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Anatomical anterior cruciate ligament reconstruction (ACLR) results in fewer rates of atraumatic graft rupture, and higher rates of rotatory knee stability: a meta-analysis

      Importance

      This review highlights the differences in outcomes between anatomical and non-anatomical anterior cruciate ligament reconstruction (ACLR) techniques.

      Objective

      To compare clinical and functional outcomes between anatomical and non-anatomical ACLR techniques.

      Evidence review

      A search of MEDLINE, Embase and PubMed from 1 January 2000 to 24 October 2019 was conducted. Randomised and prospective primary ACLR studies using autograft and a minimum of 2 years of follow-up were included. The Anatomic Anterior Cruciate Ligament Reconstruction Checklist (AARSC) was used to categorise studies as anatomical. Outcomes analysed included failure rate, knee stability and functional outcomes. A meta-analysis using risk ratio and mean differences was conducted using a random effects model.

      Findings

      Thirty-six studies were included, representing 3710 patients with a follow-up range of 24–300 months. The overall failure rate was 96/1470 (6.5%) and 131/1952 (6.7%) in the anatomical group and non-anatomical group, respectively. The pooled results of the overall failure rate showed that there was no statistically significant difference between the anatomical and the non-anatomical groups (p=0.96). There were 37/60 (61.7%) and 29/67 (43.3%) traumatic failures in the anatomical and non-anatomical groups, respectively. The number of patients with the negative postoperative pivot-shift test was 995/1252 (79.5%) and 1140/1589 (71.1%) in the anatomical and non-anatomical groups, respectively. The pooled results indicated a statistically significant higher number of patients with a positive pivot shift in the non-anatomical group compared with the anatomical group (p=0.03).

      Conclusions and relevance

      This study demonstrated that the overall failure rate was similar between the anatomical and non-anatomical approaches. However, the anatomical ACLR demonstrated a significantly superior restoration of rotatory stability, as evidenced by a higher percentage with a negative postoperative pivot-shift test. Non-anatomical ACLR resulted in higher rates of atraumatic graft ruptures and persistent rotatory knee instability. Surgeons should consider anatomical ACLR when treating rotatory knee stability in patients.

      Level of evidence

      II, systematic review and meta-analysis of level I and II studies.
      What is already known
      • During anterior cruciate ligament reconstruction (ACLR), transtibial (TT) drilling of the femoral bone tunnel has frequently resulted in non-anatomical graft positioning.
      • There has been a recent trend towards anatomical ACLR via independent tunnel drilling to allow for a more horizontal graft position that better restores native anterior cruciate ligament anatomy.
      • An 18-item anatomical ACLR scoring checklist Anatomic Anterior Cruciate Ligament Reconstruction Checklist (AARSC) was developed to adjudicate the reporting of proper anatomical ACLR.
      What are the new findings
      • In this study, anatomical compared with non-anatomical ACLR resulted in similar overall failure rates, in which the latter had a lower proportion of traumatic failure.
      • Anatomical ACLR better restored knee stability, measured by pivot-shift test, compared with the non-anatomical group.
      • Other outcomes such as Lysholm and objective International Knee Documentation Committee scores were equivalent between the two groups.

      Introduction

      The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, and the incidence of ACL rupture ranges from 30 to 78 per 100 000 person-years.
      • Allen MM
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      Are female soccer players at an increased risk of second anterior cruciate ligament injury compared with their athletic Peers?.
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      Patient predictors of early revision surgery after anterior cruciate ligament reconstruction: a cohort study of 16,930 patients with 2-year follow-up.
      ,
      • Bourke HE
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      • Waller A
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      Survival of the anterior cruciate ligament graft and the contralateral ACL at a minimum of 15 years.
      The advent of arthroscopy increased the frequency of anterior cruciate ligament reconstruction (ACLR), most commonly performed by transtibial (TT) drilling of the femoral bone tunnel. However, the TT drilling technique frequently resulted in non-anatomical graft positioning, as bone tunnels were positioned outside of the native ACL footprints.
      • Tompkins M
      • Milewski MD
      • Brockmeier SF
      • et al.
      Anatomic femoral tunnel drilling in anterior cruciate ligament reconstruction.
      In a systematic review of studies reporting long-term outcomes following ACLR, in which the TT technique was almost universally employed, ACLR was found to reduce subsequent meniscal injury and to improve activity level (as measured by Tegner scores) but neither affected Lysholm scores or International Knee Documentation Committee (IKDC) scores nor reduced the development of osteoarthritis(OA).
      • Chalmers PN
      • Mall NA
      • Moric M
      • et al.
      Does ACL reconstruction alter natural history?: A systematic literature review of long-term outcomes.
      In comparison to TT drilling, independent drilling of the femoral bone tunnel, commonly achieved through a transportal or outside-in (OI) technique, more consistently placed the bone tunnels within the native ACL footprints, constituting a more anatomical reconstruction.
      • Tompkins M
      • Milewski MD
      • Brockmeier SF
      • et al.
      Anatomic femoral tunnel drilling in anterior cruciate ligament reconstruction.
      ,
      • Kopf S
      • Forsythe B
      • Wong AK
      • et al.
      Nonanatomic tunnel position in traditional transtibial single-bundle anterior cruciate ligament reconstruction evaluated by three-dimensional computed tomography.
      As a result, independent tunnel drilling has been increasingly adopted in place of TT drilling,
      • Tibor L
      • Chan PH
      • Funahashi TT
      • et al.
      Surgical technique trends in primary ACL reconstruction from 2007 to 2014.
      as independent drilling was shown to better restore joint kinematics,
      • Musahl V
      • Plakseychuk A
      • VanScyoc A
      • et al.
      Varying femoral tunnels between the anatomical footprint and isometric positions: effect on kinematics of the anterior cruciate ligament-reconstructed knee.
      ,
      • Kato Y
      • Maeyama A
      • Lertwanich P
      • et al.
      Biomechanical comparison of different graft positions for single-bundle anterior cruciate ligament reconstruction.
      increase in situ graft forces
      • Kato Y
      • Maeyama A
      • Lertwanich P
      • et al.
      Biomechanical comparison of different graft positions for single-bundle anterior cruciate ligament reconstruction.
      and normalise tibiofemoral contact stresses in vitro cadaveric studies, with restoration of in vivo knee kinematics during dynamic movement
      • Abebe ES
      • Utturkar GM
      • Taylor DC
      • et al.
      The effects of femoral graft placement on in vivo knee kinematics after anterior cruciate ligament reconstruction.
      and joint laxity on postoperative physical examination.
      • Kondo E
      • Merican AM
      • Yasuda K
      • et al.
      Biomechanical comparison of anatomic Double-Bundle, anatomic Single-Bundle, and Nonanatomic Single-Bundle anterior cruciate ligament reconstructions.
      ,
      • Zaffagnini S
      • Signorelli C
      • Grassi A
      • et al.
      Anatomic anterior cruciate ligament reconstruction using hamstring tendons restores quantitative pivot shift.
      However, independent drilling has also been associated with higher rates of graft failure,
      • Rahr-Wagner L
      • Thillemann TM
      • Pedersen AB
      • et al.
      Increased risk of revision after anteromedial compared with transtibial drilling of the femoral tunnel during primary anterior cruciate ligament reconstruction: results from the Danish knee ligament reconstruction register.
      ,
      • Desai N
      • Andernord D
      • Sundemo D
      • et al.
      Revision surgery in anterior cruciate ligament reconstruction: a cohort study of 17,682 patients from the Swedish national knee ligament register.
      ,
      • Svantesson E
      • Sundemo D
      • Hamrin Senorski E
      • et al.
      Double-bundle anterior cruciate ligament reconstruction is superior to single-bundle reconstruction in terms of revision frequency: a study of 22,460 patients from the Swedish national knee ligament register.
      which has been attributable in part to the learning curve in adopting a new surgical technique,
      • Eysturoy NH
      • Nielsen TG
      • Lind MC
      Anteromedial portal drilling Yielded better survivorship of anterior cruciate ligament reconstructions when comparing recent versus early surgeries with this technique.
      as well as the potential higher in situ graft forces experienced due to more anatomical tunnel positioning.
      • Kato Y
      • Maeyama A
      • Lertwanich P
      • et al.
      Biomechanical comparison of different graft positions for single-bundle anterior cruciate ligament reconstruction.
      Furthermore, independent drilling is often considered synonymous with ‘anatomical’ ACLR. Although independent drilling is most commonly used to achieve anatomical tunnel positioning, the technique should not be inevitably equated with anatomical ACLR, which seeks to functionally restore the ACL to its native dimensions, collagen orientation and insertion sites according to individual anatomy.
      • van Eck CF
      • Schreiber VM
      • Mejia HA
      • et al.
      “Anatomic” anterior cruciate ligament reconstruction: a systematic review of surgical techniques and reporting of surgical data.
      In response to inconsistent and insufficient reporting of surgical details in studies of anatomical ACLR, an Anatomic Anterior Cruciate Ligament Reconstruction Checklist (AARSC) was developed to permit valid comparison of outcomes across studies and to facilitate the more consistent achievement of anatomical ACLR.
      • van Eck CF
      • Gravare-Silbernagel K
      • Samuelsson K
      • et al.
      Evidence to support the interpretation and use of the anatomic anterior cruciate ligament reconstruction checklist.
      A recent systematic review comparing long-term (≥10 years) OA prevalence following anatomical versus non-anatomical ACLR, with anatomical defined as a minimum AARSC score of 8 out of 18, found a nearly 50% reduction in radiographically defined OA with the former compared with the latter.
      • Rothrauff BB
      • Jorge A
      • de Sa D
      • et al.
      Anatomic ACL reconstruction reduces risk of post-traumatic osteoarthritis: a systematic review with minimum 10-year follow-up.
      While these findings suggested that anatomical ACLR may protect the knee joint from long-term degeneration, related studies with shorter follow-up periods were necessarily excluded, limiting a comprehensive comparison of anatomical versus non-anatomical ACLR with regard to equally important outcomes such as failure rates and knee function. Therefore, the purpose of this systematic review was to compare both anatomical and non-anatomical ACLR in terms of clinical and functional outcomes, specifically assessing failure rates, measures of knee stability, as well as other clinical outcomes, with at least 2 years of follow-up after primary ACLR, while again using the AARSC for study categorisation. It was hypothesised that anatomical ACLR will have a higher failure rate, better knee stability outcomes, as well as superior clinical and functional outcomes compared with non-anatomical ACLR.

