Failed Rotator Cuff Surgery, Evaluation and Decision Making

My Approach to Failed Rotator Cuff Repair

Failed rotator cuff repairs pose several challenges due to the high incidence rate, complexity, and range of symptoms. We propose an overview for assessing and treating failed rotator cuff repairs. For active young patients, attempt revision repair with patch augmentation if possible. When anatomic revision is not viable, but muscle is retained, consider partial repair with interposition bridging. Isolated, irreparable supraspinatus tears may benefit from superior capsule reconstruction. Tendon transfer is suitable for patients with significant atrophy and multiple irreparable cuff tears. Low-demand elderly patients or those with substantial glenohumeral arthritis may consider reverse total shoulder arthroplasty if conservative management fails. There are a variety of reported outcomes in the literature but long-term studies with larger cohorts are needed to improve the management of failed rotator cuff repair.

Drug Delivery Approaches to Improve Tendon Healing

Tendon injuries disrupt the transmission of forces from muscle to bone, leading to chronic pain, disability, and a large socioeconomic burden. Tendon injuries are prevalent; there are over 300,000 tendon repair procedures a year in the United States to address acute trauma or chronic tendinopathy. Successful restoration of function after tendon injury remains challenging clinically. Despite improvements in surgical and physical therapy techniques, the high complication rate of tendon repair procedures motivates the use of therapeutic interventions to augment healing. While many biological and tissue engineering approaches have attempted to promote scarless tendon healing, there is currently no standard clinical treatment to improve tendon healing. Moreover, the limited efficacy of systemic delivery of several promising therapeutic candidates highlights the need for tendon-specific drug delivery approaches to facilitate translation. This review article will synthesize the current state-of-the-art methods that have been used for tendon-targeted delivery through both systemic and local treatments, highlight emerging technologies used for tissue-specific drug delivery in other tissue systems, and outline future challenges and opportunities to enhance tendon healing through targeted drug delivery.

Combined Growth Factor Hydrogel Enhances Rotator Cuff Enthesis Healing in Rat But Not Sheep Model

We hypothesized that a combined growth factor hydrogel would improve chronic rotator cuff tear healing in a rat and sheep model. Insulin-like growth factor 1, transforming growth factor β1, and parathyroid hormone were combined into a tyraminated poly-vinyl-alcohol (PVA-Tyr) hydrogel and applied directly at the enthesis. In total, 30 Sprague-Dawley rats and 16 Romney ewes underwent unilateral rotator cuff tenotomy and then delayed repairs were performed after 3-4 weeks. The animals were divided into a control group (repair alone) and treatment group. The rotator cuffs were harvested at 12 weeks after surgery for biomechanical and histological analyses of the repair site. In the rat model, the stress at failure and Young's modulus were higher in the treatment group in comparison with the control group (73% improvement, p = 0.010 and 56% improvement, p = 0.028, respectively). Histologically, the repaired entheses in the treatment group demonstrated improved healing with higher semi-quantitative scores (10.1 vs. 6.55 of 15, p = 0.032). In the large animal model, there was no observable treatment effect. This PVA-Tyr bound growth factor system holds promise for improving rotator cuff healing. However, our approach was not scalable from a small to a large animal model. Further tailoring of this growth factor delivery system is still required. Level of Evidence: Basic Science Study; Biomechanics and Histology; Animal Model Impact Statement Previous studies using single-growth factor treatment to improve enthesis healing after rotator cuff repair have reported promising, but inconsistent results. A novel approach is to combine multiple growth factors using controlled-release hydrogels that mimic the normal healing process. In this study, we report that a combined growth factor hydrogel can improve the histological quality and strength of rotator cuff repair in a rat chronic tear model. This novel hydrogel growth factor treatment has the potential to be used in human clinical applications to improve healing after rotator cuff repair.

Retear bigger than preoperative tear size would lead to treatment failure after rotator cuff repair

BACKGROUND

This study aimed to (1) define treatment failure using the referred patient acceptable symptomatic state (PASS) values for pain visual analog scale (PVAS), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Single Assessment Numeric Evaluation (SANE) clinical scores and (2) identify the factors that lead to patient dissatisfaction after arthroscopic rotator cuff repair (ARCR).

