Current Concepts in Rotator Cuff Repair Techniques: Biomechanical, Functional, and Structural Outcomes

Age-different BMSCs-derived exosomes accelerate tendon-bone interface healing in rotator cuff tears model

BACKGROUND

Rotator cuff tears (RCTs) are culprit of shoulder pain and dysfunction. Tendon-bone interface (TBI) mal-healing is an essential contributor to retear after RCTs. Consequently, present project was conducted to investigate the role of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes on TBI healing.

METHOD

Young BMSCs (Y-BMSCs) and Aged BMSCs (A-BMSCs) were isolated from Young (3-month-old) and old (24-month-old) SD rats, and their-derived exosomes (A-BMSCs-exo and Y-BMSCs-exo) were identified. RCTs model was established, and A-BMSCs-exo and Y-BMSCs-exo were injected at the rotator cuff using hydrogel as a vehicle. Pathological changes of TBI were observed by HE, Sirius Red and Oil Red O staining. Western blotting and RT-qPCR were applied to assess the expression of extracellular matrix (ECM)-, tendon cell (TCs)-, osteogenic-, tendon-derived stem cell (TDSCs)- and angiogenic-associated proteins and mRNAs in TBI.

RESULT

Y-BMSCs exhibited increased activity, osteogenic and lipogenic abilities than A-BMSCs. After A-BMSCs-exo and Y-BMSCs-exo treatment, TBI displayed massive sharpey's fibers growing along the tendon longitudinally, and a collagen fiber-chondrocyte migration zone forming a typical tendon-noncalcified fibrocartilage-calcified fibrocartilage-bone structure. A-BMSCs-exo and Y-BMSCs-exo significantly upregulated the expression of collagen Col I/II/III, Aggrecan, TNMD, SCX, Runx2, OPN, CD45, Sox2, CD31 and VEGFR2 in TBI. In vitro, A-BMSCs-exo and Y-BMSCs-exo significantly enhanced the activity of TCs and TDSCs, TDSCs stemness, and reduced the osteogenic and lipogenic capacity of TDSCs. The effect of Y-BMSCs-exo was significantly stronger than that of A-BMSCs-exo.

CONCLUSION

BMSCs-derived exosomes facilitate ECM remodeling, osteogenic differentiation, angiogenesis, and stemness of TDSCs, thereby accelerating TBI healing in RCTs, with better outcomes using young individual-derived BMSCs.

Losartan in Combination With Bone Marrow Stimulation Showed Synergistic Effects on Load to Failure and Tendon Matrix Organization in a Rabbit Model

PURPOSE

To investigate the effects of combining bone marrow stimulation (BMS) with oral losartan to block transforming growth factor β1 (TGF-β1) on biomechanical repair strength in a rabbit chronic injury model.

METHODS

Forty rabbits were randomly allocated into 4 groups (10 in each group). The supraspinatus tendon was detached and left alone for 6 weeks to establish a rabbit chronic injury model and was then repaired in a surgical procedure using a transosseous, linked, crossing repair construct. The animals were divided into the following groups: control group (group C), surgical repair only; BMS group (group B), surgical repair with BMS of the tuberosity; losartan group (group L), surgical repair plus oral losartan (TGF-β1 blocker) for 8 weeks; and BMS-plus-losartan group (group BL), surgical repair plus BMS plus oral losartan for 8 weeks. At 8 weeks after repair, biomechanical and histologic evaluations were performed.

RESULTS

The biomechanical testing results showed significantly higher ultimate load to failure in group BL than in group B (P = .029) but not compared with group C or group L. A 2 × 2 analysis-of-variance model found that the effect of losartan on ultimate load significantly depended on whether BMS was performed (interaction term F1,28 = 5.78, P = .018). No difference was found between the other groups. No difference in stiffness was found between any groups. On histologic assessment, groups B, L, and BL showed improved tendon morphology and an organized type I collagen matrix with less type III collagen compared with group C. Group BL showed the most highly organized tendon matrix with more type I collagen and less type III collagen, which indicates less fibrosis. Similar results were found at the bone-tendon interface.

CONCLUSIONS

Rotator cuff repair combined with oral losartan and BMS of the greater tuberosity showed improved pullout strength and a highly organized tendon matrix in this rabbit chronic injury model.

CLINICAL RELEVANCE

Tendon healing or scarring is accompanied by the formation of fibrosis, which has been shown to result in compromised biomechanical properties, and is therefore a potential limiting factor in healing after rotator cuff repair. TGF-β1 expression has been shown to play an important role in the formation of fibrosis. Recent studies focusing on muscle healing and cartilage repair have found that the downregulation of TGF-β1 by losartan intake can reduce fibrosis and improve tissue regeneration in animal models.

Comparison of Arthroscopic Single-row and Double-row Repair for Rotator Cuff Injuries With Different Tear Sizes: A Systematic Review and Meta-analysis

Background

There is no clinical gold standard for the indications for single-row (SR) versus double-row (DR) repair according to small, large, or massive rotator cuff tear size.

Purpose

To conduct a meta-analysis to compare the clinical outcomes and retear rates after arthroscopic SR and DR repair for rotator cuff injuries with different tear sizes.

Study Design

Systematic review; Level of evidence, 3.

Methods

On the basis of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria, the PubMed, Embase, Cochrane Library databases, Web of Science, China National Knowledge Infrastructure, and China BioMedical Literature database were searched for relevant studies published before November 1, 2021, using the following search terms: "Rotator Cuff Injuries," "Rotator Cuff Tears," "Arthroscopy," "Arthroscopic Surgery," "single-row," and "double-row"; a total of 489 articles were retrieved. Quality evaluation was conducted for all the studies that met the inclusion criteria. This study evaluated the Constant-Murley score, American Shoulder and Elbow Surgeons (ASES) score, University of California, Los Angeles (UCLA) score, and range of motion (ROM) as well as retear rate. A fixed-effects or random-effects model was adopted to calculate the results and assess risk.