      Materials and methods

      The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and Revised Assessment of Multiple Systematic Reviews guidelines were used in the design of this study.
      • Moher D
      Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement (Chinese edition).
      ,
      • Kung J
      • Chiappelli F
      • Cajulis OO
      • et al.
      From systematic reviews to clinical recommendations for evidence-based health care: validation of revised assessment of multiple systematic reviews (R-AMSTAR) for grading of clinical relevance.
      The design and execution of this study included items such as a priori design, duplicate study selection and data extraction, comprehensive literature search, providing characteristics of the included studies, scientific quality assessment of the included studies, appropriate methods for combining study findings, assessment of publication bias and inclusion of the conflict of interests.
      • Moher D
      Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement (Chinese edition).
      ,
      • Kung J
      • Chiappelli F
      • Cajulis OO
      • et al.
      From systematic reviews to clinical recommendations for evidence-based health care: validation of revised assessment of multiple systematic reviews (R-AMSTAR) for grading of clinical relevance.

      Eligibility criteria

      The included studies met the following criteria: (1) original research articles, (2) level 1 randomised control trials (RCTs) or level 2 prospective studies, (3) articles in English language, (4) publication after 1 January 2000, (5) studies using autograft and (6) a minimum of 2 years' follow-up. The exclusion criteria were (1) multiligament knee reconstruction, (2) anterolateral complex injuries/repairs/reconstructions, (3) studies using allograft or hybrid graft, (4) artial tears treated with ACL augmentation, (5) non-surgical treatment studies and (6) cadaver/non-human studies.

      Data sources and search strategy

      Two reviewers searched three online databases (MEDLINE, Embase and PubMed) between 1 January 2000 and 24 October 2019 using a combination of medical subject heading and text terms encompassing “Anterior Cruciate Ligament Reconstruction (ACLR),“ “Surgery” and “Autograft” (online supplementary appendix A, table A4). Additionally, further studies were extracted following a full reference screen of the relevant articles.

      Study screening

      The studies were screened by two reviewers (YE and KN) independently and in duplicate in all stages. All inconsistencies were carried on to the next screening stage and were discussed between reviewers during the full-text stage.

      AARSC scoring and quality assessment of included studies

      Surgical techniques and descriptions from each article were screened independently and in duplicate using AARSC.
      • van Eck CF
      • Gravare-Silbernagel K
      • Samuelsson K
      • et al.
      Evidence to support the interpretation and use of the anatomic anterior cruciate ligament reconstruction checklist.
      A final score was denoted; studies with a minimum score of 8 were categorised as ‘anatomical’, and studies below a score of 8 or those using the TT technique for femoral tunnel drilling were categorised as ‘non-anatomical.‘
      The Cochrane risk of bias tool was used to assess the RCT publications (online supplementary appendix A, figure A1). Methodological Index for Non-Randomised Studies was also used to assess the quality of the level II prospective publications. The assessment tool contained 12 items, the last 4 being specifically for comparative studies. Items adequately reported were at low risk, and given a score of 2, items not reported represented a high risk and were given a score of 0; unclear items were given a score of 1. The maximum achievable score is 24.
      • Slim K
      • Nini E
      • Forestier D
      • et al.
      Methodological index for non-randomized studies (minors): development and validation of a new instrument.

      Interviewer agreement

      Cohen's kappa (κ) scores were calculated to determine the reviewer's agreement at each stage of the screening process. The kappa values of this study were all above the 0.6 κ value threshold, representing a substantial agreement between the reviewers.
      • McHugh ML
      Interrater reliability: the kappa statistic.

      Data abstraction

      Data were collected and recorded into predetermined tables independently by the reviewers (YE and KN) in Excel V.2016. The following information, if available, was extracted from the studies: primary author and year, study design, level of evidence, demographic information (ie, patient's age and number of men vs women), follow-up, surgical details (ie, method of femoral and tibial fixation, femoral drilling technique and graft type), failure rate, return to sport data (including rehabilitation time and number of patients who successfully returned to sports), meniscal and chondral lesions, knee stability measurements (ie, KT-1000 at Manual Maximum tension and pivot shift), subjective Lysholm, objective IKDC and Tegner activity level scores. Results of the Lachman test and subjective IKDC were inconsistently reported within the included studies and were therefore not extracted.

      Data analysis

      Studies that were not comparative did not qualify for the meta-analysis (and hence were not pooled) and were summarised narratively following guidelines provided in the Cochrane Handbook for Systematic Reviews.
      Descriptive analysis of data was collected using proportions and ranges, means and SDs for normally distributed data, and median and ranges for non-normally distributed data, if applicable.
      For comparative studies, a meta-analytical technique was used to synthesise the quantitative results, and the pooling of data was performed using RevMan. To compare the effects of treatments, the mean difference with 95% CIs was used for continuous data, and the risk ratio with 95% CIs was used for dichotomous variables. An a priori decision was made between reviewers that a minimum of three comparative trials would be required for the pooling of an outcome. Statistically significant difference was determined using a p value of <0.05. For studies not reporting the SD, the Cochrane Handbook for Systematic Reviews was used to estimate the SD.
      The studies were weighted based on the inverse variance, and pooling was done using a random-effects model. A sensitivity analysis was conducted for studies that had a high heterogeneity (I2 of ~65%) by removing each study consecutively.

