Adjustable-loop Devices Research Articles

Effect of Quadriceps Tendon Autograft Preparation and Fixation on Graft Laxity During Suspensory Anterior Cruciate Ligament Reconstruction: A Biomechanical Analysis.

Favorable collagen fibril density and thickness combined with advances in graft preparation and fixation have significantly increased interest in the quadriceps tendon (QT) autograft for anterior cruciate ligament (ACL) reconstruction. While various suspensory techniques have been described, the biomechanical profile of these constructs is largely undefined. To compare the biomechanics of suspensory techniques for soft tissue QT autograft fixation in an in vitro model of ACL reconstruction. Controlled laboratory study. Full-thickness QT grafts were harvested using a 9-mm graft blade. Adjustable-loop devices (ALDs) were secured to the graft (n = 6 per group) with a combination implant containing the ALD and suture tape-reinforced whipstitching (tape-reinforced [TR] group), tethered superficially to the graft with a whipstitch (onlay [OL] group), luggage-tagged through and around the graft (luggage tag [LT] group), or staggered behind superficial suturing (staggered [SG] group). Grafts were tested on an electromechanical testing machine following a validated in vitro reconstruction model of intraoperative workflow and postoperative ACL kinematics, cyclic loading, and load to failure. The TR group had significantly less postcyclic tension loss (mean, 24%) compared with the OL (56%; P = .002), LT (69%; P < .001), and SG (90%; P < .001) constructs. Cyclic elongation was below the 3.0-mm threshold defined as clinical failure for TR (1.6 mm), but not for OL (3.3 mm), LT (7.9 mm), and SG (11.3 mm). All constructs were within native ACL stiffness limits (220 ± 72 N/mm) without significant differences. Ultimate loads significantly exceeded a normal ACL loading limit of 454 N for TR (739 N; P = .023), OL (547 N; P = .020), and LT (769 N; P = .001), but not for SG (346 N; P = .236). The TR ALD construct demonstrated the most favorable time-zero biomechanical properties of modern soft tissue QT suspensory constructs, with 32% less tension loss and 52% less cyclic elongation versus the closest construct. Failure loading of all constructs was acceptable with respect to the native ACL except for the SG group, which had suboptimal ultimate load. TR ALD implants may protect soft tissue QT autografts before graft-bone healing in ACL reconstruction by minimizing time-zero laxity and fixation failure.

Arthroscopic intercruciate trans-septal posterior cruciate ligament avulsion fixation with pull-through technique using a single button adjustable loop device

Numerous arthroscopic techniques have been described for the fixation of posterior cruciate ligament avulsion, including the pull-out technique with suture or tape fixed with a knot tied over a free cortical button on the anterior tibial cortex, and the adjustable loop with double cortical buttons. We present a modification of the suture pull-out method utilizing the readily available adjustable loop with a single cortical loop button for fixation on the anteromedial tibial cortex. The surgery is performed through an intercruciate trans-septal approach with the suture bridge configuration and cross-over of suture tapes, with two diverging tibial tunnels with a single anterior opening forming a “Y-shaped tunnel.” The advantages of the suture pull-through method and the adjustable loop device can be combined using this technique modification.

Does retensioning of adjustable-loop cortical suspension devices improve performance: A systematic review and meta-analysis

Objectives: To date, there is conflicting evidence when comparing fixed-loop cortical suspension devices (FLDs) to adjustable-loop devices (ALDs). Some studies indicate that ALDs are inferior to FLD in regard to displacement and failure load while others show that they are biomechanically similar. The purpose of this study is to use a meta-analysis of biomechanical data to compare FLDs to ALDs with and without retensioning. It is hypothesized that retensioning the ALD will allow these devices to be biomechanically equivalent to the FLD in total unloaded displacement and failure load. Materials and Methods: This study sought to identify all biomechanical studies that compared fixed loops to ALD. A meta-analysis was performed to find the standardized mean difference with retensioning as a covariate. Results: The analysis of isolated tests showed that retensioning reduced the cyclic ALD displacement in comparison to non-retensioned ALD; however, both the ALD with and without retensioning had significantly higher cyclical displacement and significantly lower failure load compared to the FLD. In the meta-analysis of the animal model data, there was no significant difference between the ALD with retensioning and the FLD. Conclusion: This analysis suggests that retensioning reduces displacement of an ALD, with displacements measured in animal bone testing showing no significant difference as compared to FLD. However, in the device-only model, the ALD with retensioning and the ALD without retensioning had significantly higher cyclical displacement and significantly lower load to failure compared to the FLD. These data suggest that retensioning may be beneficial. However, there is significant heterogeneity in the pooled studies which limit the strength of this conclusion.