Results

A total of 10 clinical studies were included, with 404 cases of DR and 387 cases of SR. Regarding overall results, DR had better forward elevation ROM (mean difference [MD] = -4.03° [95% CI, -6.00° to -2.06°]; P < .0001; I 2 = 46%) and a lower retear rate (MD = 2.39 [95% CI, 1.40 to 4.08]; P = .001; I 2 = 0%) compared with SR repair. With regard to small tears (<3 cm), there was no noticeable difference on any of the 3 outcome scores between SR and DR. For large rotator cuff tears (≥3 cm), DR repair showed significantly better ASES scores (MD = -3.09 [95% CI, -6.19 to 0.02]; P = .05; I 2 = 73%) and UCLA scores (MD = -1.47 [95% CI, -2.21 to -0.72]; P = .0001; I 2 = 31%) compared with SR repair.

Conclusion

Our meta-analysis revealed that DR had better UCLA scores, ASES scores, and ROM in forward elevation and lower retear rates. In rotator cuff tears <3 cm, there were no statistical differences in clinical outcome between SR and DR.

Menstrual Blood-Derived Mesenchymal Stem Cells Encapsulated in Autologous Platelet-Rich Gel Facilitate Rotator Cuff Healing in a Rabbit Model of Chronic Tears

BACKGROUND

Successful management of chronic rotator cuff (RC) tears remains a challenge owing to its limited intrinsic healing capacity and unsatisfactory failure rate. Menstrual blood-derived mesenchymal stem cells (MenSCs) have the potential to differentiate into the chondrogenic or osteogenic lineage. Autologous platelet-rich gel (APG), a gel material derived from platelet-rich plasma (PRP), can be applied as a carrier system for cell delivery and also as a releasing system for endogenous growth factors.

PURPOSE

To investigate the effect of human MenSCs encapsulated in APG (MenSCs@APG) on the healing of chronic RC tears in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

After evaluation of the effect of PRP on MenSC proliferation or differentiation, the stem cells were encapsulated in APG for in vivo injection. Supraspinatus tenotomy from the right greater tuberosity was performed on 45 New Zealand White rabbits. After 6 weeks, these rabbits were randomly allocated to 3 supplemental treatments during supraspinatus repair: saline injection (control [CTL] group), APG injection (APG group), and MenSCs@APG injection (MenSCs@APG group). At week 18, these rabbits were sacrificed to harvest the humerus-supraspinatus tendon complexes for micro-computed tomography (CT), histological evaluation, tensile test, and MenSC tracking.

RESULTS

In vitro results showed that APG can stimulate MenSC proliferation and enhance chondrogenic or osteogenic differentiation. In vivo results showed that APG can act as a carrier for delivering MenSCs into the healing site, and also as a stimulator for enhancing the in vivo performance of MenSCs. Micro-CT showed that bone volume/total volume and trabecular thickness of the new bone in the MenSCs@APG group presented significantly larger values than those of the APG or CTL group (P < .05 for all). Histologically, compared with the CTL or APG group, significantly more mature fibrocartilage regenerated at the healing site in the MenSCs@APG group. A large number of human nuclei-stained cells were observed in the MenSCs@APG group, presenting a similar appearance to fibrochondrocytes or osteocytes. Biomechanically, the MenSCs@APG group showed significantly higher failure load and stiffness than the APG or CTL group (P < .05 for all).

CONCLUSION

Human MenSCs@APG facilitated RC healing in a rabbit model of chronic tears.

CLINICAL RELEVANCE

Autogenous MenSCs@APG may be a new stem cell-based therapy for augmenting RC healing in the clinic.

Interpositional scaffold anchor rotator cuff footprint tear repair: excellent survival, healing, and early outcomes

PURPOSE

Shoulder function limitation duration after a full-thickness rotator cuff tendon (RCT) tear may influence post-repair healing and outcomes. A suture anchor was developed to improve footprint repair fixation and healing through biological fluid delivery and scaffold augmentation. The primary multicenter study objective was to evaluate RCT repair failure rate based on 6-month MRI examination, and device survival at 1-year follow-up. The secondary objective was to compare the clinical outcomes of subjects with shorter- and longer-term shoulder function limitation duration.

METHODS

Seventy-one subjects (46 men) with moderate-to-large RCT tears (1.5-4 cm), at a median 61 years of age (range = 40-76), participated in this study. Pre-repair RCT tear location/size and 6-month healing status were confirmed by an independent radiologist. Subjects with shorter- (Group 1: 17.8 ± 21 days, n = 37) and longer-term (Group 2: 185.4 ± 89 days, n = 34) shoulder function limitation durations were also compared over 1 year for active mobility, strength, American Shoulder and Elbow Surgeon's Shoulder Score (ASES score), Veterans RAND 12 Item Health Survey (VR-12), and visual analog scale (VAS) pain and instability scores.

RESULTS

Three of the 52 subjects [5.8%] who underwent 6-month MRI experienced a re-tear at the original RCT footprint repair site. By the 1-year follow-up, overall anchor survival was 97%. Although Group 2 displayed lower ASES and VR-12 scores pre-repair (ASES = 40.1 ± 17 vs. 47.9 ± 17; VR-12 physical health (PH) = 37.2 ± 9 vs. 41.4 ± 8) (p ≤ 0.048), at 3-month post-RCT repair (ASES = 61.3 ± 19 vs. 71.3 ± 20; VR-12 PH = 40.8 ± 8 vs. 46.8 ± 9) (p ≤ 0.038), and at 6-month post-RCT repair (ASES = 77.4 ± 18 vs. 87.8 ± 13; VR-12 PH = 48.9 ± 11 vs. 54.0 ± 9) (p ≤ 0.045), by 1-year post-RCT repair, groups did not differ (n.s.). Between-groups VR-12 mental health score differences were not evident at any time period (n.s.). Shoulder pain and instability VAS scores also did not differ (n.s.), displaying comparable improvement between groups from pre-RCT repair to 1-year post-RCT repair. Groups had comparable active shoulder mobility and strength recovery at each follow-up (n.s.).

CONCLUSION

At 6-month post-RCT repair, only 3/52 of patients [5.8%] had a footprint re-tear, and at 1-year follow-up, overall anchor survival was 97%. Use of this scaffold anchor was associated with excellent early clinical outcomes regardless of shoulder function impairment duration.

LEVEL OF EVIDENCE

II.

Resorbable Bioinductive Collagen Implant Is Cost Effective in the Treatment of Rotator Cuff Tears

Purpose

This study was conducted to investigate whether the use of resorbable bioinductive collagen implant (RBI) in addition to conventional rotator cuff repair (conventional RCR) is cost-effective when compared to conventional RCR alone, in the treatment of full-thickness rotator cuff tears (FT RCT).

Methods

We developed a decision analytic model to compare the expected incremental cost and clinical consequences for a cohort of patients with FT RCT. The probabilities for healing or failure to heal (retear) were estimated from the published literature. Implant and healthcare costs were estimated from a payor's perspective in 2021 U.S. prices. An additional analysis included indirect cost estimations (e.g., productivity losses). Sensitivity analyses explored the effect of tear size, as well as the impact of risk factors.

Results

The base case analysis demonstrated that resorbable bioinductive collagen implant + conventional rotator cuff repair results in incremental costs of $232,468 and an additional 18 healed RCTs per 100 treated patients over 1 year. The estimated incremental cost-effectiveness ratio (ICER) is $13,061/healed RCT compared to conventional RCR alone. When return to work was included in the model, RBI + conventional RCR was found to be cost saving. Cost-effectiveness improved with tear size with the largest benefit seen in massive tears compared to large tears, as well as patients at higher risk of retearing.

Conclusions

This economic analysis demonstrated that RBI + conventional RCR delivered improved healing rates at a marginal increase in costs when compared to conventional RCR alone and is, therefore, cost-effective in this patient population. Considering indirect costs, RBI + conventional RCR resulted in lower costs compared to conventional RCR alone and is, therefore, deemed to be cost saving.

Level of Evidence

Level IV, economic analysis.

Knotted and knotless double row transosseous equivalent repair techniques for arthroscopic rotator cuff repair demonstrate comparable post-operative outcomes

PURPOSE

To compare failure rates and outcomes after transosseous equivalent (TOE) double row (DR) knotted suture bridge versus knotless suture tape bridge repair techniques for rotator cuff tears.

METHODS

A consecutive series of 272 shoulders in 256 patients who underwent arthroscopic, double row, TOE repair for full-thickness tears of the supraspinatus tendon were reviewed. Eighty-four shoulders were repaired using knotted suture bridge (KSB) technique, and 188 shoulders were repaired using all knotless suture tape bridge (KTB) technique. Revision procedures and concomitant subscapularis tendon repairs were excluded from analysis. The minimum follow-up was 12 months. Primary outcome was failure of surgical repair, defined as either confirmed retear on MRI and/or need for revision surgery. Secondary clinical outcome measures were assessed including range of motion, strength, visual analog scale (VAS), operative time, subjective shoulder value (SSV), Patient-Reported Outcomes Measurement Information System (PROMIS) mental and physical health, American Shoulder and Elbow Surgeons Shoulder Score (ASES), Brophy shoulder activity scores, and need for manipulation under anesthesia (MUA).

RESULTS

A total of 127 shoulders (38 KSB and 89 KTB) met inclusion criteria for the study. No significant difference in demographic variables were present between the groups at baseline. Supraspinatus tear size and average follow-up time did not differ significantly between groups. Failure rates were similar between the KSB and KTB repairs (13.1 vs 7.9%, n.s.). There was no significant difference in functional outcomes including strength, range of motion in forward flexion and external rotation, as well as patient reported outcomes including VAS, SSV, PROMIS, ASES, and Brophy scores between the groups. There was also no difference in post-operative stiffness requiring MUA.

CONCLUSION

Both KSB and KTB repair techniques demonstrate low retear rates with excellent functional outcomes when compared to pre-operative examination. Both KSB and KTB techniques are viable options for achieving a successful rotator cuff repair.

LEVEL OF EVIDENCE

Level III.

Limited Biomechanical Evidence Behind Single Row Versus Double Row Repair of Subscapularis Tears: A Systematic Review

Purpose

To systematically review the literature for studies investigating the biomechanical properties of constructs used to repair isolated subscapularis tears in time zero human cadaveric studies.

Methods

A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Three electronic databases were searched for studies that reported on the construct technique and biomechanical outcomes for the repair of isolated subscapularis tears in human cadaveric specimens. Ultimate load, gap formation, stiffness, and failure mode were documented. Methodological quality was assessed using the Quality Appraisal for Cadaveric Studies (QUACS) scale.

Results

Six articles qualified (104 shoulders [72 single-row, 26 double-row, 6 transosseous]; mean QUACS score 10.5 ± 1) and were analyzed. Studies varied in the number and type of anchors and construct technique (1-2 anchors single-row; 3-4 anchors double-row; bioabsorbable or titanium anchors) and suture(s) used (no. 2 FiberWire or FiberTape), subscapularis tear type (25%, 33%, 50%, or 100% tear), and whether a knotless or knotted fixation was used. In studies that created full-thickness, upper subscapularis tears (Fox-Romeo II/III or Lafosse II), no significant differences were seen in ultimate load, gap formation, and stiffness for knotted versus knotless single-row repair (2 studies) and single-row versus double-row repair (1 study). Double-row repair of complete subscapularis tears demonstrated higher ultimate load, stiffness, and lower gap formation in 1 study. Ultimate load differed between the studies and constructs (single-row: range, 244 N to 678 N; double-row: range 332 N to 508 N, transosseous: 453 N). Suture cutout was the most common mode of failure (59%).

Conclusion

Because of the limited number of studies and varying study designs in examining the biomechanical properties of repair constructs used for subscapularis tears, there is inconclusive evidence to determine which construct type is superior for repairing subscapularis tears.

Clinical Relevance

Results from biomechanical studies of clinically relevant subscapularis repair constructs are important to guide decision-making for choosing the optimal construct for patients with subscapularis tears.

Rotator cuff repair with single row technique provides satisfying clinical results despite consistent MRI retear rate

BACKGROUND

The number of shoulder arthroscopies is steadily increasing to treat glenohumeral joint disorders, among which the rotator cuff tear is the most common. The prevalence of this condition ranges from 13% to 37% in the general population without considering the number of asymptomatic patients. The gold standard procedure for rotator cuff repair is still undefined. The purpose of this study is to evaluate a population who underwent a single row (SR) rotator cuff repair and correlate their clinical results with MRI findings.

MATERIALS AND METHODS

Sixty-seven consecutive rotator cuff procedures were retrospectively selected. All patients were diagnosed with a full-thickness rotator cuff tear and subsequently treated with an arthroscopic SR repair technique. Each patient was clinically assessed with the DASH questionnaire and the Constant-Murley Score to grade their satisfaction. Moreover, rotator cuff repair integrity was evaluated by MRI and graded using the Sugaya score.

RESULTS

Mean follow-up was 19.5 ± 5.7 months. The mean Constant score was 82.8 ± 13.0 points, with 55 patients reporting excellent results. No patient scored less than 30 points, which could be deemed as unsatisfying. Meanwhile, on the DASH questionnaire, 6.1% of our patients rated their clinical outcome as unsatisfying, whereas 75.8% rated their outcome as excellent. Postoperative MRI classified 45 patients (83.3%) as either Sugaya type I, II, or III, whereas 9 patients (16.7%) presented a Sugaya type IV consistent with a full-thickness cuff retear. Of these nine patients, five (55.6%) and three (33.3%) reported excellent results for the Constant score and DASH questionnaire, respectively. The Mann-Whitney test reported that the retear group had worse scores than the intact repaired cuff group for pain (8.3 ± 5.0 versus 13.1 ± 3.4), Constant Score (68.8 ± 18.5 versus 83.1 ± 11.6), and DASH (66.2 ± 22.1 versus 44.2 ± 14.9). Still, range of motion (ROM) differences were not significant, except for better forward flexion in the intact group (p < 0.039).

CONCLUSIONS

Both groups with intact repaired and retorn cuffs showed improvement in their condition, but unexpectedly, there is no significant  correlation between patient satisfaction and rotator cuff integrity.

LEVEL OF EVIDENCE

IV.

Double-Row Suture Anchor Fixation and Achilles Allograft Augmentation for Chronic Patellar Tendon Rupture Repair

Patellar tendon ruptures are functionally devastating injuries that result in failure of the knee extensor mechanism and can lead to a loss of ambulation. Chronic patellar tendon injuries are defined as tears greater than 2 weeks old and are typically more complex to manage than acute tears. Recently, the use of double-row suture anchor configurations has been explored as a technique to provide improved strength in addition to tendon-to-bone compression at the anatomic footprint. The purpose of this article is to describe a surgical technique involving chronic patellar tendon rupture repair using a double-row suture construct augmented with Achilles allograft. Our technique offers a variety of benefits and permits early postoperative mobilization.

Use of Suture Tapes Versus Conventional Sutures for Arthroscopic Rotator Cuff Repairs: A Systematic Review and Meta-analysis

BACKGROUND

Various suture materials are available for arthroscopic rotator cuff repair. More recently, suture tapes have become popular as they are perceived to be easier to use with less soft tissue irritation. However, little is known about their biomechanical and clinical properties compared with conventional sutures in rotator cuff repairs.

PURPOSE

To perform a systematic review and meta-analysis on whether suture tapes are biomechanically superior to conventional sutures in arthroscopic rotator cuff repairs and whether this translates to superior functional outcomes and a lower incidence of retears.

STUDY DESIGN

Meta-analysis.

METHODS

The Cochrane Controlled Register of Trials, PubMed, Medline, and Embase were used to perform a systematic review and meta-analysis using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria with the following search terms: (rotator cuff repair OR arthroscopic rotator cuff repair) AND ("tape" OR "wire" OR "cord" OR "suture"). Data pertaining to certain biomechanical properties (contact area, contact pressure, gap formation, load to failure, and stiffness), retears, and patient-reported outcome measures (PROMs) were extracted. The pooled outcome data were analyzed by random- and fixed-effects models.

RESULTS

After abstract and full-text screening, 7 biomechanical and 6 clinical studies were included. All biomechanical studies were on animals, with 91 suture tapes and 91 conventional sutures compared. Suture tapes had higher contact pressure (mean difference [MD], 0.04 MPa; 95% CI, 0.01-0.08; P = .02), higher load to failure (MD, 52.62 N; 95% CI, 27.34-77.90; P < .0001), greater stiffness (MD, 4.47 N/mm; 95% CI, 0.57-8.38; P = .02), and smaller gap formation (MD, -0.30 mm; 95% CI, -0.45 to -0.15; P < .0001) compared with conventional sutures. From the clinical analysis of the 681 rotator cuff repairs treated with a suture tape (n = 380) or conventional suture (n = 301), there were no differences in retear rates between the groups (16% vs 20% suture tape and wire, respectively; P = .26) at a mean of 11.2 months. Qualitatively, there were no differences in PROMs between the groups at a mean of 36.8 months.

CONCLUSION

Although biomechanically superior, suture tapes showed similar retear rates and postoperative function to conventional sutures. However, higher-quality clinical studies are required to investigate whether there are no true differences.

Full-Thickness Rotator Cuff Tears Can Be Safely Treated With a Resorbable Bioinductive Bovine Collagen Implant: One-Year Results of a Prospective, Multicenter Registry

Purpose

The purpose of this study was to prospectively collect safety and efficacy data in a large group of patients undergoing arthroscopic repair of full-thickness rotator cuff tears augmented with a resorbable bioinductive bovine collagen implant designed to promote healing.

Methods

Seventeen centers across the United States enrolled patients in an institutional review board-approved registry to collect outcomes data on the implant. Patients undergoing surgical management of full-thickness rotator cuff tears augmented with the implant were enrolled. Inclusion criteria were age of ≥21 years, willingness to participate and the ability to read and speak English. Exclusion criteria included hypersensitivity to bovine-derived products. Patients were assessed before and after surgery at up to 1 year with outcomes including the single-assessment numeric evaluation (SANE), Veterans RAND 12-Item (VR-12) mental components and physical components (VR-12 PCS), American Shoulder and Elbow Surgeons (ASES), and Western Ontario Rotator Cuff (WORC) outcome measures. Ad hoc analyses were performed to compare these outcomes at all time points depending on tear size (small/medium vs large/massive). Serious complications were collected.

Results

Of 210 patients enrolled, 192 had 1-year follow-up data available. The patients experienced statistically significant improvement between baseline and 1 year for mean SANE, VR-12 PCS, ASES, and WORC scores (40.0-82.0, 33.5-47.3, 46.2-87.8, and 36.2-81.0, respectively; P < .001 for all results). Ad-hoc analysis demonstrated that similar results were obtained at 1 year regardless of tear size. Twenty patients (10.4%) experienced serious complications (10.4%), including revision surgery (n = 18), proximal humerus fracture/partial subscapularis tear resulting from multiple falls (n = 1), and adhesive capsulitis (n = 1).

Conclusions

The safety and efficacy of a bioinductive implant in the surgical management of full-thickness rotator cuff tears at 1 year was shown in this study. Implant efficacy appears to be comparable regardless of the underlying tear size.

Level of Evidence

Level IV, therapeutic case series.

Triple-Row Technique Confers a Lower Retear Rate Than Standard Suture Bridge Technique in Arthroscopic Rotator Cuff Repairs

PURPOSE

To compare the structural and clinical results between the knotless suture bridge (SB) and triple-row (TR) techniques.

METHODS

This study is a retrospective study and included 212 shoulders with repairable rotator cuff tears treated with the SB technique and 206 shoulders treated with the TR technique. In the TR technique, medial and lateral anchors were placed as they would be for the SB technique, with a middle row anchor added on the edge of footprint to reduce the torn tendons. All patients underwent primary arthroscopic rotator cuff repair and had magnetic resonance imaging 6 months postoperatively to evaluate for retear. Sugaya's classification was used to classify the retear pattern. The function of all patients preoperatively and 2 years postoperatively were assessed by the American Shoulder and Elbow Surgeons shoulder index and the University of California at Los Angeles rating scale.

RESULTS

According to Sugaya's classification, 24 (11.3%), 6 (2.8%), and 20 (9.4%) in SB-treated shoulders and 16 (7.8%), 12 (5.8%), and 8 (3.9%) in TR-treated shoulders, respectively had types 3, 4, and 5. There was a statistically significant greater type 5 retear in SB-treated shoulders (P = .038) than in TR-treated shoulders. The average clinical outcome scores at the final follow-up improved significantly relative to those before the surgeries in both groups. There were no statistical differences in the clinical outcome scores at the final follow-up between SB and TR groups.

CONCLUSIONS

The use of the TR technique in arthroscopic rotator cuff repair resulted in a lower large-size retear rate when compared with the use of the SB technique. No clinical differences were noted in the outcomes between the 2 groups.

LEVEL OF EVIDENCE

Level III, therapeutic, retrospective cohort study.

Repair Tension During Arthroscopic Rotator Cuff Repair is Correlated With Preoperative Tendon Retraction and Postoperative Rotator Cuff Integrity

PURPOSE

This study aimed to examine the correlation of repair tension during arthroscopic rotator cuff repair (ARCR) with preoperative factors and to evaluate whether measuring tension during ARCR is effective for predicting rotator cuff integrity after ARCR.

METHODS

Patients who underwent ARCR from May 2014 to June 2017 were enrolled in this study. Inclusion criteria were patients with medium or larger-sized tears and with a minimum of 6 months' follow-up. Patients with a partial repair were excluded. Intraoperative repair tension was measured according to Davidson's method. Correlation of repair tension with preoperative factors was evaluated with Pearson and Spearman correlation coefficient tests. Logistic regression analysis was performed on intraoperative factors, including repair tension, to identify independent predictors of retear after ARCR. Receiver operating characteristic (ROC) curve was used to determine the cutoff value of repair tension for retear.

RESULTS

One-hundred twenty patients met the inclusion criteria. Mean repair tension was 26.6 ± 12.6 N, and retear was found in 29 shoulders (24.2%). Among the preoperative factors, tear size in the mediolateral (P < .001) and anteroposterior (P < .001) directions, DeOrio and Cofield's classification (P <0.001), geometric classification (P <.001), and fatty infiltration of supraspinatus (P = .006) and infraspinatus (P = .003) were significantly correlated with repair tension. However, multivariable logistic regression analysis identified only tear size in the mediolateral direction as an independent predictor of repair tension (P = .036). Logistic regression analysis showed that repair tension (P = .02) and geometric classification (P < .001) are significant factors affecting rotator cuff integrity after ARCR. ROC curve analysis showed the cutoff value of repair tension of large to massive tears for retear to be 35.6 N.

CONCLUSION

This study demonstrated that intraoperative repair tension is strongly correlated with tear size in the mediolateral direction based on preoperative magnetic resonance imaging and that measuring tension during ARCR is effective for predicting rotator cuff integrity after ARCR.

LEVEL OF EVIDENCE

Level IV, prognostic study.

Retear rates after rotator cuff surgery: a systematic review and meta-analysis

Background

Rotator cuff retear (RCR) is one of the main postoperative drawbacks. RCR can be considered a multifactorial issue, which causes are related either to biological than biomechanical factors. The aim of this study was to define the incidence of RCR after surgical treatment at different time points and to identify the main factors influencing the postoperative rotator cuff (RC) healing.

Methods

A systematic review and meta-analysis were performed following the PRISMA guidelines. A comprehensive search of the literature was carried out in July 2020, using PubMed and Cochrane Library databases. Only level 1 and 2 clinical evidence studies were included. Studies were included if patients with preoperative repairable full-thickness RC tears were treated surgically, and if studies reported postoperative RCR confirmed by imaging diagnostic. The association between timing of retear and follow-up time points were investigated using an inverse-variance method of pooling data. A subgroup meta-analysis was performed using the DerSimonian and Laird method for the estimation of the between-study variance, i.e., τ². The association between retear rate after surgery and patients’ age, preoperative tear size, fatty infiltration, postoperative rehabilitation protocol, surgical techniques, and RC repairs was determined by expressing the effect measure in terms of odds ratio (OR) with 95% confidence interval (CI). The Mantel-Haenszel method with 95% CIs was used.

Results

Thirty-one articles were included in this study. The percentage of RCR after surgery was 15% at 3 months follow-up, 21% at 3–6 months follow-up, 16% at 6–12 months follow-up, 21% at 12–24 months follow-up, 16% at follow-up longer than 24 months. The main factors influencing RC healing are both patient-related (i.e., age, larger tear size, fatty infiltration) and not patient-related (i.e., postoperative rehabilitation protocol, surgical techniques, and procedures).

Conclusions

Postoperative RC healing is influenced by patient-related and non-patient-related factors. Further high-level clinical studies are needed to provide highly relevant clinical results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04634-6.

Increased acromiohumeral distance in a double-row arthroscopic rotator cuff surgery compared to a single-row surgery after 12 months

Background

Arthroscopic rotator cuff surgery is an effective treatment for rotator cuff tears with the considered use of double-row repair techniques becoming popular in the last decade. We aim to compare the effects of double- and single-row arthroscopic rotator cuff repairs (ARCR) on repair integrity (RI) and acromiohumeral distance (AHD).

Methods

In this observational study, we retrospectively identified 98 patients with degenerative rotator cuff tear treated with arthroscopic rotator cuff repair between 2016 and 2019. We excluded 22 patients with partial-thickness tears, 15 with associated subscapularis or SLAP tears, 13 with massive tears, and 5 patients lost to follow-up; we included 43 patients who had ARCR for full-thickness cuff tear and clinical, radiologic follow-up. Of these 43 patients, 23 are grouped as double-row repair group (DRG) and 20 as single-row repair group (SRG). A minimum of 12 months after the surgery, bilateral shoulder MRIs were obtained. Contralateral shoulders without asymptomatic rotator cuff tears served as a control group (CG). The operating surgeon and two other surgeons experienced in arthroscopy blindly measured the AHD and determined the RI at the control MRIs in all groups. Functional assessments relied on UCLA and qDASH Scores.

Results

The mean age was 57.89 (45–78) years, and the mean follow-up time was 28,65 (21–43) months. The mean AHD of the CG was 9.7 ± 0.96 mm, the preoperative AHD of DRG was 8.62 ± 1.45 mm, and SRG was 9.71 ± 0.95 mm. The postoperative mean AHD of DRG 9.61 ± 1.83 mm and SRG was 10.21 ± 1.97 mm. AHD differences between the preoperative and postoperative groups were significant (P=0.009). The increase of the AHD in the double-row group was significantly higher than the single-row group (P=0.004). There was a high correlation between the RI and DASH scores (P=0.005). RI did not correlate with the repair method (P=0.580).

Conclusion

Although double-row repairs can maintain greater AHD than single-row repairs in the clinical setting, this difference did not affect functional results. Regardless of the surgical intervention, functional results are favourable if RI is achieved.

Level of evidence

Level III, Retrospective Cohort Study

Two Techniques for Treating Medium-Sized Supraspinatus Tears: The Medially Based Single-Row Technique and the Suture Bridge Technique

Background

Arthroscopic rotator cuff repair emerged in the early 1990s, and the single-row repair technique (i.e., suture anchor[s] set at the center or laterally on the greater tuberosity) has shown promising outcomes; however, the healing rate of the repaired cuff is suboptimal. Although small to medium-sized rotator cuff tears have shown better clinical outcomes and structural healing than larger tears, healing failure still occurs¹.There are several factors that affect rotator cuff healing. The initial stiffness and strength of the repair, gap formation resistance, footprint coverage at the end of surgery, vascularity of the cuff, and mechanical stress on the repaired cuff are important factors². To improve tendon-to-bone healing, 2 repair techniques have been developed: the suture bridge technique and the medially based single-row technique. The suture bridge technique involves placing anchors in a 2-row fashion, with medial-row sutures from the medial anchors bridged over the footprint with lateral-row knotless anchors³. The single-bridge technique has shown biomechanical superiority in terms of ultimate strength, stiffness, and gap formation resistance⁴; however, these outcomes are achieved at the cost of relatively high tension at the suture-cuff junction, as well as interference with vascularity at the medial mattress sutures if medial mattress sutures are tied.Alternatively, the medially based single-row technique was proposed as a modification of the laterally based (traditional) single-row technique⁵. This technique is combined with the creation of bone marrow vents (microfracture technique) lateral to the inserted anchor in the footprint to promote soft-tissue regeneration (called "neotendon") over the exposed footprint. The theoretical advantages of this technique include lower tension on the repaired cuff; better screw purchase beneath the subchondral bone, which avoids weaker cancellous bone on the peripheral area of the greater tuberosity; and avoidance or reduction of lateral shift of the muscle-tendon junction. However, these outcomes are achieved with relatively weaker initial fixation strength and by exposing the uncovered greater tuberosity footprint lateral to the repaired tendon edge.Both procedures provide equivalent outcomes as measured by functional and pain scores. At present, there is no decisive superiority in treating small to medium-sized supraspinatus tears.

Description

Arthroscopic subacromial decompression is performed in both techniques.For suture bridge fixation, the suture anchor is placed at the articular margin of the humeral head as the medial row, and both limbs of each suture are passed through the tendon approximately 5 mm lateral to the muscle-tendon junction of the rotator cuff in a mattress fashion. After the medial-row knots are tied, the suture limbs are brought into 2 lateral push-in anchors.For the medially based single-row repair, suture anchors are placed lateral to the articular margin. Each suture limb is passed through the tendon approximately 1 cm medial to the torn edge of the cuff. All sutures are tied with 7 half-hitches, avoiding a sliding knot.

Alternatives

Open or mini-open rotator cuff repair⁶.Arthroscopic rotator cuff repair suture bridge technique without knot-tying⁷.Arthroscopic transosseous (i.e., anchorless) rotator cuff repair⁸.

Rationale

The suture bridge technique has achieved better mechanical properties and footprint coverage, and the medially based single-row technique has achieved lower tension on the repaired construct with neotendon regeneration. These techniques are the opposite concept as coverage-oriented and tension-oriented techniques, respectively. To our knowledge, there is presently no study showing that either of these 2 techniques is better than the other⁴. With that said, the author prefers the medially based single-row technique in cases with degenerative tendon tissue, especially among elderly patients with relatively short tendon substance and with preoperative stiffness because lowering the tension on the repaired construct would be more important than coverage of the greater tuberosity.

Expected Outcomes

Published data have not shown significant differences in the clinical outcomes and cuff integrity between these 2 techniques, with no decisive superiority when treating small to medium-sized supraspinatus tears. The choice between these techniques is solely the decision of the surgeon; however, medial cuff failure has been reported only when using the suture bridge technique, and incomplete healing was more frequent among medially based single-row techniques. One should consider the risks of medial cuff failure and incomplete healing of the repaired cuff before choosing the repair technique for medium-sized supraspinatus tears.

Important Tips

The proposed risk factors for medial cuff failure in the suture bridge technique include:○ A mattress suture configuration placed at the muscle-tendon junction○ Aggressive rehabilitation○ Use of a large-diameter suture passer○ Application of a sliding knot○ High-stress concentration around the medial knotsThe proposed risk factors for incomplete healing in the medially based single-row techniqueare:○ Lower mechanical properties (initial stiffness and strength, gap formation resistance) in the repaired site○ Lower number of sutures.

Joining soft tissues to bone: Insights from modeling and simulations

Entheses are complex multi-tissue regions of the musculoskeletal system serving the challenging task of connecting highly dissimilar materials such as the compliant tendon to the much stiffer bone, over a very small region. The first aim of this review is to highlight mathematical and computational models that have been developed to investigate the many attachment strategies present at entheses at different length scales. Entheses are also relevant in the medical context due to the high prevalence of orthopedic injuries requiring the reattachment of tendons or ligaments to bone, which are associated with a rather poor long-term clinical outcome. The second aim of the review is to report on the computational works analyzing the whole tendon to bone complex as well as targeting orthopedic relevant issues. Modeling approaches have provided important insights on anchoring mechanisms and surgical repair strategies, that would not have been revealed with experiments alone. We intend to demonstrate the necessity of including, in future models, an enriched description of enthesis biomechanical behavior in order to unravel additional mechanical cues underlying the development, the functioning and the maintaining of such a complex biological interface as well as to enhance the development of novel biomimetic adhesive, attachment procedures or tissue engineered implants.

Re-tears after rotator cuff repair: Current concepts review

Re-tear following rotator cuff repair is common and has been reported to range from between 13 and 94% despite satisfactory clinical outcomes following rotator cuff surgery. Various risk factors have been associated with an increased tear rate, including patient factors, tear and shoulder morphology, repair technique, and rehabilitation regimes. Different modes of rotator cuff failure have been described. The management of re-tear in patients following rotator cuff repair is challenging and depends on the age, functional status and requirements of the patient, and re-tear size and residual tendon length. This article aims to review the factors associated with rotator cuff re-tear. It describes which of these are associated with poor clinical outcomes, and discusses the long-term outcomes of re-tear and treatment options.

A false-pouch closure technique with an intact superior peroneal retinaculum for recurrent dislocation of the peroneal tendon

Purpose

To evaluate the usefulness of the false-pouch closure technique with an intact superior peroneal retinaculum (SPR).

Methods

From 2016 to 2020, 30 patients with recurrent dislocation of the peroneal tendon were treated with the current procedure. Clinical outcomes, including the time to resume running, the rate and time to return to sports, and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hind Foot score, were evaluated preoperatively and at the last follow-up.

Results

The rate of return to the pre-injury level of sports activity was 93.3%, and the mean duration to return to running and sports was 8.0 ± 2.8 weeks (range: 3–12 weeks) and 14.4 ± 3.2 weeks (range: 10–24 weeks), respectively. The mean preoperative AOFAS score was 79.7 ± 9.6 points (range: 41–90), which improved significantly to 98.9 ± 3.2 (87–100) postoperatively (p < 0.01).

Conclusion

The false-pouch closure technique with suture tape and anchors had a reliable clinical outcome and can enable the early return of patients to their sports activities.

Level of evidence

IV, Case series

Biomechanical comparison between single-row with triple-loaded suture anchor and suture-bridge double-row rotator cuff repair

BACKGROUND

Numerous biomechanical and clinical studies comparing different techniques for rotator cuff repair have been reported, yet universal consensus regarding the superior technique has not achieved. A medially-based single-row with triple-loaded suture anchor (also referred to as the Southern California Orthopedic Institute [SCOI] row) and a suture-bridge double-row (SB-DR) with Push-Locks have been shown to result in comparable improvement in treating rotator cuff tear, yet the biomechanical difference is unknown. The purpose of the current study was to determine whether a SCOI row repair had comparable initial biomechanical properties to a SB-DR repair.

METHODS

Six matched pairs of fresh-frozen cadaveric shoulders with full-thickness supraspinatus tendon tears we created were included. Two different repairs were performed for each pair (SCOI row and SB-DR methods). Specimens were mounted on a material testing machine to undergo cyclic loading, which was cycled from 10 to 100 N at 1 Hz for 500 cycles. Construct gap formation was recorded at an interval of 50 cycles. Samples were then loaded to failure and modes of failure were recorded. Repeated-measures analysis of variance and pair-t test were used for statistical analyses.

RESULTS

The construct gap formation did not differ between SCOI row and SB-DR repairs (P = 0.056). The last gap displacement was 1.93 ± 0.37 mm for SCOI row repair, and 1.49 ± 0.55 mm for SB-DR repair. The tensile load for 5 mm of elongation and ultimate failure were higher for SCOI row repair compared to SB-DR repair (P = 0.011 and 0.028, respectively). The ultimate failure load was 326.34 ± 11.52 N in the SCOI row group, and 299.82 ± 27.27 N in the SB-DR group. Rotator cuff repair with the SCOI row method failed primarily at the suture- tendon interface, whereas pullout of the lateral row anchors was the primary mechanism of failure for repair with the SB-DR method.

CONCLUSION

Rotator cuff repair with the SCOI row method has superior biomechanical properties when compared with the SB-DR method. Therefore, SCOI row repair using a medially-based single-row technique with triple-loaded suture anchor is recommended to improve the initial strength in treating full-thickness rotator cuff tears.

Editorial Commentary: Living in the Material World: Could Viscoelastic Properties of Sutures Impact Patient Outcomes?

The viscoelastic properties of suture may impact how soft tissue (such as the shoulder rotator cuff tendons) heals to bone and therefore may impact patient outcomes. Thus, it is logical to use suture material less likely to creep and elongate. Suture tape, in particular, may show superior biomechanical properties compared with standard sutures. However, in cadaveric studies, failure generally occurs at the tissue interface, rather than the suture material (or anchor). Thus, the quality and thickness of local tissue must be taken into consideration when determining postoperative rehabilitation or return to activity. Clinical outcome studies comparing suture materials remain elusive, but there is little reason not to use stronger suture material, and this is an option within the surgeon's control.

TGF-β3 Loaded Electrospun Polycaprolacton Fibre Scaffolds for Rotator Cuff Tear Repair: An in Vivo Study in Rats

Biological factors such as TGF-β3 are possible supporters of the healing process in chronic rotator cuff tears. In the present study, electrospun chitosan coated polycaprolacton (CS-g-PCL) fibre scaffolds were loaded with TGF-β3 and their effect on tendon healing was compared biomechanically and histologically to unloaded fibre scaffolds in a chronic tendon defect rat model. The biomechanical analysis revealed that tendon-bone constructs with unloaded scaffolds had significantly lower values for maximum force compared to native tendons. Tendon-bone constructs with TGF-β3-loaded fibre scaffolds showed only slightly lower values. In histological evaluation minor differences could be observed. Both groups showed advanced fibre scaffold degradation driven partly by foreign body giant cell accumulation and high cellular numbers in the reconstructed area. Normal levels of neutrophils indicate that present mast cells mediated rather phagocytosis than inflammation. Fibrosis as sign of foreign body encapsulation and scar formation was only minorly present. In conclusion, TGF-β3-loading of electrospun PCL fibre scaffolds resulted in more robust constructs without causing significant advantages on a cellular level. A deeper investigation with special focus on macrophages and foreign body giant cells interactions is one of the major foci in further investigations.