      Results

      Study characteristics

      The literature search yielded 1700 unique citations, of which 36 were included in this study (figure 1). Fourteen studies were categorised as anatomical; 17 were categorised as non-anatomical; and five were categorised as both anatomical and non-anatomical (table 1). The AARSC scoring for all the anatomical studies was reported in online supplementary appendix A, table A3).
      Figure thumbnail gr1
      Figure 1Preferred Reporting Items for Systematic Reviews and Meta-Analyses chart of the included studies.
      Table 1Study characteristics of the included literature
      Study (year)Level of evidence (study purpose)CountryPatients (n)Lost to follow-up (n)Age (years)Gender (male/female)Follow-up time (months)Minor score
      AN
      Xiang (2019)
      • Xiang X
      • Qu Z
      • Sun H
      • et al.
      Single-tunnel anatomic double-bundle anterior cruciate ligament reconstruction has the same effectiveness as double femoral, double tibial tunnel: a prospective randomized study.
      I (single tunnel vs double femoral, double-tibial tunnel)China58031.0 (18–40)45/1336
      Zhang (2019)
      • Zhang Q
      • Yang Y
      • Li J
      • et al.
      Functional double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts with preserved insertions is an effective treatment for tibiofemoral instability.
      II (SB vs functional DB)China2813626.897/5928.2 (26–31)20
      Järvelä (2017)
      • Järvelä S
      • Kiekara T
      • Suomalainen P
      • et al.
      Double-Bundle versus Single-Bundle anterior cruciate ligament reconstruction: a prospective randomized study with 10-year results.
      I (DB with bioabsorbable screw fixation vs SB with bioabsorbable screw fixation vs SB with metallic screw fixation)Finland90933±961/29122.4
      Karikis (2016)
      • Karikis I
      • Desai N
      • Sernert N
      • et al.
      Comparison of anatomic double- and Single-Bundle techniques for anterior cruciate ligament reconstruction using hamstring tendon autografts: a prospective randomized study with 5-year clinical and radiographic follow-up.
      I (DB vs SB)Sweden1031527 (18–52)72/3364 (55–75)
      Liu (2016)
      • Liu Y
      • Cui G
      • Yan H
      • et al.
      Comparison between single- and Double-Bundle anterior cruciate ligament reconstruction with 6- to 8-Stranded hamstring autograft.
      I (DB vs SB)China80027.7 (16–47)66/1480 (75–86)
      Thompson (2016)
      • Thompson SM
      • Salmon LJ
      • Waller A
      • et al.
      Twenty-Year outcome of a longitudinal prospective evaluation of isolated endoscopic anterior cruciate ligament reconstruction with Patellar tendon or hamstring autograft.
      II (PT vs HS)Australia180124.5 (13–52)95/8524019
      Ibrahim (2015)
      • Ibrahim SAR
      • Abdul Ghafar S
      • Marwan Y
      • et al.
      Intratunnel versus extratunnel autologous hamstring double-bundle graft for anterior cruciate ligament reconstruction: a comparison of 2 femoral fixation procedures.
      II (intratunnel vs extratunnel for femoral fixation)Kuwait70427 (21–34)66/030 (25–39)
      Gobbi (2012)
      • Gobbi A
      • Mahajan V
      • Karnatzikos G
      • et al.
      Single- versus double-bundle ACL reconstruction: is there any difference in stability and function at 3-year followup?.
      II (SB vs DB)Italy60030.4 (2.4)33/2736.2 (36–60)21
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Individualized anterior cruciate ligament surgery: a prospective study comparing anatomic single- and double-bundle reconstruction.
      II (SB vs DB)Slovenia94026.7 (16–48)NR30.1 (26–34)23
      Suomalainen (2013)
      • Suomalainen P
      • Moisala A-S
      • Paakkala A
      • et al.
      Comparison of tunnel placements and clinical results of single-bundle anterior cruciate ligament reconstruction before and after starting the use of double-bundle technique.
      II (SB vs DB)Finland5043134/1626.518
      Wipfler (2011)
      • Wipfler B
      • Donner S
      • Zechmann CM
      • et al.
      Anterior cruciate ligament reconstruction using Patellar tendon versus hamstring tendon: a prospective comparative study with 9-year follow-up.
      II (PT vs HS)Germany62831.8 (25–64)33/21105.6 (88.9–120)22
      Aglietti (2010)
      • Aglietti P
      • Giron F
      • Losco M
      • et al.
      Comparison between single-and double-bundle anterior cruciate ligament reconstruction: a prospective, randomized, single-blinded clinical trial.
      I (SB vs DB)Italy70028 (16–40)53/1724
      Jagodzinski (2010)
      • Jagodzinski M
      • Geiges B
      • von Falck C
      • et al.
      Biodegradable screw versus a Press-Fit bone plug fixation for hamstring anterior cruciate ligament reconstruction.
      I (interference screw vs press-fit fixation with a porous bone cylinder)Germany20027.8±8.817/324
      Stener (2010)
      • Stener S
      • Ejerhed L
      • Sernert N
      • et al.
      A long-term, prospective, randomized study comparing biodegradable and metal interference screws in anterior cruciate ligament reconstruction surgery: radiographic results and clinical outcome.
      I (metal vs biodegradable interference screw)Sweden771326.5 (16–46)47/1797.5 (78–120)
      NAN
      Elveos (2018)
      • Elveos MM
      • Drogset JO
      • Engebretsen L
      • et al.
      Anterior cruciate ligament reconstruction using a Bone–Patellar Tendon–Bone graft with and without a ligament augmentation device: a 25-year follow-up of a prospective randomized controlled trial.
      I (PT vs PT with LAD)Norway51325 (16–42055/45300
      Sajovic (2018)
      • Sajovic M
      • Stropnik D
      • Skaza K
      Long-Term comparison of semitendinosus and gracilis tendon versus Patellar tendon autografts for anterior cruciate ligament reconstruction: a 17-year follow-up of a randomized controlled trial.
      II (PT vs HS)Slovenia64527.028/20204
      Björnsson (2016)
      • Björnsson H
      • Samuelsson K
      • Sundemo D
      • et al.
      A randomized controlled trial with mean 16-year follow-up comparing hamstring and Patellar tendon autografts in anterior cruciate ligament reconstruction.
      II (PT vs HS)Sweden1924527.4 (14–59)52/95196.3
      Tsoukas (2016)
      • Tsoukas D
      • Fotopoulos V
      • Basdekis G
      • et al.
      No difference in osteoarthritis after surgical and non-surgical treatment of ACL-injured knees after 10 years.
      II (HS vs non-operative)Greece17021 (29–36)17/0121.2 (120–132)
      Webster (2016)
      • Webster KE
      • Feller JA
      • Hartnett N
      • et al.
      Comparison of Patellar tendon and hamstring tendon anterior cruciate ligament reconstruction.
      I (PT vs HS)Australia651826.336/11183
      Kautzner (2015)
      • Kautzner J
      • Kos P
      • Hanus M
      • et al.
      A comparison of ACL reconstruction using Patellar tendon versus hamstring autograft in female patients: a prospective randomised study.
      I (PT vs HS)Czech Republic150326 (17–47)0/14724
      Holm (2012)
      • Holm I
      • Øiestad BE
      • Risberg MA
      • et al.
      No differences in prevalence of osteoarthritis or function after open versus endoscopic technique for anterior cruciate ligament reconstruction: 12-year follow-up report of a randomized controlled trial.
      II (open vs arthroscopic)Norway34627±9.4NR140.4±6.0
      Kondo (2011)
      • Kondo E
      • Merican AM
      • Yasuda K
      • et al.
      Biomechanical comparison of anatomic Double-Bundle, anatomic Single-Bundle, and Nonanatomic Single-Bundle anterior cruciate ligament reconstructions.
      II (ECL vs ECL-BTB)Japan53624.5 (15–45)25/212424
      Noh (2011)
      • Noh JH
      • Yang BG
      • Roh YH
      • et al.
      Anterior cruciate ligament reconstruction using 4-strand hamstring autograft: conventional single-bundle technique versus oval-footprint technique.
      II (SB vs oval footprint ACLR)South Korea74428.2 (19–47)45/2932.422
      Tohyama (2011)
      • Tohyama H
      • Kondo E
      • Hayashi R
      • et al.
      Gender-Based differences in outcome after anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.
      II (male vs female)Japan1745226.5 (13–52)73/4933.8 (24–60)19
      Felmet (2010)
      • Felmet G
      Implant-free press-fit fixation for bone–patellar tendon–bone ACL reconstruction: 10-year results.
      II (implant-free press-fit fixation with PT)Germany1893338 (15–58)91/57122.4 (115.2–129.6)19
      Kondo (2008)
      • Kondo E
      • Yasuda K
      • Azuma H
      • et al.
      Prospective clinical comparisons of anatomic double-bundle versus single-bundle anterior cruciate ligament reconstruction procedures in 328 consecutive patients.
      II (SB vs DB)Japan3673926.0 (13–57)186/14224–6424
      Ibrahim (2005)
      • Ibrahim SA-R
      • Al-Kussary IM
      • Al-Misfer ARK
      • et al.
      Clinical evaluation of arthroscopically assisted anterior cruciate ligament reconstruction: Patellar tendon versus gracilis and semitendinosus autograft.
      I (PT vs HS)Kuwait1108522.3 (17–34)85/081 (60–69)
      Aglietti (2004)
      • Aglietti P
      • Giron F
      • Buzzi R
      • et al.
      Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial.
      I (PT vs HS)Italy120025 (15–39)NR24
      Shaieb (2002)
      • Shaieb MD
      • Kan DM
      • Chang SK
      • et al.
      A prospective randomized comparison of Patellar tendon versus semitendinosus and gracilis tendon autografts for anterior cruciate ligament reconstruction.
      I (PT vs HS)USA821230.947/2333 (24–45)
      Anderson (2001)
      • Anderson AF
      • Snyder RB
      • Lipscomb AB
      Anterior cruciate ligament reconstruction. A prospective randomized study of three surgical methods.
      I (PT vs HS)USA70221.9 (14–44)46/2435.3
      Aune (2001)
      • Aune AK
      • Holm I
      • Risberg MA
      • et al.
      Four-Strand hamstring tendon autograft compared with Patellar Tendon-Bone autograft for anterior cruciate ligament reconstruction.
      I (PT vs HS)Norway72826 (15–50)40/3224
      AN and NAN
      Mohtadi (2015 and 2016)
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      A randomized clinical trial comparing Patellar tendon, hamstring tendon, and Double-Bundle ACL reconstructions: patient-reported and clinical outcomes at a minimal 2-year follow-up.
      ,
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      Reruptures, Reinjuries, and revisions at a minimum 2-year follow-up: a randomized clinical trial comparing 3 graft types for ACL reconstruction.
      I (HS vs PT vs DB HS)Canada330 (AN 109, NAN 220)AN 2, NAN 628.5 (9.8)183/14724
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up.
      I (TT vs AN SB and DB)Slovenia293 (AN 221, NAN 80)AN 5, NAN 332.9 (16–74)171/11051.1 (39–63)
      Ibrahim (2009)
      • Ibrahim SAR
      • Hamido F
      • Al Misfer AK
      • et al.
      Anterior cruciate ligament reconstruction using autologous hamstring double bundle graft compared with single bundle procedures.
      I (AN DB vs SB using Endobutton vs SB using Rigidfix crosspin vs SB using bioabsorbable transfix screw)Kuwait218 (AN 50, NAN 168)18
      This study did not specify the number of patients who were lost to follow-up per group. ACLR, anterior cruciate ligament reconstruction; AN, anatomical; DB, double bundle; ECL, EndoButton CL; HS, hamstring tendon; LAD, ligament augmentation device; NAN, non-anatomical; NR, not reported; OI, outside-in; PT, patellar tendon; SB, single bundle; TT, transtibial.
      28 (21–33)218/029 (25–38)
      Aglietti (2007)
      • Aglietti P
      • Giron F
      • Cuomo P
      • et al.
      Single-And double-incision double-bundle ACL reconstruction.
      II (SB vs single-incision TT DB vs two-incision OI DB)Italy75 (AN 25, NAN 50)029 (<40)32/432423
      Data for age and follow-up time are displayed as mean and range or ±SD when available.
      Bold data indicate computed means from median.
      * This study did not specify the number of patients who were lost to follow-up per group.ACLR, anterior cruciate ligament reconstruction; AN, anatomical; DB, double bundle; ECL, EndoButton CL; HS, hamstring tendon; LAD, ligament augmentation device; NAN, non-anatomical; NR, not reported; OI, outside-in; PT, patellar tendon; SB, single bundle; TT, transtibial.
      A total of 3710 patients (1603 anatomical and 2107 non-anatomical), with an age range of 12–74 years and a follow-up range of 24–300 months (mean follow-up was 69.8 months in the anatomical group and 69.6 months in the non-anatomical group) were included in this study (table 1).

