measures require an in depth understanding and consideration of the patient’s prognostic factors such as age, fatty infiltration of the rotator cuff muscles, bone mineral density, rotator cuff retraction, anteroposterior tear size, work activity, and degenerative changes of the joint. Using these factors within the Rotator Cuff Healing Index, we can determine a patient’s surgical treatment that will yield the maximum healing rate. For nonarthritic RCTs, joint-preserving strategies should be first-line treatment options. For young, active patients with a reparable RCT and minimal fatty infiltration, a complete repair can be effective. For young patients with irreparable RCTs, superior capsular reconstructions, and tendon transfers are viable options. For elderly patients with low work activity, an irreparable RCT and significant fatty infiltration, a partial repair with or without graft augmentation can be attempted if minimal to no arthritic changes are seen.Level of EvidenceLevel V, expert opinion.     

Rotator cuff tendon-to-bone healing at 12 months after patch grafting of acellular dermal matrix in an animal model

There is no report to investigate the histology and biomechanical strength of remodeled tendon-to-bone junction more than 6 months after patch grafting with acellular dermal matrix (ADM) on rotator cuff defect. We investigated those 12 months after surgery and hypothesized that a new native enthesis is not regenerated and the biomechanical strength is inferior to normal control.Adult male Sprague–Dawley rats underwent ADM patch grafting for the rotator cuff defect. Quantitative histological analysis, immunohistochemical analysis for collagen type I and III, and biomechanical testing were performed 12 months after surgery. The controls were unoperated age-matched rats. In the grafted rats, the collagen arrangement was more irregular and the fibrocartilage layer was smaller at the tendon-bone interface than in the controls although dense collagen fibers in the remodeled tendon were observed; the number of chondrocytes, the percentage of chondrocytes aligned in rows, and the area of the fibrocartilage layer were significantly smaller than in the control group (p = 0.0252, 0.0039, and 0.0252, respectively). Grafted specimens showed significantly lower collagen organization in the midsubstance and tendon-bone interface than the controls (p = 0.0252 and 0.0374, respectively). Immunohistochemical analysis demonstrated that the remodeled tendon fibers were stained more strongly for type III than type I. At 12 months postoperatively, the ultimate load to failure was significantly lower in the graft group than normal control (p = 0.0026); that was 47.8% of normal controls.12 months after rotator cuff patch grafting with ADM, the formation of a new enthesis grossly resembled the native structure but there was poor cellular organization and the biomechanical strength of remodeled tendon-to-bone was only 48% of normal controls. Advances in tissue engineering and postoperative rehabilitation are needed to promote the healing process after rotator cuff patch grafting.     

The Histology of a Healed Superior Capsular Reconstruction Dermal Allograft: A Case Report

Acellular human dermal allograft commonly is used in the surgical treatment of complex rotator cuff tears, but little information is known about the biological fate of these grafts in human subjects. In this case report, the authors describe a patient who presented with a radiographically healed acellular human dermal allograft superior capsular reconstruction but had humeral head avascular necrosis. The healed superior capsular reconstruction, including graft?bone interfaces, was explanted after 7 months and sent for histologic analysis. A successful biological reconstruction of the superior capsule was found. The graft demonstrated gross and microscopic incorporation with the host, including a tendon-like structure, aligned collagen fibers, fibroblast-like cells, and no clear graft-host distinction. Cellular infiltration ranged from 5% to 14% (central graft) to 65% to 92% (sutured attachment points). Neovascularization and active graft remodeling were confirmed histologically.Level of EvidenceV, case report.     

“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.     

Editorial Commentary: Allogenic Dermal Fibroblasts in Collagen Matrix Scaffold Enhance Rotator Cuff Repair in an Animal Model

There has been a recent surge of interest on the use of biologic supplements to facilitate rotator cuff repair healing. Experimental evidence appears to support use of allogenic dermal fibroblasts (ADFs), either in the form of local injection or tenocytes embedded in collagen matrix scaffold, to enhance healing of a repaired rotator cuff tendon tear in an animal model. When compared with the ADFs, the platelet-rich plasma (PRP)-induced response seems to be limited in terms of the specific increases in local collagen 1 concentration, thus resulting in a bone-tendon healing response that is inferior in both biology and biomechanical behavior under the same laboratory conditions. While on the one hand, there is pilot data supporting use of dermal fibroblast in the clinical setting, thus reinforcing the animal study findings, on the other hand, we are also aware of the encouraging biologic changes that occurred in the retrieved acellular dermal matrix (ADM) allograft that was used for superior capsular reconstruction as a treatment of irreparable rotator cuff tears. In theory, ADFs locally instilled as an injection should further enhance the healing response compared to the ADM. However, this needs to be further studied to be able to be widely applicable clinically.     

