Lateral Row Anchors Research Articles

Optimal Lateral Row Anchor Positioning in Posterior-Superior Transosseous Equivalent Rotator Cuff Repair: A Micro-Computed Tomography Study.

Background:The optimal placement of suture anchors in transosseous-equivalent (TOE) double-row rotator cuff repair remains controversial.Purpose:A 3-dimensional (3D) high-resolution micro–computed tomography (micro-CT) histomorphometric analysis of cadaveric proximal humeral greater tuberosities (GTs) was performed to guide optimal positioning of lateral row anchors in posterior-superior (infraspinatus and supraspinatus) TOE rotator cuff repair.Study Design:Descriptive laboratory study.Methods:Thirteen fresh-frozen human cadaveric proximal humeri underwent micro-CT analysis. The histomorphometric parameters analyzed in the standardized volumes of interest included cortical thickness, bone volume, and trabecular properties.Results:Analysis of the cortical thickness of the lateral rows demonstrated that the entire inferior-most lateral row, 15 to 21 mm from the summit of the GT, had the thickest cortical bone (mean, 0.79 mm; P = .0001), with the anterior-most part of the GT, 15 to 21 mm below its summit, having the greatest cortical thickness of 1.02 mm (P = .008). There was a significantly greater bone volume (BV; posterior, 74.5 ± 27.4 mm3; middle, 55.8 ± 24.9 mm3; anterior, 56.9 ± 20.7 mm3; P = .001) and BV as a percentage of total tissue volume (BV/TV; posterior, 7.3% ± 2.7%, middle, 5.5% ± 2.4%; anterior, 5.6% ± 2.0%; P = .001) in the posterior third of the GT than in intermediate or anterior thirds. In terms of both BV and BV/TV, the juxta-articular medial row had the greatest value (BV, 87.3 ± 25.1 mm3; BV/TV, 8.6% ± 2.5%; P = .0001 for both) followed by the inferior-most lateral row 15 to 21 mm from the summit of the GT (BV, 62.0 ± 22.7 mm3; BV/TV, 6.1% ± 2.2%; P = .0001 for both). The juxta-articular medial row had the greatest value for both trabecular number (0.3 ± 0.06 mm–1; P = .0001) and thickness (0.3 ± 0.08 μm; P = .0001) with the lowest degree of trabecular separation (1.3 ± 0.4 μm; P = .0001). The structure model index (SMI) has been shown to strongly correlate with bone strength, and this was greatest at the inferior-most lateral row 15 to 21 mm from the summit of the GT (2.9 ± 0.9; P = .0001).Conclusion:The inferior-most lateral row, 15 to 21 mm from the tip of the GT, has good bone stock, the greatest cortical thickness, and the best SMI for lateral row anchor placement. The anterior-most part of the GT 15 to 21 mm below its summit had the greatest cortical thickness of all zones. The posterior third of the GT also has good bone stock parameters, second only to the medial row. The best site for lateral row cortical anchor placement is 15 to 21 mm below the summit of the GT.Clinical Relevance:Optimal lateral anchor positioning is 15 to 21 mm below the summit of the greater tuberosity in TOE.

Arthroscopic Double-Row Suture Anchor Repair of Acute Posterior Bony Bankart Lesion

The treatment of anterior shoulder instability is well described with various techniques, including arthroscopic double-row repair, an alternative to open stabilization procedures in high-risk groups. The surgical management of posterior instability in high-risk and athletic populations is a less-explored entity. We describe our technique for an all arthroscopic double-row suture anchor repair of a large posterior bony Bankart lesion. We prefer this technique over percutaneous cannulated screw fixation because the double-row suture technique allows for incorporation of capsular plication with bony fixation in an effort to better restore normal anatomy for capsulolabral complex. Double-row repair capsulolabral repair or fixation of the bony Bankart is performed via a suture-bridge technique. Medial row anchors are placed down the glenoid neck and shuttled around the bony fragment and labrum. The lateral-row anchor is placed at the rim of the native glenoid. This repair technique has been shown to increase the surface area for healing and more closely reconstruct the native anatomic capsulolabral complex footprint, improve force distribution, and potentially impart enhanced posterior stability to the glenohumeral joint.

