Mode of failure for rotator cuff repair with suture anchors identified at revision surgery

Rotator cuff tears are a common cause of shoulder pain and dysfunction. After surgical repair, there is a significant re-tear rate (25%-90%). The aim of this study was to determine the primary mode of mechanical failure for rotator cuffs repaired with suture anchors at the time of revision rotator cuff repair. We prospectively followed 342 consecutive torn rotator cuffs, repaired by a single surgeon using suture anchors and a mattress-suturing configuration. Of those shoulders, 21 (6%) subsequently underwent a revision rotator cuff repair by the original surgeon, and 1 underwent a second revision repair. Intraoperative findings, including the mode of failure, were systematically recorded at revision surgery and compared with the findings at the primary repair. In addition, 81 primary rotator cuff repairs had a radiographic and fluoroscopic evaluation at a mean of 37 weeks after repair to assess for any loosening or migration of the anchors. At revision rotator cuff repair, the predominant mode of failure was tendon pulling through sutures (19/22 shoulders) (P <.001). Two recurrent tears occurred in a new location adjacent to the previous repair, and one anchor was found loose in the supraspinatus tendon. The mean size of the rotator cuff tear was larger at the revision surgery (P =.043), the tendon quality ranked poorer (P =.013), and the tendon mobility decreased (P =.002), as compared with the index procedure. The radiographs and fluoroscopic examination showed that all 335 anchors in 81 patients were in bone. Rotator cuff repairs with suture anchors that underwent revision surgery failed mechanically by three mechanisms, the most common of which was tendon pulling through sutures. This suggests that the weak link in rotator cuff repairs with suture anchors and horizontal mattress sutures, as determined at revision surgery, is the tendon-suture interface.     

Primary fixation strength of rotator cuff repair techniques: a comparative study

Purpose:The goal of the study was to compare the primary fixation strength of transosseous suture, suture anchor, and hybrid repair techniques for rotator cuff repair.Type of Study:Animal model experiment.Methods:Thirty-two sheep shoulders were divided into 4 homogeneous groups, according to bone density and tendon dimensions. Infraspinatus tendons were transected from their insertions and reattached using 4 different techniques. Group 1 was repaired with a single Mason-Allen stitch and 2 transosseous tunnels for each end of the suture, knotted on the lateral cortex of proximal humerus; group 2 was repaired with double Mason-Allen stitches and 2 transosseous tunnels; group 3 was repaired with 2 Corkscrews (Arthrex, Germany); and group 4 was repaired with 2 Corkscrews combined with a single Mason-Allen transosseous suture. All specimens were tested for their fixation strengths with a material testing system.Results:The mode of failure in group 1 was mainly suture breakage. In groups 3 and 4, the tendons pulled out from the sutures. In group 2, sutures broke the bony bridge between the 2 tunnels. The mean load to failure value was 160.31 ± 34.59 N in group 1, 199.36 ± 11.73 N in group 2, 108.32 ± 15.98 N in group 3, and 214.24 ± 28.52 N in group 4. Anchor fixation was significantly weaker compared with other groups (P <.001). Combination of a transosseous suture and anchor fixation (group 4) was significantly stronger than the single transosseous suture (group 1) and double anchor techniques (group 3) (P <.001).Conclusions:Hybrid technique was the strongest among the tested rotator cuff repair techniques. With the addition of one transosseous suture to two anchors, the strength of the repair could be doubled.     

A comparison of lateral ankle ligament suture anchor strength

BackgroundLateral ankle ligament repairs increasingly use suture anchors instead of bone tunnels. Our purpose was to compare the biomechanical properties of a knotted and knotless suture anchor appropriate for a lateral ankle ligament reconstruction.MethodsIn porcine distal fibulae, 10 samples of 2 different PEEK anchors were inserted. The attached sutures were cyclically loaded between 10 N and 60 N for 200 cycles. A destructive pull was performed and failure loads, cyclic displacement, stiffness, and failure mode recorded.ResultsPushLock 2.5 anchors failed before 200 cycles. PushLock 100 cycle displacement was less than Morphix 2.5 displacement (p < 0.001). Ultimate failure load for anchors completing 200 cycles was 86.5 N (PushLock) and 252.1 N (Morphix) (p < 0.05). The failure mode was suture breaking for all PushLocks while the Morphix failed equally by anchor breaking and suture breakage.ConclusionsThe knotted Morphix demonstrated more displacement and greater failure strength than the knotless PushLock. The PushLock failed consistently with suture breaking. The Morphix anchor failed both by anchor breaking and by suture breaking.     

Cyclic loading of anchor-based rotator cuff repairs: Confirmation of the tension overload phenomenon and comparison of suture anchor fixation with transosseous fixation

Previous experimental studies of failure of rotator cuff repair have involved single pull to ultimate load. Such an experimental design does not represent the cyclic loading conditions experienced in vivo. We created 1 ×2 cm rotator cuff defects in 16 cadaver shoulders, repaired each defect with three MitekRC suture anchors (Mitek Surgical Products, Inc, Westwood, MA) using simple sutures of No. 2 Ethibond, and cyclically loaded the repairs by a servohydraulic materials test system actuator at physiological rates and loads (rate of 33 mm/s, load 180 N). A progressive gap was noted in each specimen, for a 100% rate of failure of the repairs. The central suture always failed first and by the largest magnitude, confirming tension overload centrally. One specimen exhibited combined bone and tendon failure, but the other 15 specimens failed through the tendon. Overall, the repairs failed to 5 mm and 10 mm at an average of 61 cycles and 285 cycles, respectively. Half the specimens were less than 45 years of age and had a 5-mm and 10-mm failure at an average of 107 and 478 cycles, respectively. The other half were over 45 years of age and failed to 5 mm and 10 mm at an average of 17 and 91 cycles, respectively, indicating more rapid failure of the rotator cuff tendons in the older group, and this was statistically significant (P ≤ .02). Comparison of suture anchor fixation in this study with transosseous bone tunnel fixation in a previous cyclic loading study at this institution indicates that bone fixation by suture anchors is significantly less prone to failure than bone fixation through bone tunnels (P = .0008). Changing the bone fixation from bone tunnels to suture anchors effectively transferred the weak link from bone to tendon.     

Biomechanical comparison of suture anchor versus margin convergence plus suture anchor for rotator cuff repair

Objective: To evaluate results of margin convergence versus suture anchors in rotator cuff repair, and to determine which method is mechanically superior. Methods: Eighteen kangaroo shoulders were randomly divided into three groups (n = 6). A full thickness tendon defect 1.0 cm × 1.5 cm in size was created in the supraspinatus tendon at humeral insertion, simulating a massive rotator cuff tear. Three different techniques were employed for rotator cuff repair: (i) Mitek GII suture anchor alone (Group 1); (ii) margin convergence alone (Group 2); and (iii) margin convergence plus Mitek GII suture anchor (Group 3). Combined loads were applied to each specimen. After completion of cyclic loading, the construct was loaded to failure. ANOVA and LSD (Least Significant Difference) multiple comparisons of the means were applied to results. Results: Cyclic load testing showed progressive gap formation in each repaired specimen with increasing cycles. Group 1 reached 50% failure at an average of 34 cycles, Group 2 at 75 cycles and Group 3 at 73 cycles. There were significant difference between Groups 1 and 2, and Groups 1 and 3 (P ≤ 0.001). After 100 loading cycles, the average gap size was 6.8 mm, 6.1 mm and 4.7 mm in Groups 1, 2 and 3, respectively. There was a significant difference between Groups 1 and 3 (P ≤ 0.015). All specimens eventually reached failure. Conclusion: Rotator cuff repairs with margin convergence +/? suture anchor were far stronger than suture anchor alone, both in gap formation and ultimate failure load. However, progressive gap formation with cyclic loading seems inevitable after cuff repair, which may facilitate clinical understanding of the phenomena of re‐tear or residual defect.     

Comparison of two arthroscopic repair techniques for small-medium supraspinatus tendon tear: 1 triple-loaded vs 2 double-loaded metallic sutures anchors

IntroductionSurgical repair of the rotator cuff is based on the use of anchors whose ideal numbers and configurations continue to be controversial. We compared the clinical-functional results arising from the arthroscopic repair of shoulders, with small-medium lesions of the supraspinatus tendon, among patients using one anchor with three sutures, or two anchors with two sutures.MethodsIn this retrospective study patient were resolved into 2 groups. Clinical and functional results were assessed based on Constant Score and instrumental isometric examination.ResultsPatients in Group 1 experienced shoulder repair using a single anchor with three sutures (n = 21, mean age = 56 years, range = 51–65). In Group 2, patients received two anchors with two sutures each (n = 24, mean age = 59 years, range = 24–75). The mean follow-up time was 15 months. The mean values of the operated shoulders’ Constant Score were 88.05 and 88.25 respectively. Examination of isometric test results in operated shoulders, healthy shoulders and the two different rotator cuff repair techniques did not reveal any statistically significant differences.ConclusionIn the arthroscopic repair of small-medium supraspinatus tendon tears, the short to mid-term clinical and functional outcomes arising from use of 1 triple-loaded or 2 double-loaded metallic sutures anchors are comparable.     

A biodegradable button to augment suture attachment in rotator cuff repair

Recent experimental studies suggest that the use of suture anchors for rotator cuff tear (RCT) repair transfers the "weak link" to the suture-tendon interface where failure occurs as the sutures cut through the tendon. The purpose of this study was to evaluate the effect of using a suture augmentation button on the fixation strength of rotator cuff tendon repair. A 1.5 cm by 2 cm defect was created in the supraspinatus tendon of seven cadaveric shoulder pairs and two suture anchors inserted in each humerus for suture attachment. For one of each pair, the defect was repaired with sutures placed in a horizontal mattress configuration. The other side was repaired with the sutures being passed through low profile, bioabsorbable buttons placed on the bursal tendon surface prior to knot tying. The supraspinatus tendon was cyclically loaded at a physiologic rate and load (33 mm/sec and 180 N, respectively). The number of loading cycles was recorded when the specimens developed 0.75 cm and 1.5 cm gaps at the repair site. The specimens were then tested to failure. Specimens in the unaugmented group developed 0.75 cm and 1.5 cm gaps at an average of 135 cycles and 362 cycles, respectively. The button augmented group developed these gaps at average of 420 cycles and 708 cycles, respectively. These differences were statistically significant (p < 0.05). The gaps progressively increased in all specimens, which eventually failed by suture cutting through tendon in all specimens. This study demonstrates that in vitro, suture augmentation with a low profile, bioabsorbable button provides significantly enhanced fixation when using suture anchors to repair torn rotator cuff tendon. This device may be a useful adjunct to current methods of rotator cuff repair.     

The low-profile Roman bridge technique for knotless double-row repair of the rotator cuff

With advances in arthroscopic surgery, many techniques have been developed to increase the tendon–bone contact area, reconstituting a more anatomic configuration of the rotator cuff footprint and providing a better environment for tendon healing. We present a low-profile arthroscopic rotator cuff repair technique which uses suture bridges to optimize rotator cuff tendon–footprint contact area and mean pressure. A 5.5 mm Bio-Corkscrew suture anchor (Arthrex, Naples, FL, USA), double-loaded with No. 2 FiberWire sutures (Arthrex, Naples, FL, USA), is placed in the anteromedial aspect of the footprint. Two suture limbs from a single suture are both passed through a single anterior point in the rotator cuff. One suture limb is retrieved from the cannula. The second suture limb is passed through a single posterior point in the rotator cuff producing two points of fixation in the tendon, with a tendon bridge between them. The same suture limb is retrieved through the lateral portal, and then inserted into the bone by means of a Pushlock (Arthrex, Naples, FL, USA), placed approximately 1.5–2 cm posterior to the first anchor. This second suture is passed again in the posterior aspect of the cuff. The limbs of the first suture are pulled to compress the tendon in the medial aspect of the footprint. The two free suture limbs are used to produce suture bridges over the tendon by means of a Pushlock (Arthrex, Naples, FL, USA), placed 1 cm distal to the lateral edge of the footprint relative to the medially placed suture anchors anterior to posterior. This technique allows us to perform a low-profile (single pulley–suture bridges) repair for knotless double-row repair of the rotator cuff.     

Biomechanischer Vergleich aktueller Refixationsarten im Rahmen der Rekonstruktion von Rotatorenmanschettenläsionen in einem in-vivo-Tiermodell

A significant controversy exists regarding the optimal fixation technique in rotator cuff surgery. The aim of this study was to compare the time-dependent bio-mechanical properties of the traditional open transosseous suture technique and modified Mason-Allen stitches (SMMA group) versus the double-loaded suture anchor technique and so-called arthroscopic Mason-Allen stitches (AAMA group) in rotator cuff repair. A total of 18 mature sheep were randomized to the two repair groups. After 6, 12, or 26 weeks, evaluation of the reinsertion site of the infraspinatus tendon was performed. In a biomechanical evaluation all specimens were loaded to failure at a constant displacement rate using a standard universal testing machine. The load-to-failure and stiffness of the healed bone-tendon interface were calculated. Magnetic resonance imaging analysis showed cuff integrity in all cases and no evidence of foreign body reaction to the anchors. Load-to-failure and stiffness data did not indicate any significant difference between the two treatment groups, neither at 6 weeks nor at 12 or 26 weeks. However, at time zero the AAMA group had a higher load-to-failure in comparison to the SMMA group (P<0.010), but there was no difference for the stiffness (P<0.121). This in vivo study showed that the AAMA technique provides superior stability and after healing would gain strength comparable to the SMMA technique.     

The results of tension band rotator cuff suture fixation of locked plating of displaced proximal humerus fractures

IntroductionThe purpose of this study was to assess 1-year outcomes of patients with displaced proximal humerus fractures who underwent treatment with locked plate fixation with rotator cuff suture augmentation.MethodsA total of 86 patients who had sustained 2, 3 and 4-part displaced proximal humerus fractures underwent locked plate fixation with multiple sutures placed in the cuff tendons. Clinical outcome variables included active forward elevation (AFE), active external rotation (AER), and Constant and American Shoulder and Elbow Surgeons (ASES) scores. Post-operative variables included the following complications: varus re-collapse, loss of fixation, osteonecrosis of the humeral head (AVN), screw cut out, hardware failure and infection.ResultsForty-one patients were available with minimum of 1-year follow-up. Mean AFE was 142 ± 17.0° and AER was 41 ± 13.0°. The overall complication rate was 14.6%, with osteonecrosis being the most common (12.2%). Of the 21 patients (51.2%) that initially had varus displacement, all but one maintained anatomic reduction and fixation. Mean ASES score was 78.2 ± 20.0 and average Constant score was 72.7 ± 17.6. Bivariate analyses demonstrated that pre-operative medial comminution (p = 0.297) or varus collapse (p = 0.95) were not associated with an increased likelihood of sustaining a complication.ConclusionsFollow-up of patients in this series demonstrated a low overall complication rate and excellent functional outcomes. We believe suture augmentation of the rotator cuff can counteract varus forces on proximal humerus fractures fixed with locked plates, and should be performed routinely in displaced 2, 3 and 4 part fractures.     

Mechanical strength of arthroscopic rotator cuff repair techniques: an in vitro study

BACKGROUND: Retears after rotator cuff repairs occur relatively frequently and may compromise the functional result. The goal of this study was to analyze the mechanical properties following arthroscopic techniques for rotator cuff repair and to evaluate possible alternative techniques. METHODS: In the first part, five different bone anchors (the Revo screw; Mitek Rotator Cuff anchor, 5.0-mm Statak, PANALOK RC absorbable anchor, and 5.0-mm Bio-Statak) were tested in vitro under cyclic loading on five pairs of cadaveric shoulders. Then five types of arthroscopic tendon suturing instruments were tested on rotator cuff tendons. Finally, the arthroscopically performed mattress and modified Mason-Allen stitches, fixed with either the Revo screw or the Bio-Statak, were evaluated on ten pairs of human cadaveric shoulders. RESULTS: The holding strengths of the various anchors were similar, ranging from 130 to 180 N, and approximated the holding strength of knotted number-2 suture materials. The fixation of the tested anchors yielded comparable values of stiffness except for one anchor, which showed significantly greater subsidence under cyclic load (p = 0.003). All tested, commercially available arthroscopic suturing devices were unsuitable for performing a modified Mason-Allen stitch on normal supraspinatus tendons. Modification of a commercially available suture punch with a longer needle allowed us to consistently perform a modified Mason-Allen stitch. The modified Mason-Allen stitch, which has shown favorable mechanical properties in open repairs of the rotator cuff, was not found to be stronger than the mattress stitch when performed arthroscopically and used with bone anchors. When the modified Mason-Allen stitch was fixed to one anchor, it was even weaker than a mattress stitch repaired with another anchor (168 versus 228 N). Unequal loading of the two suture branches due to the more rigid modified Mason-Allen stitch may be the reason for this difference. CONCLUSIONS: Arthroscopic techniques for rotator cuff repair with use of the mattress stitch and bone anchors allow for a relatively solid fixation. The holding strength is not improved with use of the modified Mason-Allen stitch. Although a direct comparison with previous in vitro studies is not possible, the holding strength of open fixation techniques seems to be stronger. If rotator cuffs are subjected to high postoperative loading, open repair might be preferred to reduce the risk of a retear, until stronger arthroscopic fixation techniques are developed.     

Comparison between single and double suture passing techniques in the suture bridge rotator cuff repair with a 2-mm tape: A simulation study using a three-dimensional finite element method

BackgroundSuture bridge repair has been widely used as one of the standard procedures in the arthroscopic rotator cuff repair. We compared the intratendinous stress distribution between single and double suture passing techniques in the suture bridge repair using a 2-mm tape and clarified the roles of tensioning in this procedure.MethodsA board-like model of the supraspinatus tendon and humeral head was used in order to standardize conditions and exclude the influence of anatomical variations between individuals. Reattachment of the supraspinatus tendon to the bone was simulated using both single and double suture passing techniques for the suture bridge repair using a 2-mm tape. A tensile load was applied to the medial end of the tendon, and the stress distribution pattern was observed. Elastic analysis enabled comparison of the von Mises equivalent and maximum principal stresses between the single and double suture passing techniques. The tape configuration was subsequently translated 1 mm toward the insertion points of lateral anchors to simulate the tensioning maneuver.ResultsAlthough the distribution pattern of both the equivalent and the maximum principal stresses was similar for both models, areas with a high stress concentration were smaller in the single suture passing model than those in the double suture passing model. The equivalent stress concentrated within the tendon beneath the tapes as well as in the area between the crossing tapes and the lateral end of the tendon, whereas the maximum principal stress concentrated medial to the sites of suture penetration.ConclusionsSingle suture passing technique can reduce the extent of intratendinous stress concentration compared with double suture passing technique, which might be beneficial to reduce the incidence of type 2 retear after suture bridge repair of rotator cuff tendon using a 2-mm tape.     

A novel suture anchor constructed of cortical bone for rotator cuff repair: a biomechanical study on sheep humerus specimens

Purpose

The aim of this study was to evaluate biomechanical properties of a new type of suture anchors constructed of human cortical allograft bone and compare it with the similar standard titanium screw anchor for rotator cuff tears in sheep humerus model.

Methods

Twenty-four paired sheep humeri were harvested from 12 male sheep aged 18 months. Specimens were divided into cortical bone anchor group and titanium screw anchor group. The anchors loaded with two sutures were placed at the footprint of infraspinatus tendon. Cyclic loading test was performed from 10 to 60 N at 1 Hz for 500 cycles and followed by a load-to-failure test at 33 mm/sec. A paired t-test was used to compare the biomechanical properties of the anchors of each type.

Results

No anchors failed during the cyclic phase, and the cortical bone anchors were all pulled out intact. The cyclic displacement of the cortical bone anchor was not significantly greater than that of the titanium screw anchor (P?>?0.05). Student’s t test showed no statistically significant difference between anchors in terms of failure load (cortical bone anchor: 304.74?±?64.46 N versus titanium screw anchor: 328.45?±?89.58 N; P?=?0.213), ultimate load (cortical bone anchor: 325.82?±?76.45 N versus titanium screw anchor: 345.61?±?83.56 N; P?=?0.183), yield load (cortical bone anchor: 273.78?±?44.75 N versus titanium screw anchor: 284.72?±?56.37 N; P?=?0.326) or stiffness (cortical bone anchor: 52.97?±?14.28 N/mm versus titanium screw anchor: 62.38?±?18.35 N/mm; P?=?0.112).

Conclusions

In vitro, this experimental study suggested no statistically significant difference in initial fixation stability between the new type anchor and titanium screw anchor at a chosen level of significance (P?<?0.05). The new type of suture anchor constructed of cortical bone provides comparable initial fixation strength to a similar metallic anchor for rotator cuff repair.

     

单排和双排肩袖缝合桥力学研究

目的:从生物力学的角度比较分析单排带线锚钉固定修复肩袖损伤和双排缝合桥固定修复肩袖损伤的力学差异.方法:将健康成年人肩关节的CT扫描数据依次导入Mimics,Geomagics和Hypermesh中进行两种修复模型的逆向重建、材料赋属和网格划分等操作,并设计出冈上肌撕裂的情况,处理完毕后将其导入ABAQUS软件中对其施...     

Disintegration of an absorbable rotator cuff anchor six weeks after implantation

Rotator cuff failure by suture-bone or suture anchor pull-out, suture breakage, knot slippage, and tendon pull-out are well described. I report a case of early disintegration of a bioabsorbable suture anchor. A 77-year-old woman underwent arthroscopic rotator cuff repair. On suspecting failure, the repair was repeated 40 days later. Arthroscopy revealed disintegration of the suture loop from the anchor. Open rotator cuff repair was then performed with transosseous suture and metallic anchors.     

Anatomic Reduction and Next-Generation Fixation Constructs for Arthroscopic Repair of Crescent,L-Shaped,and U-Shaped Rotator Cuff Tears

Emerging techniques and instrumentation have allowed orthopaedic surgeons to achieve rotator cuff repair through an all-arthroscopic technique. The most critical steps in rotator cuff repair consist of proper identification of the cuff tear pattern and anatomic restoration of the torn tendon footprint. With anatomic reduction of the rotator cuff tendons, a sound fixation construct can help restore rotator cuff contact pressure and kinematics, allowing for decreased repair tension and optimal healing potential. We provide surgical methods to recognize tear patterns and present a repair construct that will restore the anatomic footprint of the torn rotator cuff tendon. The key, initial maneuver to restore the anatomic footprint of the cuff includes placement of a suture anchor at the anterolateral corner for L-shaped tears and at the posterolateral corner for reverse L–shaped and U-shaped tears. After insertion of the medial-row anchors, the tendon stitches should be planned by use of a grasper to hold the tendon in a reduced position and guide location of the stitch. The lateral row with suture bridge can be visualized, and the final repair construct should produce an anatomic restoration of the rotator cuff footprint.     

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.     

The Double-Pulley Technique for Double-Row Rotator Cuff Repair

In an effort to maximize the area of footprint coverage, we developed the “double-pulley technique” for double-row rotator cuff repairs. Two suture anchors are inserted at the articular margin of the greater tuberosity (one anterior and one posterior). All 4 suture strands from each anchor are passed through a single medial point on the torn cuff. In this way, the 4 suture strands from the anteromedial anchor pass through 1 point in the cuff and the 4 strands from the posteromedial anchor pass through a different point in the cuff. A suture strand from 1 anchor is tied extracorporeally to a suture strand of the same color from the other anchor. The other ends of those 2 strands are then pulled, thereby delivering this extracorporeal knot into the joint and over the medial footprint. These 2 free suture strands are then tied together as a static knot. The procedure is repeated with the other sutures. This technique creates a double mattress suture medially, which compresses the intervening tendon bridge against its bone bed. We call this procedure the double-pulley technique because it uses the anchor eyelets as pulleys to deliver the extracorporeal knot into the shoulder. After the lateral row repair is performed, the rotator cuff footprint will be completely reconstituted.     

Use of an allograft bone button for rotator cuff repair

Bone button anchors constructed from allograft bone were investigated as an alternative for rotator cuff repair. Bone button anchors were used in 59 consecutive procedures after mechanical pullout strength and cyclical loading bench testing. Sequential radiographs demonstrated that the anchors locked in cancellous bone and provided consistent fixation with no loosening or lysis in 1 year of clinical follow-up. Mechanical testing demonstrated mean, pullout strength of 160.2 N (36 lbs), and the anchors did not migrate when cyclically loaded. Clinical results showed an allograft anchor is viable for rotator cuff tendon repair.     

Operative treatment of acromioclavicular joint dislocation: a new technique with suture anchors

Objective：To evaluate clinical outcome of suture anchors in strengthening both acromioclavicular and coracoclavicular ligaments in the surgical treatment of acromioclavicular joint dislocation.Methods：Twenty-eight patients with acute traumatic Rockwood Ⅲ,Ⅳ and Ⅴ dislocations of the acromioclavicular joint surgically treated at our institute between October 2010 and January 2012 were recruited.All patients underwent open reduction combined with suture anchors.Function was evaluated using the ConstantMurley shoulder score.Clinical and radiographic shoulder ratings were evaluated using Taft criteria at 3,6 and 12 months.Results：Two cases with fixation loosening were not included in final statistical analysis.Other patients obtained full joint reposition on immediate postoperative radiographs.Follow-up was performed with an average of 15.6 months （range,12-19）.After early range of motion exercises,96.2％ of the patients （25/26） could abduct and elevate their shoulders more than 90 degrees within postoperative 3 months.There was no infection.Average Constant-Murley score was 96.3 points （range,94-100）and mean Taft shoulder rating was 10.7 points （range,8-12） at 12 months.Conclusion：The suture anchor is a relatively simple technique and can avoid screw removal which is helpful in reconstructing both acromioclavicular and coracoclavicular ligaments in acute traumatic acromioclavicular joint dislocation.