Does Demineralized Bone Matrix Enhance Tendon-to-Bone Healing after Rotator Cuff Repair in a Rabbit Model?

BackgroudThe purpose of this study was to compare the histologic outcomes of rotator cuff (RC) repair with demineralized bone matrix (DBM) augmentation and those without DBM augmentation and to evaluate the role of DBM for tendon-to-bone (TB) healing in a rabbit model.MethodsTwenty-six adult male New Zealand white rabbits were randomly allocated to the control group (n = 13) or the DBM group (n = 13). Repair was performed 8 weeks after complete transection of the right supraspinatus tendon of all rabbits. In the control group, RC repair was achieved by a standard transosseous technique. In the DBM group, RC repair was achieved using the same technique, and DBM was interposed between the cuff and bone. After 8 weeks, the RC tendon entheses from all rabbits were processed for gross and histologic examination.ResultsOn gross TB healing, 2 of 11 specimens in the control group were unhealed and no specimen was grossly unhealed in the DBM group (p = 0.421). In the control group, the tendon midsubstance was disorganized with randomly and loosely arranged collagen fibers and rounded fibroblastic nuclei. The TB interface was predominantly fibrous with small regions of fibrocartilage, especially mineralized fibrocartilage. In the DBM group, the tendon midsubstance appeared normal and comprised densely arranged collagen fibers, with orientated crimped collagen fibers running in the longitudinal direction of the tendon. These fibers were interspersed with elongated fibroblast nuclei. The TB interface consisted of organized collagen fibers with large quantities of fibrocartilage and mineralized fibrocartilage.ConclusionsThe use of DBM for TB interface healing in rabbit experiments showed good results in gross and histologic analysis. However, it is difficult to draw a solid conclusion because the sample size is small. Further evaluation in the in vivo setting is necessary to determine clinical recommendations.     

Editorial Commentary: “Rotator-Metrics”: Understanding Risk Factors for Rotator Cuff Repair Failure May Lead to Better Outcomes

Retear following rotator cuff repair is a significant risk and is associated with worse patient-reported outcomes. Tear size, fatty infiltration, age, and chronicity have all been reported as independent risk factors. Understanding risk factors for rotator cuff repair failure may allow surgeons to optimize outcomes by addressing certain tears, such as tears involving the anterior rotator cuff cable and subscapularis, more acutely and incorporating patch augmentation in tears that are at high risk for failure.     

Editorial Commentary: Shoulder Superior Capsule Reconstruction Leads to Good Outcomes Despite Ambiguous Graft Healing Suggesting a Spacer Effect

Massive, retracted rotator cuff tears with poor tissue quality continue to pose a problem for the shoulder surgeon. Augmentation of such repairs with grafts, patches, spacers, or biologics is being closely investigated to help improve clinical outcomes and healing rates. Specifically, superior capsule reconstruction augmentation of such rotator cuff tears may lead to good outcomes. However, we do not truly understand how much native cuff tissue or graft healing is actually taking place. Clinically, superior capsule reconstruction augmentation of rotator cuff repair may simply be serving as a spacer.     

Biomechanical evaluation of a rotator cuff defect model augmented with a bioresorbable scaffold in goats

A bioresorbable patch used for augmentation of rotator cuff repair was evaluated to determine if it would increase strength of cuff repairs associated with tendon defects and also show histologic incorporation over time. Forty goats underwent rotator cuff repairs of the infraspinatus tendon bilaterally. Tendons were detached and a defect was created prior to repair. One side was repaired and augmented with a 4 cm2 polylactic acid patch in each animal. On the other side, the same size defect was repaired in the same manner but without the patch to serve as a control. Animals were sacrificed at 3, 6, 12, and 24 weeks. Ultimate load to failure and histology were reported. No significant difference in load to failure was found between groups. A cellular fibrous tissue occupied the patch at 6 weeks, which over time matured into a dense, homogeneous fibrous tissue with alignment of collagen between the scaffold bundles.     