Research progress on suture and fixation approach of arthroscopic rotator cuff repair in suture-bridge technique

With advances in arthroscopic surgery, arthroscopic repair for rotator cuff tears is often used by surgeons. Surgical methods have already developed from simple single-row fixation and double-row fixation to complicated suture-bridge fixation. Although arthroscopic suture-bridge rotator cuff repair has been proposed to be advantageous over single-row and double-row fixation in biomechanical constructs, the failure of rotator cuff repair is still higher. Different suture methods of medical row anchor in arthroscopic suture-bridge technique may change the suture-tendon loading and decrease the retear of suture-tendon. And different fixation methods of lateral row anchor in arthroscopic suture-bridge technique may decrease the anchor pull-out. These will be useful to decrease the failure of arthroscopic suture-bridge technique. There will be a good outcome if optical suture and fixation approach can be chosen according to the quality and retraction of rotator cuff, suture tension and the bone quality of the greater tuberosity in arthroscopic suture-bridge technique.

Circumferential Rotator Cuff Repair With the N+4 Portal, Subclavian Portal, and High Posteromedial Portal

Passing suture during a rotator cuff repair requires proper orientation and purchase of the rotator cuff tendon. Our technique uses a new portal to improve access to the supraspinatus and infraspinatus and uses additional portals for a circumferential repair of the tear, thereby restoring the footprint. Using a penetrating suture passer through the anterior, posterior, and superomedial portals allows 270° of coverage. The lateral anchors complete the circumferential repair. Sutures from the medial anchors are passed in a retrograde fashion using 3 small incisions with no cannula. A spinal needle is used to localize the orientation of each portal. The N+4 portal is the workhorse portal, allowing access to the supraspinatus and infraspinatus. The suture retriever enters the trapezius 5 cm from the medial border of the acromion and 1 cm anterior to the spine of the scapula. It enters the subacromial space on top of the supraspinatus. This provides protection to the suprascapular nerve in the supraspinatus fossa. The cuff is lifted with a grasper to allow perpendicular passage of suture. The suture is retrieved for tying. The tissue purchase and location of suture placement help restore the footprint of the supraspinatus and infraspinatus. Additional sutures are passed anteriorly through the subclavian portal and posteriorly through the high posteromedial portal. The repair is completed with lateral-row anchors as needed.

Cyclic Biomechanical Testing of Biocomposite Lateral Row Knotless Anchors in a Human Cadaveric Model

The purpose of this study was to assess the mechanical performance of biocomposite knotless lateral row anchors based on both anchor design and the direction of pull. Two lateral row greater tuberosity insertion sites (anterior and posterior) were identified in matched pairs of fresh-frozen human cadaveric shoulders DEXA (dual energy X-ray absorptiometry) scanned to verify comparability. The humeri were stripped of all soft tissue and 3 different biocomposite knotless lateral row anchors: HEALIX Knotless BR (DePuy Mitek, Raynham MA), BioComposite PushLock (Arthrex, Naples, FL), and Bio-SwiveLock (Arthrex). Fifty-two anchors were distributed among the insertion locations and tested them with either an anatomic or axial pull. A fixed-gauge loop (15 mm) of 2 high-strength sutures from each anchor was created. After a 10-Nm preload, anchors were cycled from 10 to 45 Nm at 0.5 Hz for 200 cycles and tested to failure at 4.23 mm/second. The load to reach 3 mm and 5 mm displacement, ultimate failure load, displacement at ultimate failure, and failure mode were recorded. Threaded anchors (Bio-SwiveLock, P = .03; HEALIX Knotless, P = .014) showed less displacement with anatomic testing than did the nonthreaded anchor (BioComposite PushLock), and the HEALIX Knotless showed less overall displacement than did the other 2 anchors. The Bio-SwiveLock exhibited greater failure loads than did the other 2 anchors (P < .05). Comparison of axial and anatomic loading showed no maximum load differences for all anchors as a whole (P = .1084). Yet, anatomic pulling produced higher failure loads than did axial pulling for the Bio-SwiveLock but not for the BioComposite PushLock or the HEALIX Knotless. The nonthreaded anchor (BioComposite PushLock) displayed lower failure loads than did both threaded anchors with axial pulling. Threaded biocomposite anchors (HEALIX Knotless BR and Bio-SwiveLock) show less anatomic loading displacement and higher axial failure loads than do the nonthreaded (BioComposite PushLock) anchor. The HEALIX Knotless BR anchor showed less displacement than did the BioComposite PushLock and Bio-SwiveLock anchors. Neither axial nor anatomic loading had an effect on overall anchor displacement. Because of the strength profiles exhibited, this study supports the use of biocomposite anchors, which have definite advantages over polyetheretherketone (PEEK) and metal products. However, the nonthreaded BioComposite PushLock anchor cannot be recommended.

Transosseous-Equivalent Rotator Cuff Repair: A Systematic Review on the Biomechanical Importance of Tying the Medial Row

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

Simultaneous Rotator Cuff Repair and Arthroscopic Biceps Tenodesis Using Lateral Row Anchor

Treatment of concomitant long head of the biceps pathology in the setting of rotator cuff repair is often required. When a tenodesis of the biceps is used, additional anchors and surgical dissection are typically required. This adds additional surgical time, morbidity of additional surgical dissection, and additional anchor load and cost. We describe a novel technique for arthroscopic biceps tenodesis that uses the anterior lateral row anchor of a double-row rotator cuff repair to simultaneously secure the biceps tenodesis and rotator cuff tear. This technique provides a simple, reproducible, cost-effective means of performing a simultaneous biceps tenodesis and double-row rotator cuff repair.

A Biomechanical Analysis of Point of Failure During Lateral-Row Tensioning in Transosseous-Equivalent Rotator Cuff Repair

The purpose of this study was to determine the maximum load and point of failure of the construct during tensioning of the lateral row of a transosseous-equivalent (TOE) rotator cuff repair. In 6 fresh-frozen human shoulders, a TOE rotator cuff repair was performed, with 1 suture from each medial anchor passed through the tendon and tied in a horizontal mattress pattern. One of 2 limbs from each of 2 medial anchors was pulled laterally over the tendon. After preparation of the lateral bone for anchor placement, the 2 limbs were passed through the polyether ether ketone (PEEK) eyelet of a knotless anchor and tied to a tensiometer. The lateral anchor was placed into the prepared bone tunnel but not fully seated. Tensioning of the lateral-row repair was simulated by pulling the tensiometer to tighten the suture limbs as they passed through the eyelet of the knotless anchor. The mode of failure and maximum tension were recorded. The procedure was then repeated for the second lateral-row anchor. The mean load to failure during lateral-row placement in the TOE model was 80.8 ± 21.0 N (median, 83 N; range, 27.2 to 115.8 N). There was no statistically significant difference between load to failure during lateral-row tensioning for the anterior and posterior anchors (P = .84). Each of the 12 constructs failed at the eyelet of the lateral anchor. Retrieval analysis showed no failure of the medial anchors, no medial suture cutout through the rotator cuff tendon, and no signs of gapping at the repair site. Our results suggest that the medial-row repair does not appear vulnerable during tensioning of the lateral row of a TOE rotator cuff repair with the implants tested. However, surgeons should exercise caution when tensioning the lateral row, especially when lateral-row anchors with PEEK eyelets are implemented. For this repair construct, the findings suggest that although the medial row is not vulnerable during lateral-row tensioning of a TOE rotator cuff repair, lateral-row anchors with PEEK eyelets appear vulnerable to early failure.

Suture Loosening and Its Effect on Tendon Fixation in Knotless Double-Row Rotator Cuff Repairs

We have occasionally observed suture loosening in initial suture legs after final fixation of adjacent suture legs in the lateral row of rotator cuff repairs during arthroscopic rotator cuff repair with transosseous-equivalent suture-bridge constructs. We sought to determine how this occurred and what effects it had on tendon fixation stability. Six pairs of fresh-frozen human shoulders were prepared with a simulated cuff defect. A suture-bridge repair was performed in each specimen with one of each pair randomized to one type of "knotless" lateral-row screw-in anchor and the other of the pair to a knotless push-in type. The repairs were cyclically loaded with 100 N for 1,000 cycles. Suture leg tensions were measured during the repair and after cycling. Lateral tendon laxity was measured before and after cycling. A pilot study on the effect of suture tension on the tendon contact footprint was also performed. The initial suture legs did not show a decrease in tension after the second lateral-row anchor was secured. Tension of the suture legs after cycling showed that no one leg loosened more than another; however, they all loosened when compared with total suture tensions before cycling (0.1 to 1.0 mm, P = .008). There was no significant difference between suture tension changes for the 2 anchor types after cycling (P = .140). Although the lateral tendon laxity increased slightly (0.04 mm) after cycling, this was not significant (P = .245), nor was there a difference between anchor types. Suture loosening occurred after cycling these rotator cuff repairs, but this did not appear to affect lateral tendon laxity for the 2 lateral anchor types studied, although medial tendon movement was observed. Suture loosening after cycling the 2 transosseous-equivalent suture-bridge repairs studied could affect the area and pressure of tendon-bone contact.

Contact area and pressure in suture bridge rotator cuff repair using knotless lateral anchors

To evaluate whether the use of knotless lateral anchors in a suture bridge construct produces better contact area and pressure parameters than a suture bridge construct with standard lateral anchors that require knots or a double-row repair. The hypothesis was that knotless lateral anchors would produce better contact area and pressure parameters than the other two constructs. A total of fifteen matched pairs of cadaveric shoulders were divided into three groups. In Group 1, a suture bridge using knotless anchors for the lateral row was performed on five shoulders. A suture bridge using standard lateral row anchors that require knots was performed on the contralateral shoulders. In Group 2, suture bridge with knotless lateral row anchors was compared with double-row repair. In Group 3, suture bridge using standard lateral row anchors was compared with double-row repair. The contact conditions of the rotator cuff footprint were measured using pressure-sensitive film. There were no statistically significant differences between any of the techniques regarding contact area F(2, 15.7)=3.09, P=0.07 or mean contact pressure F(2, 15.1)=2.35, P=0.12. A post hoc power analysis suggests differences between techniques are likely less than 91-113mm(2) for area and 0.071-0.089N for pressure. The use of knotless anchors in the lateral row of a suture bridge repair did not increase the footprint contact area or contact pressure when compared to a suture bridge repair requiring knots laterally or to a double-row repair.

Comparative Testing by Cyclic Loading of Rotator Cuff Suture Anchors Containing Multiple High-Strength Sutures

To compare isolated medial-row with isolated lateral-row anchor performance by use of cyclic loading followed by destructive testing in an in vitro cadaveric model. Using 16 human cadaveric humeri without tendons, we rotated 4 medial-row (Bio-Corkscrew FT [Arthrex, Naples FL], CrossFT PK [ConMed Linvatec, Largo, FL], TwinFix PK FT [Smith & Nephew Endoscopy, Andover, MA], and Healix PK [DePuy Mitek, Raynham, MA]) and 4 lateral-row (PopLok PK [ConMed Linvatec], PEEK [polyetheretherketone] PushLock [Arthrex], Footprint PEEK [Smith & Nephew Endoscopy], and Versalok [DePuy Mitek]) anchors among different medial (articular cartilage edge) and lateral greater tuberosity sites (anterior, central, posterior). All medial anchors were inserted into the humeral head at an angle no greater than 45 degrees . All lateral anchors were inserted "over the top," nearly planar to the superior humeral surface. After preloading, the constructs were cycled 500 times from 10 to 60 N at 1 Hz with the loads applied to the accompanying sutures. Those constructs surviving cycling were destructively tested. Cyclic displacement, ultimate load, and failure mode were recorded. In this laboratory setting, most displacement occurred in the first 100 cycles except for the Footprint anchor. Lateral-row anchors had greater mean displacements (2.6 mm) than medial-row anchors (1.2 mm) at 100 cycles and between 100 and 500 cycles (1.8 mm v 0.75 mm). Lateral-row anchors also had more total displacement (4.4 mm) than medial-row anchors (1.9 mm). A 5-mm displacement gap, defined as failure, was not seen in the Bio-Corkscrew FT, TwinFix PK FT, and Versalok anchors. Ultimate failure loads ranged from 163 N (Footprint) to 308 N (Versalok) (P < .05). The principal failure mode was anchor pullout, followed by eyelet breakage. Medial-row eyelet failures only occurred after 500 cycles at loads higher than each anchor's mean failure load. Eyelet failure for lateral-row anchors occurred before 500 cycles and at failure loads lower than each anchor's mean. Lateral row anchors benefit from medial row anchors for their security, and because of design differences demonstrate more displacement. When lateral-row anchors fail at the eyelet, it is at lower failure loads, while if medial-row anchors fail at the eyelet, it is at higher loads. Anchors designed to function as lateral-row fixation provide fixation strength inferior to that of medial-row anchors and are more likely to be subject to suture slippage.

Suture anchor loading after rotator cuff repair: Effects of an additional lateral row

Our initial hypothesis was that the medial row of double-row rotator cuff repair techniques would bear most of the load on the repaired cuff. Six cadaver shoulders underwent simulated rotator cuff repairs using sequential single row, double-row, and suture-bridge repair techniques. Suture tensions at each anchor were measured for several static, simulated shoulder positions by specially designed, instrumented anchors. Significantly greater suture tensions were measured in the anchors in a single row repair construct than either the double row repair or suture bridge repair construct (P < .001). In the double-row and suture bridge techniques, there was no apparent difference in the loads born by the medial and lateral row anchors. Shoulder abduction from 45 degrees to 60 degrees had little effect on anchor tensions; 45 degrees internal and external rotation significantly (P = .032) increased loads on the anterior and posterior anchors by at least 125%. Forces are transmitted through the entire portion of the tendon at its humeral fixation, loading the lateral anchors as well as the medial row for the techniques studied. This "load sharing" can explain the higher fixation strengths of double row techniques seen experimentally. The magnitude and distribution of anchor suture tensions could have important implications for lateral row fixation devices and post-operative positioning and activity. Basic Science.

Early pullout of lateral row knotless anchor in rotator cuff repair

Use of lateral row anchors in rotator cuff repair as a means of enhancing the strength of the repair; and improving footprint tendon contact, thus promoting healing, is becoming more popular in current arthroscopic practice. In our knowledge, failures of lateral row knotless anchors have not yet been reported. We present a case of double row rotator cuff repair using a Swivelock anchor (Arthrex) as a lateral row anchor that failed two weeks after surgery.

Arthroscopic Double-Row Suture Anchor Fixation of Minimally Displaced Greater Tuberosity Fractures

In cases of displaced greater tuberosity fractures, treatments by arthroscopic-assisted reduction and percutaneous screw fixation have been reported. However, in cases in which there is a comminuted fracture or a minimally displaced fracture combined with concomitant lesions such as rotator cuff tear or labral pathology, it is difficult to reduce the fracture and to treat other pathologies by use of a percutaneous screw. Recently, many surgeons have used the double-row repair method in rotator cuff repair, which provides a tendon-bone interface better suited for biologic healing and restoring normal anatomy. In accordance with this method, we used the arthroscopic technique of double-row suture anchor fixation for a minimally displaced greater tuberosity fracture without additional incision. Initially, debridement was performed on the fracture surface by use of a shaver, and the medial-row anchor was inserted through the anterior portal or the intact cuff. Two lateral-row anchors were inserted just anterior and posterior to the lower margin of the fractured fragment under C-arm guidance. The medial-row sutures and lateral-row sutures were then placed. Arthroscopic double-row suture anchor fixation of a displaced greater tuberosity fracture restores the original footprint of the rotator cuff and normal tendon-bone interface of the displaced greater tuberosity fracture.

First in vivo measurements of contact forces in the shoulder joint

In cases of displaced greater tuberosity fractures, treatments by arthroscopic-assisted reduction and percutaneous screw fixation have been reported. However, in cases in which there is a comminuted fracture or a minimally displaced fracture combined with concomitant lesions such as rotator cuff tear or labral pathology, it is difficult to reduce the fracture and to treat other pathologies by use of a percutaneous screw. Recently, many surgeons have used the double-row repair method in rotator cuff repair, which provides a tendon-bone interface better suited for biologic healing and restoring normal anatomy. In accordance with this method, we used the arthroscopic technique of double-row suture anchor fixation for a minimally displaced greater tuberosity fracture without additional incision. Initially, debridement was performed on the fracture surface by use of a shaver, and the medial-row anchor was inserted through the anterior portal or the intact cuff. Two lateral-row anchors were inserted just anterior and posterior to the lower margin of the fractured fragment under C-arm guidance. The medial-row sutures and lateral-row sutures were then placed. Arthroscopic double-row suture anchor fixation of a displaced greater tuberosity fracture restores the original footprint of the rotator cuff and normal tendon-bone interface of the displaced greater tuberosity fracture.