In vitro biomechanical comparison of three different types of single- and double-row arthroscopic rotator cuff repairs: analysis of continuous bone-tendon contact pressure and surface during different simulated joint positions

What is the Optimal Construct to Reduce Failure in Arthroscopic Four Anchor Rotator Cuff Repair?

Background

Re-tear following rotator cuff repair (RCR) is a concerning complication that can lead to poor patient outcomes and necessitate the need for revision surgery. The purpose of our study was to look at the combined construct of knotted vs. knotless medial row and suture vs. suture tape, focusing primarily on re-tear rates following surgery.

Methods

A retrospective observational study of 343 consecutive patients undergoing arthroscopic double row, 4-anchor rotator cuff repair from February 2014 to March 2020 was conducted. Univariate and multivariate statistics were used to assess differences in demographics, comorbidities and tear characteristics between patients who experienced a symptomatic re-tear and those who did not.

Results

The overall symptomatic re-tear rate was 7.6%. Patients who had a knotted medial row repair had a significantly lower rate of re-tear (4.7 vs. 11.3%, p = 0.022). Patients that had a knotted medial row and suture tape repair were significantly less likely to experience a re-tear (OR: 0.180, p = 0.001).

Discussion

The use of suture tape and a knotted medial row repair decreases the incidence of symptomatic re-tear following rotator cuff repair. The combined construct of suture tape and a knotted medial row in rotator cuff repair decreases the risk for symptomatic re-tear following surgery.

Rates of medial and lateral row failure and risk factors for Re-tear in arthroscopic double row rotator cuff repair

A common postoperative complication after rotator cuff repair is re-tear requiring a secondary procedure. Double row and trans-osseous equivalent repair techniques have become increasingly popular in recent years, however repair failure remains a relatively common complication after primary rotator cuff repair. A retrospective observational study of 389 consecutive patients undergoing arthroscopic double-row rotator cuff repair from February 1, 2014 to March 31, 2020 was conducted. Univariate and multivariate statistics were used to assess differences in demographics, comorbidities, and tear characteristics between patients who experienced re-tear and those who did not. Repair failures were confirmed by plain MRI or intraoperatively during repeat surgical treatment. A subgroup analysis of patients who experienced re-tear due to medial row failure was conducted. The overall re-tear rate was 8.2% (32 patients). Six patients (1.5%) experienced medial row failure, while 26 patients (6.7%) experienced lateral row failure. The average time to re-tear was 279.3 ± 291.2 days. On multivariate analysis, patients with Goutallier Classification ≥3 (OR: 4.274, p = 0.046) and 3 anchor repair (OR: 5.387, p = 0.027) were at significantly increased risk for any re-tear after controlling for other tear characteristics. No statistically significant independent risk factors for medial row failure were identified after controlling for confounding variables. Goutallier classification greater than 3 and a primary repair with 3 anchors are significant risk factors for re-tear after double row rotator cuff repair, however they are not associated with increased occurrence of medial row failure. Further evaluation of risk factors for medial row failure is required to avoid this rare but serious re-tear pattern.

Current concepts in the evolution of arthroscopic rotator cuff repair

Arthroscopic rotator cuff repair has become one of the most common and successful surgeries performed in orthopedics. It represents the culmination of advances in many diverse fields such as optics, fluid dynamics, mechanical engineering, and most recently, orthobiologics. This article reviews the current state of the art of arthroscopic rotator cuff repair, through the lens of its historical context and evolution to our present understanding. We review the limitations in the current approach, and glance toward the future of rotator cuff regeneration with emerging technologies.

Why are tapes better than wires in knotless rotator cuff repairs? An evaluation of force, pressure and contact area in a tendon bone unit mechanical model

PURPOSE

Knotless repairs have demonstrated encouraging performance regarding retear rate reduction, but literature aiming at identifying the specific variables responsible for these results is scarce and conflictive. The purpose of this paper was to evaluate the effect of the material (tape or wire suture) and medial tendon passage (single or double passage) on the contact force, pressure and area at the tendon bone interface in order to identify the key factors responsible for this repairs´ success.

METHODS

A specific knotless transosseous equivalent cuff repair was simulated using 2 tape or suture wire loaded medial anchors and 2 lateral anchors, with controlled lateral suture limb tension. The repair was performed in a previously validated sawbones® mechanical model. Testing analyzed force, pressure and area in a predetermined and constant size "repair box" using a Tekscan® sensor, as well as peak force and pressure, force applied by specific sutures and force variation along the repair box.

RESULTS

Tapes generate lower contact force and pressure and double medial passage at the medial tendon is associated with higher contact area. Suture wires generate higher peak force and pressure on the repair and higher mean force in their tendon path and at the medial bearing row. Force values decrease from medial to lateral and from posterior to anterior independently of the material or medial passage.