Editorial Commentary: Superior Capsule Reconstruction: Acellular Allograft at 45° of Glenohumeral Abduction Improves Glenohumeral Stability,but Fascia Lata Autograft Remains Superior

Originally, fascia lata autograft was used for superior capsule reconstruction (SCR) to restore glenohumeral stability in irreparable rotator cuff tears. Consistently excellent clinical outcomes with low graft tear rates have been reported, without repair of tears in the supraspinatus and infraspinatus tendons. On the basis of our experience and studies published in the 15 years since the first SCR using fascia lata autograft in 2007, we can say that this technique is the gold standard. SCR using fascia lata autograft can cover all irreparable rotator cuff tears (Hamada grade 1-3; although the indication for SCR using other grafts, including dermal allograft, biceps, and hamstrings, is only Hamada grade 1 or 2); creates excellent clinical outcomes with low graft tear rates in short-term, long-term, and multicenter studies; regenerates the fibrocartilaginous insertions at both the greater tuberosity and superior glenoid according to histological study; and enables complete restoration of shoulder stability and subacromial contact pressure in cadaveric biomechanical studies.In some countries, dermal allograft is preferred for SCR. However, high rates of graft tear and complications have been reported after SCR using dermal allografts, even in limited indications of irreparable rotator cuff tears (Hamada grade 1 or 2). This high failure rate results from the lack of stiffness and thickness of the dermal allograft. Dermal allografts in SCR can be elongated by 15% after only a couple of physiological shoulder movements, whereas fascia lata graft cannot. This 15% graft elongation, which creates less glenohumeral stability and high graft tear after SCR, is a fatal problem of dermal allograft for SCR in irreparable rotator cuff tears. Current research suggests that SCR using dermal allografts is not strongly recommended for the treatment of irreparable rotator cuff tears. Dermal allograft probably should be used only for augmentation of rotator cuff complete repair.     

Relationship between muscle fatty infiltration and the biological characteristics and stimulation potential of tenocytes from rotator cuff tears

The healing after rotator cuff surgery is still dissatisfying, and increased muscle fatty infiltration even more impairs the healing success. To achieve sufficient healing after rotator cuff reconstructions, the use of growth factors may be one possibility. The aim of the study was to identify a possible relationship between fatty infiltration of the supraspinatus muscle and cellular biological characteristics and stimulation potential of tenocyte‐like cells (TLCs). TLCs of 3 donor groups differing in grade of muscle fatty infiltration were analyzed for their cellular characteristics and were stimulated with BMP‐2 or BMP‐7 in a 3D scaffold culture. The cell count and potency for self‐renewal were significantly decreased in TLCs from donors with high muscle fatty infiltration compared to the lower fatty infiltration groups. Cell count and collagen‐I expression as well as protein synthesis were stimulated by growth factors. Interestingly, TLCs of the high fatty infiltration group exhibited a weaker stimulation potential compared to the other groups. TLCs from donors with high muscle fatty infiltration generally revealed inferior characteristics compared to cells of lower fatty infiltration groups, which may be one reason for a weaker healing potential and may represent a possible starting point for the development of future treatment options. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:129–137, 2014.     

Pathology of the torn rotator cuff tendon. Reduction in potential for repair as tear size increases

We have studied cellular and vascular changes in different stages of full thickness tears of the rotator cuff. We examined biopsies from the supraspinatus tendon in 40 patients with chronic rotator cuff tears who were undergoing surgery and compared them with biopsies from four uninjured subscapularis tendons. Morphological and immunocytochemical methods using monoclonal antibodies directed against leucocytes, macrophages, mast cells, proliferative and vascular markers were used. Histological changes indicative of repair and inflammation were most evident in small sized rotator cuff tears with increased fibroblast cellularity and intimal hyperplasia, together with increased expression of leucocyte and vascular markers. These reparative and inflammatory changes diminished as the size of the rotator cuff tear increased. Marked oedema and degeneration was seen in large and massive tears, which more often showed chondroid metaplasia and amyloid deposition. There was no association between the age of the patient and the duration of symptoms. In contrast, large and massive tears showed no increase in the number of inflammatory cells and blood vessels. Small sized rotator cuff tears retained the greatest potential to heal, showing increased fibroblast cellularity, blood vessel proliferation and the presence of a significant inflammatory component. Tissue from large and massive tears is of such a degenerative nature that it may be a significant cause of re-rupture after surgical repair and could make healing improbable in this group.     

