- Review Paper
- Open Access
Fixed-loop vs. adjustable-loop cortical button devices for femoral fixation in ACL reconstruction – a systematic review and meta-analysis
Journal of Experimental Orthopaedics volume 9, Article number: 106 (2022)
Button implants with either a fixed-loop device (FLD) or adjustable-loop device (ALD) are used frequently in Anterior Cruciate Ligament Reconstruction (ACLR). Since revision ACLR is associated with poorer clinical outcomes, it is important to investigate the difference in risk of revision between FLDs and ALDs. Therefore, this paper aims to systematically assess the risk of revision ACLR between ALDs and FLDs as well as secondary outcomes such as knee stability and patient reported outcomes (PROMs).
The online databases Embase, Medline (PubMed), and SPORTDiscus were searched, comparing FLDs and ALDs for femoral fixation in patients undergoing primary ACLR with hamstring autografts. Risk of bias was assessed with the ROBINS-I tool for non-randomised studies. Due to heterogeneity a meta-analysis on revision rates were not possible. A random-effect meta-analysis was performed for the secondary outcomes and the quality of evidence was evaluated using the GRADE approach.
Fifteen cohort studies with a total of 2686 patients were included. None of the studies found a clinical difference between ALDs and FLDs in either revision rates, knee stability or PROMS. However, the quality of evidence was graded “very low” due to study designs, risk of bias, and heterogeneity.
Studies of better quality are needed to investigate the risk of revision ACLR between ALDs and FLDs. There was no difference in knee stability and PROMs between the ALDs and FLDs; however, the interpretation of these results is challenging due to low quality of evidence.
Level of evidence
Anterior cruciate ligament reconstruction (ACLR) is a commonly performed surgical procedure that aims to re-establish knee stability after an ACL tear. Cortical button devices are frequently used to fixate the ACL graft onto the femur bone with either a fixed-loop device (FLD) or an adjustable-loop-device (ALD) . When using the FLDs, there is the need for an additional drilling depth for button flipping, which results in extra femoral bone loss. Therefore, the ALDs were designed with an adjustable loop allowing for loop re-tensioning after graft insertion and adjustment of the loop’s length . This provides surgical advantages that potentially lead to reduced bone removal , reduced femoral tunnel widening [14, 25], and improved graft healing . Biomechanical studies found ALDs to be inferior to FLDs in terms of maximum displacement after cyclic loading, ultimate load to failure, and stiffness [7, 8, 29, 38]. In contrast, clinical studies reported similar knee laxity and patient-reported outcome measures between ALDs and FLDs [1, 5, 9]. These findings have previously been reported in systematic reviews [30, 37].
However, there are no reviews with revision ACLR as primary outcome measure even though revision surgery is the ultimate failure outcome . Furthermore, revision surgery is associated with poorer patient-reported outcomes (PROM) and a higher incidence of cartilage injury with subsequent development of osteoarthritis [24, 42]. Therefore, the rate of revision surgery is an important outcome when evaluating if ALDs are as safe to use in ACLR as FLDs. New clinical studies that include revision rates have been published in recent years [11, 28, 31, 43]. These studies may allow for conducting a meta-analysis that has hitherto been difficult due to heterogeneity between studies.
A systematic review which updates the latest research and include revision surgery as primary outcome measure would contribute to the existing research. Thus, this study aimed to review and perform a meta-analysis of studies that compared revision rates between ALDs and FLDs. Knee laxity and PROMs were included as secondary outcomes. The hypothesis was that the ALDs showed similar revision rates compared with FLDs.
Materials and methods
The study was performed as a systematic review and meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) criteria .
Literature search strategy
This systematic review was registered on the Prospero registration site (ID: CRD42021285255). Literature searches were conducted between 30 November and 15 December 2021 in the following electronic databases: Embase (Embase.com), Medline (PubMed host), and SPORTDiscus (EBSCO host). The search was limited to full articles and published studies written in English. The full line search was: “((((“ACL”) OR (“anterior cruciate ligament”)) OR (“Anterior Cruciate Ligament”[Mesh] OR “Anterior Cruciate Ligament Reconstruction”[Mesh] OR “Anterior Cruciate Ligament Injuries”[Mesh])) AND (((“Endobutton”) OR (“Retrobutton”) OR (“XO button”) OR (“Rigidloop”)) OR ((“fixed” OR “fixation”) AND (loop OR button OR “length”)))) AND ((“Zipploop” OR “Tight Rope” OR “Rigidloop” OR “UltraButton”) OR ((“Adjustable” OR “variable”) AND (loop OR button OR length))).”
The Population, Intervention, Comparison, and Study (PICOS) principles guided the search strategy . Databases were searched for studies that met the following criteria: investigating revision surgery, knee laxity, or PROMs for patients receiving ACLR performed with hamstring tendon autografts and comparing adjustable-loop devices to fixed-loop devices for femoral graft fixation.
The reference list of included studies and systematic reviews, conducted on the same area known by the authors, were searched for additional studies.
The selection process was conducted using the online software Covidence. Two authors (SE) and (TN) independently conducted title and abstract screening and any discrepancies were resolved through discussions. Full text screening of included studies was carried out in the same way. The reference list from included studies and from existing reviews [30, 37] on the same topic known by the authors were searched for additional eligible studies by a single assessor (SE). Studies identified from the reference lists were screened in full text by both assessors to reach a final agreement. Studies were considered eligible is they met the PICOS criteria. The identification and screening process are outlined in Fig. 1.
Data extractions were performed using a predefined data extraction form created on the online software, Covidence. The following data was extracted through the extraction form: type of study, fixation-device fabricant, tibial fixation, number of included patients, distribution of sex and age, follow-up time, and outcome data. The rate of revision surgery was the primary outcome and was defined as a second ACLR performed on the same knee as the primary ACLR. Secondary outcomes included anterior knee laxity, measured with arthrometers (KT-1000 or Rolimeter) as the side-to-side difference (SSD) in mm between the reconstructed and healthy knee, and PROMs as measured by the International Knee Documentation Committee (IKDC)  and Lysholm score . Two reviewers (SE) and (TN) conducted data extractions independently and discrepancies were discussed to reach a consensus.
The Cochrane Risk of Bias In Non-Randomized Studies of Interventions (ROBINS-I)  was used to evaluate the risk of bias in each of the included studies. A single assessor (SE) completed the bias assessment and made an overall risk of bias assessment for each article. The results were afterwards presented to the co-authors. If a decision was unclear, the authors discussed it to reach an agreement.
The ROBINS-I contains the following seven domains of bias: due to confounding, in selecting participants, in classifying interventions, due to deviations from intended interventions, due to missing data, in measuring outcomes, and in selecting the reported result. Bias was assessed separately for each of the three outcomes: revision surgery, knee laxity, and PROMs. The important factors included in the confounding domain for each outcome were chosen after a discussion between the authors. Important confounders of revision rates and knee laxity included the use of more than one tibial fixation device, the different surgical techniques used (i.e. anteromedial, transtibial, outside-in), age, and surgery on other ligaments (i.e. posterior cruciate ligament, medial collateral ligament, or lateral collateral ligament). Important confounders for the PROMs were age and knee comorbidities (osteoarthritis/cartilage damage, meniscus injury, other ligament injuries). Rehabilitation was considered an important co-intervention for all outcomes. If the study included different rehabilitation programmes or did not report on the rehabilitation protocol, it was considered as having a moderate risk of bias in the domain of deviations from the intended intervention. For the missing data domain, it was decided that missing data for 10–19% of the participants resulted in a moderate risk of bias and missing data for > 20% of the participants resulted in a serious risk of bias. The overall risk of bias was determined by the worst degree of bias assessed across all bias domains .
The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to evaluate the quality of evidence for each meta-analysis . A single assessor (SE) conducted the GRADE evaluation, after all authors approved it.
The rates of revision surgery are reported as categorical data. The risks ratio of revision surgery is presented by an Odds ratio (OR) with a 95% confidence interval (CI). If the included studies did not report the OR, it was calculated by using the proportions stated in the study. A meta-analysis of the pooled effect size of revision rates was not estimated due to high heterogeneity between the included studies. Knee laxity by SSD and PROMs are reported as continuous data by a mean difference (MD). Random effect models were used to estimate the pooled effect of the MD for the SSD and PROMs with a 95% CI at the 2-years follow-up. Heterogeneity due to variations across the studies were assessed using the I2 test . Publication bias assessed using funnel plots were not possible due to the low number of studies included. The statistical analyses were conducted using Stata version 17 (StataCorp, College Station, Texas).
A total of 15 studies were included in this systematic review [1, 3,4,5, 9, 11, 14, 25, 28, 31, 33, 34, 36, 41, 43]. All studies were screened in full text. Four studies did not meet eligibility criteria: one could not be retrieved in full text , one was not written in English , one was conducted with several graft types , and presented other clinical outcomes than those included by this review . Three additional studies were identified from the reference list of included studies [4, 14, 33]. Key characteristics for each of the included studies are presented in Table 1.
Three studies [4, 5, 43] included revision surgery in their outcome and two studies [28, 34] reported on the number of patients undergoing revision surgery during the study period. Only the study by Asmussen et al.  analysed the rate of revision surgery with an OR and found that ALDs had 0.51 (95% CI: 0.24–1.13) lower odds of having a revision surgery compared to FLDs. However, this was not statistically significant . Boyle et al.  and Ranjan et al.  did not present an OR for the risk of having a revision surgery in the ALD group compared to the FLD group. However, this study calculated an OR based on the proportions of revision surgery reported by both Boyle et al.  and Ranjan et al. . The results are presented in Table 2. Mohamed et al.  found only one.
case of revision surgery and this was in the ALD group. Uribe et al.  reported no cases of revision surgery in either of the groups.
The SSD are reported at the 6 months follow-up in three studies [5, 34, 43], at the 1-year follow-up in three studies [4, 25, 43], and at the 2-years follow-up in five studies [5, 9, 11, 14, 34]. There was no difference in the mean SSD between the ALDs and FLDs in either of the studies Table 3.
The meta-analysis revealed an overall MD in the SSD at the 2-years follow-up of -0.15 mm (95% CI: -0.54—0.24) lower in the ALD group compared to the FLD group (Fig. 2). The I2 test revealed a high heterogeneity of 61% across the studies.
Five studies reported the PROMs with the Lysholm score at the 1-year follow-up [25, 28, 31, 33, 36] and seven studies reported them at the 2-years follow-up [1, 2, 9, 11, 14, 34, 41] (Table 4). The meta-analysis for the 2-years Lysholm scores revealed an overall MD in the Lysholm score of 0.17 points (95% CI: -040 – 0.75) higher for the ALD group compared to the FLD group (Fig. 2). Three studies reported the PROMs with the IKDC score at the 1-year follow-up [25, 33, 36] and six studies reported it at the 2-years follow-up [1, 2, 11, 14, 34, 41] as presented in Table 4.
The meta-analysis for the 2-years IKDC scores revealed an overall MD in the IKDC score of 0.48 points (95% CI: -1.06 – 2.01) higher for the ALD group compared to the FLD group (Fig. 2).
The overall risk of bias assessment showed that the included studies ranged from an overall moderate risk of bias to an overall serious risk of bias depending on the outcome measure (Fig. 3).
For the bias assessment of revision rates and knee laxity, the overall serious risk of bias judgement was mainly due to confounding. Two studies were judged as having a serious risk of bias due to confounders. One used several tibial fixation methods  and the other used two different surgical techniques . Most of the studies had a low or moderate risk of bias regarding selection of participants, deviations from intervention, measurement of outcomes, and selection in reported results. For the knee laxity outcome, one study had a serious risk of bias due to missing data .
In the bias assessment of the PROMs, the overall risk of bias was serious for all studies. This was mainly because of bias due to confounders and in measurement of the outcome since this was a subjective measure and thereby could be influenced by knowledge of intervention. Most of the studies had a low or moderate risk of bias regarding selection of participants, deviations from intervention, and selection in reported results. One study had a serious risk of bias due to missing data . The risk of bias in classifying interventions was at a low risk for all studies in all outcomes.
The GRADE evaluation demonstrated a “very low” quality of evidence for each of the three meta-analyses (Table 5).
All outcomes were initially downgraded to “low” quality of evidence because of the study design (i.e. observational studies). The meta-analysis of knee laxity was further downgraded to “very low” due to high heterogeneity (I2 = 61%). The two meta-analyses of PROMs by the Lysholm score and the IKDC score had a serious risk of bias and was thus downgraded further to “very low”.