Biomechanical Stability of Third-Generation Adjustable Suture Loop Devices Versus Continuous Loop Button Device for Cortical Fixation of ACL Tendon Grafts.

Concerns regarding the primary stability of early adjustable loop button (ALB) devices for cortical fixation of tendon grafts in anterior cruciate ligament reconstruction (ACLR) have led to the development of new implant designs. To evaluate biomechanical stability of recent ALB implants in comparison with a continuous loop button (CLB) device. Controlled laboratory study. ACLR was performed in a porcine model (n = 40) using 2-strand porcine flexor tendons with a diameter of 8 mm. Three ALB devices (Infinity Button [ALB1 group]; Tightrope II RT [ALB2 group]; A-TACK [ALB3 group]) and 1 CLB device (FlippTack with polyethylene suture) were used for cortical tendon graft fixation. Cyclic loading (1000 cycles up to 250 N) with complete unloading were applied to the free end of the tendon graft using a uniaxial testing machine, followed by load to failure. Elongation, stiffness, yield load, and ultimate failure load were recorded and compared between the groups using a Kruskal-Wallis test with post hoc Dunn correction. Elongation after 1000 cycles at 250 N was similar between groups (ALB1, 4.5 ± 0.7 mm; ALB2, 4.8 ± 0.8 mm; ALB3, 4.5 ± 0.6 mm; CLB, 4.5 ± 0.8 mm), as was load to failure (ALB1, 838 ± 109 N; ALB2, 930 ± 89 N; ALB3, 809 ± 103 N; CLB, 842 ± 80 N). Stiffness was significantly higher in the ALB1 group compared with the CLB group (262.3 ± 21.6 vs 229.3 ± 15.1 N/mm; P < .05). No significant difference was found between the 4 groups regarding yield load. Constructs failed either by rupture of the loop, breakage of the button, or rupture of the tendon. The tested third-generation ALB devices for cortical fixation in ACLR withstood cyclic loading with complete unloading without significant differences to a CLB device. The third-generation ALB devices tested in the present study provided biomechanical stability comparable with that of a CLB device. Furthermore, ultimate failure loads of all tested implants exceeded the loads expected to occur in the postoperative period after ACLR.

Augmentation of the Anterior Cruciate Ligament Using the Peroneus Longus: Description of the Surgical Technique

Background: The quadruple graft from the hamstring tendons has become a widely used option in the reconstruction of the anterior cruciate ligament (ACL), however, this graft may not have the desirable diameter for the reconstruction, increasing the risk of re-rupture. In this context, the peroneus longus tendon graft appears as an option to complement other grafts, transforming a thin quadruple graft into a sextuple graft. Indications: The sextuple graft technique for ACL reconstruction is used in patients who have a quadruple graft with a diameter of less than 8 mm, and due to its length, it is not possible to make a quintuple graft, for example. Technique Description: Initially, the hamstring tendons are removed with the aid of a tenotome. After that, the anterior half of the peroneus longus tendon is identified and removed. On the back table, the definitive graft is prepared so that we have a sextuple graft with a diameter greater than 8 mm. Finally, the ACL reconstruction is performed anatomically using an adjustable loop device in the femur and an interference screw in the tibia. Results: In our experience with patients who have a hamstring graft diameter of less than 8 mm, we obtained an average increase of 1.8 mm in graft diameter when augmentation was performed with the anterior half of the peroneus longus. Discussion: Grafts less than 8 mm in diameter are at increased risk of rupturing and failure of surgical treatment of the ACL injury. The surgeon must be prepared to make a quintuple or sextuple graft, but in some patients, the tendons are short or there is no availability of a tissue bank, making this practice impossible. The use of the anterior half of the peroneus longus to perform graft augmentation is safe, causing almost no morbidity to the donor area and is easily accessible during the procedure, making it an excellent option for increasing the diameter of thin grafts. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form.