      Surgical characteristics

      Studies used either hamstring (2870 patients) or patellar tendon (840 patients) autograft (table 1). Within the anatomical group, 13 studies used the anteromedial (AM) portal technique for femoral tunnel drilling, and one used the OI technique (table 2). Within the non-anatomical group, 11 studies used the TT technique for femoral tunnel drilling; 1 used both the TT and AM portal techniques; 4 used the AM portal technique; and 1 study used the OI technique (table 2).
      Table 2Surgical details of included studies
      StudyGraft typeFemoral drilling techniqueFemoral fixationTibial fixationMeniscal injuries (lateral/medial)Chondral lesionsReturn to sport rehab time (months)
      AN
      Xiang (2019)
      • Xiang X
      • Qu Z
      • Sun H
      • et al.
      Single-tunnel anatomic double-bundle anterior cruciate ligament reconstruction has the same effectiveness as double femoral, double tibial tunnel: a prospective randomized study.
      HSAMBio absorbable IFSBio absorbable IFS0228
      Zhang (2019)
      • Zhang Q
      • Yang Y
      • Li J
      • et al.
      Functional double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts with preserved insertions is an effective treatment for tibiofemoral instability.
      HSAMCrosspinsIFS18/18283
      Järvelä (2017)
      • Järvelä S
      • Kiekara T
      • Suomalainen P
      • et al.
      Double-Bundle versus Single-Bundle anterior cruciate ligament reconstruction: a prospective randomized study with 10-year results.
      HSAMBioabsorbable or metal IFSBioabsorbable or metal IFS27/30NR6
      Karikis (2016)
      • Karikis I
      • Desai N
      • Sernert N
      • et al.
      Comparison of anatomic double- and Single-Bundle techniques for anterior cruciate ligament reconstruction using hamstring tendon autografts: a prospective randomized study with 5-year clinical and radiographic follow-up.
      HSAMIFSIFS73
      This study included 73 meniscal and/or chondral lesions.
      This study included 73 meniscal and/or chondral lesions.
      6
      Liu (2016)
      • Liu Y
      • Cui G
      • Yan H
      • et al.
      Comparison between single- and Double-Bundle anterior cruciate ligament reconstruction with 6- to 8-Stranded hamstring autograft.
      HSAMBioabsorbable IFSStaple62328
      Thompson (2016)
      • Thompson SM
      • Salmon LJ
      • Waller A
      • et al.
      Twenty-Year outcome of a longitudinal prospective evaluation of isolated endoscopic anterior cruciate ligament reconstruction with Patellar tendon or hamstring autograft.
      PT and HSAMIFSIFS77/38NR6
      Ibrahim (2015)
      • Ibrahim SAR
      • Abdul Ghafar S
      • Marwan Y
      • et al.
      Intratunnel versus extratunnel autologous hamstring double-bundle graft for anterior cruciate ligament reconstruction: a comparison of 2 femoral fixation procedures.
      HSAMBioabsorbable pins, cortical buttonBioabsorbable IFS10/1656
      Gobbi (2012)
      • Gobbi A
      • Mahajan V
      • Karnatzikos G
      • et al.
      Single- versus double-bundle ACL reconstruction: is there any difference in stability and function at 3-year followup?.
      HSAMEndobuttonBioabsorbable IFS27136
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Individualized anterior cruciate ligament surgery: a prospective study comparing anatomic single- and double-bundle reconstruction.
      HSAMEndobuttonBioabsorbable IFS25279
      Suomalainen (2013)
      • Suomalainen P
      • Moisala A-S
      • Paakkala A
      • et al.
      Comparison of tunnel placements and clinical results of single-bundle anterior cruciate ligament reconstruction before and after starting the use of double-bundle technique.
      HSAMIFSIFSNRNRNR
      Wipfler (2011)
      • Wipfler B
      • Donner S
      • Zechmann CM
      • et al.
      Anterior cruciate ligament reconstruction using Patellar tendon versus hamstring tendon: a prospective comparative study with 9-year follow-up.
      PT and HSAMPress-fitBone bridge006
      Aglietti (2010)
      • Aglietti P
      • Giron F
      • Losco M
      • et al.
      Comparison between single-and double-bundle anterior cruciate ligament reconstruction: a prospective, randomized, single-blinded clinical trial.
      HSOIIFS and stapleBony or metallic bridge8/20NR4–5
      Jagodzinski (2010)
      • Jagodzinski M
      • Geiges B
      • von Falck C
      • et al.
      Biodegradable screw versus a Press-Fit bone plug fixation for hamstring anterior cruciate ligament reconstruction.
      HSAMCrosspinsIFS or bone block press fit3
      Included only treated meniscal/chondral injuries. AM, anteromedial; AN, anatomical; HS, hamstring tendon graft; IFS, interference screw; NAN, non-anatomical; NR, not reported; OI, out-in; PT, patellar tendon graft; TT, transtibial.
      NR6
      Stener (2010)
      • Stener S
      • Ejerhed L
      • Sernert N
      • et al.
      A long-term, prospective, randomized study comparing biodegradable and metal interference screws in anterior cruciate ligament reconstruction surgery: radiographic results and clinical outcome.
      HSAMBioabsorbable IFS or metal IFSBioabsorbable IFS or metal IFS35NR6
      NAN
      Elveos (2018)
      • Elveos MM
      • Drogset JO
      • Engebretsen L
      • et al.
      Anterior cruciate ligament reconstruction using a Bone–Patellar Tendon–Bone graft with and without a ligament augmentation device: a 25-year follow-up of a prospective randomized controlled trial.
      PTOIIFSIFS20
      Included only treated meniscal/chondral injuries. AM, anteromedial; AN, anatomical; HS, hamstring tendon graft; IFS, interference screw; NAN, non-anatomical; NR, not reported; OI, out-in; PT, patellar tendon graft; TT, transtibial.
      NR6
      Sajovic (2018)
      • Sajovic M
      • Stropnik D
      • Skaza K
      Long-Term comparison of semitendinosus and gracilis tendon versus Patellar tendon autografts for anterior cruciate ligament reconstruction: a 17-year follow-up of a randomized controlled trial.
      PT and HSAMMetal and bioabsorbable IFSBioabsorbable IFS33
      Included only treated meniscal/chondral injuries. AM, anteromedial; AN, anatomical; HS, hamstring tendon graft; IFS, interference screw; NAN, non-anatomical; NR, not reported; OI, out-in; PT, patellar tendon graft; TT, transtibial.
