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

Anterior Cruciate Ligament Reconstruction: Fixation Techniques

Anterior cruciate ligament reconstruction (ACLR) is among the most common procedures performed by orthopaedic sports medicine surgeons and has inherent challenges due to the complex anatomy and biomechanical properties required to reproduce the function and stability of the native ACL. Awareness of the anatomic and biomechanical factors, including graft selection and tunnel placement, along with graft tensioning and fixation techniques, is vital in achieving a successful clinical outcome. Common techniques for ACLR graft fixation include intratunnel fixation with interference screws, suspensory fixation, or hybrid fixation strategies, along with several supplemental fixation techniques. Interference screw fixation may decrease graft-tunnel motion, tunnel widening, and graft creep and may be performed with metallic, PEEK (polyether ether ketone), or bioabsorbable screws. Suspensory fixation techniques primarily include suture-buttons, anchors, staples, and screws/washers. Suspensory fixation allows adequate biomechanical strength, although some techniques have been linked to increased graft-tunnel motion and potential tunnel widening. Supplemental fixation techniques may be performed in the setting of concerns for adequacy of primary fixation and includes the use of suture anchors, staples, and screw/washer devices. Regardless of the implant chosen for fixation, secure fixation is paramount to avoid displacement of the graft and allow for integration into the bone tunnel and facilitates early postoperative rehabilitation. It is important for orthopaedic sports medicine surgeons performing primary and revision ACLR to be familiar with multiple fixation techniques.

Concomitant Lateral Meniscus Tear is Associated with Residual Rotatory Knee Instability 1 Year after Anterior Cruciate Ligament Reconstruction: Case-cohort Study

Lateral meniscus tear (LMT) accompanied by anterior cruciate ligament (ACL) injuries has been reported to provoke rotatory instability of the affected knee joint. Unfortunately, these previous papers did not determine whether LMT-derived rotatory knee instability is residual because only preoperative or time zero data exists. This study aimed to longitudinally investigate how the prevalence of comorbid LMT is associated with residual rotatory knee instability (RKI) 1 year after ACL reconstruction (ACLR). A total of 327 patients who underwent double-bundle ACLR (average age: 23.4 years, body mass index: 23.5 kg/m2, 215 females). The patients were divided into three groups based on arthroscopy: 1) intact lateral meniscus (LM); 2) unrepaired LMT; 3) repaired LMT. At the 1-year follow-up, the pivot-shift test was performed. The prevalence of RKI, determined according to IKDC grades (grade ≥1 denoted RKI), was compared with chi-square or Fisher's exact tests. Thirty-eight patients (11.6%) had RKI; 203 subjects (62.1%) showed LMT, and 124 patients were diagnosed with an intact LM. Out of the 203 patients, 79 (38.9%) underwent LM repair. RKI was more prevalent in the LMT group than in the intact group (13.8% versus 8.1%, p = 0.117; Odds ratio: 1.499 [95%CI: 0.864 - 2.600]). In addition, the prevalence of RKI was significantly higher in the LM-repair group than in the intact-LM group (17.7% versus 8.1%, p = 0.038; Odds Ratio: 2.455 [95%CI: 1.032 - 5.842]). Medial meniscus tear (MMT) was detected in 113 patients (34.6%); RKI prevalence was not statistically different between the intact-MM group and the MMT group (12.2% versus 10.6%, p = 0.681). The current cohort study clarified that LMT comorbid with ACL injury was longitudinally associated with increased RKI prevalence 1 year after ACLR. Therefore, patients who underwent both ACLR and LM repair demonstrated a significantly higher prevalence of residual RKI.

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

Purpose

This 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.

Methods

Prospectively 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.

Results

A 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.

Conclusions

FLDs 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 Evidence

Level III, retrospective comparative trial.

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.

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

BACKGROUND

Adjustable 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.

METHODS

This 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.

RESULTS

Overall, 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).

CONCLUSION

The 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.

Does loop length change after anterior cruciate ligament reconstruction with adjustable loop cortical suspension device?: Observation of the hamstring graft completely filling the femoral tunnel

PURPOSE

The adjustable loop cortical suspension device (ALD) is a useful femoral fixation device in anterior cruciate ligament (ACL) reconstructions, but the possibility of loosening has been suggested. The purpose of this study was to evaluate the elongation of an adjustable loop and the position of the hamstring graft inside the femoral socket.

METHODS

The subjects were 33 patients who underwent ACL reconstruction with a hamstring tendon. The graft was fixed using ALD and completely filled the femoral socket. Magnetic resonance images were taken one week and one year after the operation. The loop length, femoral socket length, and graft length inside the socket were measured and statistically compared with the clinical outcomes.

RESULTS

The loop length one week after surgery was 18.9 ± 4.4 mm, and 1 year after surgery was 19.9 ± 4.5 mm (P < 0.001). The gap between the top of the graft and femoral socket was 0.9 ± 1.8 mm one week after surgery and 1.3 ± 1.7 mm one year after surgery (P = 0.259). At one week post-operation, a gap was found in nine patients (27.3%). The loop length and gap did not strongly correlate with clinical findings.

CONCLUSION

ACL reconstruction using ALD showed a gap between the graft and femoral socket at the one week post-operation mark in 27.3% of participants. One year after the surgery, there were cases where the gap increased and/or decreased, but the elongation of the loop was 1 mm on average. Our findings suggest that ALD is clinically safe to use; however, has the possibility of initial loop elongation and non-uniform changes.

LEVEL OF EVIDENCE

IV.

Current trends in graft choice for anterior cruciate ligament reconstruction - part I: anatomy, biomechanics, graft incorporation and fixation

Graft selection in anterior cruciate ligament (ACL) reconstruction is critical, as it remains one of the most easily adjustable factors affecting graft rupture and reoperation rates. Commonly used autografts, including hamstring tendon, quadriceps tendon and bone-patellar-tendon-bone, are reported to be biomechanically equivalent or superior compared to the native ACL. Despite this, such grafts are unable to perfectly replicate the complex anatomical and histological characteristics of the native ACL. While there remains inconclusive evidence as to the superiority of one autograft in terms of graft incorporation and maturity, allografts appear to demonstrate slower incorporation and maturity compared to autografts. Graft fixation also affects graft properties and subsequent outcomes, with each technique having unique advantages and disadvantages that should be carefully considered during graft selection.

Current strategies for enhancement of the bioactivity of artificial ligaments: A mini-review

Background and objective

Anterior cruciate ligament (ACL) reconstruction calls for artificial ligaments with better bioactivity, however systematic reviews regarding bioactivity enhancement strategies, technologies, and perspectives of artificial ligaments have been rarely found.

Methods

Research papers, reviews, and clinical reports related to artificial ligaments were searched and summarized the current status and research trends of artificial ligaments through a systematic analysis.

Results

Having experienced ups and downs since the very first record of clinical application, artificial ligaments differing in material, and fabrication methods have been reported with different clinical performances. Various manufacturing technologies have developed and realized scaffold- and cell-based strategies. Despite encouraging in-vivo and in-vitro test results, the clinical results of such new designs need further clinical examinations.

Conclusion

As the demand for ACL reconstruction dramatically increases, novel artificial ligaments with better osteoinductivity and mechanical performance are promising.

The translational potential of this article

To develop novel artificial ligaments simultaneously possessing excellent osteoinductivity and satisfactory mechanical performance, it is important to grab a glance at recent research advances. This systematic analysis provides researchers and clinicians with comprehensive and comparable information on artificial ligaments, thus being of clinical translational significance.

Adjustable-Loop Cortical Suspensory Fixation Results in Greater Tibial Tunnel Widening Compared to Interference Screw Fixation in Primary Anterior Cruciate Ligament Reconstruction

Background: Although the use of adjustable-loop suspensory fixation has increased in recent years, the influence of the shortcomings of suspensory fixation, such as the bungee-cord or windshield-wiper effects, on tunnel widening remains to be clarified. Hypothesis/Purpose: The purpose of this study was to compare adjustable-loop femoral cortical suspensory fixation and interference screw fixation in terms of tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR). We hypothesized that tunnel widening in the adjustable-loop femoral cortical suspensory fixation (AL) group would be comparable to that in the interference screw fixation (IF) group. Methods: This study evaluated patients who underwent primary ACLR at our institution between March 2015 and June 2019. The femoral and tibial tunnel diameters were measured using plain radiographs in the immediate postoperative period and 2 years after ACLR. Tunnel widening and clinical outcomes (Lysholm score, 2000 International Knee Documentation Committee subjective score, and Tegner activity level) were compared between the two groups. Results: There were 48 patients (mean age, 29.8 ± 12.0 years) in the AL group and 44 patients (mean age, 26.0 ± 9.5 years) in the IF group. Tunnel widening was significantly greater in the AL group than that in the IF group at the tibia anteroposterior (AP) middle (2.03 mm vs. 1.32 mm, p = 0.017), tibia AP distal (1.52 mm vs. 0.84 mm, p = 0.012), tibia lateral proximal (1.85 mm vs. 1.00 mm, p = 0.001), tibia lateral middle (2.36 mm vs. 1.03 mm, p < 0.001), and tibia lateral distal (2.34 mm vs. 0.85 mm, p < 0.001) levels. There were no significant differences between the two groups with respect to femoral tunnel widening and clinical outcomes. Conclusions: Tibial tunnel widening was significantly greater in the AL group than in the IF group at 2 years after primary ACLR. However, the clinical outcomes in the two groups were comparable at 2 years.

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

PURPOSE

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.

METHODS

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 > 15 years 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.

RESULTS

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 0.97 mm (95% CI 0.90-1.03) in the ALD group and 1.45 mm (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.

CONCLUSION

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.

LEVEL OF EVIDENCE

III.

ACL reconstruction with femoral and tibial adjustable versus fixed-loop suspensory fixation: a retrospective cohort study

Background

Cortical suspensory fixation (CSF) devices gain more and more popularity as a reliable alternative to interference screws for graft fixation in anterior cruciate ligament (ACL) reconstruction. Adjustable-loop fixation may be associated with increased anterior laxity and inferior clinical outcome. The purpose of the study was to compare anterior laxity and clinical outcome after minimally invasive all-inside ACL reconstruction using an adjustable-loop (AL) to a standard technique with a fixed-loop (FL) CSF device.

Methods

Patients who underwent primary single-bundle ACL reconstruction with a quadrupled hamstring autograft at a single institution between 2012 and 2016 were reviewed. In the AL group minimally invasive popliteal tendon harvesting was performed with an all-inside approach (femoral and tibial sockets). In the FL group a traditional anteromedial approach was used for tendon harvesting and a femoral socket and full tibial tunnel were drilled. An objective clinical assessment was performed with Telos x-rays and the International Knee Documentation Committee (IKDC) Objective Score. Patient-reported outcomes (PRO) included the IKDC Subjective Score, the Lysholm Knee Score, the Knee Injury and Osteoarthritis Score (KOOS) and the Tegner Activity Scale.

Results

A total of 67 patients were enrolled in this retrospective study with a mean follow-up of 4 (± 1.5) years. The groups were homogenous at baseline regarding age, gender, and the time to surgery. At follow-up, no statistically significant differences were found regarding anterior laxity (AL: 2.3 ± 3 mm vs. FL: 2.3 ± 2.6 mm, p = 0.981). PRO scores were comparable between the AL and FL groups (IKDC score, 84.8 vs. 88.8, p = 0.185; Lysholm 87.3 vs. 89.9, p = 0.380; KOOS 90.7 vs. 91.4, p = 0.720; Tegner 5.5 vs. 6.2, p = 0.085). The rate of saphenous nerve lesions was significantly lower in the AL group with popliteal harvesting of the tendon (8.3% vs. 35.5%, p = 0.014).

Conclusion

The use of an adjustable-loop device on the femoral and tibial side led to similar stability and clinical results compared to a fixed-loop device.

Laterally shifted tibial tunnel can be the risk of residual knee laxity for double-bundle anterior cruciate ligament reconstruction

PURPOSE

To elucidate the relationship between graft tunnel position and knee laxity in the cases of double-bundle ACL reconstruction.

METHODS

Total of 132 cases were included. Femoral and tibial tunnels were evaluated by quadrant method on 3D-CT. As additional reference of tibia, the distances from medial tibial spine to the tunnel center (D_MS) and from Parsons' knob to the tunnel center (D_PK) were evaluated; %D_MS/ML and %D_PK/AP were calculated (ML and AP: mediolateral and anteroposterior width of tibial plateau). Preoperative and postoperative (1 year from surgery) stabilities were evaluated by Lachman and pivot-shift procedures. If there was ≥ 2 mm side-to-side difference, the subject was defined as having anterior knee laxity (AKL); if the pivot-shift phenomenon was observed with IKDC grade ≥ 1, there was rotatory knee laxity (RKL). Multiple logistic regression analysis was conducted with the prevalence of AKL or RKL as the dependent variable and with tunnel positions as the independent variables.

RESULTS

Overall, 21 subjects (15.9%) showed AKL, and 15 subjects (11.4%) showed RKL. Those with postoperative laxity showed higher %D_MS/ML and higher femoral position than those without laxity. Regarding posterolateral bundle, logistic regression model estimated that %D_MS/ML was associated with the prevalence of AKL (B = 0.608; p < 0.001) and RKL (B = 0.789; p < 0.001); %high-low femoral tunnel position (B =  - 0.127; p = 0.023) was associated with that of RKL.

CONCLUSION

There was the risk of residual knee laxity in ACL-reconstructed knee when tibial tunnel shifted more laterally or higher femoral tunnel was created with regard to posterolateral bundle.

LEVEL OF EVIDENCE

III.

Continuous-Loop Tape Technique Has Greater Stiffness and Less Elongation Compared With Tied-Suture Fixation of Full-Thickness All-Soft Tissue Quadriceps Tendon Autografts

Background

Many graft fixation techniques are utilized for full-thickness soft tissue quadriceps tendon autografts during anterior cruciate ligament reconstruction (ACLR).

Purpose

To determine the tensile properties of all-soft tissue quadriceps tendon graft fixation using a tied-suture versus continuous-loop tape technique. It was hypothesized that the continuous-loop tape technique would have less cyclic elongation and greater ultimate load to failure and stiffness compared with a commonly used tied-suture technique.

Study Design

Controlled laboratory study.

Methods

Sixteen fresh-frozen human knee specimens were used to harvest a full-thickness all-soft tissue quadriceps tendon graft; half were secured using a Krackow suture technique with 2 braided sutures, and half were secured using a continuous-loop tape suspensory fixation button with a rip-stop stitch. Cyclic and permanent elongation, toe- and linear-region stiffness, and ultimate load were determined. Statistical analysis was performed at P <.05.

Results

The tied-suture fixation group demonstrated significantly higher permanent elongation (11.7 ± 3.6 vs 4.2 ± 1.0 mm, P < .001) and cyclic elongation (5.9 ± 1.3 vs 2.0 ± 0.4 mm, P < .001) compared with the continuous-loop tape fixation group. There was a significantly higher linear-region stiffness with continuous-loop tape fixation compared with tied-suture fixation (98.8 ± 12.7 vs 85.5 ± 7.5 N/mm, P = .022). No significant difference in ultimate load between groups (517.1 ± 149.2 vs 465.6 ± 64.6 N) was found. The mode of failure was tendon pull-through for the continuous-loop tape group and suture breakage in the tied-suture group (P < .001).

Conclusion

Continuous-loop tape fixation is superior to tied-suture fixation in regard to elongation and stiffness for all-soft tissue quadriceps tendon grafts, but there was no significant difference in ultimate load.

Clinical Relevance

Continuous-loop tape fixation of all-soft tissue quadriceps tendon grafts for ACLR is a valid technique with superior tensile properties.

Comparison Between Early and Late Retensioning of an Adjustable-Loop Cortical Suspension Device During Hamstring ACL Reconstruction

Background:

Biomechanical studies have demonstrated significant loosening of the adjustable-loop device as compared with the fixed-loop device used in anterior cruciate ligament reconstruction. Retensioning of the adjustable loop has been recommended; however, the timing of the retensioning is unknown.

Hypothesis:

Early (ER) and late retensioning (LR) will show similar gapping between the femoral tunnel and graft on follow-up magnetic resonance imaging (MRI) and similar clinical outcomes.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This study included 101 patients who underwent hamstring anterior cruciate ligament reconstruction using the adjustable-loop device for femoral fixation between June 2016 and January 2018. All patients a had follow-up MRI on postoperative day 1. Patients with revision surgery and those with reinjury after reconstruction were excluded. In the ER group, retensioning and knot tying of the initially tightened adjustable loop were performed after the flip of the button and before the graft was fixed at the tibia. In the LR group, retensioning and knot tying were performed after initial tightening of the adjustable loop and graft fixation at the tibial side. The tunnel-graft gap measured on multiplanar reformatted images of MRI scans was compared between the groups, as were clinical outcomes.

Results:

The mean age of the patients at the time of surgery was 30.3 years (range, 14-61 years). ER and knot tying were performed in 56 patients and LR and knot tying in 45. Preoperative characteristics of the 2 groups showed no significant differences. The mean ± SD tunnel-graft gap was 1.5 ± 2.0 mm in the ER group and 5.4 ± 4.0 mm in the LR group (P < .001). There were no significant differences in clinical outcomes between the groups.

Conclusion:

ER and knot tying demonstrated less tunnel-graft gap than that of LR. However, there were no differences in clinical outcomes according to the timing of retensioning.

Comparative Risk-Benefit Profiles of Individual Devices for Graft Fixation in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Network Meta-analysis

PURPOSE

To compare the efficacy and safety of individual devices for femoral and/or tibial graft fixation in anterior cruciate ligament (ACL) reconstruction.

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases were searched from inception to December 12, 2018. Randomized controlled trials comparing individual devices for ACL graft fixation were included. Bayesian network meta-analysis was performed to assess the efficacy profile using the following outcomes: Lysholm score, International Knee Documentation Committee (IKDC) category, laxity, range of motion, and Tegner score. The incidence of infection, effusion, and graft rupture for each device was reported.

RESULTS

We included 57 randomized controlled trials involving 4,304 patients aged 23.8 to 40.9 years. The female proportion ranged from 0% to 100%. The length of follow-up ranged from 6 to 144 months. Of the 13 studied femoral fixation devices, none was significantly different from the others regarding the Lysholm score, IKDC category, range of motion, and Tegner score. Bioabsorbable interference screws (standardized mean difference, 1.3; 95% credible interval, 0.0-2.5) showed higher laxity than the EndoPearl at a borderline level of statistical significance, but the difference varied substantially within multiple sensitivity analyses. Infection (2.0%) was most commonly seen with the EndoPearl, whereas the bone mulch screw had the highest incidence of effusion (5.5%) and graft rupture (5.5%). For the 9 studied tibial fixation devices, no significant difference was observed in the aforementioned efficacy measurements. Bioabsorbable interference screws with staples had the highest incidence of infection (11.1%) and effusion (15.6%), whereas graft rupture was most commonly seen with the bone plug (4.0%).

CONCLUSIONS

Graft fixation devices in ACL reconstruction share a similar efficacy profile in terms of the Lysholm score, IKDC category, range of motion, and Tegner score but not laxity. On the other hand, safety profiles seem to vary among different devices. These findings can support surgeons, alongside their experience and preference, as well as the relative cost of each device, in delivering an individualized plan for an optimal operation.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and II studies.

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.

Editorial Commentary: Are Adjustable-Length Loop Devices Adequate for Femoral Fixation of Anterior Cruciate Ligament Graft?

To date, there is no consensus regarding which type of cortical suspension device is biomechanically superior during anterior cruciate ligament reconstruction. Retensioning or knotting has been reported to improve the biomechanical profile of adjustable-length devices, although fixed-length devices demonstrated overall superior biomechanical properties. Intraoperative or postoperative loop slippage and graft displacement should be investigated in future clinical and radiographic studies including serial magnetic resonance imaging.