A radiological evaluation of loop length change in adjustable versus fixed loop femoral cortical fixation devices in arthroscopic anterior cruciate ligament reconstruction: a prospective study

Background: In anterior cruciate ligament reconstructions, fixed devices require over-drilling to flip the button whereas loops of adjustable devices can be adjusted intraoperatively, and they minimize over-drilling. But they can loosen rendering the reconstruction incompetent. Most studies comparing them are bio-mechanical studies. Our aim was to record and compare loop length change radiologically in adjustable versus fixed devices in clinical settings. Methods: 32 patients were divided into 2 groups of 16 patients each. Hamstring graft were prepared. It was loaded in the suspension device and the apex of the graft was marked using silicon vascular radio-opaque marker. In adjustable devices, lengthening was checked after cycling and re-tensioning was done intra-operatively. Post-surgery, digital X-ray of the knee was taken in true antero-posterior and lateral view. Distance between the centre point of the button and the centre-point of the radio-opaque inert silicon marker was recorded at immediate post-operative and at 6 weeks respectively and compared. Results: 15 patients in each group were incorporated. Intra-operatively, loop lengthening was seen in all 15 patients with adjustable loop and re-tensioning was done. 2 of the 15 cases showed evidence of radiological loop lengthening however in both cases the lengthening was less than 3 mm and thus was not significant. Conclusions: We in in vivo radiology based clinical study did not find any significant loop lengthening in patients with adjustable loop devices. Hence fixed and adjustable loop devices are comparable.

Biomechanical Comparison of 3 Adjustable-Loop Suspensory Devices for All-Inside ACL Reconstruction: A Time-Zero Full-Construct Model.

Little is known about the stability of adjustable-loop devices (ALDs) for anterior cruciate ligament (ACL) reconstruction (ACLR). To evaluate the stabilization behavior of 3 different types of ALDs for all-inside ACLR in a full-construct surgical technique-based manner. Controlled laboratory study. The femoral and tibial devices of Ultrabutton (Smith & Nephew), Infinity (Conmed), and TightRope II (Arthrex) were applied to quadrupled bovine tendon grafts (n = 8 each) with tibial-sided traction applied (350 N) for graft tensioning in a simulated fully extended knee. Knotless femoral graft fixation was based on either a suture-locking device (SLD; Ultrabutton), button-locking device (BLD; Infinity), or dual-locking device (DLD; TightRope II). All constructs were progressively loaded (50 N/500 cycles) from 50 to 300 N for 3000 cycles (0.75 Hz), including complete unloading situations and pull to failure (50 mm/min). Construct elongation, stiffness, and ultimate load were analyzed. BLD showed significantly greater initial elongation (-2.69 ± 0.15 mm) than DLD (-3.19 ± 0.21 mm; P < .001) but behaved similarly to SLD (-2.93 ± 0.23 mm). While DLD and SLD had the smallest initial elongation at the same significance level, they behaved opposite to each other with gradually increasing peak loading. At the end of testing, DLD had the lowest (-0.64 ± 0.32 mm) and SLD the highest (3.41 ± 1.01 mm) total elongation (P < .003 for both). SLD displayed significantly higher dynamic elongation (6.34 ± 0.23 mm) than BLD (3.21 ± 0.61 mm) and DLD (2.56 ± 0.31 mm) (P < .001 for both). The failure load of BLD (865.0 ± 183.8 N) was significantly lower (P < .026) compared with SLD and DLD (>1000 N). The predominant failure mode was suture rupture and tibial bone breakage with button subsidence (SLD, n = 4). No significant difference in stiffness between constructs was found. While DLD successfully restricted critical construct elongation, BLD partially and SLD completely exceeded the clinical failure threshold (>3 mm) of plastic elongation with loop lengthening during increasing cyclic peak loading with complete unloading. Higher failure loads of SLD and DLD implants (>1000 N) were achieved at similar construct stiffness to BLD. A detailed biomechanical understanding of the stabilization potential is pertinent to the continued evolution of ALDs to improve clinical outcomes.

Both Adjustable and Fixed Loop Hamstring Tendon Graft Fixation Have Similar Clinical and Patient-Reported Outcomes in Anterior Cruciate Ligament Reconstruction

PurposeThis study aims to compare the outcomes of fixed-loop device (FLD) vs adjustable-loop device (ALD) graft fixation with up to 2-year follow-up in patients undergoing primary anterior cruciate ligament reconstruction (ACLR) in a predominantly Asian setting. MethodsProspectively collected outcome measures as well as clinical records of patients who underwent primary ACLR using either FLD or ALD fixation of hamstring tendon autograft performed by a single surgeon were reviewed. The surgeon in this study used a fixed-loop device from 2018 to 2019 and then changed to adjustable loop from 2019 to 2020. Suspensory fixation was performed on the femoral side, and aperture (interference screw) fixation was performed on the tibial side. Outcome measures included knee range of motion, KT-1000 arthrometer testing, Lysholm knee score, and Tegner activity scale. Patients were assessed preoperatively and postoperatively at regular intervals of 6, 12, and 24 months. ResultsA total of 105 patients were identified. Forty-six were excluded due to incomplete follow-up data, so 59 patients with full 2-year follow-up were included in the final study group. Both groups (FLD vs ALD) were similar in demographics except for age (P = .042). Out of 105, there were 59 patients remaining in the study group with 2-year follow-up data. No significant differences were observed between the 2 groups at all respective testing intervals. ConclusionsFLDs and ALDs for suspensory fixation of hamstring tendon autograft in ACLR had similar clinical outcomes with a minimum of 2-year follow up. There is no evidence of graft loosening from loop lengthening. Level of EvidenceLevel III, retrospective comparative trial.

Clinical outcomes of three different techniques using adjustable-loop fixation in arthroscopic single-bundle anterior cruciate ligament reconstruction: A prospective randomized clinical trial

BackgroundAdjustable femoral suspensory fixation for anterior cruciate ligament reconstruction (ACLR) become popular in recent years. The purpose of this study is to evaluate and compare the clinical outcomes of three different techniques using an adjustable-loop fixation in ACRL. MethodsThis study included 38 patients who underwent ACLR using the adjustable-loop device for femoral fixation between January 2018 and November 2021. All the participants were randomly assigned to a standard (group 1), retensioning (group 2), retensioning and knot tying (group 3). Clinical outcome parametres included Tegner – Lysholm Score, IKDC score, KT-1000 displacement and isokinetic muscle function tests. ResultsOverall, 38 patients (group 1: n = 13 [mean ± SD age, 30.1 ± 9.40 years]; group 2: n = 12 [mean ± SD age, 24.5 ± 7.79 years]; group 3 = 13 [mean ± SD age, 27.8 ± 6.59 years]) were included in the final analysis. The follow-up period was 9.7 ± 1.2; 9.5 ± 1.7 and 10 ± 1.5 months for groups 1, 2 and 3 respectively. From preoperatively to postoperatively, the mean Tegner-Lysholm scores improved significantly in all three groups (group 1: from 63.5 to 95.6; group 2: from 61.58 to 98.5; group 3: from 66.6 to 95.9, P < 0.0001 for all), as did the mean IKDC score (group 1: 53.9–88.8; group 2: 61.3–94.9; group 3: 60.7–94.6 (P < 0.0001 for all). ConclusionThe retensioning with or without knot-tying method is believed to increase stability in graft fixation. However, there were no significant differences in clinical outcomes in each technique.

Preliminary experience of an international orthopaedic registry: The ESSKA Paediatric Anterior Cruciate Ligament Initiative (PAMI) registry

To evaluate the effect of preconditioning according to intraoperative workflow on initial tension and elongation behavior for femoral adjustable loop devices (ALDs) and closed loop devices (CLDs) in suspensory anterior cruciate ligament reconstruction (ACLR) with tibial screw fixation in a biomechanical in vitro study.Three ACLR groups with tibial screw fixation were biomechanically tested in a full-construct setup using porcine tibias. Groups (n = 8 per group) varied by femoral fixation method and consisted of a CLD (group 3) and ALD fixation with (group 2) and without simulated intraoperative preconditioning (group 1). The change in tension after screw insertion and the displacement to restore the initial loading situation were measured. Grafts underwent dynamic cycling (1,000 cycles at 0.75 Hz) using both a position and a force control mode.Data are presented as mean [standard deviation]. Placement of an interference screw induced a graft tension loss of 62% (49.4 [0.4] N vs 19.0 [10.0] N, P < .001) by introducing a laxity of 0.53 [0.26] mm. Intraoperative preconditioning led to a higher initial load level (228.3 [19.8] N) compared with unconditioned ALD (156.1 [25.5] N, P < .001) and CLD groups (156.6 [12.8] N, P < .001) with less force decrease over position-controlled cyclic loading. Furthermore, initial (−0.22 [0.16] mm) and dynamic elongation (0.88 [0.23] mm) were reduced compared with the unconditioned ALD (0.65 [0.35] mm, P < .001; and 1.56 [0.19] mm, P < .001) and CLD groups (0.16 [0.26] mm, P < .001; and 1.64 [0.24] mm, P < .001).ACLR with femoral ALD fixation and intraoperative preconditioning allows for restoration of time-zero screw-imparted slack and leads to significantly reduced cyclic elongation in accordance with native ACL function. Both ALD and CLD control groups behaved similarly, with total elongation less than 3 mm including time-zero slack.Although the clinical relevance of time-zero graft tension loss is uncertain, the use of an ALD in concert with tibial screw fixation may be favorable to allow for tension optimization.

Biomechanical Comparison of Adjustable-Loop Femoral Cortical Suspension Devices for Soft Tissue ACL Reconstruction

Several new adjustable-loop devices (ALDs) for anterior cruciate ligament reconstruction (ACLR) have not been tested in vitro. To compare the biomechanical performances of 5 ALDs under a high cyclic load and forces representative of the return-to-play conditions seen in the recovering athlete. Controlled laboratory study. A total of 10 devices for each of 5 chosen ALDs (UltraButton [Smith & Nephew], RigidLoop [DePuy Mitek], ProCinch [Stryker], TightRope [Arthrex], and ToggleLoc [Biomet]) were tested in a device-only model. The devices were secured to a servohydraulic test machine and preconditioned from 10 to 75 N at a rate of 0.5 Hz for 20 cycles. They were then subjected to high cyclic forces (100-500 N for 4000 cycles) and subsequently pulled to failure at 50 mm/min. The preconditioning displacement, permanent deformation, cumulative peak displacement, stiffness coefficient, and load to failure data were collected. The UltraButton displayed the greatest preconditioning displacement (0.22 ± 0.20 mm), followed by the RigidLoop (0.11 ± 0.03 mm), ProCinch (0.07 ± 0.04 mm), TightRope (0.07 ± 0.02 mm), and ToggleLoc (0.02 ± 0.03 mm). The TightRope displayed the greatest permanent deformation (3.19 ± 1.03 mm) followed by the UltraButton (2.14 ± 0.92 mm), ToggleLoc (2.02 ± 1.09 mm), RigidLoop (1.67 ± 0.1 mm), and ProCinch (1.38 ± 0.18 mm). The TightRope displayed the greatest cumulative peak displacement (3.69 ± 1.03 mm) followed by the UltraButton (2.46 ± 0.92 mm), ToggleLoc (2.37 ± 1.08 mm), RigidLoop (2.01 ± 0.1 mm), and ProCinch (1.75 ± 0.19 mm). The UltraButton displayed the largest stiffness coefficient (1347.22 ± 136.33 N/mm) followed by the RigidLoop (1325.4 ± 116.37 N/mm), ToggleLoc (1216.62 ± 131.32 N/mm), ProCinch (1155.56 ± 88.04), and TightRope (848.48 ± 31.94). The ToggleLoc displayed the largest load to failure (1874.42 ± 101.08 N) followed by the RigidLoop (1614.12 ± 129.11 N), UltraButton (1391.69 ± 142.04 N), ProCinch (1384.85 ± 58.62 N), and TightRope (991.8 ± 51.1 N.). The 5 ALDs exhibited different biomechanical properties. None of them had peak cumulative displacements for which the confidence interval lay above 3 mm, thus no single device was determined to have a higher rate of clinical failure compared with the others. ALD choice may affect biomechanics after ACLR.

Arthroscopic Primary Repair of Posterior Cruciate Ligament Using Ring Suture Attached to Adjustable Loop Device

Posterior cruciate ligament (PCL) injuries occur most often in the setting of a multiligamentous injured knee and are frequently the result of high-energy trauma. For severe and multiligamentous PCL injuries, surgical intervention is recommended. Although PCL reconstruction has traditionally been the standard treatment, arthroscopic primary PCL repair has been revisited over the past few years for proximal tears with sufficient tissue quality. Current PCL repair techniques report two technical issues: the risk of suture abrasion/laceration during the stitching process, and the inability to retension the ligament after fixation with either suture anchors or ligament buttons. In this technical note, we describe the surgical technique of arthroscopic primary repair of proximal PCL tears using a looping ring suture device (FiberRing), combined with an adjustable loop cortical fixation device (ACL Repair TightRope). The goals of this technique are to offer a minimally invasive option to preserve the native PCL and to avoid the observed shortcomings of other arthroscopic primary repair techniques.

Dynamic Anterior Stabilization of the Shoulder With Adjustable-Loop Device

Dynamic anterior stabilization of the shoulder is a surgical procedure based on a triple soft-tissue block. This procedure is designed to fit within a gray zone between the Bristow-Latarjet procedure and the Bankart procedure, where the patient would not need a bone graft; however, capsular reconstruction alone may be insufficient to yield reliable stabilization. This article describes dynamic anterior stabilization of the shoulder using the adjustable-loop device.

Comparison of the mechanical properties and mechanical damages to tendon tissue in three suspensory fixation techniques

BackgroundAnterior cruciate ligament (ACL) injury is the most common traumatic injury to the knee joint. Suspensory fixation has become popular in ACL reconstruction because of its high primary stability, less invasiveness, and surgical convenience. There are two common types of suspensory fixation devices: those with fixed-length and those with adjustable-length loops. Owing to structural differences and differences in initial tensioning techniques, it is expected that mechanical property and damage to the tendons will vary from device to device; however, no literature has examined this so far. The main purpose of this study was to evaluate the damage caused to the tendon by three different suspensory fixation devices. An effective mechanical test was carried out as a prerequisite. MethodsFirst, the mechanical properties of simple loop device (SLD) as fixed-length loop device, first-generation, and second-generation adjustable devices (AD1 and AD2) as adjustable-length loop devices were tested (isolated device testing). Second, each device was tested using bovine extensor tendons (specimen testing). Cyclic testing included 2000 cycles; the devices were subsequently displaced until failure, and the ultimate tensile strength was determined using isolated device testing. Six samples of 3 devices were used in each testing experiment. After specimen testing, the surface structure of the tendon was evaluated quantitatively using optical coherence tomography (OCT) and our original histological scoring system. ResultsDuring isolated device testing, SLD demonstrated the least cyclic displacement, followed by AD1 and AD2. The highest ultimate tensile strength was observed in AD2, followed by SLD and AD1. In specimen testing, the least cyclic displacement was observed in SLD, followed by AD1 and AD2. Histologically, AD1 demonstrated a significantly lower score, with damaged surface morphology, than SLD and AD2. OCT values were significantly higher, with a more disturbing tendon surface structure, in AD1 than in SLD and AD2. ConclusionsThe first-generation adjustable loop device exhibited greatest graft tissue damage at the suspensory site in a clinically relevant setting. The thinner adjustable loop mechanism may have elevated graft damage by frictional stresses during loop adjustment or by repetitive tensioning stresses.

Return to duty in military personnel after ACL reconstruction: STG versus ST4 double adjustable-loop device

IntroductionACL ligamentoplasty with a quadruple semitindosus graft (ST4) and double adjustable endobutton (ST4E) allow the preservation of the gracilis, which should allow more rapid recovery of soldiers following ACL reconstruction. However, the literature does not report any superiority of this technique over others in terms of return to duty and sport. HypothesisThe ST4E system allows a return to military duty at least equivalent to the semitendinosus and gracilis graft (STG) with screw fixation. Material and methodA total of 133 soldiers operated on for ACL were included, 64 by the STG technique and 69 by ST4E, with an average follow-up of 4 years. The return to duty was assessed, with recovery of skills between the first and second postoperative year, as well as the medico-administrative status at the last follow-up, muscle recovery through isokinetic tests, the sports level before/after surgery, and the failure rate. ResultsNo difference was found in the return to the soldier's previous post between the STG (64%) and the ST4E (64%) (p=0.97). No difference was found for the medico-administrative status at the last follow-up, but the short-term muscle recovery, the return to sport, and the failure rate were in favor of the ST4E group. DiscussionThe ST4E, adjustable double endobutton system, is comparable to the STG technique in terms of return to military duty. On the other hand, it offers faster muscle recovery with better sports results and fewer patients on prolonged sick leave (PSL). This study demonstrated that two-thirds of soldiers operated on for anterior cruciate ligamentoplasty regained their initial aptitude regardless of the technique used, which influences the army's operational capacity and on disability pension requests after service. Level of evidenceIII, single center retrospective comparative study.

Does an Adjustable-Loop Device Loosen following ACL Reconstruction with a Hamstring Graft? A Retrospective Study with a Follow-Up of Two Years.

Arthroscopic anatomic anterior cruciate ligament reconstruction (ACLR) is the gold standard treatment for an ACL tear and requires the use of fixed or adjustable-loop devices to fix a femoral-side graft. Although the adjustable mechanism is designed to provide one-way tensioning, there is a concern that the adjustable loop will loosen and lengthen during cyclic loads, creating graft laxity. The present paper is a retrospective study of patients who underwent ACLR with the fixation of a hamstring graft with an adjustable loop on the femoral side from November 2016 to October 2018. The knee’s functional outcome was evaluated using an International Knee Documentation Committee (IKDC) score, Lysholm score, Lachman test, and pivot shift test. The patients were assessed preoperatively and finally postoperatively after two years of surgery. Thirty-two patients were analyzed. Significant improvement was obtained in the final clinical outcome of the patients. Twenty-seven patients (84.4%) were Lachman negative, and twenty-eight patients (87.5%) were pivot shift test negative, the mean Lysholm score was 96.91, and the IKDC score was 91.47 (p < 0.001). There was no infection, graft failure, or flexion restriction. Arthroscopic ACLR with an adjustable-loop suspensory device is a successful fixation method for femoral-side graft fixation and offers a similar functional outcome as with fixed-loop devices.

Adjustable-loop implants are non-inferior to fixed-loop implants for femoral fixation in anterior cruciate ligament reconstruction.

Button implants with an adjustable-loop device (ALD) are often used in anterior cruciate ligament reconstruction (ACLR). Clinical research comparing ALDs with fixed-loop devices (FLD) has mainly been conducted in small patient populations with short follow-up times. To determine whether ALDs are safe to use in ACLR, a non-inferiority study with a large sample population and a long follow-up period would be beneficial. This study compared ALDs with FLDs to determine non-inferior revision surgery rates, knee stability, and patient-reported outcomes (PROM) in ACLRs. This non-inferiority register-based cohort study was conducted using data from the Danish Knee Ligament Reconstruction Registry (DKRR). A total of 12,723 patients > 15years of age with primary ACLR using hamstring tendon autografts and either an FLD or ALD for femoral fixation were included: 9719 patients were in the FLD group, and 3014 patients were in the ALD group. The primary outcome was revision ACLR with a non-inferiority margin for ALDs at 4% at the 2-year follow-up. The secondary outcomes were anterior and rotatory knee stability and PROMs based on the Knee Injury and Osteoarthritis Outcome Score (KOOS) at the 1-year follow-up. The crude cumulative revision rates in ALD implants at 2 and 5 years were 2.1% (95% CI 1.62-2.68) and 5.0% (95% CI 4.22-5.96), respectively. In the FLD group, the rates were 2.2% (95% CI 1.89-2.48) at 2 years and 4.7% (95% CI 4.31-5.20) at 5 years. The 1-year side-to-side differences were 0.97mm (95% CI 0.90-1.03) in the ALD group and 1.45mm (95% CI 1.41-1.49) in the FLD group. In the FLD group, 13% had a positive pivot shift, and in the ALD group, 6% had a positive pivot shift. There were no differences in KOOS. ALDs were non-inferior to FLDs regarding revision rates, knee stability, and patient-reported outcomes. Based on this conclusion, ALDs are safe to use for femoral fixation in ACLR. III.

Evaluation of Tibial Fixation Devices for Quadrupled Hamstring ACL Reconstruction.

Background:Shortcomings to tibial-side fixation have been reported as causes of failure after anterior cruciate ligament reconstruction. Adjustable-loop suspensory devices have become popular; however, no comparison with hybrid fixation (ie, interference screw and cortical button) exists to our knowledge.Purpose:The purpose of this study was to compare the biomechanical properties of adjustable loop devices (ALDs) in full-tunnel and closed-socket configurations in relation to hybrid fixation. We hypothesized that primary stability of fixation by a tibial ALD will not be inferior to hybrid fixation.Study Design:Controlled laboratory study.Methods:Tibial fixation of a quadrupled tendon graft was biomechanically investigated in a porcine tibia–bovine tendon model using 5 techniques (n = 6 specimens each). The tested constructs included hybrid fixation with a cortical fixation button and interference screw (group 1), single cortical fixation with the full-tunnel technique using an open-suture strand button (group 2) or an ALD (group 3), or closed-socket fixation using 2 different types of ALDs (groups 4 and 5). Each specimen was evaluated using a materials testing machine (1000 cycles from 50-250 N and pull to failure). Force at failure, cyclic displacement, stiffness, and ability to pretension the graft during insertion were compared among the groups.Results:No differences in ultimate load to failure were found between the ALD constructs (groups 3, 4, and 5) and hybrid fixation (group 1). Cyclic displacement was significantly higher in group 2 vs all other groups (P < .001); however, no difference was observed in groups 3, 4, and 5 as compared with group 1. The remaining tension on the construct after fixation was significantly higher in groups 3 and 4 vs groups 1, 2, and 5 (P < .02 for all comparisons), irrespective of whether a full-tunnel or closed-socket approach was used.Conclusion:Tibial anterior cruciate ligament graft fixation with knotless ALDs achieved comparable results with hybrid fixation in the full-tunnel and closed-socket techniques. The retention of graft tension appears to be biomechanically more relevant than tunnel type.Clinical Relevance:The study findings emphasize the importance of the tension at which fixation is performed.

Biomechanical Evaluation of Suture Tape Internal Brace Reinforcement of Soft Tissue Allografts for ACL Reconstruction Using a Porcine Model.

Background:Internal bracing of anterior cruciate ligament (ACL) surgery is a newer concept gaining popularity.Purpose/Hypothesis:To assess the biomechanical performance of soft tissue ACL reconstruction allografts reinforced with suture tape. It was hypothesized that load to failure would increase and cyclic displacement would decrease at time zero in the constructs reinforced with internal brace suture tape compared with those without suture tape augmentation.Study Design:Controlled laboratory study.Methods:We performed ACL reconstruction on porcine knees using bovine extensor tendon soft tissue allografts: 10 knees without (control) and 10 knees with (reinforced) suture tape reinforcement. An all-inside reconstruction technique was utilized with retrograde tunnel creation. An adjustable-loop device was used for femoral and tibial fixation of all grafts. The suture tape was placed through the tension loop in the femoral fixation construct and independently fixed in the tibia with an interference screw anchor. For each specimen, the authors recorded ultimate load, yield load, stiffness, cyclic displacement, and mode of failure. Outcomes between groups were compared using the Student t test.Results:There was a 33% decrease in mean cyclic displacement in the specimens with reinforced grafts (reinforced vs control: 3.9 ± 0.7 vs 5.8 ± 1.5 mm; P = .001). The reinforced grafts also had a 22% higher mean ultimate load (921 ± 180 vs 717 ± 122 N; P = .008) and a 25% higher mean yield load (808 ± 201 vs 602 ± 155 N; P = .020). There was no significant difference in stiffness between the reinforced versus nonreinforced grafts (136 ± 16 vs 132 ± 18 N/mm; P = .617). Three of the 10 control specimens failed at the graft, compared with 1 of 10 reinforced grafts. All other constructs in both groups failed at the tibial fixation site.Conclusion:Suture tape reinforcement of soft tissue grafts significantly decreased cyclic displacement while significantly increasing ultimate and yield loads without increasing graft construct stiffness during biomechanical testing at time zero in a porcine animal model.Clinical Relevance:The improved biomechanical performance of suture tape–reinforced graft constructs could allow patients to participate in earlier advancement of aggressive rehabilitation and potentially reduce failure rates as graft remodeling progresses.

Additional tying on the adjustable-loop device improves the outcomes of anterior cruciate ligament reconstruction using hamstring autograft.

The purpose of this study was to verify the efficacy of a novel technique for additional tying on the adjustable-loop device to prevent stress concentration on the graft loop end and gradual loop lengthening. A total of 124 patients who underwent anterior cruciate ligament reconstruction using hamstring autografts from 2014 to 2017 were included in this retrospective study. After 1:1 propensity score matching, two groups were formed (group I: 50 patients without tying vs. group II: 50 patients with tying). Anterior laxity was evaluated using side-to-side differences. Tunnel length, loop length, and graft-tunnel gap were measured using follow-up magnetic resonance imaging. The signal-to-noise ratio was calculated at the loop end, loop inner side, tunnel entrance, and graft mid-substance. The clinical outcomes were assessed using the International Knee Documentation Committee score, Lysholm score, pivot shift test, and Lachman test. The average follow-up period was 63.2 ± 4.8 and 53.8 ± 11.9months in groups I and II, respectively. Anterior laxity showed that side-to-side differences improved significantly 6months postoperatively in both the groups. Although the anterior laxity improved in group II (2.9 ± 1.0 to 1.6 ± 0.8, p < 0.001), it deteriorated in group I (2.5 ± 1.5 to 3.3 ± 1.3mm, p < 0.001) at the final follow-up. The graft-tunnel gap was significantly larger in group I (p < 0.001). The signal-to-noise ratios of the loop end and loop inner side were significantly higher in group I (p < 0.001 and p = 0.020, respectively). The clinical outcomes at the final follow-up were not significantly different between the groups. The additional tying on the adjustable-loop device was not superior to the control group in clinical stability examination or outcome. However, it was effective in anterior laxity measured by stress radiographs, preventing stress on the adjustable-loop device, and gradual graft loop lengthening. Level III.