METHODS

We analyzed the arthroscopic rotator cuff surgery registry data from January 2015 to December 2016. Patients were followed for ≥2 years and categorized as dissatisfied or satisfied based on our own definition of treatment failure at 2 years postoperatively. For defining treatment failure, the referred PASS values for the PVAS, ASES, and SANE scores were used. Patients who failed to attain the PASS value for the PVAS, ASES, or SANE score were categorized into the dissatisfied group. Pre- and postoperative imaging and basic demographic data were compared between groups. Univariable and multivariable logistic regression analyses were performed to identify the factors affecting patient satisfaction at 2 years after rotator cuff repair.

RESULTS

Of 117 patients, 30 (25.6%) were defined as the dissatisfied group (mean follow-up period, 37.5 months). Seventeen patients (14.5%) had confirmed retear on follow-up magnetic resonance imaging. In the univariate analysis, sex significantly differed between the groups (female, satisfied vs. dissatisfied groups: 39 [44.8%] vs. 22 [73.3%]; P = .010). Retear alone did not affect patient satisfaction in the univariate analysis (P = .11). Progressed retear size featured a significantly higher risk of patient dissatisfaction (P = .024; odds ratio 6.430, 95% confidence interval 1.270-32.541) in the multivariable analysis using symptom duration, sex, preoperative ASES score, preoperative tear size, retear, and progressed retear size as variables. Moreover, female sex had an increased odds for dissatisfaction (odds ratio 4.646, 95% confidence interval 1.590-13.578; P = .005).

CONCLUSION

Two years after ARCR, most patients (74.4%) reported satisfaction with their outcomes. However, satisfaction levels can be altered by female sex or progressed retear size compared with the preoperative state.

Cell-based therapies for the treatment of sports injuries of the upper limb

Introduction: The use of cell-based therapies in the management of sports injuries of the upper limb is increasingly popular despite the limited scientific evidence available for their use. We aim to evaluate the evidence for the use of cell-based therapies in these injuries and recommend areas for further research.Areas covered: In accordance with a published protocol (PROSPERO; Registration No. CRD42020193258), a comprehensive search of the literature was performed using the MEDLINE and EMBASE databases from inception to June 2020. All human studies reporting on the clinical, histological, or radiological outcomes following the use of cell-based therapies in the management of epicondylitis or rotator cuff pathology were included in this study. This resulted in 22 studies being included in this review, all of which underwent risk of bias assessments.Expert opinion: The evidence for the use of cell-based therapies in upper limb sports injuries is limited and generally of low quality. Given the heterogeneity in the cell types used, their harvesting methods and cell amounts, future research should be targeted at developing standardization of the reporting of these studies and more direct comparative studies looking at the efficacy of the different cell types.

Factors Related to Pain in Patients With Retorn Rotator Cuffs: Early Postoperative Pain Predicts Pain at 12 Months Postoperatively

Background:

Retearing of a repaired rotator cuff leads to diverse symptoms, including pain, regardless of the degree of the tear, but the relationship between pain and retears is poorly understood.

Purpose:

To determine which factors are correlated with shoulder pain in retears of a repaired rotator cuff.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We retrospectively reviewed a cohort of patients who were diagnosed as having a retear on magnetic resonance imaging after primary rotator cuff repair. The primary outcome variable of interest was the visual analog scale (VAS) for pain score at 12-month and final follow-up (mean, 25.2 months). We evaluated the relationship of pain at 12-month and final follow-up with preoperative patient factors (age, sex, and underlying conditions), preoperative range of motion, and preoperative pain; postoperative pain at 3 and 6 months; and perioperative conditions (tear extent, tear size, accompanying lesions, and procedures other than rotator cuff repair).

Results:

A total of 48 patients were reviewed. The VAS score at 3 months postoperatively showed a positive correlation with the VAS score at 12 months postoperatively (ρ = 0.537; P < .001) and at final follow-up (ρ = 0.537; P < .001). Univariate and multivariate regression analyses revealed that the VAS score at 3 months postoperatively (P = .0001 and P = .0017, respectively), hypertension (P = .0108 and P = .0073, respectively), and late detection of the retear (P = .0091 and P = .0208, respectively) were significant predictors of pain at 12 months postoperatively.

Conclusion:

The presence of pain in the early postoperative period, underlying hypertension, and late detection of the retear were related to pain severity in patients 12 months after rotator cuff surgery.