      NR6
      Björnsson (2016)
      • Björnsson H
      • Samuelsson K
      • Sundemo D
      • et al.
      A randomized controlled trial with mean 16-year follow-up comparing hamstring and Patellar tendon autografts in anterior cruciate ligament reconstruction.
      PT and HSTT or AMIFSIFS97496
      Tsoukas (2016)
      • Tsoukas D
      • Fotopoulos V
      • Basdekis G
      • et al.
      No difference in osteoarthritis after surgical and non-surgical treatment of ACL-injured knees after 10 years.
      HSAMEndobuttonBioabsorbable IFS006
      Webster (2016)
      • Webster KE
      • Feller JA
      • Hartnett N
      • et al.
      Comparison of Patellar tendon and hamstring tendon anterior cruciate ligament reconstruction.
      PT and HSTTEndobuttonIFS14/216NR
      Kautzner (2015)
      • Kautzner J
      • Kos P
      • Hanus M
      • et al.
      A comparison of ACL reconstruction using Patellar tendon versus hamstring autograft in female patients: a prospective randomised study.
      PT and HSTTCrosspinIFSNRNR3-6
      Holm (2012)
      • Holm I
      • Øiestad BE
      • Risberg MA
      • et al.
      No differences in prevalence of osteoarthritis or function after open versus endoscopic technique for anterior cruciate ligament reconstruction: 12-year follow-up report of a randomized controlled trial.
      PTTTMetal IFSMetal IFS16NR6
      Kondo (2011)
      • Kondo E
      • Merican AM
      • Yasuda K
      • et al.
      Biomechanical comparison of anatomic Double-Bundle, anatomic Single-Bundle, and Nonanatomic Single-Bundle anterior cruciate ligament reconstructions.
      HSTTCrosspinCrosspinsNRNR12
      Noh (2011)
      • Noh JH
      • Yang BG
      • Roh YH
      • et al.
      Anterior cruciate ligament reconstruction using 4-strand hamstring autograft: conventional single-bundle technique versus oval-footprint technique.
      HSTTEndobuttonStaples6/9NR6
      Tohyama (2011)
      • Tohyama H
      • Kondo E
      • Hayashi R
      • et al.
      Gender-Based differences in outcome after anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.
      HSTTEndobuttonStaples30/161512
      Felmet (2010)
      • Felmet G
      Implant-free press-fit fixation for bone–patellar tendon–bone ACL reconstruction: 10-year results.
      PTAMPress fitPress fit59/8173NR
      Kondo (2008)
      • Kondo E
      • Yasuda K
      • Azuma H
      • et al.
      Prospective clinical comparisons of anatomic double-bundle versus single-bundle anterior cruciate ligament reconstruction procedures in 328 consecutive patients.
      HSTTEndobuttonStaples106
      Included only treated meniscal/chondral injuries. AM, anteromedial; AN, anatomical; HS, hamstring tendon graft; IFS, interference screw; NAN, non-anatomical; NR, not reported; OI, out-in; PT, patellar tendon graft; TT, transtibial.
      NR12
      Ibrahim (2005)
      • Ibrahim SA-R
      • Al-Kussary IM
      • Al-Misfer ARK
      • et al.
      Clinical evaluation of arthroscopically assisted anterior cruciate ligament reconstruction: Patellar tendon versus gracilis and semitendinosus autograft.
      PT and HSTTIFS and EndobuttonIFS and Washer or screw10/20248
      Aglietti (2004)
      • Aglietti P
      • Giron F
      • Buzzi R
      • et al.
      Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial.
      PT and HSTTTunneloc screw or bone mulch screwIFS or WasherLoc device23/63NR6
      Shaieb (2002)
      • Shaieb MD
      • Kan DM
      • Chang SK
      • et al.
      A prospective randomized comparison of Patellar tendon versus semitendinosus and gracilis tendon autografts for anterior cruciate ligament reconstruction.
      PT and HSAMIFSIFS20/19176
      Anderson (2001)
      • Anderson AF
      • Snyder RB
      • Lipscomb AB
      Anterior cruciate ligament reconstruction. A prospective randomized study of three surgical methods.
      PT and HSTTStaplesNonabsorbable sutures and stitches29/27NR6–7
      Aune (2001)
      • Aune AK
      • Holm I
      • Risberg MA
      • et al.
      Four-Strand hamstring tendon autograft compared with Patellar Tendon-Bone autograft for anterior cruciate ligament reconstruction.
      PT and HSTTPost and washerIFS or post and washer27
      Included only treated meniscal/chondral injuries. AM, anteromedial; AN, anatomical; HS, hamstring tendon graft; IFS, interference screw; NAN, non-anatomical; NR, not reported; OI, out-in; PT, patellar tendon graft; TT, transtibial.
      4
      Included only treated meniscal/chondral injuries. AM, anteromedial; AN, anatomical; HS, hamstring tendon graft; IFS, interference screw; NAN, non-anatomical; NR, not reported; OI, out-in; PT, patellar tendon graft; TT, transtibial.
      6
      AN versus NAN
      Mohtadi (2015 and 2016)
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      A randomized clinical trial comparing Patellar tendon, hamstring tendon, and Double-Bundle ACL reconstructions: patient-reported and clinical outcomes at a minimal 2-year follow-up.
      ,
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      Reruptures, Reinjuries, and revisions at a minimum 2-year follow-up: a randomized clinical trial comparing 3 graft types for ACL reconstruction.
      PT and HSAM and TTEndobuttonBio absorbable IFS88/80 AN vs 169/152 NAN58 AN vs 107 NANNR
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up.
      HSAM and TTEndobuttonBio absorbable IFS51 AN vs 18 NAN16 AN vs 4 NAN9
      Ibrahim (2009)
      • Ibrahim SAR
      • Hamido F
      • Al Misfer AK
      • et al.
      Anterior cruciate ligament reconstruction using autologous hamstring double bundle graft compared with single bundle procedures.
      HSAM and TTEndobuttonBio absorbable IFS12/20 AN vs 30/56 NAN2 AN vs 4 NAN6
      Aglietti (2007)
      • Aglietti P
      • Giron F
      • Cuomo P
      • et al.
      Single-And double-incision double-bundle ACL reconstruction.
      HSTT and AMEndobutton or IFS and stapleWasherLoc or bony bridge6/9 AN vs 3/17 NANNR4
      Data reported as number of patients.
      * This study included 73 meniscal and/or chondral lesions.
      Included only treated meniscal/chondral injuries.AM, anteromedial; AN, anatomical; HS, hamstring tendon graft; IFS, interference screw; NAN, non-anatomical; NR, not reported; OI, out-in; PT, patellar tendon graft; TT, transtibial.