CONCLUSION

Contrary to most biomechanical literature, suture tape use lowers the pressure and force applied at the tendon bone junction, while higher number of suture passage points medially increases the area of contact. These findings may explain the superior clinical results obtained with the use uf suture tapes because its smaller compressive effect over the tendon may create a better perfusion environment healing while maintaining adequate biomechanical stability.

Sliding or Nonsliding Arthroscopic Knots for Shoulder Surgery: A Systematic Review

Background

Knot tying is a crucial component of successful arthroscopic shoulder surgery. It is currently unknown whether sliding or nonsliding techniques result in superior clinical outcomes.

Purpose

To assess the clinical outcomes of arthroscopic sliding knot (SK)- versus nonsliding knot (NSK)-tying techniques during arthroscopic shoulder surgery, including rotator cuff repair, Bankart repair, and superior labral anterior-posterior (SLAP) repair.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic search of the PubMed, Embase, and Cochrane Library databases was performed using PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. All English-language literature published between 2000 and 2018 reporting clinical outcomes utilizing SK- or NSK-tying techniques during rotator cuff repair, Bankart repair, and SLAP repair with a minimum 24-month follow-up was reviewed by 2 independent reviewers. Information on type of surgery, knot used, failure rate, patient satisfaction, and patient-reported outcomes was collected. Patient-reported outcome measures included the Constant-Murley score, Rowe score, and visual analog scale for pain. Study quality was evaluated using the modified Coleman Methodology Score.

Results

Overall, 9 studies (6 level 3 and 3 level 4) with a total of 671 patients (mean age, 52.8 years [range, 16-86 years]; 65.7% male; 206 SK and 465 NSK) were included. There were 4 studies that reported on Bankart repair in 148 patients (63 SK and 85 NSK), 3 on SLAP repair in 59 patients (59 SK), and 2 on rotator cuff repair in 464 patients (84 SK and 380 NSK). Also, 6 studies compared knot-tying with knotless techniques (3 Bankart repair studies and 3 SLAP repair studies), while the studies reporting the outcomes of SLAP repair evaluated SK-tying techniques only. The failure rate for Bankart repair was 3.2% (2/63) for SKs and 4.7% (4/85) for NSKs. The failure rate for rotator cuff repair was 2.4% (2/84) for SKs and 6.3% (24/380) for NSKs. The failure rate for SLAP repair was 11.9% (7/59). Because of inconsistencies in outcomes and procedures, no quantitative analysis was possible. The mean modified Coleman Methodology Score for all studies was 65.1 ± 8.77, indicating adequate methodology.

Conclusion

The literature on clinical outcomes using SKs or NSKs for shoulder procedures is limited to level 4 evidence. Future studies should be prospective and focus on comparing the use of SKs and NSKs for shoulder procedures to elucidate which arthroscopic knot results in superior clinical outcomes.

A Prospective Randomized Trial Comparing Suture Bridge and Medially Based Single-Row Rotator Cuff Repair in Medium-Sized Supraspinatus Tears

PURPOSE

To compare the clinical and imaging outcomes between the suture bridge technique (SB) and the medially based single-row technique (medSR) in patients with 1- to 3-cm tear sizes.

METHODS

All patients were evaluated preoperatively and postoperatively (at 12 and 24 months) using the modified University of California, Los Angeles scoring system; active range of motion (flexion and external rotation); and a visual analog scale for pain. Healing status was examined by postoperative magnetic resonance imaging.

RESULTS

Clinical and imaging evaluations were completed by 92 patients at 1-year follow-up and by 74 patients at 2 years. No significant differences were found between the 2 groups across all measures at final follow-up: The University of California, Los Angeles scores were 33.4 points in SB patients and 33.0 points in medSR patients (P = .58); the visual analog scale scores were 6 mm and 7 mm, respectively (P = .38); the active flexion angles were 161° and 159°, respectively (P = .34); and the external rotation angles were 49° and 52°, respectively (P = .37). Retears were observed in 6.5% of SB patients and 2.1% of medSR patients (P = .31). Medial cuff failure was observed only in SB patients (4.3%, 2 cases), whereas incomplete healing (deep-layer retraction pattern) was observed only in medSR patients (8.7%, 4 cases). Neo-tendon regeneration in the medSR group was observed in 93% of patients.

CONCLUSIONS

This study did not show any significant differences in the clinical outcomes and cuff integrity between the 2 treatment groups at final follow-up; however, medial cuff failure was observed only in the SB group, and incomplete healing was more frequent in the medSR group. One should consider the risk of medial cuff failure and incomplete healing of the repaired cuff before choosing the repair technique for medium-sized supraspinatus tears.

LEVEL OF EVIDENCE

Level I, therapeutic, prospective, randomized trial.

Different suture anchor fixation techniques affect contact properties in humeral greater tuberosity fracture: a biomechanical study

Background

Suture anchor-based fixations of humeral greater tuberosity (GT) fractures have yielded good outcomes in both clinical and biomechanical studies. Be that as it may, the interface contact properties of these fixations have yet to be elaborated. In response, the contact characteristics of two double-row suture anchor fixations for the management of GT fracture were compared.

Methods

Two suture anchor-based fixation techniques, namely the Double-Row Suture Anchor Fixation (DR) and Suture-Bridge Technique (SB), were used to repair humeral GT fractures in 12 fresh-frozen human cadaveric shoulders. A Tekscan pressure sensor placed between the repaired tuberosity and humerus recorded continuous data points directly after repair and for 60 min at set time intervals. The constructs were then cyclically loaded until 100 N, and the shoulders tested at 0°, 30°, and 60° of abduction. Under an applied force, the contact pressure and contact area of the interface were determined.

Results

Although both fixation configurations showed decreased contact pressure and area over time, the SB group had higher contact pressure right after fixation and at all time points thereafter. In contrast, the DR group demonstrated significantly more contact pressure and area at each abduction position with the applied load. Nevertheless, contact pressure and area decreased in response to increasing abduction position for both fixation constructs.

Conclusion

Findings suggest that despite the SB construct having superior interface contact immediately after fixation, the DR construct offered better contact performance at all abduction angles with applied force.

Level of evidence

Basic Science, Biomechanics.

Rotator Cuff Repair: Single Row Repair Versus Double Row Repair and Superior Capsular Reconstruction

The surgical management of rotator cuff (RC) tears has progressed considerably in recent decades. Arthroscopic procedures now represent the mainstay of contemporary treatment approaches. The success of repair is predicated upon the achievement of a secure, durable repair that promotes tendon-to-bone healing. Both single and double row (DR) suture anchor configurations have been described to achieve stable fixation. Although consensus is lacking with regard to the clinical superiority of one configuration over another, trends in the literature suggest that DR repairs may optimize the likelihood of tendon healing and restoration of shoulder strength. In cases of truly irreparable RC tears, superior capsular reconstruction is a promising alternative to open tendon transfer and arthroplasty procedures. The purposes of this concise review are to: (1) explain our preference for a DR repair configuration in almost all circumstances; and (2) advocate superior capsular reconstruction as a viable treatment tactic for truly irreparable RC tears in the absence of significant glenohumeral arthritis.

Double row equivalent for rotator cuff repair: A biomechanical analysis of a new technique

Introduction

There are numerous configurations of double row fixation for rotator cuff tears however, there remains to be a consensus on the best method. In this study, we evaluated three different double-row configurations, including a new method. Our primary question is whether the new anchor and technique compares in biomechanical strength to standard double row techniques.

Methods

Eighteen prepared fresh frozen bovine infraspinatus tendons were randomized to one of three groups including the New Double Row Equivalent, Arthrex Speedbridge and a transosseous equivalent using standard Stabilynx anchors. Biomechanical testing was performed on humeri sawbones and ultimate load, strain, yield strength, contact area, contact pressure, and a survival plots were evaluated.

Results

The new double row equivalent method demonstrated increased survival as well as ultimate strength at 415N compared to the remainder testing groups as well as equivalent contact area and pressure to standard double row techniques.

Conclusions

This new anchor system and technique demonstrated higher survival rates and loads to failure than standard double row techniques. This data provides us with a new method of rotator cuff fixation which should be further evaluated in the clinical setting.

Level of Evidence

Basic science biomechanical study.

Effectiveness of Biologic Factors in Shoulder Disorders

Background:

Shoulder pathology can cause significant pain, discomfort, and loss of function that all interfere with activities of daily living and may lead to poor quality of life. Primary osteoarthritis and rotator cuff diseases with its sequalae are the main culprits. Management of shoulder disorders using biological factors gained an increasing interest over the last years. This interest reveals the need of effective treatments for shoulder degenerative disorders, and highlights the importance of a comprehensive and detailed understanding of the rapidly increasing knowledge in the field.

Methods:

This study will describe most of the available biology-based strategies that have been recently developed, focusing on their effectiveness in animal and clinical studies.

Results:

Data from in vitro work will also be briefly presented; in order to further elucidate newly acquired knowledge regarding mechanisms of tissue degeneration and repair that would probably drive translational work in the next decade. The role of platelet rich-plasma, growth factors, stem cells and other alternative treatments will be described in an evidence-based approach, in an attempt to provide guidelines for their clinical application. Finally, certain challenges that biologic treatments face today will be described as an initiative for future strategies.

Conclusion:

The application of different growth factors and mesenchymal stem cells appears as promising approaches for enhancing biologic repair. However, data from clinical studies are still limited, and future studies need to improve understanding of the repair process in cellular and molecular level and evaluate the effectiveness of biologic factors in the management of shoulder disorders.

Comparison of Passive Stiffness Changes in the Supraspinatus Muscle After Double-Row and Knotless Transosseous-Equivalent Rotator Cuff Repair Techniques: A Cadaveric Study

PURPOSE

To investigate the alteration of passive stiffness in the supraspinatus muscle after double-row (DR) and knotless transosseous-equivalent (KL-TOE) repair techniques, using shear wave elastography (SWE) in cadavers with rotator cuff tears. We also aimed to compare altered muscular stiffness after these repairs to that obtained from shoulders with intact rotator cuff tendon.

METHODS

Twelve fresh-frozen cadaveric shoulders with rotator cuff tear (tear size: small [6], medium-large [6]) were used. Passive stiffness of 4 anatomic regions in the supraspinatus muscle was measured based on an established SWE method. Each specimen underwent DR and KL-TOE footprint repairs at 30° glenohumeral abduction. SWE values, obtained at 0°, 10°, 20°, 30°, 60°, and 90° abduction, were assessed in 3 different conditions: preoperative (torn) and postoperative conditions with the 2 techniques. The increased ratio of SWE values after repair was compared among the 4 regions to assess stiffness distribution. In addition, SWE values were obtained on 12 shoulders with intact rotator cuff tendons as control.

RESULTS

In shoulders with medium-large-sized tears, supraspinatus muscles showed an increased passive stiffness after rotator cuff repairs, and this was significantly observed at adducted positions. KL-TOE repair showed uniform stiffness changes among the 4 regions of the supraspinatus muscle (mean, 189% to 218% increase after repair), whereas DR repair caused a significantly heterogeneous stiffness distribution within the muscle (mean, 187% to 319% after repair, P = .002). Although a repair-induced increase in muscle stiffness was observed also in small-sized tears, there were no significant differences in repaired stiffness changes between DR and KL-TOE (mean, 127% to 138% and 127% to 130% after repairs, respectively). Shoulders with intact rotator cuff tendon showed uniform SWE values among the 4 regions of the supraspinatus muscle (mean, 38.2 to 43.0 kPa).

CONCLUSIONS

Passive stiffness of the supraspinatus muscle increases after rotator cuff repairs for medium-large-sized tears. KL-TOE technique for the medium-large-sized tear provided a more uniform stiffness distribution across the repaired supraspinatus muscles compared with the DR technique.

CLINICAL RELEVANCE

Based on this insight, investigating rotator cuff muscle stiffness changes, further studies using SWE may determine the optimal repair technique for various sizes of rotator cuff tears.

Tendoscopic Double-Row Suture Bridge Peroneal Retinaculum Repair for Recurrent Dislocation of Peroneal Tendons in the Ankle

Traumatic dislocation of peroneal tendons in the ankle is an uncommon lesion that mainly affects young adults. Unfortunately, most cases lead to recurrent dislocation of the peroneal tendons of the ankle (RPTD). Therefore, most cases need operative treatment. One of the most common operative procedures is superior peroneal retinaculum (SPR) repair. Recently, surgery for RPTD has been achieved with less invasive arthroscopic procedures. In this article, tendoscopic surgery for RPTD using a double-row suture bridge technique is introduced. This technique consists of debridement of the lateral aspect of the fibula under an intrasheath pseudo-cavity, suture anchor insertion into the fibular ridge, and reattachment of the SPR to the fibula using a knotless anchor screwed into the lateral aspect of the fibula. This technique mimics the double-row suture bridge technique for rotator cuff tear repair. The double-row suture bridge technique requires more surgical steps than the single-row technique, but it provides a wider bone-SPR contact surface and tighter fixation than the single-row technique. This procedure is an attractive option because it is less invasive and has achieved results similar to open procedures.

Clinical Outcomes of Modified Mason-Allen Single-Row Repair for Bursal-Sided Partial-Thickness Rotator Cuff Tears: Comparison With the Double-Row Suture-Bridge Technique

BACKGROUND

Various repair techniques have been reported for the operative treatment of bursal-sided partial-thickness rotator cuff tears. Recently, arthroscopic single-row repair using a modified Mason-Allen technique has been introduced.

HYPOTHESIS

The arthroscopic, modified Mason-Allen single-row technique with preservation of the articular-sided tendon provides satisfactory clinical outcomes and similar results to the double-row suture-bridge technique after conversion of a partial-thickness tear to a full-thickness tear.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective study was conducted on 84 consecutive patients with symptomatic, bursal-sided partial-thickness rotator cuff tears involving more than 50% thickness of the tendon. A total of 47 patients were treated by the modified Mason-Allen single-row repair technique, preserving the articular-sided tendon, and 37 patients were treated by the double-row suture-bridge repair technique after conversion to a full-thickness tear. The clinical and functional outcomes were evaluated using the American Shoulder and Elbow Surgeons (ASES) and Constant scores and a visual analog scale (VAS) for pain and satisfaction of patients. Magnetic resonance imaging (MRI) was used to analyze the integrity of tendons at 6-month follow-up. Patients were followed up for a mean of 32.5 months.

RESULTS

In the 47 patients treated with the modified Mason-Allen suture technique, the VAS score decreased from a preoperative mean of 5.3 ± 0.3 to 0.9 ± 0.5 at the time of final follow-up. There was a statistically significant increase in the mean ASES score (from 45.4 ± 2.9 to 88.6 ± 4.5) and mean Constant score (from 66.9 ± 2.6 to 88.1 ± 2.4) (P < .001). Four of 47 patients (8.5%) demonstrated retears at 6-month postoperative MRI. There was no statistical difference in terms of functional outcomes and the retear rate compared with those of patients with the suture-bridge repair technique (3 patients, 8.1%). However, the mean number of suture anchors used in the patients with modified Mason-Allen suture repair (1.2 ± 0.4) was significantly fewer than that in the patients with suture-bridge repair (3.2 ± 0.4) (P < .01).

CONCLUSION

The modified Mason-Allen single-row repair technique that preserved the articular-sided tendon provided satisfactory clinical outcomes in patients with symptomatic, bursal-sided partial-thickness rotator cuff tears. Despite a fewer number of suture anchors, the shoulder functional outcomes and retear rate in patients after modified Mason-Allen repair were comparable with those of patients who underwent double-row suture-bridge repair. Therefore, the modified Mason-Allen single-row repair technique using a triple-loaded suture anchor can be considered as an effective treatment in patients with bursal-sided partial-thickness rotator cuff tears.

In vivo blood flow after rotator cuff reconstruction in a sheep model: comparison of single versus double row

PURPOSE

Arthroscopic double-row (DR) suture anchor repair of rotator cuff tears has been shown to be superior to most single-row (SR) techniques with regard to footprint reconstruction, load to failure and tendon-to-bone contact pressures. The hypothesis of this study was that the greater contact pressures of DR techniques would compromise blood flow to a higher degree than SR repair. The aim of this experimental study was to evaluate the effect of a DR and a SR technique on tendon blood flow in a sheep model.

METHODS

Eighteen sheep underwent detachment and immediate repair of the infraspinatus tendon using either a Mason-Allen or a suture-bridge technique. Tendon blood flow was measured using laser Doppler flowmetry before detachment, immediately after repair and 12 weeks thereafter. Six regions of interest were measured, three over the lateral and three over the medial aspect of the footprint.

RESULTS

Immediately after repair, tendon blood flow decreased significantly in both repair groups (P = 0.004). In the SR group, blood flow decreased by 100.1 arbitrary units (AU) (83.6 %) after repair, in the DR by 81.4 AU (90.5 %). Subgroup analysis showed blood flow over the lateral aspect of the footprint decreased by 126.3 AU (92.2 %) in the SR and 84.4 AU (90.9 %) in the DR group, whereas over the medial aspect, it decreased by 73.9 AU (72.0 %) in the SR and 78.5 AU (90.1 %) in the DR group. None of the differences between the groups were significant. At 12 weeks, measured blood flow in the DR group had increased to 90.1 AU (100.2 %) compared to the native tendons and was at 72.5 AU (60.5 %) for the SR group. Again, the difference between SR and DR group was not statistically significant (n.s.). Assessment for retears showed that 4 of 8 tendons (50 %) in the DR group and 3 of 9 tendons (33.3 %) in the SR group had to be classified as re-ruptures.

CONCLUSION

Suture anchor repair leads to an intraoperative decrease in tendon blood flow regardless of the repair technique. A significant difference between SR and DR repair was not found. These findings indicate that tendon blood flow should not be a factor to determine the use of either repair technique over the other.

Does autologous leukocyte-platelet-rich plasma improve tendon healing in arthroscopic repair of large or massive rotator cuff tears?

PURPOSE

To evaluate the clinical and magnetic resonance imaging (MRI) outcome of arthroscopic rotator cuff repair with the use of leukocyte-platelet-rich plasma (L-PRP) in patients with large or massive rotator cuff tears.

METHODS

A comparative cohort of patients with large or massive rotator cuff tears undergoing arthroscopic repair was studied. Two consecutive groups of patients were included: rotator cuff repairs with L-PRP injection (group 1, n = 35) and rotator cuff repairs without L-PRP injection (group 2, n = 35). A double-row cross-suture cuff repair was performed by a single surgeon with the same rehabilitation protocol. Patients were clinically evaluated with the Constant score; Simple Shoulder Test score; University of California, Los Angeles (UCLA) score; and strength measurements by use of a handheld dynamometer. Rotator cuff healing was evaluated by postoperative MRI using the Sugaya classification (type 1 to type 5).

RESULTS

We prospectively evaluated the 2 groups at a minimum 2-year follow-up. The results did not show differences in cuff healing between the 2 groups (P = .16). The size of recurrent tears (type 4 v type 5), however, was significantly smaller in group 1 (P = .008). There was no statistically significant difference in the recurrent tear rate (types 4 and 5) between the 2 groups (P = .65). There was no significant difference between group 1 and group 2 in terms of University of California, Los Angeles score (29.1 and 30.3, respectively; P = .90); Simple Shoulder Test score (9.9 and 10.2, respectively; P = .94); Constant score (77.3 and 78.1, respectively; P = .82); and strength (7.5 and 7.0, respectively; P = .51).

CONCLUSIONS

In our study the use of autologous L-PRP did not improve the quality of tendon healing in patients undergoing arthroscopic repair of large or massive rotator cuff tears based on postoperative MRI evaluation. The only significant advantage was that the L-PRP patients had smaller iterative tears. However, the functional outcome was similar in the 2 groups of patients.

LEVEL OF EVIDENCE

Level III, case-control study.

Tensile properties of a morphologically split supraspinatus tendon

The supraspinatus tendon consists morphologically of two sub-regions, anterior and posterior. The anterior sub-region is thick and tubular while the posterior is thin and strap-like. The purpose of this study was to compare the structural and mechanical properties of the anterior and posterior sub-regions of the supraspinatus tendon. The supraspinatus tendons from seven human cadaveric shoulders were morphologically divided into the anterior and posterior sub-regions. Length, width, and thickness were measured. A servo-hydraulic testing machine (MTS Systems Corporation, Minneapolis, MN) was used for tensile testing. The maximal load at failure, modulus of elasticity and ultimate tendon stress were calculated. Repeated measures were used for statistical comparisons. The mean anterior tendon cross-sectional area was 47.3 mm(2) and the posterior was 32.1 mm(2) . Failure occurred most often at the insertion site: anterior (5/7) and posterior (6/7). All parameters of the anterior sub-region were significantly greater than those of the posterior sub-region. The moduli of elasticity at the insertion site were 592.4 MPa in the anterior sub-region and 217.7 MPa in the posterior (P = 0.01). The ultimate failure loads were 779.2 N in the anterior sub-region and 335.6 N in the posterior (P = 0.003). The ultimate stresses were 22.1 MPa in the anterior sub-region and 11.6 MPa in the posterior (P = 0.008). We recognized that the anterior and posterior sub-regions of the SSP tendon have significantly different mechanical properties. In a future study, we need to evaluate how best to repair an SSP tendon considering these region-specific properties.

Outcomes of single-row versus double-row arthroscopic rotator cuff repair: a systematic review and meta-analysis of current evidence

PURPOSE

Our purpose was to perform a systematic review and meta-analysis of the clinical outcomes of single-row versus double-row repair.

METHODS

An electronic search was performed using PubMed, EMBASE, and the Cochrane Library up to September 30, 2012. Studies that met the inclusion and exclusion criteria were assessed for quality of methodology. The primary analysis included Level I evidence from studies examining single-row versus double-row repair. The second meta-analysis and subgroup analysis were performed for evidence Levels I, II, and III.

RESULTS

The primary analysis of studies providing 6 Level I randomized controlled trials showed no clinically significant differences in Constant scores, University of California, Los Angeles (UCLA), and American Shoulder and Elbow Surgeons (ASES) scores between double-row and single-row rotator cuff repair. The overall odds ratio (OR) of intact rotator cuff tendon healing was 1.93 in patients treated with double-row versus single-row repair, and the difference was significant. The results of the second meta-analysis including evidence Levels I, II, and III were similar to those of the primary analysis. In the subgroup with tears less than 3 cm, there was no statistically significant difference between the groups with regard to shoulder functional score and structure integrity. A statistically significant benefit of double-row repair in the ASES and UCLA scores was observed in the subgroup with tears greater than 3 cm; however, these differences were not clinically significant. The OR for tendon healing was found to be more favorable for double-row repair than for single-row repair in the subgroup with tears greater than 3 cm.

CONCLUSIONS

Double-row repair provides a significantly higher rate of intact tendon healing than does single-row repair, and this advantage was mainly reflected in patients with large or massive tears. However, this benefit did not translate into clinically confirmed functional improvement. Thus, the double-row technique should be used only in carefully selected patients.

LEVEL OF EVIDENCE

Level III, systematic review of Levels I, II, and III studies.

Biomechanical properties of double- and single-row suture anchor repair for surgical treatment of insertional Achilles tendinopathy

BACKGROUND

Because of intratendinous ossifications, retrocalcaneal bursitis, or intratendinous necrosis commonly found in insertional tendinosis, it is often necessary to detach the tendon partially or entirely from its tendon-to-bone junction.

HYPOTHESIS

Double-row repair for insertional Achilles tendinopathy will generate an increased contact area and demonstrate higher biomechanical stability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eighteen cadaver Achilles tendons were split longitudinally and detached, exposing the calcaneus; an ostectomy was performed and the tendon was reattached to the calcaneus in 1 of 2 ways: 2 suture anchors (single row) or a 4-anchor (double row) construct. Footprint area measurements over time, displacement after cyclic loading (2000 cycles), and final load to failure were measured.

RESULTS

The double-row refixation technique was statistically superior to the single-row technique in footprint area measurement initially and 5 minutes after repair (P = .009 and P = .01, respectively) but not after 24 hours (P = .713). The double-row construct demonstrated significantly improved measures for peak load (433.9 ± 84.3 N vs 212.0 ± 49.7 N; P = .042), load at yield (354.7 ± 106.2 N vs 198.7 ± 39.5 N; P = .01), and slope (51.8 ± 9.9 N/mm vs 66.7 ± 16.2 N/mm; P = .021). Cyclic loading did not demonstrate significant differences between the 2 constructs.

CONCLUSION

Double-row construct for reinsertion of a completely detached Achilles tendon using proximal and distal rows resulted in significantly larger contact area initially and 5 minutes after repair and led to significantly higher peak load to failure on destructive testing.

CLINICAL RELEVANCE

In treatment for insertional Achilles tendinosis, the tendon often has to be detached and anatomically reattached to its insertion at the calcaneus. To our knowledge there is a lack of biomechanical studies supporting either a number or a pattern of suture anchor fixation. Because the stresses going across the insertion site of the Achilles tendon are significant during rehabilitation and weightbearing activities, it is imperative to have a strong construct that allows satisfactory healing during the early postoperative process.

Characteristic retear patterns assessed by magnetic resonance imaging after arthroscopic double-row rotator cuff repair

PURPOSE

The purpose of this study was to examine magnetic resonance imaging (MRI) findings and elucidate retear pattern and its characteristics after surgical repair of the rotator cuff using an arthroscopic double-row suture anchor (DRSA) method.

METHODS

Forty-seven patients with complete rotator cuff tears treated by the DRSA method under arthroscopy whose repair condition was assessed by MRI approximately 12 months after the procedure were included in the study. The mean age at treatment was 65 years (range, 42 to 82 years). The mean follow-up period was 26 months (range, 24 to 32 months).

RESULT

The repair integrity was classified into 5 groups according to MRI findings. A well-repaired tendon was seen in 34 shoulders. Partial retearing of the deep layer was observed in 2. Partial retearing of the superficial layer around the medial anchors was observed in 3. Complete retearing of the tendon around the medial anchors with a well-preserved footprint was observed in 4. Complete retearing of the tendon from the footprint was observed in 4. The retear patterns involving superficial retearing and complete retearing around the medial anchors were unexpected and unique. These types of retears seem to be characteristic of the DRSA method and were seen in cases with medium-sized tears. The incidence of characteristic retearing was 7 of 47.

CONCLUSIONS

Superficial-side partial tearing and complete tearing around the medial-row anchors with a well-repaired tendon on the footprint could be characteristics of the DRSA method. These retear patterns were observed in 7 of 13 retear cases and 7 of 47 cases overall. The retear rate by the characteristic retear was high. Exploring the causes of this retear and preventing it could lead to better clinical results with the DRSA method.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Comparable biomechanical results for a modified single-row rotator cuff reconstruction using triple-loaded suture anchors versus a suture-bridging double-row repair

PURPOSE

To compare the biomechanical properties and footprint coverage of a single-row (SR) repair using a modified suture configuration versus a double-row (DR) suture-bridge repair in small to medium and medium to large rotator cuff tears.

METHODS

We created 25- and 35-mm artificial defects in the rotator cuff of 24 human cadaveric shoulders. The reconstructions were performed as either an SR repair with triple-loaded suture anchors (2 to 3 anchors) and a modified suture configuration or a modified suture-bridge DR repair (4 to 6 anchors). Reconstructions were cyclically loaded from 10 to 60 N. The load was increased stepwise up to 100, 180, and 250 N. Cyclic displacement and load to failure were determined. Furthermore, footprint widths were quantified.

RESULTS

In the 25-mm rupture, ultimate load to failure was 533 ± 107 N for the SR repair and 681 ± 250 N for the DR technique (P ≥ .21). In the 35-mm tear, ultimate load to failure was 792 ± 122 N for the SR reconstruction and 891 ± 174 N for the DR reconstruction (P ≥ .28). There were no statistically significant differences for both tested rupture sizes. Cyclic displacement showed no significant differences between the tested configurations at 60 N (P = .563), 100 N (P = .171), 180 N (P = .211), and 250 N (P = .478) for the 25-mm tear. For the 35-mm tear, cyclic displacement showed significantly lower gap formation for the SR reconstruction at 180 N (P = .037) and 250 N (P = .020). No significant differences were found at 60 N (P = .296) and 100 N (P = .077). A significantly greater footprint width (P = .028) was seen for the DR repair (16.2 mm) compared with the SR repair (13.8 mm). However, both reconstructions were able to achieve complete footprint coverage compared with the initial footprint.

CONCLUSIONS

The tested SR repair using a modified suture configuration was similar in load to failure and cyclic displacement to the DR suture-bridge technique independent of the tested initial sizes of the rupture. The tested DR repair consistently restored a larger footprint than the SR method. However, both constructs achieved complete footprint coverage.

CLINICAL RELEVANCE

SR repairs with modified suture configurations might combine the biomechanical advantages and increased footprint coverage that are described for DR repairs without increasing the overall costs of the reconstruction.

Tendon fixation in arthroscopic latissimus dorsi transfer for irreparable posterosuperior cuff tears: an in vitro biomechanical comparison of interference screw and suture anchors

BACKGROUND

The fixation of the tendon to the bone remains a challenging problem in the latissimus dorsi tendon transfer for irreparable cuff tears and can lead to unsatisfactory results. A new arthroscopic method of tendon to bone fixation using an interference screw has been developed and the purpose of this study was to compare its biomechanical properties to the ones of a standard fixation technique with anchors.

METHODS

Six paired fresh frozen cadaveric human humeri were used. The freed latissimus dorsi tendon was randomly fixed to the humeral head with anchors or with interference screw after a tubularization procedure. Testing consisted to apply 200 cycles of tensile load on the latissimus dorsi tendon with maximal loads of 30 N and 60 N, followed by a load to failure test. The stiffness, displacements after cyclic loadings, ultimate load to failure, and site of failure were analysed.

FINDINGS

The stiffness was statistically higher for the tendons fixed with interference screws than for the ones fixed with anchors for both 30 N and 60 N loadings. Likewise, the relative bone/tendon displacements after cyclic loadings were lower with interference screws compared to anchors. Load to failure revealed no statistical difference between the two techniques.

INTERPRETATION

Compared to the standard anchor fixation, the interference screw fixation technique presents higher or similar biomechanical performance. These results should be completed by further biomechanical and clinical trials to confirm the interest of this new technique as an alternative in clinical use.

Arthroscopic treatment of rotator cuff disease

The goal of this article is to summarize the current concepts on rotator cuff disease with an emphasis on arthroscopic treatment. Most rotator cuff tears are the result of an ongoing attritional process. Once present, a tear is likely to gradually increase in size. Partial-thickness and subscapularis tears can both be successfully treated arthroscopically if conservative management fails. Partial tears involving greater than 50% of tendon thickness should be repaired. Articular-sided partial tears involving less than 50% of the rotator cuff can reliably be treated with debridement. A more aggressive approach should be considered for low-grade tears (<50%) if they occur on the bursal side. Biomechanical and anatomic studies have shown clear superiority with dual-row fixation compared with single-row techniques. However, current studies have yet to show clear clinical advantage with dual-row over single-row repairs. Biceps tenotomy or tenodesis can reliably provide symptomatic improvement in patients with irreparable massive tears. True pseudoparalysis of the shoulder is a contraindication to this procedure alone and other alternatives should be considered.

Clinical and structural evaluation of arthroscopic double-row suture-bridge rotator cuff repair: early results of a novel technique

PURPOSE

Assessment of repair integrity and clinical outcome after arthroscopic repair of rotator cuff tears in double-row suture-bridge technique with the use of a new knotless suture-anchor system.

METHODS

The first treated 25 patients with arthroscopic rotator cuff repair in the suture-bridge technique using a novel knotless anchor and chain-link suture system were evaluated. Patients with isolated full-thickness supraspinatus tears were selected. They were followed clinically with functional scores (Constant score, ASES index), visual analog scale (VAS), and instrumentally with Isobex digital strength analyzer preoperatively, at 6 and 14 months postoperatively. The repair integrity was evaluated with MRI at an average of 14 months postoperatively.

RESULTS

Significant improvement of pain, strength, range of motion, and functional scores occurred (P < 0.05). There was a re-tear rate of 20%. The subjective parameters (VAS and ASES Index) showed non-significant (n.s.) differences between the re-tear and intact repair groups, whereas the objective parameters (Constant score, muscle power and active ROM) showed significant differences between both groups (P < 0.05).

CONCLUSION

The functional outcome has improved significantly with this new knotless anchor-chain system and was more superior in shoulders with intact repair, whereas the resulted repair integrity was not better than other types of double-row repair techniques mentioned in the recent literature. However, this early report of the novel technique may show limited power for comparison due to the relatively small sample size.