Rotator Cuff Tendon Adhesion to the Acromial Undersurface: Identification and Management Techniques

Identifying and mobilizing rotator cuff tissue during arthroscopic revision rotator cuff repair can be challenging. A particularly complex situation is encountered when rotator cuff tendons become adhered to surrounding bony structures. Tendon adherence to the undersurface of the acromion may occur after rotator cuff repair, especially when concurrent acromioplasty was carried out during the index procedure. This adhered and retracted rotator cuff tissue may be difficult to both recognize and mobilize, once identified, arthroscopically. The authors present a technique that can aid in both identifying and lateralizing this adhered rotator cuff tissue within the subacromial space.

Is Arthroscopic Transosseous Rotator Cuff Repair Strength Dependent on the Tunnel Angle?

Background

Previous studies have aimed to biomechanically improve the transosseous tunnel technique of rotator cuff repair. However, no previous work has addressed tunnel inclination at the time of surgery as an influence on the strength of the repair construct.

Hypothesis

We hypothesized that the tunnel angle and entry point would influence the biomechanical strength of the transosseous tunnel in rotator cuff repair. Additionally, we investigated how tunnel length and bone quality affect the strength of the repair construct.

Study Design

Controlled laboratory study.

Methods

Mechanical testing was performed on 10 cadaveric humeri. Variations in the bone tunnel angle were imposed in the supraspinatus footprint to create lateral tunnels with inclinations of 30°, 45°, and 90° relative to the longitudinal axis of the humeral shaft. A closed loop of suture was passed through the bone tunnel, and cyclic loading was applied until failure of the construct. Load to failure and distance between entry points were the dependent variables. Analysis of variance, post hoc paired t tests, and the Bonferroni correction were used to analyze the relationship between the tunnel angle and failure load. The Pearson correlation coefficient was then used to evaluate the correlation of the distance between entry points to the ultimate failure load, and t tests were used to compare failure loads between healthy and osteoporotic bone.

Results

Tunnels drilled perpendicularly to the longitudinal axis (90°) achieved the highest mean failure load (167.51 ± 48.35 N). However, there were no significant differences in the failure load among the 3 tested inclinations. Tunnels drilled perpendicularly to the longitudinal axis (90°) measured 13.86 ± 1.35 mm between entry points and were significantly longer (P = .03) than the tunnels drilled at 30° and 45°. We found no correlation of the distance between entry points and the ultimate failure load. Within the scope of this study, we could not identify a significant effect of bone quality on failure load.

Conclusion

The tunnel angle does not influence the strength of the bone-suture interface in the transosseous rotator cuff repair construct.

Clinical Relevance

The transosseous technique has gained popularity in recent years, given its arthroscopic use. These findings suggest that surgeons should not focus on the tunnel angle as they seek to maximize repair strength.

Identify differential gene expressions in fatty infiltration process in rotator cuff

Background

Rotator cuff tears are one of the most frequent upper extremity injuries and lead to pain and disability. Recent studies have implicated fatty infiltration in rotator cuff is a key failure element with the higher re-tear rates and poorer functional prognosis. Therefore, we investigated the differential expression of key genes in each stage of rotator cuff tear.

Methods

A published expression profile was downloaded from the Gene Expression Omnibus database and analyzed using the Linear Models for Microarray Data (LIMMA) package in R language to identify differentially expressed genes (DEGs) in different stages of injured rotator cuff muscles. Gene ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to annotate the function of the DEGs. Finally, PPI network and module analysis were used to identify hub genes.

Results

A total of 1089 fatty infiltration-related DEGs were identified, including 733 upregulated and 356 downregulated genes, and GO analyses confirmed that fatty infiltration was strongly associated with inflammatory response, aging, response to lipopolysaccharide, and immune response. Significantly enriched KEGG pathways associated with these DEGs included the phagosome, cell adhesion molecules, tuberculosis, and osteoclast differentiation. Further analyses via a PPI network and module analysis identified a total of 259 hub genes. Among these, Tmprss11d, Ptprc, Itgam, Mmp9, Tlr2, Il1b, Il18, Ccl5, Cxcl10, and Ccr7 were the top ten hub genes.

Conclusions

Our findings indicated the potential key genes and pathways involved in fatty degeneration in the development of fatty infiltration and supplied underlying therapeutic targets in the future.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1182-1) contains supplementary material, which is available to authorized users.

Increasing Numbers of Shoulder Corticosteroid Injections Within a Year Preoperatively May Be Associated With a Higher Rate of Subsequent Revision Rotator Cuff Surgery

PURPOSE

To identify any dose-dependent association between the use of subacromial corticosteroid injections within a year before rotator cuff repair (RCR) and subsequent need for revision rotator cuff surgery.

METHODS

Two large administrative databases were queried for patients undergoing arthroscopic RCR. A minimum of 1 year of preoperative database exposure and 2 years of postoperative database follow-up were required for inclusion. Patients were stratified into groups that received 0 (control), 1, 2, or 3 or more ipsilateral corticosteroid shoulder injections within the year prior to RCR. The outcome of interest was ipsilateral revision arthroscopic or open RCR or arthroscopic debridement for a diagnosis of rotator cuff tear within 2 years of the index surgery. Revision rates were compared between groups using a multivariate logistic regression analysis controlling for demographic and comorbidity confounders.

RESULTS

A total of 110,567 patients from the Medicare database and 12,892 patients from the private insurance database were included. There was no association between a single injection within the year prior to RCR and revision surgery in either cohort. The use of 2 or more injections was associated with a significant increase in the risk of requiring revision surgery in both the Medicare (odds ratio [OR], 2.76-3.26; P < .0001) and private insurance (OR, 2.53-2.87; P < .0001) populations.

CONCLUSIONS

A single shoulder injection within a year prior to arthroscopic RCR was not associated with any increased risk of revision surgery; however, the administration of 2 or more injections was associated with a substantially increased risk of subsequent revision rotator cuff surgery (OR, 2.53-3.26). Although causality cannot be established on the basis of this database review, caution is recommended when considering more than 1 shoulder corticosteroid injection in patients with potentially repairable rotator cuff tears.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Boosting tendon repair: interplay of cells, growth factors and scaffold-free and gel-based carriers

Background

Tendons are dense connective tissues and critical components for the integrity and function of the musculoskeletal system. Tendons connect bone to muscle and transmit forces on which locomotion entirely depends. Due to trauma, overuse and age-related degeneration, many people suffer from acute or chronic tendon injuries. Owing to their hypovascularity and hypocellularity, tendinopathies remain a substantial challenge for both clinicians and researchers. Surgical treatment includes suture or transplantation of autograft, allograft or xenograft, and these serve as the most common technique for rescuing tendon injuries. However, the therapeutic efficacies are limited by drawbacks including inevitable donor site morbidity, poor graft integration, adhesion formations and high rates of recurrent tearing. This review summarizes the literature of the past 10 y concerning scaffold-free and gel-based approaches for treating tendon injuries, with emphasis on specific advantages of such modes of application, as well as the obtained results regarding in vitro and in vivo tenogenesis.

Results

The search was focused on publications released after 2006 and 83 articles have been analysed. The main results are summarizing and discussing the clear advantages of scaffold-free and hydrogels carriers that can be functionalized with cells alone or in combination with growth factors.

Conclusion

The improved understanding of tissue resident adult stem cells has made a significant progress in recent years as well as strategies to steer their fate toward tendon lineage, with the help of growth factors, have been identified. The field of tendon tissue engineering is exploring diverse models spanning from hard scaffolds to gel-based and scaffold-free approaches seeking easier cell delivery and integration in the site of injury. Still, the field needs to consider a multifactorial approach that is based on the combination and fine-tuning of chemical and biomechanical stimuli. Taken together, tendon tissue engineering has now excellent foundations and enters the period of precision and translation to models with clinical relevance on which better treatment options of tendon injuries can be shaped up.

Tissue-engineered tendon constructs for rotator cuff repair in sheep

Current rotator cuff repair commonly involves the use of single or double row suture techniques, and despite successful outcomes, failure rates continue to range from 20 to 95%. Failure to regenerate native biomechanical properties at the enthesis is thought to contribute to failure rates. Thus, the need for technologies that improve structural healing of the enthesis after rotator cuff repair is imperative. To address this issue, our lab has previously demonstrated enthesis regeneration using a tissue-engineered graft approach in a sheep anterior cruciate ligament (ACL) repair model. We hypothesized that our tissue-engineered graft designed for ACL repair also will be effective in rotator cuff repair. The goal of this study was to test the efficacy of our Engineered Tissue Graft for Rotator Cuff (ETG-RC) in a rotator cuff tear model in sheep and compare this novel graft technology to the commonly used double row suture repair technique. Following a 6-month recovery, the grafted and contralateral shoulders were removed, imaged using X-ray, and tested biomechanically. Additionally, the infraspinatus muscle, myotendinous junction, enthesis, and humeral head were preserved for histological analysis of muscle, tendon, and enthesis structure. Our results showed that our ETC-RCs reached 31% of the native tendon tangent modulus, which was a modest, non-significant, 11% increase over that of the suture-only repairs. However, the histological analysis showed the regeneration of a native-like enthesis in the ETG-RC-repaired animals. This advanced structural healing may improve over longer times and may diminish recurrence rates of rotator cuff tears and lead to better clinical outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:289-299, 2018.

Rotator cuff tears: Review of epidemiology, clinical assessment and operative treatment

Rotator cuff tears (RTCs) are the most common cause of shoulder disability. There has been a proportional increase in the prevalence of RCT in accordance with the rising trend of an ageing population. In this article we review the current literature encompassing RCT epidemiology, risk factors and aetiopathogenesis. We also summarize the current diagnostic modalities, treatment options, rehabilitation and outcomes.

Management of failed rotator cuff repair: a systematic review

Importance

Recurrent tear after rotator cuff repair (RCR) is common. Conservative, and open and arthroscopic revisions, have been advocated to treat these failures.

Aim or objective

The purpose of this systematic review was to evaluate the different options for managing recurrent rotator cuff tears.

Evidence review

A search was conducted of level I through 4 studies from January 2000 to October 2015, to identify studies reporting on failed RCR. 10 articles were identified. The overall quality of evidence was very low.

Findings

Mid-term to long-term follow-up of patients treated conservatively revealed acceptable results; a persistent defect is a well-tolerated condition that only occasionally requires subsequent surgery. Conservative treatment might be indicated in most patients, particularly in case of posterosuperior involvement and poor preoperative range of motion. Revision surgery might be indicated in a young patient with a repairable lesion, a 3 tendon tear, and in those with involvement of the subscapularis.

Conclusions and relevance

The current review indicates that arthroscopic revision RCR can lead to improvement in functional outcome despite a high retear rate. Further studies are needed to develop specific rehabilitation in the case of primary rotator cuff failure, to better understand the place of each treatment option, and, in case of repair, to optimise tendon healing.

Tendon basic science: Development, repair, regeneration, and healing

Tendinopathy and tendon rupture are common and disabling musculoskeletal conditions. Despite the prevalence of these injuries, a limited number of investigators are conducting fundamental, basic science studies focused on understanding processes governing tendinopathies and tendon healing. Development of effective therapeutics is hindered by the lack of fundamental guiding data on the biology of tendon development, signal transduction, mechanotransduction, and basic mechanisms underlying tendon pathogenesis and healing. To propel much needed progress, the New Frontiers in Tendon Research Conference, co-sponsored by NIAMS/NIH, the Orthopaedic Research Society, and the Icahn School of Medicine at Mount Sinai, was held to promote exchange of ideas between tendon researchers and basic science experts from outside the tendon field. Discussed research areas that are underdeveloped and represent major hurdles to the progress of the field will be presented in this review. To address some of these outstanding questions, conference discussions and breakout sessions focused on six topic areas (Cell Biology and Mechanics, Functional Extracellular Matrix, Development, Mechano-biology, Scarless Healing, and Mechanisms of Injury and Repair), which are reviewed in this special issue and briefly presented in this review. Review articles in this special issue summarize the progress in the field and identify essential new research directions.

Revision versus primary arthroscopic rotator cuff repair: a 2-year analysis of outcomes in 360 patients

BACKGROUND

Symptomatic rotator cuff tears are often treated surgically. However, there is a paucity of information regarding the outcomes of revision arthroscopic rotator cuff repairs.

PURPOSE

To evaluate the outcome of revision arthroscopic rotator cuff surgery when compared with primary arthroscopic rotator cuff surgery in a large cohort of patients.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHOD

A consecutive series of 50 revision arthroscopic rotator cuff repairs performed by a single surgeon, with minimum 2-year follow-up, were retrospectively reviewed using prospectively collected data. As a comparison, 3 primary arthroscopic rotator cuff repair cases (primary group; n = 310) were chosen immediately before each revision case, and 3 were chosen after. Standardized patient-ranked outcomes, examiner-determined assessments, and ultrasound-determined rotator cuff integrity were assessed preoperatively at 6 months and at a minimum of 2 years after surgery.

RESULTS

The revision group was older (mean age, 63 years; range, 43-80 years) compared with the primary group (mean age, 60 years; range, 18-88 years) (P < .05) and had larger tear size (mean ± SEM) (4.1 ± 0.5 cm(2)) compared with the primary group (3.0 ± 0.2 cm(2)) (P < .05). Two years after surgery, the primary group reported less pain at rest (P < .02), during sleep (P < .05), and with overhead activity (P < .01) compared with the revision group. The primary group had better passive forward flexion (+13°; P < .05), abduction (+18°; P < .01), internal rotation (+2 vertebral levels; P < .001) and also significantly greater supraspinatus strength (+15 N; P < .001), lift-off strength (+9.3 N; P < .05), and adduction strength (+20 N; P < .01) compared with the revision group at 2 years. When compared with the primary group, the revision group was more satisfied with the overall shoulder function before surgery but was less satisfied with their shoulder function than the primary group at 2 years (P < .005). The retear rate for primary rotator cuff repair was 16% at 6 months and 21% at 2 years, while the retear rate for revision rotator cuff repair was 28% at 6 months and deteriorated to 40% at 2 years (P < .05).

CONCLUSION

The short-term clinical outcomes of patients undergoing revision rotator cuff repair were similar to those after primary rotator cuff repair. However, these results did not persist, and by 2 years patients who had revision rotator cuff repair were twice as likely to have retorn compared with those undergoing primary repair. The increase in retear rate in the revision group at 2 years was associated with increased pain, impaired overhead function, less passive motion, weaker strength, and less overall satisfaction with shoulder function.

Result from arthroscopic surgical treatment of renewed tearing of the rotator cuff of the shoulder

OBJECTIVES

To evaluate function among patients with postoperative recurrence of rotator cuff injuries that was treated arthroscopically (case series) and compare this with function in patients without recurrence (control group); and to compare function among patients with recurrence of rotator cuff injuries that were greater than and smaller than 3 cm.

METHODS

This was a retrospective evaluation of patients who underwent arthroscopic revision of rotator cuff injuries using the ASES, Constant & Murley and UCLA scores and a visual analog pain scale, in comparison with patients in a control group who underwent primary rotator cuff repair.

RESULTS

The size of the rotator cuff injury recurrence had a statistically significant influence on the result from the arthroscopic surgical treatment. The functional scores showed worse results than those from the first procedure.

CONCLUSION

Arthroscopic surgical treatment of renewed tearing of rotator cuff injuries showed worse functional scores than those from primary repair of the injury.

The biomechanical effects of polytetrafluoroethylene suture augmentations in lateral-row rotator cuff repairs in an ovine model

BACKGROUND

This study investigated the biomechanical effects of expanded polytetrafluoroethylene (ePTFE) suture augmentation patches in rotator cuff repair constructs.

METHODS

The infraspinatus tendon in 24 cadaveric ovine shoulders was repaired using an inverted horizontal mattress suture with 2 knotless bone anchors (ArthroCare, Austin, TX, USA) in a lateral-row configuration. Four different repair groups (6 per group) were created: (1) standard repair using inverted horizontal mattress sutures, (2) repair with ePTFE suture augmentations on the bursal side of the tendon, (3) repair with ePTFE suture augmentations on the articular side, and, (4) repair with ePTFE suture augmentations on both sides of the tendon. Footprint contact pressure, stiffness, and the load to failure of the repair constructs were measured.

RESULTS

Repairs with ePTFE suture augmentations on the bursal side exerted significantly more footprint contact pressure (0.40 ± 0.01 MPa) than those on the articular side (0.34 ± 0.02 MPa, P = .04) and those on both sides (0.33 ± 0.02 MPa, P = .01). At 15 degrees of abduction, ePTFE-augmented repairs on the bursal side had higher footprint contact pressure (0.26 ± 0.03 MPa) compared with standard repairs (0.15 ± 0.02 MPa, P = .01) and with ePTFE-augmented repairs on the articular side (0.18 ± 0.02 MPa, P = .03). The ePTFE-augmented repairs on the bursal side demonstrated significantly higher failure loads (178 ± 18 N) than standard repairs (120 ± 17 N, P = .04).

CONCLUSIONS

Inverted horizontal mattress sutures augmented with ePTFE patches on the bursal side of the tendon enhanced footprint contact pressures and the ultimate load to failure of lateral-row rotator cuff repairs in an ovine model.