      Failure rate

      Of the studies reporting failure, the overall failure rate was 96/1470 (6.5%) (94 patients with graft rerupture and 2 patients with extension deficits) in the anatomical group and 131/1952 (6.7%) (117 patients with graft rerupture and 14 patients with extension/flexion deficits) in the non-anatomical group (table 3). The type of rerupture was described in 60 of the 94 failures in the anatomical group and in 67 of the 117 failures in the non-anatomical group. In the anatomical and non-anatomical groups, respectively, 37 of 60 (61.7%) vs 29 of 67 patients (43.3%) patients had a traumatic graft rupture, and 23 (38.3%) vs 38 (56.7%) had an atraumatic graft rupture (table 3 and figure 2). The pooled results of the comparative studies showed no statistically significant difference in the overall failure rate between the anatomical and the non-anatomical group (p=0.96) (figure 3).
      Table 3Failure rate, type and time of failure of the included studies
      StudyFailure rate (%)Failure type (n)Time of failure
      AN
      Xiang (2019)
      • Xiang X
      • Qu Z
      • Sun H
      • et al.
      Single-tunnel anatomic double-bundle anterior cruciate ligament reconstruction has the same effectiveness as double femoral, double tibial tunnel: a prospective randomized study.
      0/58 (0)
      Zhang (2019)
      • Zhang Q
      • Yang Y
      • Li J
      • et al.
      Functional double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts with preserved insertions is an effective treatment for tibiofemoral instability.
      1/156 (0.6)Traumatic rerupture (1)9 months
      Jarvela (2017)
      • Järvelä S
      • Kiekara T
      • Suomalainen P
      • et al.
      Double-Bundle versus Single-Bundle anterior cruciate ligament reconstruction: a prospective randomized study with 10-year results.
      11/81 (13.6)Traumatic rerupture (11)2–5 years
      Karikis (2016)
      • Karikis I
      • Desai N
      • Sernert N
      • et al.
      Comparison of anatomic double- and Single-Bundle techniques for anterior cruciate ligament reconstruction using hamstring tendon autografts: a prospective randomized study with 5-year clinical and radiographic follow-up.
      0/87 (0)
      Liu (2016)
      • Liu Y
      • Cui G
      • Yan H
      • et al.
      Comparison between single- and Double-Bundle anterior cruciate ligament reconstruction with 6- to 8-Stranded hamstring autograft.
      4/78 (5.1)Traumatic rerupture (2)80 months
      2° extension deficit (2)
      Thompson (2016)
      • Thompson SM
      • Salmon LJ
      • Waller A
      • et al.
      Twenty-Year outcome of a longitudinal prospective evaluation of isolated endoscopic anterior cruciate ligament reconstruction with Patellar tendon or hamstring autograft.
      25/180 (13.9)Rerupture (25)NR
      Ibrahim (2015)
      • Ibrahim SAR
      • Abdul Ghafar S
      • Marwan Y
      • et al.
      Intratunnel versus extratunnel autologous hamstring double-bundle graft for anterior cruciate ligament reconstruction: a comparison of 2 femoral fixation procedures.
      0/66 (0)
      Gobbi (2012)
      • Gobbi A
      • Mahajan V
      • Karnatzikos G
      • et al.
      Single- versus double-bundle ACL reconstruction: is there any difference in stability and function at 3-year followup?.
      0/60 (0)
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Individualized anterior cruciate ligament surgery: a prospective study comparing anatomic single- and double-bundle reconstruction.
      2/94 (2.1)Traumatic rerupture (2)30 months
      Suomalainen (2013)
      • Suomalainen P
      • Moisala A-S
      • Paakkala A
      • et al.
      Comparison of tunnel placements and clinical results of single-bundle anterior cruciate ligament reconstruction before and after starting the use of double-bundle technique.
      4/46 (8.7)Rerupture (4)2 years
      Wipfler (2011)
      • Wipfler B
      • Donner S
      • Zechmann CM
      • et al.
      Anterior cruciate ligament reconstruction using Patellar tendon versus hamstring tendon: a prospective comparative study with 9-year follow-up.
      This study reported mean time of failure between surgery and rerupture.
      6/54 (11.1)Traumatic rerupture (4)2.4 years
      Rerupture (2)
      Aglietti (2010)
      • Aglietti P
      • Giron F
      • Losco M
      • et al.
      Comparison between single-and double-bundle anterior cruciate ligament reconstruction: a prospective, randomized, single-blinded clinical trial.
      4/70 (5.7)Traumatic rerupture (1)1–2 years
      Atraumatic rerupture (3)
      Jagodzinski (2010)
      • Jagodzinski M
      • Geiges B
      • von Falck C
      • et al.
      Biodegradable screw versus a Press-Fit bone plug fixation for hamstring anterior cruciate ligament reconstruction.
      1/20 (5)Traumatic rerupture (1)5 months
      Stener (2010)
      • Stener S
      • Ejerhed L
      • Sernert N
      • et al.
      A long-term, prospective, randomized study comparing biodegradable and metal interference screws in anterior cruciate ligament reconstruction surgery: radiographic results and clinical outcome.
      3/64 (4.7)Traumatic rerupture (3)NR
      NAN
      Elveos (2018)
      • Elveos MM
      • Drogset JO
      • Engebretsen L
      • et al.
      Anterior cruciate ligament reconstruction using a Bone–Patellar Tendon–Bone graft with and without a ligament augmentation device: a 25-year follow-up of a prospective randomized controlled trial.
      16/48 (33.3)Rerupture (12)8 years (five patients), NR (seven patients)
      ≥5° extension deficit (2)
      ≥10° flexion deficit (2)
      Sajovic (2018)
      • Sajovic M
      • Stropnik D
      • Skaza K
      Long-Term comparison of semitendinosus and gracilis tendon versus Patellar tendon autografts for anterior cruciate ligament reconstruction: a 17-year follow-up of a randomized controlled trial.
      6/54 (11.1)Rerupture (6)NR
      • Chalmers PN
      • Mall NA
      • Moric M
      • et al.
      Does ACL reconstruction alter natural history?: A systematic literature review of long-term outcomes.


      11 years
      • Allen MM
      • Pareek A
      • Krych AJ
      • et al.
      Are female soccer players at an increased risk of second anterior cruciate ligament injury compared with their athletic Peers?.
      Björnsson (2016)
      • Björnsson H
      • Samuelsson K
      • Sundemo D
      • et al.
      A randomized controlled trial with mean 16-year follow-up comparing hamstring and Patellar tendon autografts in anterior cruciate ligament reconstruction.
      12/147 (8.2)Rerupture (11)NR
      Extension deficit (1)
      Tsoukas (2016)
      • Tsoukas D
      • Fotopoulos V
      • Basdekis G
      • et al.
      No difference in osteoarthritis after surgical and non-surgical treatment of ACL-injured knees after 10 years.
      0/17 (0)
      Webster (2016)
      • Webster KE
      • Feller JA
      • Hartnett N
      • et al.
      Comparison of Patellar tendon and hamstring tendon anterior cruciate ligament reconstruction.
      4/47 (8.5)Traumatic rerupture (1)6 months
      Rerupture (2)t3-15 years
      Kautzner et al (2015)
      • Kautzner J
      • Kos P
      • Hanus M
      • et al.
      A comparison of ACL reconstruction using Patellar tendon versus hamstring autograft in female patients: a prospective randomised study.
      7/147 (4.8)Traumatic rerupture (4)1-2 years
      Atraumatic rerupture (2)
      10° extension deficit (1)
      Holm (2012)
      • Holm I
      • Øiestad BE
      • Risberg MA
      • et al.
      No differences in prevalence of osteoarthritis or function after open versus endoscopic technique for anterior cruciate ligament reconstruction: 12-year follow-up report of a randomized controlled trial.
      7/28 (25.0)Rerupture (7)12 years
      Kondo (2011)
      • Kondo E
      • Merican AM
      • Yasuda K
      • et al.
      Biomechanical comparison of anatomic Double-Bundle, anatomic Single-Bundle, and Nonanatomic Single-Bundle anterior cruciate ligament reconstructions.
      1/47 (2.1)Traumatic rerupture (1)NR
      Noh (2011)
      • Noh JH
      • Yang BG
      • Roh YH
      • et al.
      Anterior cruciate ligament reconstruction using 4-strand hamstring autograft: conventional single-bundle technique versus oval-footprint technique.
      2/74 (2.7)Traumatic rerupture (1)NR
      5° extension deficit (1)
      Tohyama (2011)
      • Tohyama H
      • Kondo E
      • Hayashi R
      • et al.
      Gender-Based differences in outcome after anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.
      0/122 (0)
      Felmet (2010)
      • Felmet G
      Implant-free press-fit fixation for bone–patellar tendon–bone ACL reconstruction: 10-year results.
      6/189 (3.2)Rerupture (6)NR
      Kondo (2008)
      • Kondo E
      • Yasuda K
      • Azuma H
      • et al.
      Prospective clinical comparisons of anatomic double-bundle versus single-bundle anterior cruciate ligament reconstruction procedures in 328 consecutive patients.
      2/398 (0.5)Rerupture (2)NR
      Ibrahim (2005)
      • Ibrahim SA-R
      • Al-Kussary IM
      • Al-Misfer ARK
      • et al.
      Clinical evaluation of arthroscopically assisted anterior cruciate ligament reconstruction: Patellar tendon versus gracilis and semitendinosus autograft.
      0/85 (0)
      Aglietti (2004)
      • Aglietti P
      • Giron F
      • Buzzi R
      • et al.
      Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial.
      NRNR
      Shaieb (2002)
      • Shaieb MD
      • Kan DM
      • Chang SK
      • et al.
      A prospective randomized comparison of Patellar tendon versus semitendinosus and gracilis tendon autografts for anterior cruciate ligament reconstruction.
      4/70 (5.7)Traumatic rerupture (3)1-2 years
      Atraumatic rerupture (1)
      Anderson (2001)
      • Anderson AF
      • Snyder RB
      • Lipscomb AB
      Anterior cruciate ligament reconstruction. A prospective randomized study of three surgical methods.
      7/68 (10.3)3°–5° extension deficit (4)NR
      6°–10° flexion deficit (2)
      17° flexion deficit (1)
      Aune (2001)
      • Aune AK
      • Holm I
      • Risberg MA
      • et al.
      Four-Strand hamstring tendon autograft compared with Patellar Tendon-Bone autograft for anterior cruciate ligament reconstruction.
      3/61 (4.9)Traumatic rerupture (3)NR
      AN and NAN
      Mohtadi (2015 and 2016)
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      A randomized clinical trial comparing Patellar tendon, hamstring tendon, and Double-Bundle ACL reconstructions: patient-reported and clinical outcomes at a minimal 2-year follow-up.
      ,
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      Reruptures, Reinjuries, and revisions at a minimum 2-year follow-up: a randomized clinical trial comparing 3 graft types for ACL reconstruction.
      In this study, 17 of 26 traumatic failures, were complete traumatic failures that occurred at a mean of 18.3 months. Four patients in the anatomical group and three patients in the non-anatomical group had a traumatic failure before 12 months postoperatively. ‡In this study, the traumatic failure was reported at 6 months only. AN, anatomical; NAN, non-anatomical; NR, not reported.
      AN 31/110 (28.2)Traumatic rerupture (11)
      Atraumatic rerupture (20)
      NAN 48/220 (21.8)Traumatic rerupture (15)
      Atraumatic rerupture (33)
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up.
      AN 3/221 (1.4)Rerupture (3)NR
      NAN 3/80 (3.8)Rerupture (3)NR
      Ibrahim (2009)
      • Ibrahim SAR
      • Hamido F
      • Al Misfer AK
      • et al.
      Anterior cruciate ligament reconstruction using autologous hamstring double bundle graft compared with single bundle procedures.
      NR
      Aglietti (2007)
      • Aglietti P
      • Giron F
      • Cuomo P
      • et al.
      Single-And double-incision double-bundle ACL reconstruction.
      AN 1/25 (4)Traumatic rerupture (1)NR
      NAN 3/50 (6)Traumatic rerupture (1)
      Atraumatic rerupture (2)
      * This study reported mean time of failure between surgery and rerupture.
      In this study, 17 of 26 traumatic failures, were complete traumatic failures that occurred at a mean of 18.3 months. Four patients in the anatomical group and three patients in the non-anatomical group had a traumatic failure before 12 months postoperatively.‡In this study, the traumatic failure was reported at 6 months only.AN, anatomical; NAN, non-anatomical; NR, not reported.
      Figure thumbnail gr2
      Figure 2Failure rate types and proportions between the anatomical group versus the non-anatomical group.
      Figure thumbnail gr3
      Figure 3Pooled comparison between anatomic and non-anatomic anterior cruciate ligament reconstructions in the failure rate. IV, inverse variance

      Knee stability tests: pivot shift and KT-1000

      Within the anatomical group, 995 of 1252 (79.5%) patients had a negative pivot-shift test result, while 1160 of 1611 (72.0%) non-anatomical patients had a negative pivot-shift test result (table 4). The pooled results of the comparative studies indicated a statistically significant higher number of patients with a positive pivot shift in the non-anatomical group (p=0.03) (figure 4A). To assess the stability of the results within the pooled estimates, a sensitivity analysis was performed by removing one study at a time from the analysis. Mohtadi et al
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      A randomized clinical trial comparing Patellar tendon, hamstring tendon, and Double-Bundle ACL reconstructions: patient-reported and clinical outcomes at a minimal 2-year follow-up.
      increased the heterogeneity of the pooled results for negative pivot shift to 94% (figure 4A). The pooled results of the comparative studies following the removal of Mohtadi et al
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      A randomized clinical trial comparing Patellar tendon, hamstring tendon, and Double-Bundle ACL reconstructions: patient-reported and clinical outcomes at a minimal 2-year follow-up.
      still indicated a statistically significant higher number of patients with a positive pivot shift in the non-anatomical group (p=0.0005) and an I2=60% (figure 4B).
      Table 4Pivot-shift and KT-1000 results of the non-comparative studies
      StudyKT-1000 (mm)Negative pivot-shift test, n (%)
      AN
      Xiang (2019)
      • Xiang X
      • Qu Z
      • Sun H
      • et al.
      Single-tunnel anatomic double-bundle anterior cruciate ligament reconstruction has the same effectiveness as double femoral, double tibial tunnel: a prospective randomized study.
      1.7±1.453/58 (91.4)
      Zhang (2019)
      • Zhang Q
      • Yang Y
      • Li J
      • et al.
      Functional double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts with preserved insertions is an effective treatment for tibiofemoral instability.
      NR123/156 (78.8)
      Jarvela (2017)
      • Järvelä S
      • Kiekara T
      • Suomalainen P
      • et al.
      Double-Bundle versus Single-Bundle anterior cruciate ligament reconstruction: a prospective randomized study with 10-year results.
      NR69/70 (98.6)
      Karikis (2016)
      • Karikis I
      • Desai N
      • Sernert N
      • et al.
      Comparison of anatomic double- and Single-Bundle techniques for anterior cruciate ligament reconstruction using hamstring tendon autografts: a prospective randomized study with 5-year clinical and radiographic follow-up.
      2.2±2.770/87 (80.5)
      Liu (2016)
      • Liu Y
      • Cui G
      • Yan H
      • et al.
      Comparison between single- and Double-Bundle anterior cruciate ligament reconstruction with 6- to 8-Stranded hamstring autograft.
      NR45/66 (68.2)
      Thompson (2016)
      • Thompson SM
      • Salmon LJ
      • Waller A
      • et al.
      Twenty-Year outcome of a longitudinal prospective evaluation of isolated endoscopic anterior cruciate ligament reconstruction with Patellar tendon or hamstring autograft.
      1.3±1.786/92 (93.4)
      Ibrahim (2014)
      • Ibrahim SAR
      • Abdul Ghafar S
      • Marwan Y
      • et al.
      Intratunnel versus extratunnel autologous hamstring double-bundle graft for anterior cruciate ligament reconstruction: a comparison of 2 femoral fixation procedures.
      NR53/66 (80.3)
      Gobbi (2012)
      • Gobbi A
      • Mahajan V
      • Karnatzikos G
      • et al.
      Single- versus double-bundle ACL reconstruction: is there any difference in stability and function at 3-year followup?.
      NR51/60 (85)
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Individualized anterior cruciate ligament surgery: a prospective study comparing anatomic single- and double-bundle reconstruction.
      1.5±0.985/94 (89.4)
      Suomalainen (2013)
      • Suomalainen P
      • Moisala A-S
      • Paakkala A
      • et al.
      Comparison of tunnel placements and clinical results of single-bundle anterior cruciate ligament reconstruction before and after starting the use of double-bundle technique.
      NR27/42 (64.3)
      Wipfler (2011)
      • Wipfler B
      • Donner S
      • Zechmann CM
      • et al.
      Anterior cruciate ligament reconstruction using Patellar tendon versus hamstring tendon: a prospective comparative study with 9-year follow-up.
      0.8NR
      Aglietti (2010)
      • Aglietti P
      • Giron F
      • Losco M
      • et al.
      Comparison between single-and double-bundle anterior cruciate ligament reconstruction: a prospective, randomized, single-blinded clinical trial.
      1.8±1.452/70 (74.3)
      Jagodzinski (2010)
      • Jagodzinski M
      • Geiges B
      • von Falck C
      • et al.
      Biodegradable screw versus a Press-Fit bone plug fixation for hamstring anterior cruciate ligament reconstruction.
      1.6±1.6NR
      Stener (2010)
      • Stener S
      • Ejerhed L
      • Sernert N
      • et al.
      A long-term, prospective, randomized study comparing biodegradable and metal interference screws in anterior cruciate ligament reconstruction surgery: radiographic results and clinical outcome.
      NRNR
      NAN
      Elveos (2018)
      • Elveos MM
      • Drogset JO
      • Engebretsen L
      • et al.
      Anterior cruciate ligament reconstruction using a Bone–Patellar Tendon–Bone graft with and without a ligament augmentation device: a 25-year follow-up of a prospective randomized controlled trial.
      2 (-5–5)20/22 (90.9)
      This study combined grade 0 and 1 pivot-shift results. AN, anatomical; NAN, non-anatomical; NR, not reported.
      Sajovic (2018)
      • Sajovic M
      • Stropnik D
      • Skaza K
      Long-Term comparison of semitendinosus and gracilis tendon versus Patellar tendon autografts for anterior cruciate ligament reconstruction: a 17-year follow-up of a randomized controlled trial.
      1.8±1.937/48 (77.1)
      Björnsson (2016)
      • Björnsson H
      • Samuelsson K
      • Sundemo D
      • et al.
      A randomized controlled trial with mean 16-year follow-up comparing hamstring and Patellar tendon autografts in anterior cruciate ligament reconstruction.
      1.5±2.992/147 (62.6)
      Tsoukas (2016)
      • Tsoukas D
      • Fotopoulos V
      • Basdekis G
      • et al.
      No difference in osteoarthritis after surgical and non-surgical treatment of ACL-injured knees after 10 years.
      1.2±0.2NR
      Webster (2016)
      • Webster KE
      • Feller JA
      • Hartnett N
      • et al.
      Comparison of Patellar tendon and hamstring tendon anterior cruciate ligament reconstruction.
      NRNR
      Kautzner 2015)
      • Kautzner J
      • Kos P
      • Hanus M
      • et al.
      A comparison of ACL reconstruction using Patellar tendon versus hamstring autograft in female patients: a prospective randomised study.
      NRNR
      Holm (2012)
      • Holm I
      • Øiestad BE
      • Risberg MA
      • et al.
      No differences in prevalence of osteoarthritis or function after open versus endoscopic technique for anterior cruciate ligament reconstruction: 12-year follow-up report of a randomized controlled trial.
      1.4±2.9NR
      Kondo (2011)
      • Kondo E
      • Merican AM
      • Yasuda K
      • et al.
      Biomechanical comparison of anatomic Double-Bundle, anatomic Single-Bundle, and Nonanatomic Single-Bundle anterior cruciate ligament reconstructions.
      1.2±1.535/46 (76.1)
      Noh (2011)
      • Noh JH
      • Yang BG
      • Roh YH
      • et al.
      Anterior cruciate ligament reconstruction using 4-strand hamstring autograft: conventional single-bundle technique versus oval-footprint technique.
      NR62/70 (88.6)
      Tohyama (2011)
      • Tohyama H
      • Kondo E
      • Hayashi R
      • et al.
      Gender-Based differences in outcome after anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.
      NR100/122 (82.0)
      Felmet (2010)
      • Felmet G
      Implant-free press-fit fixation for bone–patellar tendon–bone ACL reconstruction: 10-year results.
      NR133/138 (96.4)
      Kondo (2008)
      • Kondo E
      • Yasuda K
      • Azuma H
      • et al.
      Prospective clinical comparisons of anatomic double-bundle versus single-bundle anterior cruciate ligament reconstruction procedures in 328 consecutive patients.
      NR219/328 (66.8)
      Ibrahim (2005)
      • Ibrahim SA-R
      • Al-Kussary IM
      • Al-Misfer ARK
      • et al.
      Clinical evaluation of arthroscopically assisted anterior cruciate ligament reconstruction: Patellar tendon versus gracilis and semitendinosus autograft.
      NR72/85 (84.7)
      Aglietti (2004)
      • Aglietti P
      • Giron F
      • Buzzi R
      • et al.
      Anterior cruciate ligament reconstruction: bone-patellar tendon-bone compared with double semitendinosus and gracilis tendon grafts. A prospective, randomized clinical trial.
      2.199/120 (82.5)
      Shaieb (2002)
      • Shaieb MD
      • Kan DM
      • Chang SK
      • et al.
      A prospective randomized comparison of Patellar tendon versus semitendinosus and gracilis tendon autografts for anterior cruciate ligament reconstruction.
      2.057/66 (86.4)
      Anderson (2001)
      • Anderson AF
      • Snyder RB
      • Lipscomb AB
      Anterior cruciate ligament reconstruction. A prospective randomized study of three surgical methods.
      NR46/66 (69.7)
      Aune (2001)
      • Aune AK
      • Holm I
      • Risberg MA
      • et al.
      Four-Strand hamstring tendon autograft compared with Patellar Tendon-Bone autograft for anterior cruciate ligament reconstruction.
      2.7±2.1NR
      AN and NAN
      Mohtadi (2015 and 2016)
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      A randomized clinical trial comparing Patellar tendon, hamstring tendon, and Double-Bundle ACL reconstructions: patient-reported and clinical outcomes at a minimal 2-year follow-up.
      ,
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      Reruptures, Reinjuries, and revisions at a minimum 2-year follow-up: a randomized clinical trial comparing 3 graft types for ACL reconstruction.
      NRAN 38/107 (35.5)
      NAN 64/206 (31.1)
      Hussein (2012)
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up.
      AN 1.5±0.9AN 174/209 (83.3)
      NAN 2.0±0.9NAN 30/72 (41.7)
      Ibrahim (2009)
      • Ibrahim SAR
      • Hamido F
      • Al Misfer AK
      • et al.
      Anterior cruciate ligament reconstruction using autologous hamstring double bundle graft compared with single bundle procedures.
      NRAN 48/50 (96)
      NAN 65/150 (43.0)
      Aglietti (2007)
      • Aglietti P
      • Giron F
      • Cuomo P
      • et al.
      Single-And double-incision double-bundle ACL reconstruction.
      NRAN 21/25 (84)
      NAN 33/50 (66.0)
      * This study combined grade 0 and 1 pivot-shift results.AN, anatomical; NAN, non-anatomical; NR, not reported.
      Figure thumbnail gr4
      Figure 4(A) Pooled comparison between anatomic and non-anatomic anterior cruciate ligament reconstructions in the number of patients with a positive pivot shift test. IV represents inverse variance; df represents degrees of freedom. (B) This figure represents a sensitivity analysis after the removal of Mohtadi 2015, 2016 article.
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      A randomized clinical trial comparing Patellar tendon, hamstring tendon, and Double-Bundle ACL reconstructions: patient-reported and clinical outcomes at a minimal 2-year follow-up.
      ,
      • Mohtadi N
      • Chan D
      • Barber R
      • et al.
      Reruptures, Reinjuries, and revisions at a minimum 2-year follow-up: a randomized clinical trial comparing 3 graft types for ACL reconstruction.
      IV, inverse variance.
      KT-1000 scores were inconsistently reported across the studies (table 4).

      Lysholm, Tegner and objective IKDC scores

      The mean results of the subjective Lysholm score ranged from 82.8 to 95.0 and from 80.2 to 97.5 in the anatomical and non-anatomical groups, respectively. Tegner activity level scores were inconsistently reported across the studies (online supplementary appendix A, table A1). Six hundred eighty-eight of 744 patients (92.5%) and 995/1095 (90.9%) patients in the anatomical and non-anatomical groups, respectively, had either grade A or B objective IKDC rating (online supplementary appendix A, table A1). The pooled results of the comparative studies showed no statistically significant difference in objective IKDC rating between the anatomical and the non-anatomical groups (p=0.62) (figure 5).
      Figure thumbnail gr5
      Figure 5Pooled comparison between anatomical and non-anatomical anterior cruciate ligament reconstructions in the number of patients with grade C or D objective International Knee Documentation Committee scores. IV, inverse variance.

      Discussion

      Despite the similar overall failure rate between surgical techniques, the most important finding of this systematic review and meta-analysis is a higher rate of traumatic failure with anatomical ACLR and, inversely, atraumatic failure with non-anatomical ACLR. Secondarily, anatomical ACLR resulted in superior knee stability, as measured by a higher proportion of negative pivot-shift test, compared with non-anatomical ACLR. Nevertheless, additional clinical and functional outcomes, including Lysholm and IKDC scores, were similar between anatomical and non-anatomical ACLR, and other outcomes such as KT-1000 and Tegner scores were inconsistently reported to preclude further analysis.
      Meta-analyses of clinical studies comparing TT versus independent femoral tunnel drilling techniques have consistently found that the latter better restores postoperative knee stability,
      • Riboh JC
      • Hasselblad V
      • Godin JA
      • et al.
      Transtibial versus independent drilling techniques for anterior cruciate ligament reconstruction: a systematic review, meta-analysis, and meta-regression.
      ,
      • Chen Y
      • Chua KHZ
      • Singh A
      • et al.
      Outcome of Single-Bundle hamstring anterior cruciate ligament reconstruction using the anteromedial versus the transtibial technique: a systematic review and meta-analysis.
      ,
      • Chen H
      • Tie K
      • Qi Y
      • et al.
      Anteromedial versus transtibial technique in single-bundle autologous hamstring ACL reconstruction: a meta-analysis of prospective randomized controlled trials.
      as most commonly measured by the KT-1000 and Lachman tests for translational stability and the pivot-shift test for rotational stability. This meta-analysis of outcomes following anatomical and non-anatomical ACLR, as categorised by use of the AARSC, similarly found that anatomical ACLR (achieved by AM or OI drilling) significantly reduced the proportion of patients with a positive pivot-shift test, as compared with non-anatomical ACLR.
      Despite the better restoration of native knee kinematics provided by anatomical ACLR, the clinical adoption of independent drilling has been tempered by reports of a higher failure/revision rates than TT drilling,
      • Rahr-Wagner L
      • Thillemann TM
      • Pedersen AB
      • et al.
      Increased risk of revision after anteromedial compared with transtibial drilling of the femoral tunnel during primary anterior cruciate ligament reconstruction: results from the Danish knee ligament reconstruction register.
      ,
      • