Suture looping technique for coracoclavicular fixation biomechanically outperforms fixation constructs utilizing either a metallic anchor or an all-suture anchor.

Background:Subpectoral biceps tenodesis can be performed with cortical fixation using different repair techniques. The goal of this technique is to obtain a strong and stable reduction of biceps tendon in an anatomic position.Purpose/Hypothesis:The purpose of this study was to compare (1) displacement during cyclic loading, (2) ultimate load, (3) construct stiffness, and (4) failure mode of the biceps tenodesis fixation methods using onlay techniques with an all-suture anchor versus an intramedullary unicortical button. It was hypothesized that fixation with all-suture anchors using a Krackow stitch would exhibit biomechanical characteristics similar to those exhibited by fixation with unicortical buttons.Study Design:Controlled laboratory study.Methods:Ten pairs of fresh-frozen cadaveric shoulders (N = 20) were dissected to the humerus, leaving the biceps tendon-muscle unit intact for testing. A standardized subpectoral biceps cortical (onlay) tenodesis was performed using either an all-suture anchor or a unicortical button. The biceps tendon was initially cycled from 5 to 70 N at a frequency of 1.5 Hz. The force on the tendon was then returned to 5 N, and the tendon was pulled until ultimate failure of the construct. Displacement during cyclic loading, ultimate failure load, stiffness, and failure modes were assessed.Results:Cyclic loading resulted in a mean displacement of 12.5 ± 2.5 mm for all-suture anchor fixation and 29.2 ± 9.4 mm for unicortical button fixation (P = .005). One all-suture anchor fixation and 2 unicortical button fixations failed during cyclic loading. The mean ultimate failure load was 170.4 ± 68.8 N for the all-suture anchor group and 125.4 ± 44.6 N for the unicortical button group (P = .074), with stiffness 59.3 ± 11.6 N/mm and 48.6 ± 6.8 N/mm (P = .091), respectively. For the unicortical button, failure occurred by suture tearing through tendon in 100% of the specimens. For the all-suture anchor, failure occurred by suture tearing through tendon in 56% and knot failure in 44% of the specimens.Conclusion:The all-suture anchor fixation using a Krackow stitch for subpectoral biceps tenodesis provided ultimate load and stiffness similar to unicortical button fixation using a nonlocking whipstitch. The all-suture anchor fixation technique was shown to be superior in terms of displacement during cyclic loading when compared with the unicortical button fixation technique. However, the results of this study help to show that the fixation method used on the humeral side is less implicative of the overall construct strength than stitch location and technique, as the biceps tendon tissue and stitch configuration seem to be the limiting factor in subpectoral onlay tenodesis techniques.Clinical Relevance:All-suture anchors have a smaller diameter than traditional suture anchors, can be inserted through curved guides, and preserve humeral bone stock without compromising postoperative imaging. This study supports use of the all-suture anchor fixation technique for subpectoral biceps tenodesis, with high biomechanical fixation strength and low displacement, as an alternative to the subpectoral onlay biceps tenodesis technique.

Background:Pediatric patellofemoral instability is common, and medial patellofemoral ligament (MPFL) reconstruction is a highly effective treatment option. Femoral graft fixation methods include suture anchors (SAs) and interference screws (ISs), although comparative biomechanical studies in pediatric bone are lacking.Purpose:To compare the biomechanical properties of SA versus IS femoral graft fixation in pediatric MPFL reconstruction.Study Design:Controlled laboratory study.Methods:Ten fresh-frozen pediatric knees underwent femoral MPFL graft fixation using SA and IS (mean age, 9.5 years; range, 8-10 years). Posterior tibialis tendon allograft was used in both groups. For the IS group, 8-mm tunnels were drilled and 8 × 25–mm biocomposite IS was used for graft fixation. For the SA group, a 1.8-mm knotless all-suture SA was placed and secured to the graft. Specimens were loaded onto an Instron 5944 and subjected to cyclic preconditioning, followed by an ultimate failure load at 6 mm/s. The load displacement curve was then used to calculate stiffness (N/mm). Data were analyzed using repeated-measures analysis of variance to account for multiple measurements on the same specimens.Results:IS graft fixation demonstrated significantly higher ultimate failure load than SA (246.4 ± 79.7 N vs 90.4 ± 20.6 N, P < .001). Similarly, stiffness was significantly greater for IS compared to SA (17.8 ± 4.1 N/mm vs 13.4 ± 2.2 N/mm, P = .009). All but 1 IS reconstruction failed by graft pullout from the femoral tunnel, whereas all 10 SA reconstructions failed by anchor pullout.Conclusion:IS offers significantly higher ultimate failure load and stiffness values compared to SA femoral MPFL graft fixation in human pediatric knees. Mean ultimate failure load values for femoral MPFL fixation in pediatric bone may be lower than in adult bone, based on comparative adult studies. These results provide initial biomechanical data comparing 2 commonly used femoral fixation methods in skeletally immature patients.Clinical Relevance:This study characterized the biomechanical strength of SA and IS femoral MPFL fixation in pediatric bone, revealing differences in ultimate failure load and stiffness between constructs and compared to adult bone. While SA may pose less risk for growth alteration from physeal injury in younger patients, greater “time-zero” MPFL fixation strength with IS may allow for accelerated rehabilitation and earlier return to sport, which is a key patient and family satisfaction variable. In some circumstances, SA fixation may be preferred due to physeal proximity, and postoperative therapy regimens may be modified to account for lower fixation strength. These findings can help surgeons optimize implant selection, tailor rehabilitation protocols, and minimize the risk of graft failure in skeletally immature patients.

Biomechanical Comparison of All-Suture Anchor Fixation and Interference Screw Technique for Subpectoral Biceps Tenodesis

Hemiarthroplasty of the shoulder is commonly indicated for younger patients with osteoarthritis who desire to continue recreational and employment activities. In patients who have undergone prior shoulder surgery, metallic suture anchors may be present in the glenoid. We present a case of bilateral shoulder metallosis following bilateral resurfacing hemiarthroplasty for arthropathy in the setting of previous shoulder instability; the prostheses caused eventual glenoid erosion, leading to contact with the retained metal anchors. Because glenoid erosion is a common complication after shoulder hemiarthroplasty, patients with retained metal anchors are at risk for secondary metallosis due to medial protrusion of the prosthesis in the glenoid, with subsequent erosion of the metal anchors.

BackgroundThe management of acromioclavicular (AC) joint dislocation remains controversial. Recently, anatomic coracoclavicular (CC) fixation with a double clavicular tunnel and three flip-buttons has shown promising results. This study aimed to evaluate functional and radiological outcomes in patients with high-grade AC joint dislocation treated with anatomic CC fixation using double clavicular tunnels and three flip-buttons. MethodsA retrospective, unicentric study was performed. The study included patients with high-grade AC joint dislocation who underwent surgery with anatomic CC fixation using double clavicular tunnels and three flip-buttons. Demographic data were obtained from medical records. A functional evaluation using subjective shoulder value (SSV), visual analog scale (VAS), and disabilities of the arm, shoulder and hand (DASH) questionnaires was performed, and an evaluation of preoperative and postoperative comparative Zanca view images was performed. Factors associated with functional outcomes and radiological AC reduction were analyzed. ResultsA total of 83 patients completed follow-up and were included in the analysis. The mean SSV, VAS, and DASH scores were 92.8, 0.8, and 6.4, respectively. Patients who had complications experienced significantly worse functional outcomes (DASH: P=0.037). Suboptimal final AC reduction was observed in nine patients (11.1%), and significantly more frequently in patients older than 40 years (P=0.031) and in surgeries performed more than 7 days after injury (P=0.034). There were two reoperations (2.4%). ConclusionsAnatomic CC fixation with a double clavicular tunnel and three flip-buttons leads to good functional outcomes, low complication rates, and high rates of optimal AC reduction. ConclusionsAnatomic CC fixation with a double clavicular tunnel and three flip-buttons leads to good functional outcomes, low complication rates, and high rates of optimal AC reduction. Level of EvidenceLevel IV, case series.

