A biomechanical comparison of anterior cruciate ligament suspensory fixation devices in a porcine cadaver model

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

Background

Little is known about the stability of adjustable-loop devices (ALDs) for anterior cruciate ligament (ACL) reconstruction (ACLR).

Purpose

To evaluate the stabilization behavior of 3 different types of ALDs for all-inside ACLR in a full-construct surgical technique-based manner.

Study Design

Controlled laboratory study.

Methods

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.

Results

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.

Conclusion

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.

Clinical Relevance

A detailed biomechanical understanding of the stabilization potential is pertinent to the continued evolution of ALDs to improve clinical outcomes.

A Higher Initial Tensioning Force of an ACL Graft Results in a Higher Graft Force After Screw Fixation Irrespective of the Screw Diameter: A Biomechanical Study

BACKGROUND

The intra-articular graft force (IAGF) in anterior cruciate ligament reconstruction decreases quickly over the first hours after surgery. Nevertheless, little is known about whether the initial extra-articular tensioning force (EATF) and screw diameter affect the graft force after fixation.

PURPOSE

To investigate the effects of different EATFs on the IAGF of a soft tissue graft fixated via a bioabsorbable interference screw over 100 minutes after fixation and to evaluate the effects of different screw diameters within 1 mm of the tunnel width during this process.

STUDY DESIGN

Controlled laboratory study.

METHODS

In this biomechanical study, a porcine quadruple-strand soft tissue graft was inserted into the tibial anterior cruciate ligament tunnel. On the extra-articular side, 3 loads were applied during retrograde insertion of the bioabsorbable interference screw (6, 7, and 8 mm): 20 N, 80 N, and maximum manual EATF (N_max). Nine study groups consisting of 10 tibiae each were created to test the effects of different EATFs and screw sizes. The IAGF was measured up to 100 minutes after the EATF was released.

RESULTS

An EATF ≥80 N resulted in a larger IAGF for all screw sizes at 100 minutes. There were no significant associations between the IAGF at 100 minutes and different screw diameters. Inserting the tibial screw significantly increased the IAGF in all groups, with the exception of N_max applied in groups with 7- or 8-mm screws. When compared with the end of screw insertion, after the release of the EATF, the IAGF dropped by 55% to 77 % at 100 minutes.

CONCLUSION

An initial EATF ≥80 N is associated with a significantly larger IAGF at 100 minutes in this cadaveric simulation. The IAGF in soft tissue grafts decreased substantially after the retrograde placement of an interference screw. A recommendation regarding screw diameter with respect to the IAGF cannot be given.

CLINICAL RELEVANCE

To obtain a higher residual graft force after bioabsorbable interference screw fixation, an initial EATF ≥80 N should be applied according to this model. The significant decrease in graft force after the release of the EATF indicates that the reconstructed knee cannot be mechanically stabilized after the surgery.

Current and future of anterior cruciate ligament reconstruction techniques

In recent years, anterior cruciate ligament (ACL) reconstruction has generally yielded favorable outcomes. However, ACL reconstruction has not provided satisfactory results in terms of the rate of returning to sports and prevention of osteoarthritis (OA) progression. In this paper, we outline current techniques for ACL reconstruction such as graft materials, double-bundle or single-bundle reconstruction, femoral tunnel drilling, all-inside technique, graft fixation, preservation of remnant, anterolateral ligament reconstruction, ACL repair, revision surgery, treatment for ACL injury with OA and problems, and discuss expected future trends. To enable many more orthopedic surgeons to achieve excellent ACL reconstruction outcomes with less invasive surgery, further studies aimed at improving surgical techniques are warranted. Further development of biological augmentation and robotic surgery technologies for ACL reconstruction is also required.

Assessment of fixation for anterior cruciate ligament reconstruction using oversized suspensory devices on full-length femoral tunnels

BACKGROUND

In ACL repair, full-length single-diameter tunnels facilitate anatomic femoral fixation with suspensory devices, especially with outside-in techniques, and are required after accidental cortical perforation. With tunnel diameters over 6 mm, fixation resistance using regular suspensory devices may not suffice. Oversized cortical footprint devices could be a solution to guarantee fixation performance in larger tunnel diameters. This study aims to assess the biomechanical properties of ACL femoral fixation provided by two enlarged suspensory devices of similar characteristics, a fixed loop (G-Lok™ with G-Lok-XL™) and an adjustable loop (ProCinch™ with G-Lok-XL™), resting on a full-length 9 mm diameter tunnel compared to the widely accepted regular fixed-loop device (G-Lok™) on a socket tunnel.

METHODS

Twenty-seven fresh frozen porcine femurs and flexor digitorum profundus tendons were randomly assigned to a study group depending on the fixation method used (N = 9). Graft-femur constructs were subjected to a traction cyclic test (5000 cycles, [50-250]N load, 1 Hz) followed by a load-to-failure test (v = 1 mm/s). Residual displacement during the cyclic test and stiffness, displacements at physiological loads, ultimate load and corresponding displacement during the load-to-failure test were determined.

FINDINGS

No significant differences could be established for any parameter measured in the comparison between the control with the socket tunnel and the oversized fixations with full-length tunnels.

INTERPRETATION

ACL femoral fixation achieved in full-length single diameter tunnels by using an enlarged suspension device, both with a fixed or an adjustable loop, provide similar biomechanical properties to the gold-standard fixed-loop device in a socket tunnel. Therefore, its clinical use may be safe.

Biomechanical testing of fixed and adjustable femoral cortical suspension devices for ACL reconstruction under high loads and extended cyclic loading

Purpose

To compare loop elongation after 5000 cycles, loop-elongation at failure, and load at failure of the fixed-loop G-Lok device and three adjustable-loop devices (UltraButton, RigidLoop Adjustable and ProCinch RT), during testing over extended cycles under high loading.

Methods

Five devices of each type were tested on a custom-built rig fixed to an Instron machine. The testing protocol had four stages: preloading, cyclic preconditioning, incremental cyclic loading and pull-to-failure. Outcome measures were loop elongation after 5000 cycles, loop-elongation at failure, and load at failure.

Results

The loop elongation after 5000 cycles for G-Lok was 1.46 ± 0.25 mm, which was comparable to that of RigidLoop (1.51 ± 0.16 mm, p = 1.000) and ProCinch (1.60 ± 0.09 mm, p = 1.000). In comparison, the loop elongation for UltraButton was 2.66 ± 0.28 mm, which was significantly larger than all other devices (p = 0.048). The failure load for all devices ranged between 1455 and 2178 N. G-Lok was significantly stronger than all adjustable-loop devices (p = 0.048). The elongation at failure was largest for UltraButton (4.20 ± 0.33 mm), which was significantly greater than G-Lok (3.17 ± 0.33 mm, p = 0.048), RigidLoop (2.88 ± 0.20 mm, p = 0.048) and ProCinch (2.78 ± 0.08 mm, p = 0.048). There was no significant difference in elongation at failure for the rest of the devices.

Conclusions

Our study has shown that the G-Lok fixed-loop device and the three adjustable-loop devices (UltraButton, RigidLoop Adjustable and ProCinch RT) all elongated less than 3 mm during testing over an extended number of cycles at high loads, nonetheless, the fixed loop device performed best in terms of least elongation and highest load at failure.

The improved cortical button shows better breaking strength of sutures compared with 10 original cortical button after cyclic loading

Background

Suspensory cortical buttons are widely used for fixation of reconstructed ligaments during anterior cruciate ligament (ACL) reconstruction because they have high usability and a favorable fixing force. However, it is not always easy to fix a reconstructed ACL while maintaining appropriate ligament tension. Therefore, we developed an improved cortical button that provides temporary tension until suturing is completed.

Methods

Button holes of our improved EndoButton are not perpendicular to the bone surface on which the button is placed, but have an angle of 45 degrees so that the button can be temporarily fixed by applying tension to the suture. The improved EndoButton and the original EndoButton (Smith & Nephew Inc., Andover, Massachusetts) were each tied to FiberWire 5/7 metric (5 M) (manufactured by Arthrex). Ten cycles of preliminary loading (0–50 N) were applied to each suture, followed by test loading (0–250 N) for 500 or 1000 cycles. Then, a tensile test was performed at a displacement velocity of 20 mm/min.

Results

The breaking strength of the sutures of the improved EndoButton were tend to higher than those of the sutures of the original EndoButton after 1000 loading cycles (p = 0.067, d = 0.883). The moduli of rigidity of the sutures of the improved EndoButton were higher than those of the sutures of the original EndoButton after 500 loading cycles (p = 0.027) and remained almost the same regardless of the number of loading cycles.

Conclusion

We found that compared with the original cortical button, the improved cortical button was better able to retain suture breaking strength and modulus of rigidity, regardless of the number of load cycles.

Biomechanical Evaluation of a Novel Loop Retention Mechanism for Cortical Graft Fixation in ACL Reconstruction

BACKGROUND

Implant fixation by means of a cortical fixation device (CFD) has become a routine procedure in anterior cruciate ligament reconstruction. There is no clear consensus whether adjustable-length CFDs are more susceptible to loop lengthening when compared with pretied fixed-length CFDs.

PURPOSE

To assess biomechanical performance measures of 3 types of CFDs when subjected to various loading protocols.

STUDY DESIGN

Controlled laboratory study.

METHODS

Three types of CFDs underwent biomechanical testing: 1 fixed length and 2 adjustable length. One of the adjustable-length devices is based on the so-called finger trap mechanism, and the other is based on a modified sling lock mechanism. A device-only test of 5000 cycles (n = 8 per group) and a tendon-device test of 1000 cycles (n = 8 per group) with lower and upper force limits of 50 and 250 N, respectively, were applied, followed by ramp-to-failure testing. Adjustable-length devices then underwent further cyclic testing with complete loop unloading (n = 5 per group) at each cycle, as well as fatigue testing (n = 3 per group) over a total of 1 million cycles. Derived mechanical parameters were compared among the devices for statistical significance using Kruskal-Wallis analysis of variance followed by post hoc Mann-Whitney U testing with Bonferroni correction.

RESULTS

All CFDs showed elongation <2 mm after 5000 cycles when tested in an isolated manner and withstood ultimate tensile forces in excess of estimated peak in vivo forces. In both device-only and tendon-device tests, differences in cyclic performance were found among the devices, favoring adjustable-length fixation devices over the fixed-length device. Completely unloading the suspension loops, however, led to excessive loop lengthening of the finger trap device, whereas the modified sling lock device remained stable throughout the test. The fixed-length device displayed superior ultimate strength over both adjustable-length devices. Both adjustable-length devices showed adequate fatigue behavior during high-cyclic testing.

CONCLUSION

All tested devices successfully prevented critical construct elongation when tested with constant tension and withstood ultimate loads in excess of estimated in vivo forces during the rehabilitation phase. The finger trap device gradually lengthened excessively when completely unloaded during cyclic testing.

CLINICAL RELEVANCE

Critical loop lengthening may occur if adjustable-length devices based on the finger trap mechanism are repeatedly unloaded in situ.

Stratifying the mechanical performance of a decellularized xenogeneic tendon graft for anterior cruciate ligament reconstruction as a function of graft diameter: An animal study

Objectives

This study investigated the biomechanical performance of decellularized porcine superflexor tendon (pSFT) grafts of varying diameters when utilized in conjunction with contemporary ACL graft fixation systems. This aimed to produce a range of ‘off-the-shelf’ products with predictable mechanical performance, depending on the individual requirements of the patient.

Methods

Decellularized pSFTs were prepared to create double-bundle grafts of 7 mm, 8 mm, and 9 mm diameter. Femoral and tibial fixation systems were simulated utilizing Arthrex suspension devices and interference screws in bovine bone, respectively. Dynamic stiffness and creep were measured, followed by ramp to failure from which linear stiffness and load at failure were measured. The mechanisms of failure were also recorded.

Results

Dynamic stiffness was found to increase with greater graft diameter, with significant differences between all groups. Conversely, dynamic creep reduced with increasing graft diameter with significant differences between the 7 mm and 9 mm groups and the 8 mm and 9 mm groups. Significant differences were also found between the 7 mm, 8 mm, and 9 mm groups for linear stiffness, but no significant differences were found between groups for load at failure. The distribution of failure mechanisms was found to change with graft diameter.

Conclusion

This study showed that decellularized pSFTs demonstrate comparable biomechanical properties to other ACL graft options and are a potentially viable option for ACL reconstruction. Although grafts can be stratified by their diameter to provide varying biomechanical properties, it may be more appropriate to alter the fixation technique to stratify for a greater diversity of biomechanical requirements.

Cite this article: Bone Joint Res 2019;8:518–525.

Fixed- Versus Adjustable-Loop Devices for Femoral Fixation in Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To compare biomechanical and clinical outcomes between adjustable-loop devices (ALDs) and fixed-loop devices (FLDs) in the femoral fixation component of anterior cruciate ligament reconstruction (ACLR) using a hamstring autograft or allograft.

METHODS

A multi-database search was performed on July 18, 2018, according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. All articles directly comparing ALDs and FLDs in ACLR using hamstring grafts were included. Non-English-language articles were excluded.

RESULTS

We included 13 biomechanical, 2 prospective, and 6 retrospective studies in this review. Retensioning of ALDs was performed in 4 of 13 biomechanical studies and in all clinical studies. Biomechanically, 11 studies showed a statistically significantly larger maximum irreversible displacement of the graft in the ALD group. Two studies showed no statistically significant difference with retensioning of the TightRope ALD, whereas all 3 studies that examined knotting of ALDs showed no statistically significant difference between the FLD and ALD groups. Five studies reported statistically significantly higher graft stiffness for FLDs than ALDs. Retensioning or knotting did not produce any significant change in construct stiffness. Nine studies reported a statistically significantly higher ultimate load to failure for FLDs. With knotting of ALDs, this difference was no longer statistically significant in only 1 study. Clinical studies showed no statistically significant differences in clinical, functional, radiologic, and complication outcomes between both groups.

CONCLUSIONS

Despite the superior biomechanical properties of FLDs, ALDs and FLDs yielded similar clinical outcome scores and graft rerupture rates. Biomechanical outcomes were improved with retensioning of ALDs after tibial fixation, as per manufacturer recommendations.

LEVEL OF EVIDENCE

Level III, systematic review of Level III and IV studies.

A biomechanical comparison of all-inside cruciate ligament graft preparation techniques

Background

The all-inside cruciate ligament graft preparation technique has become popular due to its utility in sparing a growing physis, preserving a tendon in ACL surgery, and/or reduction of pain. However, few studies have compared graft preparation techniques to determine the ideal construct for cruciate ligament reconstruction. We sought to compare biomechanical properties of two quadrupled all-inside cruciate ligament graft preparation techniques and three alternative all-inside graft preparation techniques that may be used when the available tendon is too short to be quadrupled.

Methods

Fifty porcine extensor tendons were evenly divided into five groups (n = 10) representing all-inside graft preparation techniques, including two quadrupled (Quad-A, Quad-B) and three alternative methods (Tripled, Folded, Two-Doubled). Each graft construct underwent preconditioning (10 loading cycles from 20 to 50 N at 0.1 Hz), cyclic loading (500 loading cycles from 50 to 250 N at 1.0 Hz) and load-to-failure (tension applied at 20 mm/min).

Results

Quad-A and Quad-B demonstrated no significant differences in cyclic displacement (10.5 ± 0.3 vs 11.7 ± 0.4 mm; p = 0.915), cyclic stiffness (1086.2 ± 487.3 vs 460.4 ± 71.4 N/mm; p = 0.290), pullout stiffness (15.9 ± 4.3 vs 7.4 ± 4.4 N/mm; p = 0.443), ultimate failure load (641.2 ± 84.7 vs 405.9 ± 237.4 N; p = 0.672), or ultimate failure displacement (47.3 ± 6.7 vs 55.5 ± 0.7 mm; p = 0.778). The mean cyclic displacement of the Two-Doubled group was significantly greater than the Quad-A (29.7 ± 2.2 vs 10.5 ± 0.3 mm; p < 0.001), Quad-B (29.7 ± 2.2 vs 11.7 ± 0.4 mm; p < 0.001), Tripled (29.7 ± 2.2 vs 11.3 ± 0.2 mm; p < 0.001), and Folded group (29.7 ± 2.2 vs 13.3 ± 0.2 mm; p < 0.001). There were no other statistically significant differences between the three alternative all-inside graft preparation techniques.

Conclusion

The current study demonstrates the biomechanical properties of two quadrupled all-inside graft constructs, Quad-A and Quad-B, are not significantly different. When the available tendon is of insufficient length, the Two-Doubled group demonstrated more than twice the cyclic displacement of all other graft preparation techniques, and is therefore not recommended for use in all-inside cruciate ligament reconstruction.

Biomechanical analysis of a double fixation method for tendon graft in porcine tibia – using an interference screw plus staple

Objective

The aim of the study was to compare the mechanical behavior of interference screw tibial fixation vs. screw-plus-staple tibial fixation in an animal model.

Methods

Thirty-six pieces of swine knee specimens were selected and divided into two groups: Group 1, tibial fixation with interference screw (n = 17), and Group 2, fixation with interference screw and staple (n = 19). The models were submitted to a single cycle of tension testing. The following variables were measured: graft cross-sectional area, failure point on 10 mm (F₁₀), yield load (F_y), and stiffness.

Results

The mean values of graft cross-sectional area, F₁₀, F_y, and stiffness did not present significant differences between the groups.

Conclusion

The addition of a second staple-type ligament fixation device, complementing the interference screw, did not increase the mechanical safety of the system.

Biomechanical Comparison of Fixed-Loop and Adjustable-Loop Cortical Suspensory Devices for Metaphyseal Femoral-Sided Soft Tissue Graft Fixation in Anatomic Anterior Cruciate Ligament Reconstruction Using a Porcine Model

PURPOSE

To compare the displacement, stiffness, and ultimate failure load of a fixed-loop cortical suspensory device with 2 adjustable-loop devices when positioned on metaphyseal bone.

METHODS

Thirty devices (10 of each device) were positioned on the metaphyseal cortex of 30 porcine femora simulating anatomic anterior cruciate ligament femoral tunnel placement. Bovine tendons were used for soft tissue grafts, and the constructs were then cycled 1,000 times and pulled to failure, measuring displacement, stiffness, and failure load.

RESULTS

Initial displacement, cyclic displacement, and total displacement were 2.98 mm, 2.09 mm, and 5.08 mm for the Endobutton CL (ECL), 2.82 mm, 2.27 mm, and 5.09 mm for the Tightrope (TRT), and 4.25 mm, 3.19 mm, and 7.44 mm for the adjustable-loop ToggleLoc Inline with Ziploop (TLZ), respectively. There was no difference between the ECL and the TRT on any measured outcome. Differences between the TLZ and ECL were statistically significant (initial displacement P = .024, cyclic displacement P < .001, and total displacement P < .001), as were those between the TLZ and TRT (initial displacement P = .010, cyclic displacement P = .001, and total displacement P < .001). Failure loads were 804 N, 801 N, and 682 N for the TRT, ECL, and TLZ, respectively, with no statistically significant difference.

CONCLUSIONS

When positioned on the metaphyseal cortex, there was no difference in the biomechanical performance of the fixed-loop ECL and adjustable-loop TRT, and no lengthening of the TRTs was observed during cycling. However, the TLZ showed statistically significantly lower stiffness and more displacement during cycling with lengthening of the adjustable loop, the clinical significance of which is unknown.

CLINICAL RELEVANCE

When used for femoral-sided soft tissue graft fixation in an anatomically placed femoral tunnel, the adjustable-loop TRT was biomechanically equivalent to the fixed-loop ECL. However, the adjustable-loop TLZ showed displacement during biomechanical testing that could potentially contribute to clinical failure after anterior cruciate ligament reconstruction. However, the clinical significance was not directly tested.

Are porcine flexor digitorum profundus tendons suitable graft substitutes for human hamstring tendons in biomechanical in vitro-studies?

INTRODUCTION

Although a plenty of studies exist assessing the strength of ligamentous fixation techniques using porcine flexor digitorum profundus tendons as graft substitutes for human hamstring tendons, there is no biomechanical study comparing these two tendons. To interpret the results obtained with porcine flexor digitorum profundus tendons, knowledge of their biomechanical properties is essential. The purpose of this study was to compare the biomechanical properties of human hamstring tendons and porcine flexor digitorum profundus tendons.

MATERIALS AND METHODS

A total of six human hamstring tendons and six porcine flexor digitorum profundus tendons were analysed in this study. Quadruple-bundle human hamstring tendons and double-bundle porcine flexor digitorum profundus tendons with a diameter of 9 mm were used. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 50 N for 10 min following cyclic loading of 1500 cycles between 50 and 200 N at 0.5 Hz for measurement of elongation. Subsequently, ultimate failure load and failure mode analysis were performed with a ramp speed of 20 mm/min.

RESULTS

Human hamstring tendons showed significantly higher maximum load to failure values compared to porcine flexor digitorum profundus tendons (1597 ± 179.6 N vs. 1109 ± 101.9 N; p = 0.035). Human hamstring tendons yielded significantly lower initial elongation during preload, but not during cyclical loading.

CONCLUSIONS

When porcine flexor digitorum profundus tendons are used as graft substitutes for human hamstring tendons in biomechanical studies, maximum load to failure is underestimated while elongation is comparable to that of human hamstring tendons. Transferring results of biomechanical studies into clinical practice, the lower maximum load to failure of porcine flexor digitorum profundus tendons needs to be taken into consideration.

Biomechanical and Computed Tomography Analysis of Adjustable Femoral Cortical Fixation Devices for Anterior Cruciate Ligament Reconstruction in a Cadaveric Human Knee Model

PURPOSE

To evaluate and compare two adjustable femoral cortical suspensory fixation devices used for anterior cruciate ligament reconstruction through a novel, direct computed tomography (CT) analysis metric and biomechanical laxity testing in a matched cadaveric human knee study.

METHODS

Anterior cruciate ligament reconstructions with bovine tendon grafts were performed using two adjustable femoral cortical suspensory fixation devices (RigidLoop Adjustable [DePuy Synthes Mitek, Raynham, MA] and TightRope [Arthrex, Naples, FL]) in 12 knees (6 matched pairs). A mechanical testing series was used to determine each knee's laxity in the intact condition. After reconstruction, each specimen was again tested for laxity and also imaged with CT. The laxity testing and CT imaging were then repeated after 1,000 cycles of anteroposterior loading on each knee to compare changes in laxity for the two fixation devices and to visualize changes in button-to-graft distance migration through a three-dimensional CT imaging method.

RESULTS

No significant differences were found between the two fixation groups' laxity measures after reconstruction (all P values ≥ .620) or after cycling (all P values ≥ .211) at any flexion angle. In addition, no significant differences were found between the two groups regarding button-to-graft distance migration (P = .773; mean, 0.61 ± 0.6 mm [95% confidence interval, -0.1 to 1.3 mm] in RigidLoop Adjustable group and 0.53 ± 0.6 mm [95% confidence interval, -0.1 to 1.2 mm] in TightRope group).

CONCLUSIONS

There were no significant differences between the two femoral cortical suspensory adjustable-loop devices regarding laxity outcomes or loop displacement as measured by button-to-graft distance migration.

CLINICAL RELEVANCE

Use of either of the adjustable-loop cortical suspensory devices in our analysis would appear to produce similar, acceptable laxity outcomes and minimal effects in terms of device-related loop displacement.

Suspensory fixation versus novel transverse crosspin for femoral fixation in anterior cruciate ligament reconstruction

BACKGROUND AND AIM

There is still no gold standard technique for graft fixation during anterior cruciate ligament reconstruction. We compared the functional outcomes of patients receiving either ToggleLoc with ZipLoop technology or Translig transverse crosspin device for femoral graft fixation.

MATERIALS AND METHODS

A total of 118 patients were randomly allocated into two groups to receive either Translig(®) transverse crosspin (Translig group 1: n = 51, mean age 28.34 ± 7.83 years, age 18-40 years) or ToggleLoc with ZipLoop technology (ToggleLoc group: n = 67, mean age 26.85 ± 8.76, age 16-41 years) for femoral graft fixation. Early and 1-year assessment was made with Lysholm knee scale, International Knee Documentation Committee Scoring, Tegner Activity Level Scale, KT-1000 arthrometer and pivot shift test.

RESULTS

Preoperative vs. postoperative functional parameters showed significant improvement in both groups. Two groups were similar in terms of Lysholm knee scale, IKDC and Tegner activity scores (p > 0.05). The KT-1000 arthrometer revealed slightly less anterior sliding in Translig group than that in ToggleLoc group (p > 0.05). ToggleLoc technique allowed a radiographically more horizontal placement of the graft than Translig technique.

CONCLUSION

Two distinct techniques used in this study are likely to be suitable for femoral graft fixation during anterior cruciate ligament reconstruction with the femoral tunnel being created via anteromedial approach.