Treatment of massive irreparable rotator cuff tears using dermal allograft bridging reconstruction

AimsVarious options are available for treating massive irreparable rotator cuff tears, but all have their own limitations and no gold standard currently exists. Our aim was to report on outcomes of bridging repair with a dermal allograft for symptomatic massive irreparable rotator cuff tears where primary or partial repair was not possible.Patients and methodsWe prospectively reviewed 22 patients who underwent an open interposition bridging repair with an allograft (GraftJacket) sutured medially to the residual rotator cuff stump and laterally to the footprint with suture anchors. Mean age at time of surgery was 59 years (range 53–66 years). The Oxford Shoulder Score, pain visual analogue scale and range of motion were compared pre-operatively and at mean follow up of 2.8 years. All patients had a postoperative MRI scan.ResultsThere was a significant improvement in mean Oxford Shoulder Score from a pre-operative score of 14.2–34.3 points (p < 0.01) at final follow up. Pain VAS score improved from 6.6 points to 2.8 points (p < 0.05). Significant improvements in range of motion were also seen. Postoperative MRI scans showed a retear in 8 patients (36%), but the retear size was smaller and an improvement in outcomes maintained at final follow up.ConclusionOpen dermal allograft bridging repair for massive irreparable rotator cuff tears can lead to satisfactory outcomes and delay the need for a reverse shoulder arthroplasty.     

Management of failed arthroscopic rotator cuff repair

Most patients experience pain relief and functional improvement following arthroscopic rotator cuff repair, but some continue to experience symptoms postoperatively. Patients with so-called failed rotator cuff syndrome, that is, with continued pain, weakness, and limited active range of motion following arthroscopic rotator cuff repair, present a diagnostic and therapeutic challenge. A thorough patient history, physical examination, and imaging studies (eg, plain radiography, MRI, magnetic resonance arthrography, ultrasonography) are required for diagnosis. Management is determined based on patient age, functional demands, rotator cuff competence, and the presence or absence of glenohumeral arthritis. Treatment options include revision repair, nonanatomic repair with or without biologic or synthetic augmentation, tendon transfer, and arthroplasty.     

Clinical and Anatomical Outcomes of Arthroscopic Repair of Large Rotator Cuff Tears with Allograft Patch Augmentation: A Prospective,Single-Blinded,Randomized Controlled Trial with a Long-term Follow-up

BackgroundArthroscopic rotator cuff repair using human dermal matrix allograft augmentation has been widely used. We assessed the effect of acellular human dermal matrix augmentation after arthroscopic repair of large rotator cuff tears through a prospective, single-blinded, randomized controlled trial with a long-term follow-up.MethodsSixty patients with large-sized rotator cuff tears were randomly assigned to two groups. Patients in the control group underwent arthroscopic rotator cuff repair. Allograft patch augmentation was additionally performed in the allograft group. All patients were subdivided into a complete coverage (CC) group or an incomplete coverage (IC) group according to footprint coverage after cuff repair. Constant and American Shoulder and Elbow Surgeons (ASES) scores were assessed preoperatively and at final follow-up. Magnetic resonance imaging was also performed at the same time to evaluate the anatomical results.ResultsForty-three patients were followed up for an average of 5.7 years. Clinical scores (Constant and ASES) increased significantly at the last follow-up in both groups. The increase in ASES score in the allograft group was statistically significantly greater than that in the control group. The degree of Constant score improvement did not differ significantly between the two groups. The retear rate was 9.1% in the allograft group, which was significantly lower than that in the control group (38.1%). In the control group, the CC subgroup had a statistically significantly lower retear rate (16.7%) than did the IC subgroup. There were no retear cases in the CC subgroup of the allograft group.ConclusionsLong-term follow-up of arthroscopic repair of large rotator cuff tears with allograft patch augmentation showed better clinical and anatomical results. Footprint coverage after rotator cuff repair was an important factor affecting the retear rate. If the footprint was not completely covered after rotator cuff repair, allograft patch augmentation may reduce the retear rate.