Purpose The purpose of this study is to investigate the in vitro biocompatibility of three different suture anchors (all-suture anchor, metal anchor, and polyetheretherketone anchor), commonly used for the rotator cuff repair.Methods To assess the biocompatibility of the anchors, the possible cytotoxicity and the immunogenicity of the devices were assessed by cell viability assay and cell count on cultures of bone marrow stem cells (BMSCs) and peripheral blood leucocytes (PBLs), respectively. The possible inhibitory effect of the devices on BMSCs osteogenic potential was evaluated by alkaline phosphatase activity and matrix deposition assay.Results The viability of BMSCs was slightly reduced when cultured in the presence of the devices (−24 ± 3%). Nevertheless, they were able to differentiate toward the osteogenic lineage in all culture conditions. The proliferation of PBLs and the production of interleukin-2 were not enhanced by the presence of any device.Conclusion The analyzed devices did not significantly affect the normal cells functions when directly cultured with human primary BMSCs or PBLs, in terms of osteogenic differentiation and inflammatory reaction.Clinical Relevance A deeper knowledge of the biological reactions to different devices used in rotator cuff surgeries would improve the clinical outcome of these procedures.

Comparison of all-suture anchors with metallic anchors in arthroscopic cuff repair: Structural and functional properties and clinical suitability

We evaluated the biomechanical strength of two all suture anchors (ASA) of reduced diameter (1.4 mm) and compared them with the standard screw anchor (SA) with larger diameter (5.5 mm) used in rotator cuff tears. We conducted 30 uniaxial vertical pullout tests using Material Testing System Instron 5566A until failure of the anchorage defined as rupture of the threads or anchor or detachment of the anchor. Anchor fixation was on tuberosities of fresh bovine humerus bone. ASAs were spaced four millimetres apart and were compared with a control SA implanted on the same greater tubercle at two centimetres. The tests were all performed at room temperature in a dry environment. Tensile loads (10 mm/min) were applied parallel to the axis of insertion. A preloading of 10 N was used to overcome loading artifacts of the test sample at the beginning of the test. Student's t test showed no statistically significant difference between anchors in terms of load to failure (ASA: force 265.06 ± 87.25 N versus SA : 325.35 ± 113.46 N; p = 0.09) and mean elongation at rupture (ASA : 23 ± 7 mm versus SA : 21 ± 6 mm; p = 0.46). In vitro, this experimental study showed no statistically significant difference in pullout strength and displacement between ASA and SA at a chosen level of significance (p < 0.05).

This human cadaveric study compares the biomechanical properties of quadriceps tendon repair with suture anchors and the commonly applied transosseous sutures. The hypothesis was that suture anchors provide at least equal results concerning gap formation and ultimate failure load compared with transosseous suture repair. Thirty human cadaveric knees underwent tenotomy followed by repair with either 5.5-mm-double-loaded suture anchors [titanium (TA) vs. resorbable hydroxyapatite (HA)] or transpatellar suture tunnels using No. 2 Ultrabraid™ and the Krackow whipstitch. Biomechanical analysis included pretensioning the constructs with 20N for 30s and then cyclic loading of 250 cycles between 20 and 100N at 1Hz in a servohydraulic testing machine with measurement of elongation. Ultimate failure load analysis and failure mode analysis were performed subsequently. Tendon repairs with suture anchors yielded significantly less gap formation during cyclic loading (20th-250th cycle: TA 1.9±0.1, HA 1.5±0.5, TS 33.3±1.9mm, p<0.05) and resisted significantly higher ultimate failure loads (TA 740±204N, HA 572±67N, TS 338±60N, p<0.05) compared with transosseous sutures. Common failure mode was pull-out of the eyelet within the suture anchor in the HA group and rupture of the suture in the TA and TS group. Quadriceps tendon repair with suture anchors yields significantly better biomechanical results than the commonly applied transosseous sutures in this human cadaveric study. These biomechanical findings may change the future clinical treatment for quadriceps tendon ruptures. Randomised controlled clinical trials are desirable for the future. Not applicable, controlled laboratory human cadaveric study.

This study presents an arthroscopic removal technique for proud metallic suture anchor after Bankart repair and analyzes the cause of anchor failures. Six male patients with an average age 23 years who had proud anchor on the glenoid surface were included. The diagnosis of six patients at the time of the primary surgery was traumatic anterior shoulder instability. Four patients had arthroscopic repair and two had open Bankart repair previously. Four patients complained of pain accompanying a metallic clicking sound during shoulder motion which increased with abduction and external rotation. One patient had pain with apprehension of dislocation and another patient suffered from only pain. Most symptoms had been revealed during the rehabilitation period (average 8.3 months) and confused with postoperative pain. The protruded anchors were detected through plain radiographs in four patients and during arthroscopic examination in two patients. To extract the proud anchor arthroscopically, a screw driver of a larger diameter than that of the proud suture anchor was used to retrieve the anchor. A larger screw driver was striked with a hammer along the previous suture anchor hole to make a room between the suture anchor and the adjacent glenoid bone so that the hole of the suture anchor became larger. After the hole was widened, the suture anchor had enough room to move freely and it could be removed with a grasper or a mosquito easily. The location of the proud anchor was 2, 3 and 5 o'clock in three patients and 4 o'clock in three patients. In two patients, the suture anchor was malpositioned about 5 mm medial from the anterior glenoid rim. All patients had chondral damage on the humeral head. Following the procedure none had shoulder instability in 3 years of follow-up. Preoperative visual analog scale score for pain was an average of 3.5. The visual analog scale score for pain was decreased to 1.2 after surgery. All patients had a slight limitation of external rotation preoperatively, and they showed a normal range of motion postoperatively. Constant score improved from 65 to 89, and similarly, American Shoulder and Elbow Society score increased from 67 to 88 after the operation. Despite small numbers of patients, a successful removal of proud metal suture anchors was achieved using a large empty suture anchor screw driver, which is a simple and reproducible method to remove a proud metallic suture anchor arthroscopically.

The histologic and biomechanical response of two commercially available small glenoid anchors for use in labral repairs

Three anchor concepts for rotator cuff repair in standardized physiological and osteoporotic bone: a biomechanical study

BackgroundThe purpose of this study is to investigate clinical outcomes and radiological findings of cyst formation in the glenoid around suture anchors after arthroscopic Bankart repair with either biocomposite suture anchor or all-suture anchor in traumatic anterior shoulder instability. We hypothesized that there would be no significant difference in clinical and radiological outcomes between the two suture materials.MethodsThis retrospective study reviewed 162 patients (69 in group A, biocomposite anchor; 93 in group B, all-suture anchor) who underwent arthroscopic Bankart repair of traumatic recurrent anterior shoulder instability with less than 20% glenoid defect on preoperative en-face view three-dimensional computed tomography. Patient assignment was not randomized. ResultsAt final follow-up, the mean subjective shoulder value, Rowe score, and University of California, Los Angeles shoulder score improved significantly in both groups. However, there were no significant differences in functional shoulder scores and recurrence rate (6%, 4/69 in group A; 5%, 5/93 in group B) between the two groups. On follow-up magnetic resonance arthrography/computed tomography arthrography, the incidence of peri-anchor cyst formation was 5.7% (4/69) in group A and 3.2% (3/93) in group B, which was not a significant difference. ConclusionsConsidering the low incidence of peri-anchor cyst formation in the glenoid after Bankart repair with one of two anchor systems and the lack of association with recurrence instability, biocomposite and all-suture anchors in Bankart repair yield satisfactory outcomes with no significant difference.

Objectives:All-suture anchors are a recent addition that serve as an alternative to conventional suture anchors utilized for arthroscopic rotator cuff repair (RCR). We hypothesize that there will be no difference in functional outcomes or complication rates in patients who underwent arthroscopic rotator cuff repair with all-suture medial row anchors compared to traditional suture anchors during a transosseous equivalent repair. The study design for this investigation is a level III retrospective case-control study.Methods:Patients undergoing primary arthroscopic RCR from January 1st, 2017, to August 31st, 2021 were eligible for inclusion. Operative notes were reviewed to determine tear size, type of anchors utilized, and concomitant pathology diagnosed and treated. Patients were separated into 2 groups based on which suture anchor was used (all-suture versus traditional (screw in anchors)). Patient medical records were examined to determine postoperative range of motion (ROM) and strength. Patient reported outcome (PRO) measures such as American Shoulder and Elbow Surgeons (ASES) score, Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, Simple Shoulder Test (SST), and Visual Analogue Pain Scale (VAS) were gathered.Results:In total, 252 patients were ultimately included for final analysis. 118 patients (46.8%) underwent aRCR with all-suture anchors while 134 (53.2%) patients had aRCR with traditional suture anchors. Size of tear was significantly larger in the all-suture cohort (18.21 ± 12.9 mm) than the traditional anchor cohort (13.93 ± 6.1 mm) (p=0.037). The number of sutures used (8.26 ± 4.3 vs. 5.0 ± 2.1) as well as number of anchors used (2.97 ± 1.4 vs. 2.6 ± 1.3) were significantly greater in the all-suture cohort than the traditional anchor cohort (p<0.001 and p=0.018, respectively). No other demographic or operative information was significantly different between groups (p>0.05). Abduction was found to be greater in the all-suture cohort (176.2° ± 14.8 vs. 168° ± 18.6, p<0.001). No other ROM parameter was significantly different between groups (p>0.05). The all-suture cohort also demonstrated greater proportions of postoperative strength in the 4+/5 and 5/5 categories when compared to traditional anchor patients (p=0.015). All-suture patients reported lower (better) VAS Pain scores postoperatively (1.2 ± 1.1 vs. 2.8 ± 2.1, p<0.001). ASES, DASH, and SST scores did not differ between cohorts (p>0.05)Conclusions:Patients who undergo arthroscopic rotator cuff repair using all-suture medial row anchors have increased abduction and strength postoperatively, as well as lower pain scores compared to traditional suture anchors during a transosseous equivalent repair.

Background Different metal and biodegradable suture anchors are available for rotator cuff repair. Poor bone quality may result in anchor loosening and tendon rerupture. Hypotheses Higher bone mineral density is associated with higher pull-out strength of suture anchors. Depending on anchor placement, pull-out strengths of anchors are different within the greater tuberosity. Study Design Cadaveric biomechanical study. Methods Trabecular and cortical bone mineral densities were determined for different regions within the greater tuberosity. Metal screw-type and biodegradable hook-type anchors were cyclically loaded. Results Mean failure load of metal and biodegradable anchors was 273 N and 162 N, respectively, for the proximal part (P < .01) and 184 N and 112 N, respectively, for the distal part (P < .01). Both types of anchors showed higher failure loads in the proximal-anterior and -middle parts of the greater tuberosity than in the distal part (P < .01). A significant positive correlation was found between cortical bone mineral density and failure load of metal anchors (P < .01). Conclusion Bone quality, anchor type, and anchor placement have a significant impact on anchor failure loads. Clinical Relevance Suture anchors should be placed in the proximal-anterior and -middle parts of the greater tuberosity. In the distal parts, biodegradable hook-like anchors should be used with caution.