A biomechanical comparison of 2 technical variations of double-row rotator cuff fixation: the importance of medial row knots

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.

Comparison of clinical outcomes of arthroscopic rotator cuff repair utilizing suture-bridge procedures with or without medial knots: a meta-analysis

PURPOSE

This investigation aimed to compare the medical efficacy of the knotted and knotless suture-bridge procedures in rotator cuff repair.

METHODS

The Pubmed, Embase, and Cochrane Library datasets were searched for all available publications comparing the medical results of arthroscopic rotator cuff repairs utilizing knotted or knotless suture-bridge procedures. Two researchers utilized Newcastle-Ottawa Scale and Cochrane risk-of-bias tool to evaluate the included studies. Employing Revman 5.3 software, meta-analysis was conducted following the PRISMA reporting guideline.

RESULTS

Eleven investigations with 1083 patients were considered suitable for the final meta-analysis. 522 individuals were assigned to the knotted group, whereas 561 were assigned to the knotless group. No statistical difference was found between the knotted and knotless groups, regarding VAS score (WMD, 0.17; 95% CI, - 0.10 to 0.44; P = 0.21); Constant score (WMD, -1.50; 95% CI, - 3.52 to 0.52; P = 0.14); American Shoulder and Elbow Surgeons Shoulder (WMD, -2.02; 95% CI, - 4.53 to 0.49; P = 0.11); University of California Los Angeles score (WMD, -0.13; 95% CI, - 0.89 to 0.63; P = 0.73); ROM of flexion (WMD, 1.57; 95% CI, - 2.11 to 5.60; P = 0.37), abduction (WMD, 1.08; 95% CI, - 4.53 to 6.70; P = 0.71) and external rotation (WMD, 1.90; 95% CI, - 1.36 to 5.16; P = 0.25); re-tear rate (OR, 0.74; 95% CI, 0.50 to 1.08; P = 0.12), and medical complications (OR, 0.90; 95% CI, 0.37 to 2.20; P = 0.82).

CONCLUSION

For arthroscopic rotator cuff repairs, there were no statistical differences in medical results among knotted and knotless suture-bridge procedures. Overall, both techniques showed excellent clinical outcomes and could be safely utilized to treat rotator cuff injuries.

A comparison between knotted and knotless medial row of suture bridge technique in arthroscopic rotator cuff repair surgery: a meta-analysis

BACKGROUND

The shoulder arthroscopic suture bridge technique is currently very popular, but scientific evidence relating to the clinical outcomes of the medial row with or without knots has not been systematic reviewed.

PURPOSE

The purpose of this study was to compare the clinical outcomes of knotted versus knotless double-row suture bridges for rotator cuff repairs.

STUDY DESIGN

Meta-analysis.

METHOD

Five databases that contain literature in English were searched (Medline, PubMed, Embase, Web of Science, and the Cochrane Library), with a focus on works published between 2011 and 2022. Clinical data relating to arthroscopic rotator cuff repair with the suture bridge approach was examined and the outcomes of medial row knotting contrasted with that of the knotless technique. The search phrase used was: (double row) AND (rotator cuff) AND (repair), and the search method is subject term plus free word search. Literature quality evaluation was performed using the Cochrane "risk of bias" tool 1.0 and the Newcastle-Ottawa scale quality assessment instrument.

RESULTS

One randomized controlled trial, four prospective cohort studies, and five retrospective cohort studies were included in this meta-analysis. Data pertaining to 1146 patients was drawn from these ten original papers and analyzed. Meta-analyses that were performed on 11 postoperative outcomes revealed that none of the differences were statistically significant (P > 0.05) and that the publications were unbiased (P > 0.05). Postoperative retear rate and postoperative retear categorization were the outcomes assessed. Scores on postoperative pain, forward flexion, abduction, and external rotation mobility were collated and evaluated. The University of California, Los Angeles scoring systems in the first year following surgery, the American Shoulder and Elbow Surgeons score and Constant scales in the first and second years after surgery were the secondary outcomes spotlighted in this study.

CONCLUSION

The clinical outcomes of shoulder arthroscopic rotator cuff repair with the suture bridge technique with or without a knotted medial row was proven to be equivalent. These outcomes are about postoperative retear, postoperative retear classification, postoperative shoulder function score, postoperative shoulder mobility, and postoperative pain, respectively. It should be noted that the conclusions are based on short-term clinical follow-up data.

Modified Double-Pulley And Rip-Stop Suture Bridge Technique In Arthroscopic Rotator Cuff Repair

Numerous techniques have been formulated for increasing the tendon-bone contact area and for providing a better healing environment for the tendon in cases of rotator cuff tear. An ideal rotator cuff repair maximizes the tendon-bone interface and provides the rotator cuff with sufficient biomechanical strength for it to withstand a high load. In this article, we propose a technique with the advantages of both the double-pulley and the rip-stop suture-bridge techniques, which increases the pressurized contact area along the medial row, achieves higher failure loads than non-rip-stop techniques, and reduces tendon cut-through.

Arthroscopic Double-Row Repair of Posterosuperior Rotator Cuff Tears: Suture Bridge Technique Reinforced With Modified Mason-Allen and Simple Sutures

Rotator cuff (RC) tears represent one of the most common causes of pain and dysfunction of the shoulder. Numerous RC repair techniques have been reported. In this Technical Note, we introduce an arthroscopic double-row repair technique that combines a suture bridge construct with modified Mason-Allen and simple suture fixation to optimize load-sharing and compression of the RC to the footprint. The described technique is ideal for crescent-shaped and large reparable U-shaped posterosuperior RC tears.

Arthroscopic therapy of rotator cuff diseases: A bibliometric study of the past 2 decades (2002–2021)

Purpose

Rotator cuff diseases, as a common cause of shoulder pain and disability, have seriously affected the patients' daily life. Rotator cuff repair techniques have been a hot topic in the arthroscopic therapy field. Our study was to use bibliometrics analysis to clarify the current status and research trends in the field of arthroscopic therapy of rotator cuff diseases.

Methods

The publications relating to arthroscopic therapy of rotator cuff diseases published from 2001 to 2021 were obtained from the Web of Science Core Collection (WoSCC) database. The R software and VOSviewer software were used for the cross-sectional bibliometric and scientometric analysis.

Results

A total of 4,567 publications about arthroscopic therapy of rotator cuff diseases published between 2002 and 2021 retrieved from the WoSCC database were analyzed in our study. The results showed that the United States made the largest contribution to this field. The most relevant institutions were Seoul National University, Rush University, and Hospital for Special Surgery. Stephen S Burkhart was the most relevant researcher in this field with the largest number of publications, as well as the highest H-index and G-index. The journal ARTHROSCOPY contributed the largest number of publications in the past 2 decades. Considering the H-index and G-index, ARTHROSCOPY was also the journal with the largest impact in this field.

Conclusions

Arthroscopic Therapy of Rotator Cuff Diseases Related research presented a rising trend in the past 2 decades. The United States can be regarded as the leader because of its huge contributions to this field. The journal ARTHROSCOPY published the largest number of publications in this field. It can be predicted that research about advanced arthroscopic techniques and postoperative pain management of patients with rotator cuff diseases will be the next research hotspots in the following years.

Evaluation of the Clinical Outcomes of the Arthroscopic Treatment of Rotator Cuff Tears Using the Modified Suture Bridge Technique

Objective  To evaluate the postoperative clinical outcomes of the arthroscopic repair of rotator cuff injuries using a suture configuration we have developed based on a modification of the Suture Bridge (Arthrex, Naples, FL, United States). Methods  A retrospective study with 28 male (41.2%) and 40 female (58.8%) subjects with a mean age of 60 years. All patients underwent rotator cuff repair with the modified Suture Bridge technique and follow-up for a minimum period of 18 months. The clinical assessment was performed using the University of California, Los Angeles (UCLA) Shoulder Score. Results  The mean postoperative range of motion was of 134° (range: 110° to 140°) for elevation, 58° (range: 40° to 70°) for lateral rotation, and T10 (range: L4 to T7) for medial rotation. The mean increase was of 15° for elevation, 14° for lateral rotation, and 2 vertebral levels for medial rotation. The outcomes were excellent in 61 (83.6%) cases, good in 8 (10.9%), and regular in 4 cases (5.5%). Conclusion  The modified Suture Bridge technique for the arthroscopic repair of rotator cuff injuries led to excellent or good postoperative clinical outcomes in most cases (69; 94.5%).

