Introduction and Aims: To evaluate the technique of the knotless suture anchor for the treatment of anterior shoulder instability. Method: 109 patients were reviewed. Each patient underwent a standardised procedure by the same surgeon under a regional interscalene block and/or general anaesthesia. An average of three anchors were placed in the 3, 4 and 5 o’clock positions. 40 patients had additional thermal shrinkage to reduce excess capsular volume. Each patient was assessed using the Constant, Rowe and Walch-Duplay scores. Results: Follow-up period was 18 months, with an average of two years. The average operating time was one hour. Four patients (3.6%) redislocated following surgery. Two of these patients had a glenoid bone deficiency of > 20% and associated full thickness rotator cuff tears, one had an associated humeral avulsion of the glenohumeral ligament (HAGL) lesion, which was not repaired arthroscopically, and one had returned to contact sports as early as 12 weeks after surgery. Three patients had single episodes of subluxations that have not required revision. The average Rowe score was 90.8, average Constant score was 89.9 and the average Walch-Duplay score was 81.4. Conclusion: Early results indicate that capsulolabral reconstruction using the knotless suture anchor is an effective procedure in the treatment of post-traumatic anterior shoulder instability. The incorporation of a south to north capsular shift technique during labral reattachment reduces the necessity of additional thermal to reduce redundant capsular volume. Relative contraindications of this technique include; presence of a HAGL lesion, and anterior glenoid bone deficiency. The procedure may be performed as a day case under regional anaesthesia, has a high index of patient satisfaction and is an acceptable alternative to open surgery

Background: Arthroscopic stabilisation surgery for the shoulder remains a controversial choice of treatment for post traumatic anterior instability. We present the results of a consecutive initial series of 50 patients who were stabilised using a knotless labral repair technique. Methods: The study group included 41 men and 9 women with an average age of 26 years. 58% were affected on the dominant side. The average duration of preoperative syptoms was 3.8 years. 72% of patients had dislocations, whilst the remainder experienced subluxations. Each patient underwent a standardised procedure by the same surgeon with a regional interscalene block and/or general anaesthesia. Anchors were placed in the 3, 4 and 5 o’clock positions. Each patient was assessed using the Constant, Rowe and Walch-Duplay scores at an average of 18 months follow up (range 12–36 months). Results: At review 95% of shoulders remained stable. One patient had a true dislocation 6 months post surgery. One patient experienced a subluxation following a direct whilst skiing. 6 patients remained apprehensive. 3 patients had minor restriction of external rotation. The average Rowe score was 90.8, average Constant score was 89.9 and the average Walch-Duplay score was 81.4Conclusions: Early results indicate that capsulolabral reconstruction using the knotless suture anchor combined with a south to north capsular shift is an effective procedure in the treatment of post-traumatic anterior shoulder instability. This procedure may be performed as a day case under regional anaesthesia and is associated with a high index of patient satisfaction with a return to sporting activities

Arthroscopic stabilisation of the shoulder is a technically-demanding and developing technique, and the reported results have yet to match those for open surgery. We present a consecutive initial series of 55 patients with post-traumatic recurrent anteroinferior instability managed since September 1999 using a titanium knotless suture anchor. Patients were reviewed from 12–33 months postoperatively and assessed using the Rowe, Walch-Duplay and Constant scores. Following mobilisation of the capsulolabral complex, labral reconstruction was achieved using a two-portal technique and an average of three anchors placed on the glenoid articular rim. In 13 cases, additional electrothermal shrinkage was required to reduce capsular redundancy in the anterior and inferior recesses following labral repair, although 11 of these were in the first 18 months. Incorporation of a south-to-north capsular shift has reduced the need for supplementary shrinkage. Complications have included one instance of anchor migration requiring open retrieval and two documented episodes of recurrent instability, although these occurred in patients having surgery within the first six months after the introduction of this technique. Based on our initial experience, we believe that arthroscopic labral repair is a viable alternative to open Bankart repair and have now expanded the indications to include patients with primary dislocation, those participating in gymnastic and contact/collision sports, and revision cases with failed open repairs

One of the recently introduced anchors is the absorbable suture anchor BIOKNOTLESS-RC, a press-fit anchor whose special feature is the knotless reconstruction of the ruptured rotator cuff. We compared the new knotless anchor BIOKNOTLESS-RC with established anchors.

The absorbable pressfit anchor BIOKNOTLESS-RC (DePuyMitek, Raynham, MA, USA), the titanium screw anchor SUPER-REVO 5mm and the tilting anchor ULTRASORB (both ConmedLinvatec, Largo, FL, USA) were tested 12 times in the greater tuberosity of human cadaveric humeri (mean age: 74 years). They were inserted according to the manufacturers instructions with the supplied suture material. An incremental cyclic loading was performed, starting with 75N. Until failure the tensile load was increased by 25N after every 50 cycles. The ultimate failure loads, the anchor displacements and the modes of failure were recorded.

The anchor displacement of the BIOKNOTLESS-RC (15.3mm) after the first cycle with 75N was significantly higher than with the two others (SUPER-REVO 2.1mm, ULTRASORB: 2.7mm). The ultimate failure loads of the tested anchors were comparable: BIOKNOTLESS-RC 150N, SUPER-REVO 150N, ULTRASORB 151N (p> 0,05).

Rupture of the suture material at the eyelet occurred more frequently with the SUPER-REVO. BIOKNOTLESS-RC and ULTRASORB showed a tendency towards anchor pullout.

Our results do not confirm the higher pullout strength of metal anchors, which was found in other studies. Knotless anchors facilitate surgery by eliminating the technically challenging step of arthroscopic knot tying. The disadvantage of the BIOKNOTLESS-RC is its unsatisfactory primary stability. Its initial displacement of a mean of 15.3 mm is clinically significant and jeopardizes the rotator cuff repair.

Because of the high initial displacement and the possible gap formation between tendon and bone, the use of the BIOKNOTLESS-RC in a zone of minor tension, for instance as a second-row anchor in double row technique only is recommend.

Objectives. This study evaluated the mechanical performance, under low-load cyclic loading, of two different knotless suture anchor designs: sutures completely internal to the anchor body (SpeedScrew) and sutures external to the anchor body and adjacent to bone (MultiFIX P). Methods. Using standard suture loops pulled in-line with the rotator cuff (approximately 60°), anchors were tested in cadaveric bone and foam blocks representing normal to osteopenic bone. Mechanical testing included preloading to 10 N and cyclic loading for 500 cycles from 10 N to 60 N at 60 mm/min. The parameters evaluated were initial displacement, cyclic displacement and number of cycles and load at 3 mm displacement relative to preload. Video recording throughout testing documented the predominant source of suture displacement and the distance of ‘suture cutting through bone’. Results. In cadaveric bone and foam blocks, MultiFIX P anchors had significantly greater initial displacement, and lower number of cycles and lower load at 3 mm displacement than SpeedScrew anchors. Video analysis revealed ‘suture cutting through bone’ as the predominant source of suture displacement in cadaveric bone (qualitative) and greater ‘suture cutting through bone’ comparing MultiFIX P with SpeedScrew anchors in foam blocks (quantitative). The greater suture displacement in MultiFIX P anchors was predominantly from suture cutting through bone, which was enhanced in an osteopenic bone model. Conclusions. Anchors with sutures external to the anchor body are at risk for suture cutting through bone since the suture eyelet is at the distal tip of the implant and the suture directly abrades against the bone edge during cyclic loading. Suture cutting through bone may be a significant source of fixation failure, particularly in osteopenic bone. Cite this article: Y. Ono, J. M. Woodmass, A. A. Nelson, R. S. Boorman, G. M. Thornton, I. K. Y. Lo. Knotless anchors with sutures external to the anchor body may be at risk for suture cutting through osteopenic bone. Bone Joint Res 2016;5:269–275. DOI: 10.1302/2046-3758.56.2000535

Aim: To evaluate the results of arthroscopic repair of anterior and superior glenoid labral tears in the shoulder with metallic knotless suture anchors with an average follow up of 31 months. Material and methods: Between 2000 and 2002, 55 patients with labral tears underwent arthroscopic repair with metallic knotless suture anchors (Mitek, Ethicon Ltd). Their average age was 36 years (range 16 to 67). Thirty-seven patients presented with anterior instability. Twenty-one patients presented with painful shoulder without instability. In the instability group there were eight acute dislocations and twenty-nine recurrent dislocations. All patients underwent examination under anaesthesia, arthroscopic repair of labral tears using the metallic knotless suture anchors, thermal capsulorraphy and closure of the rotator interval. Subacromial decompression was performed when indicated. Rehabilitation consisted of sling immobilisation for four weeks followed by gradual strengthening program over three months with the physiotherapist. Contact sports were allowed at 1 year. Evaluation: Patients were evaluated preoperatively and at the time of final follow-up using Constant score and Modified Rowe – Zarin score system. Results: Three out of the thirty-seven patients in the instability group had recurrent dislocation. A fourth patient had pain with a positive anterior apprehension test thus making the overall recurrence rate of 11%. In the painful shoulder group, good and excellent results were recorded in twenty out of twenty-one patients (95%). Of the fifty five patients who had labral repair, five had poor functional outcome secondary to pain in their shoulder (9%). One patient had a fall and required further surgery to replace one dislodged anchor. Conclusions: We found the metallic knotless suture anchor easy to use and stabilised the torn labrum well. The success rate for instability compares well with the published literature. However, we have some concern of our observation of early degenerative changes in some of our patients treated for recurrent dislocation

Introduction: Arthroscopic stabilisation of shoulder joint for instability following a traumatic dislocation is gaining popularity. It has various advantages like being minimally invasive, causes minimal damage to the shoulder muscles, quicker rehabilitation, minimal loss of external rotation, and addresses the pathology. This can be performed using non-absorbable suture anchors to repair the Bankart’s lesion, which involves arthroscopic knot tying. Recently, devices, which avoid tying knots, and are absorbable, have been developed for arthroscopic shoulder stabilisation. Aim: To evaluate the clinical results of arthroscopic Bankart’s repair using knotless, bio-absorbable suture anchor device. Methods: A total of 32 patients with recurrent anterior dislocation of shoulder of traumatic origin underwent arthroscopic stabilisation using absorbable knotless suture anchors (Mitek U.K.). Average follow up was 2.4 years. Oxford shoulder instability score were used to evaluate clinical outcomes. Results: The average age of patients at surgery was 24 (18–28). The average number of dislocations per patient were three. The average hospital stay was 1.1 days. The mean operating time was 70 minutes. 90.6 % (29 out of 32) had no further instability or dislocation. The recurrence rate was 9.4% (3 out of 32). The two redislocations required open repair and one patient has a residual instability. The average Oxford instability score was 22. All the patients returned to their pre-operative occupation. Of the 7 keen sportsmen, 5 returned to their contact sports at pre-injury level and 2 returned to their contact sports at a slightly lower level. In two cases we had breakage of anchor loop intraoperatively. Two patients had initial stiffness, which eventually resolved. No other complication was noted. Conclusion: The clinical outcome of arthroscopic stabilisation of shoulder using knotless bio-absorbable suture anchors are good and are comparable to other methods of arthroscopic Bankart’s repair. The advantages are that the anchors are absorbable and there is no knot tying involved

Introduction: Knotless Suture Anchors provide numerous advantages in arthroscopic rotator-cuff (RC) repair such as, reducing the difficulties of knot tying, reducing surgical exposure, thus decreasing morbidity. The purpose of this in-vitro study was to compare the pull-out strength of three new knotless suture anchors in correlation with bone quality using the following anchors: Opus Magnum 2 -ArthroCare Co., USA; Push Lock and Swivel Lock -Arthrex Inc., USA. Material & Methods: Ten healthy and ten osteopenic macroscopically intact humeri with an average age of 51.7 and 79.5 years, respectively, were loaded with the three knotless suture anchors according to the manufacturers’ description. The healthy humeri had a mean trabecular BMD of 152.77 mgCa-HA/ml. The osteopenic humeri had a mean trabecular bone mineral density of 54.02 mgCa-HA/ml. The humeri were positioned in a custom - engineered adjustable fixation device, stabilising the direction of the pull of the sutures at an angle of 135° to the axis of the humeral shaft (Universal testing device Z010/TN2A – Zwick GmbH, Ulm, Germany). The anchors were cyclically loaded to simulate postoperative conditions. The ultimate pull-out strenngth, the initial displacement in millimeters after the first pull with 75 N and the modes of failure were recorded. Results: The mean ultimate failure loads of the Opus Magnum 2, PushLock and SwiveLock anchors in osteopenic humeri were 135.0, 102.5 and 130.0 N (p> 0.05), respectively, and in healthy humeri 142.5 N, 182.5 N and 202.5 N (p> 0.05), respectively. The initial system displacement in osteopenic humeri of the Opus Magnum 2, PushLock and SwiveLock anchors were 3.53 mm, 16.11 mm and 3.23 mm (p< 0.01), respectively, and in healthy humeri 3.71 mm, 1.98 mm, and 1.96 mm (p> 0.05), respectively. Discussion: The results of this study show that in osteopenic humeri, the Opus Magnum 2 and SwiveLock anchors display significant superiority in system displacement with an initial pull of 75N compared to the PushLock anchor in osteopenic bone, but all three anchors fail to provide significance in the ultimate failure load. PushLock anchor might cause a greater gap formation between the RC-tendon and greater tubercle interface in osteopenic humeri due to inferior gripping and therefore should not be used solely for RC repair. Due to a manufacturing flaw the suture holding fixture of the Opus Magnum 2 anchor “breaks” when a mean force of 138.75 N is applied to the system, regardless of the bone quality, thus disabling the anchor to unfold it’s properties in healthy bone. Whereas the results in osteopenic bone are comparable to the other two anchors. SwiveLock provides the best support of all three anchors in healthy humeri

Summary. Strong mechanical fixation is critical to the success of rotator cuff repairs. In this comparative study in cadaveric shoulders, single-tendon full-thickness supraspinatus tears were repaired using two different types of PEEK knotless suture anchors-ReelX STT (Stryker) and Opus Magnum PI (Arthrocare)-using a single-row technique in both instances. Cyclic testing was performed followed by loading until mechanical failure. No significant difference was observed in gap formation, measured as the distance between the supraspinatus tendon and bone at the repair site, during cyclic loading. However, the maximum load was statistically higher for repairs with the ReelX anchor. Purpose. The objective of this study was to compare the gap formation during cyclic loading and maximum repair strength of single-row full thickness supraspinatus repairs performed using two different types of PEEK knotless suture anchors in a cadaveric model. Methods. Nine matched pairs of cadaveric shoulders were used in this study. All soft tissue was removed except for the supraspinatus, and a full thickness tear was formed. Single-row repairs were performed with two anchors per repair using either the Opus Magnum PI (Arthrocare) or the ReelX STT (Stryker). The specimens were mounted to an Instron at 45° to simulate an anatomic direction of load, and fiducial markers were placed on the repair in anterior and posterior positions. A 10 N preload was applied and held for 60 seconds, and then the tendon was cycled from 10 N to 90 N at 0.25 Hz for 500 cycles, followed by load to failure at 1 mm/s. A video digitizing system was used to track the markers and measure gap formation during loading. Gap formation was calculated by subtracting the distance between the markers at 10 N preload from the maximum displacement at 5 and 500 cycles. Paired t-tests were used to compare the cyclic displacement and max load. Results. One specimen from each of two matched pairs (one from each anchor group) failed during cyclic loading, leaving seven matched pairs for analysis. No significant difference was found in cyclic displacement between the two groups in either anterior or posterior positions at 5 and 500 cycles. However, maximum load to failure was significantly greater for repairs performed with the ReelX STT anchors (289N ± 57N) as compared to the OPUS anchors (178N ± 36N), with a p=0.009. Conclusions. These results suggest that the anchor type chosen for cuff repairs may affect the overall stability of the repair. Achieving stable fixation is critical for promoting healing of the tendon back to bone and to the long-term success of the repair, and using anchors that provide stronger fixation may decrease the occurrence of post-surgical tears and instability. The ReelX STT anchor outperformed the Opus Magnum PI anchor in terms of supporting significantly higher loads before failure, potentially leading to stronger repairs clinically

The February 2013 Shoulder & Elbow Roundup³⁶⁰ looks at: whether we should replace fractured shoulders; the limited evidence for shoulder fractures; cuffs and early physio; matrix proteins and cuff tears; long-term SLAP tear outcomes; suture anchors; recurrent Bankart repairs; and acromial morphology and calcific tendonitis.