The most important finding of this systematic review and meta-analysis was that there was no difference in revision surgery rates comparing ALDs to FLDs for femoral graft fixation using hamstring tendon autografts in ACLR. Furthermore, this systematic review found that the overall risk of bias assessment ranged from moderate to serious and that the quality of evidence in the meta-analyses was “very-low”.
Five studies reported the rate of revision surgery for ALDs and FLDs. Asmussen et al.  included the largest patient population in their registry-based cohort study and was the only study that compared the rate of revision surgery between ALDs and FLDs using statistics. They found that ALDs had a lower risk of revision surgery compared to FLDs. This result was not statistically significant, and the study had a serious overall risk of bias. Uribe et al.  was the only study that reported no cases of revision surgery; however, their study included the fewest number of patients, which may explain this finding. None of the included studies specified rehabilitation protocols and return-to-sport criteria. Two studies [5, 28] reported that patients returned to sports from 6 months postoperatively and the remaining three studies [4, 34, 43] did not report whether the patients returned to sports. The lack of information in the studies on rehabilitation protocols and return-to-sport criteria is of importance since higher sport activity levels and an early return to sports before meeting the appropriate criteria are associated with a greater risk of reinjury and a possible revision surgery [15, 18]. A meta-analysis was not performed due to heterogeneity of the study design i.e. surgical technique for tunnel drilling, differences in tibial fixation methods, number of patients, and different follow-up time. To reduce bias, studies that only performed ACLR with hamstring tendon autografts were included, since allografts have demonstrated a greater risk of graft failure compared to autografts [16, 22].
Secondary, this systematic review found no difference between ALDs and FLDs in knee laxity and PROMs. The results from the meta-analysis of knee laxity showed that there was no significant difference between ALDs and FLDs in the SSD in anterior knee laxity when measured with the KT-1000 arthrometer. However, due to study design and a large heterogeneity from the I2 test, the GRADE evaluation demonstrated a “very low” quality of evidence. The large heterogeneity may be partially explained by differences in the force applied during the KT-1000 measurements. The studies by Choi et al.  and Firat et al.  stated that the KT-1000 measurements were performed at maximal force as opposed to the studies by Ranjan et al.  and Djordjevíc et al. , who did not specify the force applied. The inter-reader reliability with the KT-1000 arthrometer was found poor by Runer et al. , who stated that this could partially be explained by differences in the force that the assessors applied. The meta-analysis conducted on PROMs showed that ALDs did not improve the PROMs compared to the FLDs when using either the IKDC or the Lysholm score. The GRADE assessment graded the result as a “very low” quality of evidence due to study design and serious risk of bias in the confounding and measurement of outcome domains. Since PROMs are subjective, the measures are considered to run a high risk of bias by the ROBINS-I tool.
To the authors’ knowledge, this review is the first to provide a schematic overview and to update the knowledge on the differences in revision rates between ALDs and FLDs from the latest research. Also, this review is the first to provide a thorough bias assessment with the ROBINS-I  bias assessment tool, specifically developed to assess bias in non-randomized studies. Furthermore, this systematic review provides a detailed meta-analyses of knee laxity and PROMs and is the first to evaluate these results using the recognized GRADE approach .
The primary aim of this systematic review was to use a meta-analysis to evaluate the risk of revision surgery between ALDs and FLDs. However, this was not possible due to the low number of studies evaluating revision surgery rates and high heterogeneity between the studies. Furthermore, none of the studies presented a sample size calculation based on detecting a difference in revision rates, which raises concerns about the statistical power of these studies. Studies with a powered sample size and a longer follow-up period would contribute to existing research. Another limitation is that all studies included in this systematic review and meta-analysis were cohort studies, thereby impacting the quality of evidence evaluated by GRADE. Following the GRADE approach, it is recommended to grade observational studies as “low” because of their limitations compared to randomised controlled trials.
Despite the low quality of evidence, the results of this systematic review and meta-analysis are in accordance with the findings of previous systematic reviews [30, 37]. Biomechanical studies have previously raised concerns about the use of ALDs due to elongation. However, based on the results from this systematic review and meta-analysis, ALD usage as femoral fixation during ACL reconstruction is not associated with greater knee laxity and higher revision rates than FLD usage.
This systematic review and meta-analysis provide clinicians with a detailed and schematic summary on clinical outcomes between ALDs and FLDs. Furthermore, it indicates that further research on revision rates of better quality could benefit the existing knowledge.
This systematic review found that there was no difference in revision rates between ALDs and FLDs in either of the included studies. Furthermore, the meta-analysis showed no differences regarding knee laxity and PROMs. These data suggest that both types of loop devices are safe to use in ACLR, supporting the existing research. However, the available clinical studies’ quality is low and shows serious bias risk.
Anterior cruciate ligament reconstruction
Patient-reported outcome measures
Preferred Reporting Items for Systematic Reviews and Meta-analyses
Population, Intervention, Comparison, and Study
International Knee Documentation Committee
Risk of Bias In Non-Randomised Studies – of Interventions
Grading of Recommendations Assessment, Development, and Evaluation
Ahn HW, Seon JK, Song EK, Park CJ, Lim HA (2019) Comparison of Clinical and Radiologic Outcomes and Second-Look Arthroscopic Findings After Anterior Cruciate Ligament Reconstruction Using Fixed and Adjustable Loop Cortical Suspension Devices. Arthroscopy 35:1736–1742
Ahn JH, Ko TS, Lee YS, Jeong HJ, Park JK (2018) Magnetic Resonance Imaging and Clinical Results of Outside-in Anterior Cruciate Ligament Reconstruction: A Comparison of Fixed- and Adjustable-Length Loop Cortical Fixation. Clin Orthop Surg 10:157–166
Ahn JH, Ko TS, Lee YS, Jeong HJ, Park JK (2018) Magnetic resonance imaging and clinical results of outside-in anterior cruciate ligament reconstruction: A comparison of fixed-and adjustable-length loop cortical fixation. CiOS Clinics in Orthopedic Surgery 10:157–166
Asmussen CAP, Attrup ML, Thorborg K, Hölmich P (2018) Passive Knee Stability After Anterior Cruciate Ligament Reconstruction Using the Endobutton or ToggleLoc With ZipLoop as a Femoral Fixation Device: A Comparison of 1654 Patients From the Danish Knee Ligament Reconstruction Registry. Orthop J Sports Med 6:2325967118778507
Boyle MJ, Vovos TJ, Walker CG, Stabile KJ, Roth JM, Garrett WE Jr (2015) Does adjustable-loop femoral cortical suspension loosen after anterior cruciate ligament reconstruction? A retrospective comparative study. Knee 22:304–308
Briggs KK, Lysholm J, Tegner Y, Rodkey WG, Kocher MS, Steadman JR (2009) The reliability, validity, and responsiveness of the Lysholm score and Tegner activity scale for anterior cruciate ligament injuries of the knee: 25 years later. Am J Sports Med 37:890–897
Chang MJ, Bae TS, Moon YW, Ahn JH, Wang JH (2018) A Comparative Biomechanical Study of Femoral Cortical Suspension Devices for Soft-Tissue Anterior Cruciate Ligament Reconstruction: Adjustable-Length Loop Versus Fixed-Length Loop. Arthroscopy 34:566–572
Cheng J, Paluvadi SV, Lee SJ, Yoo SJ, Song EK, Seon JK (2018) Biomechanical comparisons of current suspensory fixation devices for anterior cruciate ligament reconstruction. Int Orthop 42:1291–1296
Choi NH, Yang BS, Victoroff BN (2017) Clinical and Radiological Outcomes After Hamstring Anterior Cruciate Ligament Reconstructions: Comparison Between Fixed-Loop and Adjustable-Loop Cortical Suspension Devices. Am J Sports Med 45:826–831
da Costa Santos CM, de Mattos Pimenta CA, Nobre MR (2007) The PICO strategy for the research question construction and evidence search. Rev Lat Am Enfermagem 15:508–511
Djordjević D, Petrović M, Žunčić SD, Stojiljković P, Golubović I, Kadija M et al (2021) Application of two types of suspensory fixation in reconstruction of anterior cruciate ligament with a semitendinosus-gracilis graft – A randomized prospective study. Vojnosanit Pregl 78:1053–1059
Eslami S, Mousavi SH, Ghadimi K (2019) Comparing outcomes of reconstruction of anterior cruciate ligament rupture with fixed loop and adjustable loop. Tehran Univ Med J 77:548–552
Eysturoy NH, Nissen KA, Nielsen T, Lind M (2018) The Influence of Graft Fixation Methods on Revision Rates After Primary Anterior Cruciate Ligament Reconstruction. Am J Sports Med 46:524–530
Firat A, Catma F, Tunc B, Hacihafizoglu C, Altay M, Bozkurt M et al (2014) The attic of the femoral tunnel in anterior cruciate ligament reconstruction: a comparison of outcomes of two suspensory femoral fixation systems. Knee Surg Sports Traumatol Arthrosc 22:1097–1105
Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA (2016) Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med 50:804–808
Group TM (2014) Effect of graft choice on the outcome of revision anterior cruciate ligament reconstruction in the Multicenter ACL Revision Study (MARS) Cohort. Am J Sports Med 42:2301–2310
Guyatt G, Oxman AD, Akl EA, Kunz R, Vist G, Brozek J et al (2011) GRADE guidelines: 1. Introduction-GRADE evidence profiles and summary of findings tables. J Clin Epidemiol 64:383–394
Hadley CJ, Rao S, Tjoumakaris FP, Ciccotti MG, Dodson CC, Marchetto PA et al (2022) Safer Return to Play After Anterior Cruciate Ligament Reconstruction: Evaluation of a Return-to-Play Checklist. Orthop J Sports Med 10:23259671221090412
Higgins JP, Thompson SG, Deeks JJ, Altman DG (2003) Measuring inconsistency in meta-analyses. Bmj 327:557–560
Ibrahim MF, Md Yusof BA, Mat Dom F (2017) Fixed loop versus adjustable loop fixation in ACL reconstruction: Functional outcome. Malaysian Orthopaedic J 11
Irrgang JJ, Ho H, Harner CD, Fu FH (1998) Use of the International Knee Documentation Committee guidelines to assess outcome following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 6:107–114
Kaeding CC, Pedroza AD, Reinke EK, Huston LJ, Spindler KP (2015) Risk Factors and Predictors of Subsequent ACL Injury in Either Knee After ACL Reconstruction: Prospective Analysis of 2488 Primary ACL Reconstructions From the MOON Cohort. Am J Sports Med 43:1583–1590
Kamitani A, Hara K, Arai Y, Atsumi S, Takahashi T, Nakagawa S et al (2021) Adjustable-Loop Devices Promote Graft Revascularization in the Femoral Tunnel After ACL Reconstruction: Comparison With Fixed-Loop Devices Using Magnetic Resonance Angiography. Orthop J Sports Med 9:2325967121992134
Kievit AJ, Jonkers FJ, Barentsz JH, Blankevoort L (2013) A cross-sectional study comparing the rates of osteoarthritis, laxity, and quality of life in primary and revision anterior cruciate ligament reconstructions. Arthroscopy 29:898–905
Lanzetti RM, Monaco E, De Carli A, Grasso A, Ciompi A, Sigillo R et al (2016) Can an adjustable-loop length suspensory fixation device reduce femoral tunnel enlargement in anterior cruciate ligament reconstruction? A prospective computer tomography study. Knee 23:837–841
Lind M, Menhert F, Pedersen AB (2012) Incidence and outcome after revision anterior cruciate ligament reconstruction: results from the Danish registry for knee ligament reconstructions. Am J Sports Med 40:1551–1557
Mayr R, Smekal V, Koidl C, Coppola C, Eichinger M, Rudisch A et al (2020) ACL reconstruction with adjustable-length loop cortical button fixation results in less tibial tunnel widening compared with interference screw fixation. Knee Surg Sports Traumatol Arthrosc 28:1036–1044
Mohamed R, El-Din El-Shafie MH, El-Sheikh MA (2020) Clinical Outcome of Fixed Versus Adjustable Loop Cortical Suspension Devices in Arthroscopic Anterior Cruciate Ligament Reconstruction. Ortop Traumatol Rehabil 22:181–185
Nye DD, Mitchell WR, Liu W, Ostrander RV (2017) 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. Arthroscopy 33:1225-1232.e1221
Onggo JR, Nambiar M, Pai V (2019) Fixed- Versus Adjustable-Loop Devices for Femoral Fixation in Anterior Cruciate Ligament Reconstruction: A Systematic Review. Arthroscopy 35:2484–2498
Ono Y, Sato Y, Mukai H, Enomoto T, Kimura S, Nakagawa R et al (2021) Randomized comparative study of suspension femoral fixation device in graft position maintenance in anterior cruciate ligament reconstruction: EndoButton CL vs TightRope RT. Asia Pac J Sports Med Arthrosc Rehabil Technol 25:42–46
Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD et al (2021) The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 372:n71
Pokharel B, Bhalodia M, Raut A, Gajjar S (2018) Comparative study on fixed versus adjustable-length loop device for femoral fixation of graft in anterior cruciate ligament reconstruction. Int J Orthopaedics Sci 4:889–892
Ranjan R, Gaba S, Goel L, Asif N, Kalra M, Kumar R et al (2018) In vivo comparison of a fixed loop (EndoButton CL) with an adjustable loop (TightRope RT) device for femoral fixation of the graft in ACL reconstruction: A prospective randomized study and a literature review. J Orthop Surg (Hong Kong) 26:2309499018799787
Runer A, Roberti di Sarsina T, Starke V, Iltchev A, Felmet G, Braun S et al (2021) The evaluation of Rolimeter, KLT, KiRA and KT-1000 arthrometer in healthy individuals shows acceptable intra-rater but poor inter-rater reliability in the measurement of anterior tibial knee translation. Knee Surg Sports Traumatol Arthrosc 29:2717–2726
Sheth H, Salunke AA, Barve R, Nirkhe R (2019) Arthroscopic ACL reconstruction using fixed suspensory device versus adjustable suspensory device for femoral side graft fixation: What are the outcomes? J Clin Orthop Trauma 10:138–142
Singh S, Shaunak S, Shaw SCK, Anderson JL, Mandalia V (2020) Adjustable Loop Femoral Cortical Suspension Devices for Anterior Cruciate Ligament Reconstruction: A Systematic Review. Indian J Orthop 54:426–443
Smith PA, Piepenbrink M, Smith SK, Bachmaier S, Bedi A, Wijdicks CA (2018) Adjustable- Versus Fixed-Loop Devices for Femoral Fixation in ACL Reconstruction: An In Vitro Full-Construct Biomechanical Study of Surgical Technique-Based Tibial Fixation and Graft Preparation. Orthop J Sports Med 6:2325967118768743
Sonnery-Cottet B, Rezende FC, Martins Neto A, Fayard JM, Thaunat M, Kader DF (2014) Arthroscopically confirmed femoral button deployment. Arthrosc Tech 3:e309-312
Sterne JA, Hernán MA, Reeves BC, Savović J, Berkman ND, Viswanathan M et al (2016) ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ 355:i4919
Sundararajan SR, Sambandam B, Singh A, Rajagopalakrishnan R, Rajasekaran S (2018) Does Second-Generation Suspensory Implant Negate Tunnel Widening of First-Generation Implant Following Anterior Cruciate Ligament Reconstruction? Knee Surg Relat Res 30:341–347
Svantesson E, Hamrin Senorski E, Kristiansson F, Alentorn-Geli E, Westin O, Samuelsson K (2020) Comparison of concomitant injuries and patient-reported outcome in patients that have undergone both primary and revision ACL reconstruction-a national registry study. J Orthop Surg Res 15:9
Uribe-Echevarria B, Magnuson JA, Amendola A, Bollier MJ, Wolf BR, Hettrich CM (2020) Anterior Cruciate Ligament Reconstruction: A Comparative Clinical Study Between Adjustable and Fixed Length Suspension Devices. Iowa Orthop J 40:121–127
Wise BT, Patel NN, Wier G, Labib SA (2017) Outcomes of ACL Reconstruction With Fixed Versus Variable Loop Button Fixation. Orthopedics 40:e275–e280
Yavari P, Mohammadsharifi G, Fadaei B, Talebi S, Akbari M (2020) A survey on prognosis of anterior cruciate ligament (ACL) reconstruction surgeries following fixed loop and adjustable loop methods. Int J Physiol Pathophysiol Pharmacol 12:173–177
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
The original online version of this article was revised: The abstract was missing from the article version published 21 Oct 2022.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Elmholt, S.B., Nielsen, T.G. & Lind, M. Fixed-loop vs. adjustable-loop cortical button devices for femoral fixation in ACL reconstruction – a systematic review and meta-analysis. J EXP ORTOP 9, 106 (2022). https://doi.org/10.1186/s40634-022-00544-1