A biomechanical study of the medial row tightening on stability of single stitch suture-bridge construct

Purpose

To define the more stable knot tightening of a suture bridge when a single limb is preserved.

Methods

Five different sutures were tested: No. 2 Ethibond (Ethicon), Hi-Fi (ConMed Linvatec), Sutblue (SBM), SingleFlat (SBM), Hi-Fi Ribbon (ConMed Linvatec). A Surgeon’s Knot was tied around a 30-mm circumference device, 6 times for each experiment. A single limb was kept to analyze failure modes of the knot. First step was to analyze which of pulling or sliding suture of the construct must be kept preventing failure of the knot. The cutting distance from the knot was evaluated at 1 mm and 4 mm with the suture loops pre-tensioned to 10 N and fixed to a second row after a 50 N tension load. The more stable construct was found: a single-pull load to 100 N and cyclic load (to 50 N for 30 cycles) experiments were conducted to evaluate the impact of cycling on knot loosening.

Results

The more stable construct was obtained when the non-post limb was tensioned, and the post limb was cut at 4 mm (p < 0.01). Loop circumference increased after each experiment for all tested sutures, independently of the preserved limb and the cutting distance. Elongation was significant for all tested sutures in all groups. Knot failure mostly occurred by slippage, only with tapes.

Conclusions

A suture-bridge construct with the non-post limb preserved and the post limb cut at a 4 mm distance from the knot provides with the best security. Sutures are safer than tapes in suture bridge.

Knotted Versus Knotless Medial-Row Transosseous-Equivalent Double-Row Rotator Cuff Repairs Have Similar Clinical and Functional Outcomes

Purpose

To retrospectively investigate the clinical and functional outcomes of patients who underwent knotted medial-row rotator cuff repair (KT-RCR) compared with patients who underwent knotless medial-row rotator cuff repair (KL-RCR).

Methods

A retrospective chart review of patients who underwent double-row transosseous-equivalent rotator cuff repair in 2016 was performed at a single institution with 2-year follow-up. Information regarding demographic characteristics, preoperative tear size (magnetic resonance imaging), surgical variables (including method of suture stabilization), preoperative and postoperative American Shoulder and Elbow Surgeons (ASES) scores, and all complications (e.g., cuff failure, adhesive capsulitis, and persistent pain) was compiled.

Results

A total of 189 patients met the inclusion criteria: 72 in the KL-RCR group and 117 in the KT-RCR group. No significant difference in preoperative ASES scores was found between the KL-RCR and KT-RCR groups (48.3 vs 45.4, P = .327). Postoperative ASES scores did not differ between the groups (82.4 for KL-RCR vs 78.8 for KT-RCR, P = .579). We found no significant difference in cuff failure rates after 2 years, determined by magnetic resonance imaging (5.6% for KL-RCR vs 6.1% for KT-RCR, P > .999), or complication rates (11.1% for KL-RCR vs 8.6% for KT-RCR, P = .743).

Conclusions

The knotted approach and knotless approach to double-row rotator cuff repair showed similar outcome scores, cuff failure rates, and complication rates at minimum 2-year follow-up.

Level of Evidence

Level III, retrospective therapeutic comparative trial.

Knotted Transosseous-Equivalent Technique for Rotator Cuff Repair Shows Superior Biomechanical Properties Compared With a Knotless Technique: A Systematic Review and Meta-analysis

PURPOSE

To compare the biomechanical properties of the knotted versus knotless transosseous-equivalent (TOE) techniques for rotator cuff repair (RCR).

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using PubMed, Embase, and the Cochrane Library to identify studies that compared the biomechanical properties of knotted and knotless TOE RCR techniques. The search phrase used was as follows: (Double Row) AND (rotator cuff) AND (repair) AND (biomechanical). Evaluated properties included ultimate load to failure, cyclic displacement, stiffness, footprint characteristics, and failure mode.

RESULTS

Eight studies met the inclusion criteria, including a total of 67 specimens in each group. Of 6 studies reporting on ultimate load to failure, 4 found tendons repaired with the knotted TOE technique to experience significantly higher ultimate load to failure compared with knotless TOE repairs (knotted range, 323.5-549.0 N; knotless range, 166.0-416.8 N; P < .05). Of 6 studies reporting on failure stiffness, 2 found knotted TOE repairs to have significantly higher failure stiffness compared with knotless TOE repairs (knotted range, 30.0-241.8 N/mm; knotless range, 28.0-182.5 N/mm; P < .05), whereas 1 study found significantly higher failure stiffness in knotless TOE repairs compared with knotted TOE repairs (P = .039). Cyclic gap formation favored the knotted TOE group in 2 of 3 studies (knotted range, 0.6-5.2 mm; knotless range, 0.4-9.1 mm; P < .05). The most common mode of failure in both groups was suture tendon tear.

CONCLUSIONS

On the basis of the included cadaveric studies, rotator cuff tendons repaired via the knotted TOE technique display superior time-zero biomechanical properties, including greater ultimate load to failure, compared with rotator cuffs repaired via the knotless TOE technique. Suture tearing through the tendon remains a common failure method for both techniques.

CLINICAL RELEVANCE

The results of this systematic review provide helpful insight into the biomechanical differences between 2 popular techniques for RCR. Although these results should be carefully considered by surgeons who are using either of these techniques in the operating room, they should not be mistaken for direct clinical applicability because cadaveric studies may not directly correlate to clinical outcomes.

Long-term follow-up of perianchor cyst formation after rotator cuff repair

Background

Perianchor cyst formation (PCF) can occur after arthroscopic rotator cuff repair with poly-L-lactic acid (PLLA) anchors; however, little is known about PCF after all-suture anchor (ASA) use.

Methods

We reviewed patients who underwent double-row arthroscopic rotator cuff repair from 2012 to 2017 with ASAs implanted in the medial row and PLLA anchors in the lateral row. We evaluated PCF (graded on magnetic resonance imaging) and compared physical examination and functional surveys between patients with PCF (WC) and without PCF (WoC) at long-term follow-up.

Results

Among twenty-two patients (23 shoulders), 93% of PLLA anchors (vs. 79% ASA) displayed a grade 0 PCF, P = .100. No PLLA anchors had a grade 3 or 4 PCF, compared to 11% of ASAs, P = .158. At a mean postoperative follow-up time of 113 weeks, there was no significant difference between WC and WoC cohorts with regard to range of motion, rotator cuff strength, American Shoulder and Elbow Surgeons survey scores, or retear rates. However, the WoC cohort had a significantly higher University of California at Los Angeles shoulder survey score at final follow-up (34.3 WoC vs. 30.9 WC, P = .024).

Conclusion

No difference was found in PCF between ASAs and PLLA anchors. At long-term follow-up, WoC patients had significantly improved functional outcome scores, based on the University of California at Los Angeles survey, but equivalent range of motion and rotator cuff strength examinations compared with WC patients.

Fixationssysteme und Techniken zur arthroskopischen Rotatorenmanschettenrekonstruktion

Arthroskopische Rotatorenmanschettenrekonstruktionen wurden initial mit einer einreihigen („single row“) Technik beschrieben. Im Rahmen technischer Weiterentwicklungen der arthroskopischen Chirurgie wurden diverse Techniken zur zweireihigen („double row“), transossären und transossär-äquivalenten Sehnenfixation entwickelt, nicht zuletzt durch eine zunehmende Verbreitung knotenloser Anker. Die klinischen Ergebnisse zeigen keine relevanten Unterschiede zwischen den jeweiligen Techniken. Biomechanisch sind zweireihige Rekonstruktionen jedoch durch Vergrößerung der Kontaktfläche an der Insertionsstelle und der erreichten Stabilität überlegen, insbesondere mit medial geknoteten Fäden, welche in eine laterale Reihe als sog. Suture-Bridge abgespannt werden. Klassischerweise wurden Schraubanker aus Metall für eine arthroskopische Sehnenfixierung verwendet. Im Laufe der letzten Jahre wurde das Anker-Portfolio jedoch durch moderne bioresorbierbare und nichtresorbierbare (PEEK) Schraub- und Einschlaganker sowie auch um reine Fadenanker (All-suture) erweitert. Ein allgemeingültiger Goldstandard für die Ankerverwendung existiert bis dato nicht, wobei die meisten gängigen Anker – zumindest bei guter Knochenqualität – ausreichende Stabilität gewährleisten. Beim Nahtmaterial kam es ebenso zu relevanten Weiterentwicklungen, sodass dem Versagen der Nähte heutzutage weniger Bedeutung zukommt. Das Aufkommen von bandartigem Nahtmaterial (Tapes) konnte in diversen biomechanischen Studien seine Überlegenheit nachweisen, jedoch ist bei geknoteten Techniken mit Tapes aufgrund des womöglich negativen Einflusses durch größere Knoten Vorsicht geboten. Nicht zuletzt ist die mediale Stichposition möglichst nahe des Rotatorenkabels von großer Bedeutung, da der häufigste Versagensmechanismus einer Rotatorenmanschettenrekonstruktion mit modernem Naht- und Ankermaterial weiterhin ein Hindurchschneiden der Fäden durch das vorgeschädigte Sehnengewebe ist.

Biomechanical Properties of Double-Row Transosseous Rotator Cuff Repair Combined With the Cinch Stitch in the Lateral Row

Background:

The self-cinching stitch has been verified to have high mechanical strength. The mechanical strength of combining transosseous rotator cuff repair (RCR) and the self-cinching stitch in the lateral row is unknown.

Purpose/Hypothesis:

The purpose of this study was to evaluate the biomechanical properties of transosseous RCR combined with the cinch stitch in the lateral row. We hypothesized that this construct would have better mechanical strength than would transosseous repair using a vertical cinch stitch or simple stitch.

Study Design:

Controlled laboratory study.

Methods:

Rotator cuff tears were simulated in 48 porcine shoulder specimens. The tears were repaired using 1 of 6 repair configurations: 2–simple stitch transosseous repair alone (group 2TO), with a vertical cinch stitch (group 2TO-VC), or with a horizontal cinch stitch (group 2TO-HC) or 4–simple stitch transosseous repair alone (group 4TO), with a vertical cinch stitch (group 4TO-VC), or with a horizontal cinch stitch (group 4TO-HC). All specimens were set at a 45° angle from the footprint and underwent cyclic loading from 10 to 160 N for 200 cycles, followed by a load-to-failure test at 10 mm/min.

Results:

During cyclic loading, all specimens in group 2TO and half of the specimens in group 2TO-VC failed by suture pullout. In the other groups, none of the specimens failed before 200 cycles. The yield load in group 2TO-HC was significantly greater than that in group 2TO-VC (261.43 vs 219.54 N, respectively; P < .05). There were significant differences between groups 4TO-HC and 4TO with regard to elongation (3.92 vs 5.68 mm, respectively), yield load (304.04 vs 246.94 N, respectively), and linear stiffness (63.44 vs 52.28 N/mm, respectively) (P < .01 for all). Group 4TO-HC also had shorter elongation and a superior yield load and linear stiffness compared with group 2TO-HC (P < .05 for all), and group 4TO-VC had shorter elongation and a stronger maximum load to failure and yield load than did group 2TO-VC (P < .05 for all).

Conclusion:

Increasing the number of medial simple stitches can prevent suture pullout. Adding the horizontal cinch stitch to the lateral row in transosseous repair can further improve biomechanical properties through a self-cinching mechanism.

Clinical Relevance:

Transosseous RCR with a horizontal cinch stitch in the lateral row may reduce the retear rate.

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.

Biomechanical evaluation of a novel double rip-stop technique with medial row knots for rotator cuff repair: an in vitro study

Aims

Many biomechanical studies have shown that the weakest biomechanical point of a rotator cuff repair is the suture-tendon interface at the medial row. We developed a novel double rip-stop (DRS) technique to enhance the strength at the medial row for rotator cuff repair. The objective of this study was to evaluate the biomechanical properties of the DRS technique with the conventional suture-bridge (SB) technique and to evaluate the biomechanical performance of the DRS technique with medial row knots.

Methods

A total of 24 fresh-frozen porcine shoulders were used. The infraspinatus tendons were sharply dissected and randomly repaired by one of three techniques: SB repair (SB group), DRS repair (DRS group), and DRS with medial row knots repair (DRSK group). Specimens were tested to failure. In addition, 3 mm gap formation was measured and ultimate failure load, stiffness, and failure modes were recorded.

Results

The mean load to create a 3 mm gap formation in the DRSK and DRS groups was significantly higher than in the SB group. The DRSK group had the highest load to failure with a mean ultimate failure load of 395.0 N (SD 56.8) compared to the SB and DRS groups, which recorded 147.1 N (SD 34.3) and 285.9 N (SD 89.8), respectively (p < 0.001 for both). The DRS group showed a significantly higher mean failure load than the SB group (p = 0.006). Both the DRS and DRSK groups showed significantly higher mean stiffness than the SB group.

Conclusion

The biomechanical properties of the DRS technique were significantly improved compared to the SB technique. The DRS technique with medial row knots showed superior biomechanical performance than the DRS technique alone.

Modified Double-Row Suture Bridge Technique With Double-Row Biceps Tenodesis for Massive Rotator Cuff Tear

This article aims to describe a modification of the arthroscopic suture bridge technique for repair of a massive (>3 cm) rotator cuff tear. The method uses 2 medial anchors and 2 lateral anchors for rotator cuff repair, as well as double-row biceps tenodesis. This operative modification may impart better tendon healing and fewer rupture complications than the traditional double-row repair techniques.

Is it necessary to tie the medial row in rotator cuff repair double-row constructs when using suture tape?

PURPOSE

To evaluate the selected biomechanical differences of a double-row trans-osseous equivalent rotator cuff repair with a knotless versus knot-tying medial row using suture tape in regard to repair displacement, stiffness, and ultimate load to failure.

METHODS

In 16 fresh-frozen human shoulders (8 matched pairs), double-row rotator cuff repairs were performed with medial-row mattress knots (MK) on one side, the other without (NK). Two DVRT (Differential Variable Reluctance Transducer) sensors were attached between the humerus and 3 mm above the repair site and were used to measure the displacement across the repair during cycling. The biomechanical parameters measured were repair displacement, stiffness, and ultimate load to failure. The supraspinatus was loaded in a similar fashion to previously described protocol using cyclic loading and load to failure testing.¹.

RESULTS

All data from paired specimens were compared using paired Student t tests. No statistically significant difference (SSD) in displacement across the repair over the 200 cycles of the test was noted between the two groups (MK = 0.591 ± 0.501 mm; NK = 0.439 ± 0.417 mm, p = 0.618). No SSD in stiffness was noted between the two groups (MK = 32.87 ± 6.31 N/mm; NK = 27.98 ± 9.69 N/mm, p = 0.120). No SSD in ultimate load to failure was noted between the two groups (MK = 501.2 ± 126.1 N; NK = 416.8 ± 120.0 N, p = 0.116).

CONCLUSION

There was no statistically significant different between knotless versus knotted medial row double row rotator cuff repair constructs using suture tape in regard to displacement across the repair site, stiffness and ultimate load to failure. Despite previous evidence suggesting inferiority of knotless medial row technique using suture constructs, this evidence may support the biomechanical equivalency of knotless medial row technique using suture tape.

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

There is substantial evidence indicating that double-row (DR) repair restores more of the anatomic rotator cuff footprint and is biomechanically superior to single-row (SR) repair. Transosseous-equivalent (TOE) techniques have shown biomechanical advantages when compared with traditional DR, including increased contact at the rotator cuff footprint, higher pressure at the tendon-bone interface, and increased failure strength. Several meta-analyses of evidence level 1 and 2 studies have shown a lower rate of failed/incomplete healing when DR repair was compared with SR repair types. There is some limited evidence that TOE techniques improve healing rates in large and massive tears as compared with SR and DR. Overall, most level 1 and 2 studies have failed to prove a significant difference between SR and DR repairs in terms of clinical outcomes. However, most studies include only short-term follow-up, minimizing the impact that the higher rate of retears/failed healing seen with SR repairs can have in the long term. There are no high-quality clinical studies comparing different DR configurations, and there are currently not enough clinical data to determine the functional advantages of various DR technique modifications over one another. Although numerous biomechanical and clinical studies comparing different rotator cuff repair techniques have been published in the past decade, none has achieved universal acceptance. It is essential for the orthopaedic surgeon to know in detail the available literature to be able to apply the most appropriate and cost-effective technique in terms of healing and functional outcomes. This review provides a critical analysis of the comparative biomechanical and clinical studies among SR, DR, and TOE techniques reported in the literature in the past decade.

Arthroscopic Rotator Cuff Repair in 2019: Linked, Double Row Repair for Achieving Higher Healing Rates and Optimal Clinical Outcomes

The primary aim of rotator cuff repair surgery is to restore the musculotendinous units by creating a complete, tension-free repair construct that optimizes conditions for tendon-to-bone healing. There are many factors outside the control of the surgeon that are capable of affecting the healing process; however, there are also a number of important technical considerations that the surgeon can control, including familiarity with methods to deal with immobile tissues and techniques to perform novel repair constructs. It is clear that linked double row repairs are more likely to heal, and healed rotator cuff repairs best restore shoulder strength, improve patients' satisfaction, and maximize functional outcomes.

Biomechanical Strength of Rotator Cuff Repairs: A Systematic Review and Meta-regression Analysis of Cadaveric Studies

BACKGROUND

Biomechanical cadaveric studies of rotator cuff repair (RCR) have shown that transosseous equivalent and double-row anchored repairs are stronger than other repair constructs.

PURPOSE

To identify technical and procedural parameters that most reliably predict biomechanical performance of RCR constructs.

STUDY DESIGN

Systematic review.

METHODS

The authors systematically searched the EMBASE and PubMed databases for biomechanical studies that measured RCR performance in cadaveric specimens. The authors performed a meta-regression on the pooled data set with study outcomes (gap formation, failure mode, and ultimate failure load) as dependent variables and procedural parameters (eg, construct type, number of suture limbs) as covariates. Stratification by covariates was performed. An alpha level of .05 was used.

RESULTS

Data from 40 eligible studies were included. Higher number of suture limbs correlated with higher ultimate failure load (β = 38 N per limb; 95% CI, 28 to 49 N) and less gap formation (β = -0.6 mm per limb; 95% CI, -1 to -0.2 mm). Other positive predictors of ultimate failure load were number of sutures, number of mattress stitches, and use of wide suture versus standard suture. When controlling for number of suture limbs, we found no significant differences among single-row anchored, double-row anchored, transosseous equivalent, and transosseous repairs. Higher number of suture limbs and transosseous equivalent repair both increased the probability of catastrophic construct failure.

CONCLUSION

This study suggests that the number of sutures, suture limbs, and mattress stitches in a RCR construct are stronger predictors of overall strength than is construct type. There is a need to balance increased construct strength with higher risk of type 2 failure.

Arthroscopic double-row rotator cuff repair: a comprehensive review of the literature

Rotator cuff repairs seek to achieve adequate tendon fixation and to secure the fixation during the process of biological healing. Currently, arthroscopic rotator cuff repair has become the gold standard. One of the earliest defined techniques is single-row repair but the inadequacy of single-row repair to precisely restore the anatomical footprint as well as the significant rates of retear especially in large tears have led surgeons to seek other techniques. Double-row repair techniques, which have been developed in response to these concerns, have various modifications like the number and placement of anchors and suture configurations.

When the literature is reviewed, it is possible to say that double-row repairs demonstrate superior biomechanical properties. In regard to retear rates, both double row and transosseous equivalent (TOE) techniques have also yielded more favorable outcomes compared to single-row repair. But the clinical results are conflicting and more studies have to be conducted. However, it is more probable that superior structural integrity will yield better structural and functional results in the long run. TOE repair technique is regarded as promising in terms of better biomechanics and healing since it provides better footprint contact. Knotless TOE structures are believed to reduce impingement on the medial side of tendons and thus aid in tendon nutrition; however, there are not enough studies about its effectiveness.

It is important to optimize the costs without endangering the treatment of the patients. We believe that the arthroscopic TOE repair technique will yield superior results in regard to both repair integrity and functionality, especially with tears larger than 3 cm. Although defining the pattern of the tear is one of the most important guiding steps when selecting the repair technique, the surgeon should not forget to evaluate every patient individually for tendon healing capacity and functional expectations.

Clinical and structural outcomes after arthroscopic rotator cuff repair: a comparison between suture bridge techniques with or without medial knot tying

Purpose

To compare arthroscopic suture bridge (SB) techniques with medial tying to those without tying, considering clinical and structural outcomes.

Methods

We included 124 patients with rotator cuff tears after arthroscopic rotator cuff repair (ARCR). Fifty-three patients with clinical and structural evaluations 3, 12, and 24 months postoperatively were included and divided into 29 patients with medial tying (WMT group) and 24 without tying (WOMT group). Clinical outcomes comprised the University of California Los Angeles (UCLA) and Japanese Orthopaedic Association (JOA) scores. Structural outcomes were evaluated with magnetic resonance images (MRI) using Sugaya classifications.

Results

JOA and UCLA scores in the WMT and WOMT groups improved significantly from before surgery to 24 months after surgery (P < 0.01, respectively). No significant difference was noted between groups. No significant postoperative retears (Sugaya types 4 and 5) between WMT and WOMT groups were noted at 3 months (5 vs 3 cases), 12 months (6 vs 5 cases), and 24 months (7 vs 6 cases) postoperatively. Complete healing (Sugaya type 1) was noted at 3 months (8 vs 11 cases), 12 months (10 vs 10 cases), and 24 months (8 vs 13 cases, P = 0.024) postoperatively. Incomplete healing (Sugaya types 2 and 3) were noted at 3 months (16 vs 10 cases), 12 months (13 vs 9 cases), and 24 months (14 vs 5 cases, P = 0.024) postoperatively.

Conclusion

Clinical outcomes for both techniques were comparable, but the number of incompletely healed tendons in SB with medial tying was significantly larger at 24 months after surgery.

Level of evidence

This study is a level III, case-control study.

Clinical relevance

This study revealed the influence of medial tying in rotator cuff repair.

Knotless Fixation Is Stronger and Less Variable Than Knotted Constructs in Securing a Suture Loop

Background:

Historically, tendon-to-bone fixation has relied on knot tying. However, considerable variability exists in knot-tying strength among surgeons.

Purpose/Hypothesis:

The purpose of this study was to compare the biomechanical properties of knotted and knotless fixation and to evaluate variability among surgeons. The hypothesis was that knotless constructs would be stronger and have less variability as compared with knotted constructs.

Study Design:

Controlled laboratory study.

Methods:

A total of 34 orthopaedic surgeons participated in a laboratory study to compare knotted and knotless constructs, where 104 knotted constructs were performed with No. 2 suture, 21 knotless constructs with No. 2 suture (K2 group), and 79 knotless constructs with suture tape (KT group). Mechanical testing was performed to compare load at 3 mm of displacement, load to failure, and stiffness of each construct.

Results:

The mean load at 3 mm of displacement was greatest in the KT group, with significant differences among all 3 groups (P < .001). Load to failure was significantly greater in the KT group as compared with the K2 group and the knotted group (P < .001), but there was no difference between the K2 and knotted groups (P ≥ .999). Stiffness and displacement were also greatest in the KT group. Based on the F test, the variance in load to failure was significantly different between the knotted and knotless constructs, with the knotted group demonstrating greater variability (SD, 94 N) than the KT (SD, 38 N) and K2 (SD, 17 N) groups (P < .001).

Conclusion:

Knotless fixation with suture tape had improved biomechanical performance as compared with knots or knotless fixation with No. 2 suture. In addition, knotless fixation had less variability in biomechanical properties among multiple surgeons.

Clinical Relevance:

This study may be relevant for surgeons choosing between knotted and knotless constructs as well as for considerations in the design of rotator cuff repair constructs.

Arthroscopic knotless rotator cuff repair: Factors associated with construct selection and recent trends from a manual review of 1617 cases

Purpose

Our aim was to identify predictors of construct selection and recent trends for arthroscopic knotless rotator cuff repair (RCR).

Methods

A manual review of 1617 operative reports was performed.

Results

A medium-sized tear had a threefold increase in odds of single row (SR) knotless repair (OR, 6.91; p = 0.009) versus SR knotted (OR, 3.05; p = 0.003). Generalist orthopaedic surgeons were 79% less likely to perform SR knotless repairs versus sports medicine trained specialists (p < 0.001).

Conclusion

There was a significant increase from 2009 to 2016 in SR knotless and double row medial row knotless constructs contrasting the declining use of the SR knotted technique.

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.

[Arthroscopic rotator cuff surgery : New and established methods]

This present article summarizes established and current developments and aspects of rotator cuff surgery. Achieved milestones as well as current approaches are presented and assessed with respect to their clinical and radiographic impact. Despite biomechanical and technical improvements in modern rotator cuff repair techniques, re-defect and re-tearing rates could not be fully eliminated. Meanwhile, the importance of biological processes around successful tendon-bone reintegration has been increasingly recognized. Hence, this article presents the current scientific standing regarding biological growth factors, platelet-rich plasma and rotator cuff augmentation techniques (with allogenic/autologous grafts). In summary, there are clear biomechanical advantages as well as many promising approaches to biological augmentation; however, the latter have not yet been transferred into regular clinical application.

Knotless double-row SutureBridge rotator cuff repairs have improved self-reinforcement compared with double-row SutureBridge repairs with tied medial knots: a biomechanical study using an ovine model

BACKGROUND

In double-row SutureBridge (Arthrex, Naples, FL, USA) rotator cuff repairs, increasing tendon load may generate progressively greater compression forces at the repair footprint (self-reinforcement). SutureBridge rotator cuff repairs using tied horizontal mattress sutures medially may limit this effect compared with a knotless construct.

MATERIALS AND METHODS

Rotator cuff repairs were performed in 9 pairs of ovine shoulders. One group underwent repair with a double-row SutureBridge construct with tied horizontal medial-row mattress sutures. The other group underwent repair in an identical fashion except that medial-row knots were not tied. Footprint contact pressure was measured at 0° and 20° of abduction under loads of 0 to 60 N. Pull-to-failure tests were then performed.

RESULTS

In both repair constructs, each 10-N increase in rotator cuff tensile load led to a significant increase in footprint contact pressure (P < .0001). The rate of increase in footprint contact pressure was greater in the knotless construct (P < .00022; ratio, 1.69). The yield point approached the ultimate load to failure more closely in the knotless model than in the knotted construct (P = .00094). There was no difference in stiffness, ultimate failure load, or total energy to failure between the knotless and knotted techniques.

CONCLUSION

In rotator cuff repair with a double-row SutureBridge configuration, self-reinforcement is seen in repairs with and without medial-row knots. Self-reinforcement is greater with the knotless technique.

"Double-Row Rip-Stop" Technique for Arthroscopic Rotator Cuff Repair

Rotator cuff repair depends on both the fixation strength of the chosen repair construct and the local healing response of the repaired tissue. Among a growing discussion surrounding the superiority of one surgical technique over another, the surgeon's ability to complete a rotator cuff repair with technical acuity in a timely manner remains paramount. Double-row repairs as well as rip-stop configurations have been proposed to limit failures found after arthroscopic rotator cuff repairs. Implementation of both techniques during arthroscopic shoulder surgery may represent a technical challenge for the average orthopaedist. The purpose of this article is to give simple instructions for reproduction of an arthroscopic double-row rip-stop repair for rotator cuff fixation.

Tight medial knot tying may increase retearing risk after transosseous equivalent repair of rotator cuff tendon

BACKGROUND

Retearing mechanism after transosseous equivalent (TOE) rotator cuff repair has not been fully clarified yet.

OBJECTIVE

The purposes of this study were to compare the stress distribution pattern in the tendon stump between knotted and knotless TOE repair and to investigate the role of suture tension applied during medial knot tying using a 3-dimensional finite element (3D-FE) method.

METHODS

Both knotted and knotless TOE repairs were simulated on the 3D-FE human rotator cuff tear model. Elastic analysis was performed to compare the stress distribution pattern inside the tendon between the two models. The amount of compressive load applied to the medial-row sutures was then changed as 0, 20, 40, 60, 80, and 100 N in the knotted model.

RESULTS

Knotted model demonstrated more distinct stress concentration inside the tendon around medial-row sutures than the knotless model. Mean von Mises equivalent stress in this area in the 0, 20, 40, 60, 80, and 100 N models was 0.26, 0.35, 0.50, 0.70, 1.11, and 1.14 MPa, respectively.

CONCLUSIONS

In the knotted TOE repair, tight medial knot tying might cause a high stress concentration around medial knots, which may constitute one of the pathogenetic factors of postoperative retearing at this site.

Suture Anchor Fixation in Osteoporotic Bone: A Biomechanical Study in an Ovine Model

PURPOSE

To evaluate the load to failure strength of anchor techniques suitable for osteoporotic bone.

METHODS

Using an osteoporotic ovine model in 72 humeri, 6 fixation techniques were tested. Group 1: two interlocking 5-mm anchors with fewer, wider threads; group 2: one 5-mm anchor; group 3: one 5-mm anchor reinforced laterally by a 6.5-mm cancellous screw; group 4: one 5-mm anchor in an area reinforced with a cancellous plug; group 5: two interlocking 5-mm anchors with smaller threads; group 6: one 5-mm smaller threaded anchor. After a 10-N preload, the specimens were cyclically loaded between 10 N and 30 N for 50 cycles and then destructively tested. Peak-to-peak displacement, cyclic elongation, ultimate load, stiffness, and failure mode were recorded.

RESULTS

Group 1 had lower peak-to-peak displacement than group 3 (P = .001), group 5 (P = .001), and group 6 (P = .033). In addition, group 1 showed lower cyclic elongation than group 3 (P = .001), group 5 (P = .035), and group 6 (P = .001). Group 1 had a higher ultimate load than group 2 (P = .002), group 3 (P = .019), and group 6 (P = .006). Group 1 also showed higher stiffness than group 2 (P = .007) and group 3 (P = .022). Mode of failure was predominantly caused by anchor pullout for all of the groups except group 3, which mainly failed by suture rupture.

CONCLUSIONS

Two interlocking suture anchors are stronger than a single anchor in osteoporotic bone. The anchor with fewer, wider threads and a smaller core diameter showed greater strength and less elongation than the other constructs. Reinforcement by cancellous autografting increased suture anchor strength.

CLINICAL RELEVANCE

Considering concerns about suture anchor pullout from osteoporotic bone, interlocking a second suture anchor with the first increases load to failure resistance. Anchors with small core diameters and fewer but wider threads are more efficient in osteoporotic bone.

Biomechanical Comparison of Modified Suture Bridge Using Rip-Stop versus Traditional Suture Bridge for Rotator Cuff Repair

Purpose. To compare the biomechanical properties of 3 suture-bridge techniques for rotator cuff repair. Methods. Twelve pair-matched fresh-frozen shoulder specimens were randomized to 3 groups of different repair types: the medially Knotted Suture Bridge (KSB), the medially Untied Suture Bridge (USB), and the Modified Suture Bridge (MSB). Cyclic loading and load-to-failure test were performed. Parameters of elongation, stiffness, load at failure, and mode of failure were recorded. Results. The MSB technique had the significantly greatest load to failure (515.6 ± 78.0 N, P = 0.04 for KSB group; P < 0.001 for USB group), stiffness (58.0 ± 10.7 N/mm, P = 0.005 for KSB group; P < 0.001 for USB group), and lowest elongation (1.49 ± 0.39 mm, P = 0.009 for KSB group; P = 0.001 for USB group) among 3 groups. The KSB repair had significantly higher ultimate load (443.5 ± 65.0 N) than USB repair (363.5 ± 52.3 N, P = 0.024). However, there was no statistical difference in stiffness and elongation between KSB and USB technique (P = 0.396 for stiffness and P = 0.242 for elongation, resp.). The failure mode for all specimens was suture pulling through the cuff tendon. Conclusions. Our modified suture bridge technique (MSB) may provide enhanced biomechanical properties when compared with medially knotted or knotless repair. Clinical Relevance. Our modified technique may represent a promising alternative in arthroscopic rotator cuff repair.

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.

The Medial Stitch in Transosseous-Equivalent Rotator Cuff Repair: Vertical or Horizontal Mattress?

BACKGROUND

Despite advances in surgical technique, rotator cuff repair retears continue to occur at rates of 10%, 22%, and 57% for small, medium, and large tears, respectively. A common mode of failure in transosseous-equivalent rotator cuff repairs is tissue pullout of the medial mattress stitch. While the medial mattress stitch has been studied extensively, no studies have evaluated a vertical mattress pattern placed near the musculotendinous junction in comparison with a horizontal mattress pattern.

HYPOTHESIS

Vertical mattress stitches will have higher load to failure and lower gapping compared with horizontal mattress stitches in a transosseous-equivalent rotator cuff repair.

STUDY DESIGN

Controlled laboratory study.

METHODS

Double-row transosseous-equivalent rotator cuff repairs were performed in 9 pairs of human male cadaveric shoulders (mean age ± SD, 58 ± 10 years). One shoulder in each pair received a medial-row suture pattern using a vertical mattress stitch, and the contralateral shoulder received a horizontal mattress. Specimens were mounted in a materials testing machine and tested in uniaxial tensile deformation for cyclic loading (500 cycles at 1 Hz to 1.0 MPa of effective stress), followed by failure testing carried out at a rate of 1 mm/s. Construct gapping and applied loads were monitored continuously throughout the testing.

RESULTS

Vertical mattress sutures were placed in 5 right and 4 left shoulders. Peak cyclic gapping did not differ between vertical (mean ± SD, 2.8 ± 1.1 mm) and horizontal mattress specimens (3.0 ± 1.2 mm) (P = .684). Vertical mattress sutures failed at higher loads compared with horizontal mattress sutures (568.9 ± 140.3 vs 451.1 ± 174.3 N; P = .025); however, there was no significant difference in failure displacement (8.0 ± 1.6 vs 6.0 ± 2.1 mm; P = .092). Failure stiffness did not differ between the suture patterns (P = .204).

CONCLUSION

In transosseous-equivalent rotator cuff repairs near the musculotendinous junction, a vertical mattress suture used as the medial stitch has a higher load to failure but no difference in gapping compared with a horizontal mattress pattern.

CLINICAL RELEVANCE

A vertical mattress suture may offer enhanced strength of repair for transosseous-equivalent repairs.

Footprint Contact Area and Interface Pressure Comparison Between the Knotless and Knot-Tying Transosseous-Equivalent Technique for Rotator Cuff Repair

PURPOSE

To quantify and compare the footprint contact area and interface pressure on the greater tuberosity between knotless and knot-tying transosseous-equivalent (TOE) repair using pressure-sensitive film.

METHODS

We used 11 pairs of fresh-frozen cadaveric shoulders (22 specimens), in which rotator cuff tears were created before repair. Each pair was randomized to either conventional medial knot-tying TOE repair (group A) or medial knotless TOE repair using the modified Mason-Allen technique (group B). Pressure-sensitive film was used to quantify the pressurized contact area and interface pressure between the greater tuberosity and supraspinatus tendon.

RESULTS

The mean pressurized contact area was 33.2 ± 2.5 mm(2) for group A and 28.4 ± 2.4 mm(2) for group B. There was a significant difference between groups (P = .005). Although the overall contact configuration of both groups was similar and showed an M shape, group A showed a greater pressurized configuration around the medial row. The mean interface pressure was 0.20 ± 0.02 MPa for group A and 0.17 ± 0.02 MPa for group B. There was a significant difference between groups (P = .001).

CONCLUSIONS

Contrary to our hypothesis, in this time-zero study, medial knotless TOE repair using a modified Mason-Allen suture produced a significantly inferior footprint contact area and interface pressure compared with conventional medial knot-tying TOE repair.

CLINICAL RELEVANCE

Even though we found a statistically significant difference between the 2 repair methods, it is still unknown if this statistical difference seen in our study has any clinical and radiologic significance.

Biomechanical comparison of traditional anchors to all-suture anchors in a double-row rotator cuff repair cadaver model

BACKGROUND

To further reduce the invasiveness of arthroscopic rotator cuff repair surgery the all-suture anchor has been developed. The all-suture anchor requires less bone removal and reduces the potential of loose body complications. The all-suture anchor must also have adequate biomechanical strength for the repair to heal. The hypothesis is there is no significant difference in the biomechanical performance of supraspinatus repairs using an all-suture anchor when compared to traditional solid-body suture anchors.

METHODS

Using nine shoulders per group, the supraspinatus tendon was dissected from the greater tuberosity. The four different double row repairs tested were (medial row/lateral row): A: ICONIX2/ICONIX2; B: ICONIX2/Stryker ReelX 3.9mm; C: ICONIX2/Stryker ReelX 4.5mm; D: Arthrex BioComposite CorkScrew FT 4.5mm/Arthrex BioComposite SwiveLock 4.75mm. The ICONIX2 was the only all-suture anchor tested. Tendons underwent cyclic loading from 10 to 100N for 500 cycles, followed by load-to-failure. Data was collected at cycles 5, 100, 200, 300, 400, and 500. One-way ANOVA analysis was used to assess significance (P≤0.05).

FINDINGS

The anchor combinations tested did not differ significantly in anterior (P>0.4) or posterior (P>0.3) gap formation, construct stiffness (P>0.7), ultimate load (P=0.06), or load to 5mm gap formation (P=0.84).

INTERPRETATION

The all-suture anchor demonstrated comparable biomechanical performance in multiple double-row anchor combinations to a combination of traditional solid-body anchors. Thus it may be an attractive option to further reduce the invasiveness of rotator cuff repairs.

A review of biomechanics of the shoulder and biomechanical concepts of rotator cuff repair

In this article, we describe the basic knowledge about shoulder biomechanics, which is thought to be useful for surgeons. Some clinical reports have described that the excellent outcome after cuff repair without acromioplasty and a limited acromioplasty might be enough for subacromial decompression. It was biomechanically demonstrated that a 10-mm medial shift of the tendon repair site has a minimum effect on biomechanics. Many biomechanical studies reported that the transosseous equivalent repair was superior to other techniques, although the tendon may lose its inherent elasticity. We herein introduce our recent experiment data and latest information on biomechanics.

Suture placement near the musculotendinous junction in the supraspinatus: implications for rotator cuff repair

BACKGROUND

Transosseous-equivalent rotator cuff repair has an increased incidence of medial rotator cuff failure compared with single-row repair. No studies have evaluated the influence of the proximity of the suture row to the musculotendinous junction (MTJ) on cyclic gapping and failure properties.

HYPOTHESIS

A single row of horizontal mattress sutures placed within the supraspinatus tendon lateral to the MTJ will experience less gap formation and higher failure loads than a similar suture row placed at the MTJ.

STUDY DESIGN

Controlled laboratory study.

METHODS

Paired supraspinatus tendons were isolated from human cadaveric specimens and resected at the tendon insertion to the humerus. Randomized within a pair, a single row of 4 horizontal mattress sutures was placed either in the tendon 5 mm lateral to the MTJ or at the MTJ. The tied sutures secured the tendon to a fixture that ensured consistent placement of the suture row in the tendon and static fixation of the row. The muscle belly was gripped in a cryoclamp, and a servohydraulic materials testing machine was used to provide uniaxial tensile deformation for 500 cycles at 1 Hz, followed by load to failure at 1 mm/s. Fiducial markers with video tracking were used to quantify gap formation at the suture line, while the materials testing machine recorded loading for the cyclic and failure tests.

RESULTS

During cyclic loading, both constructs experienced gross initial gap formation, followed by progressive gap formation that plateaued after cycle 200. The MTJ specimens had significantly higher mean cumulative gapping than the tendon specimens: 3.6±1.0 mm versus 2.4±0.6 mm, respectively (P=.012). The tendon specimens had significantly higher mean loads to failure than did the MTJ specimens: 567.1±121.8 N versus 434.2±148.1 N, respectively (P=.013). The mean failure displacement did not differ between groups for the tendon and MTJ: 5.7±2.5 mm versus 4.5±2.0 mm, respectively (P=.144).

CONCLUSION

A horizontal suture row placed at the MTJ has inferior mechanical properties (increased gapping, decreased load support) as compared with a suture row placed 5 mm laterally within the tendon.

CLINICAL RELEVANCE

The integrity of rotator cuff repair may be compromised if sutures are placed too close to the MTJ.

Does transosseous-equivalent rotator cuff repair biomechanically provide a "self-reinforcement" effect compared with single-row repair?

BACKGROUND

Transosseous-equivalent (TOE) rotator cuff repair has been theorized to be "self-reinforcing" against potentially destructive and increasing tendon loads. The goal of this study was to biomechanically verify and characterize the effect of increasing tendon load on frictional resistance over a repaired footprint for single-row (SR) and TOE repair techniques.

METHODS

In 10 fresh frozen human shoulders, TOE and SR supraspinatus tendon repairs were performed in each specimen. For all repairs, a pressure sensor was secured at the tendon-footprint interface. The supraspinatus tendon was loaded with 0, 20, 40, 60, and 80 N at 0° and 30° abduction. Paired t tests and multivariate regression analyses were used for comparisons.

RESULTS

The SR repair had significant increases in footprint contact force, area, and pressure between each and all tendon-loading conditions (P < .05). The TOE repair similarly demonstrated increases in footprint contact force with increasing tendon load (P < .05). Comparing between repairs, TOE repair had more footprint contact force, area, pressure, and peak pressure at each load for both abduction angles (P < .05). With increasing load, the TOE repair had a significantly higher progression (slope) of footprint force and pressure compared with the SR repair.

CONCLUSIONS

Self-reinforcing capacity in rotator cuff repair has been biomechanically characterized and verified. The TOE repair, with tendon-bridging sutures fixed medially and spanning the footprint, provides disproportionately more progressive footprint frictional resistance with increasing tendon loads compared with the SR repair secured over isolated fixation points. This self-reinforcing effect could help sustain structural integrity and potentially improve healing biology.

Knotted versus knotless suture bridge repair of the achilles tendon insertion: a biomechanical study

BACKGROUND

Surgical treatment of insertional Achilles tendinopathy often involves detachment and debridement of the Achilles tendon insertion. A recent study has shown that knotted suture bridge fixation of the Achilles to the calcaneus is biomechanically superior to single-row fixation, but there is an absence of literature on the use of different suture bridge constructs to repair the Achilles tendon.

HYPOTHESIS

There will be no significant difference in the load to failure, mode of failure, tendon strain, tendon stiffness, repair site gapping, or footprint size when comparing knotted suture bridge repair to knotless suture bridge repair of the Achilles tendon after detachment for insertional Achilles tendinopathy.

STUDY DESIGN

Controlled laboratory study.

METHODS

A single specimen from each pair of 10 cadaveric Achilles tendons was randomized to 1 of 2 Achilles insertion repair groups: knotted (n = 10) or knotless (n = 10) suture bridge repair. Repaired footprint size was measured, and then cyclic testing from 10 to 100 N for 2000 cycles was performed. This was followed by measurement of tendon strain, repair site displacement, load to failure, and tendon stiffness.

RESULTS

The knotted suture bridge repair had a significantly higher load to failure compared with the knotless suture bridge (mean ± SD, 317.8 ± 93.6 N vs 196.1 ± 12.1 N, respectively; P = .001). All constructs failed at the tendon-suture interface. Tendon strain after cyclic testing was significantly greater in the knotless (1.20 ± 1.05) compared with the knotted (0.39 ± 0.4) suture repair groups (P = .011). There was no significant difference in footprint size between the knotted (230.3 ± 63.3 mm(2)) and knotless (248.5 ± 48.8 mm(2)) groups (P = .40). There was also no significant difference in stiffness (knotted = 76.4 ± 8.0 N/mm; knotless = 69.6 ± 10.9 N/mm; P = .17) and repair site displacement after cyclic testing (knotted = 2.8 ± 1.2 mm; knotless = 3.6 ± 1.1 mm; P = .17).

CONCLUSION

During suture bridge repair of the Achilles tendon after detachment, knots at the proximal suture anchors significantly improve the biomechanical strength of the repair.

CLINICAL RELEVANCE

This study demonstrated that the knotless suture bridge repair had a significantly lower load to failure than the knotted suture bridge. Surgeons should be aware of these biomechanical differences, as they influence the postoperative rehabilitation protocol and may lead to higher surgical complication rates.

Gap formation in a transosseous rotator cuff repair as a function of bone quality

BACKGROUND

The transosseous approach has been well known for a long time as a valid repair approach. Over time, various criticisms have been raised over this technique principally classifiable in two main categories: technical difficulty and related reproducibility in an arthroscopic environment, and repair stability (in the suture-bone contact area). About cyclic performance, several authors have conceived test setups with the aim of simulating a real environment in dynamic load conditions. The aim of this study was to monitor gap formation in a cyclic test setup.

METHODS

The performance (measured as gap formation) has been monitored as a function of bone density to verify the effect of the latter. The test blocks have been shaped using sawbones® test bricks (Malmo, Sweden) of different densities, and the following values have been tested: 10, 15, 20, 30 and 40pcf.

FINDINGS

The comparison has been made between the two groups: traditional transosseous and new approach with an interposed device. Regarding the traditional transosseous approach in a 10-pcf environment, not even the first loading cycle was completed, the whole bone bridge was destroyed in the first loading ramp and no further loading capability was present in the repair. By increasing the block density, the surface damage in the suture-block contact decreased.

INTERPRETATION

With this work, it has been demonstrated how the traditional transosseous approach is strongly influenced by the bone quality up to the point where, in certain conditions, a safe and reliable repair is not guaranteed.

Biomechanical effects of a 2 suture-pass medial inter-implant mattress on transosseous-equivalent rotator cuff repair and considerations for a "technical efficiency ratio"

BACKGROUND

Rotator cuff repair involving fewer tendon suture passes without compromising biomechanical performance would represent a technical advancement. An inter-implant "medial pulley-mattress" transosseous-equivalent (MP-TOE) repair requiring fewer tendon suture-passes was hypothesized to provide equivalent biomechanical characteristics compared to the control.

METHODS

In 6 human cadaveric shoulders, a transosseous-equivalent (TOE) repair (control) was performed utilizing 2 separate medial mattresses resulting in 4 tendon-bridging sutures. In 6 matched-pairs, 2 single-loaded anchors were used to create a medial inter-implant mattress construct (all sutures shuttled in 1 tendon pass per anchor)-after knot-tying, the same tendon-bridging pattern as the control was created. A materials testing machine cyclically loaded each repair from 10-180 N for 30 cycles; each repair subsequently underwent failure testing. Gap and strain were measured with a video digitizing system. A "technical efficiency ratio" (TER) was defined as: (#knots + #suture passes + #suture limbs)/#fixation points.

RESULTS

Cyclic and failure testing demonstrated no significant differences between constructs. Gap formation at cycle 30 was 5.3 ± 0.8 mm (TOE) and 5.0 ± 0.3 mm (MP-TOE) (P = .62). Cycle 30 anterior strain values were -16.0 ± 7.3% (TOE) and -15.8 ± 6.6% (MP-TOE) (P = .99). Yield loads were 208.7 ± 2.7 N (TOE) and 204.0 ± 1.3 N (MP-TOE) (P = .17). Mode of failure demonstrated less tendon cut-out with the MP-TOE repair. The MP-TOE repair has a TER of 2.0 vs 2.5 for the control.

CONCLUSION

The MP-TOE repair requiring fewer tendon suture passes, yet creating an additional inter-implant mattress configuration, is biomechanically equivalent to the original TOE technique, and may limit failure with improved medial load-sharing capacity. A TER may help quantify technical ease and help standardize comparisons between repair techniques.

Biomechanical characteristics of the horizontal mattress stitch: implication for double-row and suture-bridge rotator cuff repair

BACKGROUND

We investigated the effects of bite-size horizontal mattress stitch (distance between the limbs passed through the tendon) on the biomechanical properties of the repaired tendon.

METHODS

We anchored 20 bovine Achilles tendons to bone using no. 2 high-strength suture and 5-mm titanium suture anchors in a mattress-suture technique. Tendons were allocated randomly into two groups of ten each to receive stitches with a 4- or 10-mm bite. Specimens underwent cyclic loading from 5 to 30 N at 1 mm/s for 30 cycles, followed by tensile testing to failure. Gap formation, tendon strain, hysteresis, stiffness, yield load, ultimate load, energy to yield load, and energy to ultimate load were compared between groups using unpaired t tests.

RESULTS

The 4-mm group had less (p < 0.05) gap formation and less (p < 0.05) longitudinal strain than did the 10-mm group. Ultimate load (293.6 vs. 148.9 N) and energy to ultimate load (2,563 vs. 1,472 N-mm) were greater (p < 0.001) for the 10-mm group than the 4-mm group. All tendons repaired with 4-mm suturing failed at the suture-tendon interface, with sutures pulling through the tendon, whereas the suture itself failed before the tendon did in seven of the ten specimens in the 10-mm group.

CONCLUSIONS

Whereas a 4-mm bite fixed the tendon more tightly but at the cost of decreased ultimate strength, a 10-mm bite conveyed greater ultimate strength but with increased gap and strain. These results suggest that for the conventional double-row repair, small mattress stitches provide a tighter repair, whereas large stitches are beneficial to prevent sutures from pulling through the tendon after surgery. For suture-bridge rotator cuff repair, large stitches are beneficial because the repaired tendon has a higher strength, and the slightly mobile medial knot can be tightened by lateral fixation.

Ultrasound evaluation of arthroscopic full-thickness supraspinatus rotator cuff repair: single-row versus double-row suture bridge (transosseous equivalent) fixation. Results of a prospective, randomized study

BACKGROUND

The purpose of this study was to compare the structural outcomes of a single-row rotator cuff repair and double-row suture bridge fixation after arthroscopic repair of a full-thickness supraspinatus rotator cuff tear.

MATERIAL AND METHODS

We evaluated with diagnostic ultrasound a consecutive series of ninety shoulders in ninety patients with full-thickness supraspinatus tears at an average of 10 months (range, 6-12) after operation. A single surgeon at a single hospital performed the repairs. Inclusion criteria were full-thickness supraspinatus tears less than 25 mm in their anterior to posterior dimension. Exclusion criteria were prior operations on the shoulder, partial thickness tears, subscapularis tears, infraspinatus tears, combined supraspinatus and infraspinatus repairs and irreparable supraspinatus tears. Forty-three shoulders were repaired with single-row technique and 47 shoulders with double-row suture bridge technique. Postoperative rehabilitation was identical for both groups. Ultrasound criteria for healed repair included visualization of a tendon with normal thickness and length, and a negative compression test.

RESULTS

Eighty-three patients were available for ultrasound examination (40 single-row and 43 suture-bridge). Thirty of 40 patients (75%) with single-row repair demonstrated a healed rotator cuff repair compared to 40/43 (93%) patients with suture-bridge repair (P = .024).

CONCLUSION

Arthroscopic double-row suture bridge repair (transosseous equivalent) of an isolated supraspinatus rotator cuff tear resulted in a significantly higher tendon healing rate (as determined by ultrasound examination) when compared to arthroscopic single-row repair.

Biomechanical validation of rotator cuff repair techniques and considerations for a "technical efficiency ratio"

Biomechanical studies are commonly used to validate new or modified rotator cuff repair techniques. Additional knots, more tendon suture passes, and obligatory suture management requirements are often the "cost" for improved biomechanical results. This cost can amount to increased technical difficulty and surgical times. However, technical ease or difficulty as a measurable variable has not been quantified. A basic measure for technical ease would allow surgeons the ability to objectively assess and compare rotator cuff repair practicality and potentially help in the design of future studies to standardize repair techniques alongside biomechanical measures. A proposed rotator cuff repair "technical efficiency ratio" is defined as follows: (No. of knots + No. of tendon suture passes + No. of suture limbs)/No. of pilot holes created. This can give a measure of "work" or utility achieved per fixation point created for a particular type of repair (e.g., single or double row), with a smaller number representing relatively more efficiency per anchor or fixation point used. If repairs validated in the laboratory are too cumbersome to perform in vivo from a practical standpoint, technical ease should be a prerequisite measure, and the success of a repair technique should not necessarily be based on biomechanics alone.

Arthroscopic double-row repair of the rotator cuff: a comparison of bio-absorbable and non-resorbable anchors regarding osseous reaction

PURPOSE

The aim of this study was to analyse the osseous reaction after arthroscopic double-row rotator cuff repair using bio-absorbable poly-L-lactic acid (PLLA) and non-absorbable polyetheretherketone (PEEK) suture anchors. Focus of interest was the appearance of peri-implant fluid and anchor tunnel widening.

METHODS

Thirty-six patients were evaluated at final follow-up (16 PLLA and 20 PEEK). Clinical results were acquired by use of the subjective shoulder value, the Constant score and the Western Ontario Rotator Cuff Index. Radiological results were analysed by supraspinatus tendon integrity, footprint coverage, muscular atrophy and fatty infiltration. Furthermore, anchor tunnel expansion was measured, anchor structure and peri-implant fluids graduated.

RESULTS

At 28.4 ± 8.9-month follow-up, clinical outcome was similar (n.s.). MRI investigation revealed osseous reaction in both groups; tunnel widening was 0.9 ± 0.7 mm in PLLA and 0.8 ± 0.6 mm in PEEK anchors (n.s.). Peri-implant fluid was pronounced in PLLA anchors (p < 0.05). Tunnel widening was significantly higher in lateral anchors irrespectively of the material used. Tendon integrity, muscular atrophy, fatty infiltration and footprint coverage were not significantly different (n.s.).

CONCLUSION

Both materials lead to osseous reaction in this study, whereas consequences of pronounced fluid in PLLA patients remain unclear. Pronounced tunnel widening in lateral anchors leads to the assumption that other causes such as mechanical stress potentially have to be considered when analysing osseous reaction.

LEVEL OF EVIDENCE

III.

Current biomechanical concepts for rotator cuff repair

For the past few decades, the repair of rotator cuff tears has evolved significantly with advances in arthroscopy techniques, suture anchors and instrumentation. From the biomechanical perspective, the focus in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. To accomplish these objectives, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. In addition, the healing response may be compromised by intrinsic factors such as decreased vascularity, hypoxia, and fibrocartilaginous changes or aforementioned extrinsic compression factors. Furthermore, it is well documented that torn rotator cuff muscles have a tendency to atrophy and become subject to fatty infiltration which may affect the longevity of the repair. Despite all the aforementioned factors, initial fixation strength is an essential consideration in optimizing rotator cuff repair. Therefore, numerous biomechanical studies have focused on elucidating the strongest devices, knots, and repair configurations to improve contact characteristics for rotator cuff repair. In this review, the biomechanical concepts behind current rotator cuff repair techniques will be reviewed and discussed.

Transosseous-equivalent rotator cuff repair: a systematic review on the biomechanical importance of tying the medial row

PURPOSE

Double-row and transosseous-equivalent repair techniques have shown greater strength and improved healing than single-row techniques. The purpose of this study was to determine whether tying of the medial-row sutures provides added stability during biomechanical testing of a transosseous-equivalent rotator cuff repair.

METHODS

We performed a systematic review of studies directly comparing biomechanical differences.

RESULTS

Five studies met the inclusion and exclusion criteria. Of the 5 studies, 4 showed improved biomechanical properties with tying the medial-row anchors before bringing the sutures laterally to the lateral-row anchors, whereas the remaining study showed no difference in contact pressure, mean failure load, or gap formation with a standard suture bridge with knots tied at the medial row compared with knotless repairs.

CONCLUSIONS

The results of this systematic review and quantitative synthesis indicate that the biomechanical factors ultimate load, stiffness, gap formation, and contact area are significantly improved when medial knots are tied as part of a transosseous-equivalent suture bridge construct compared with knotless constructs. Further studies comparing the clinical healing rates and functional outcomes between medial knotted and knotless repair techniques are needed.

CLINICAL RELEVANCE

This review indicates that biomechanical factors are improved when the medial row of a transosseous-equivalent rotator cuff is tied compared with a knotless repair. However, this has not been definitively proven to translate to improved healing rates clinically.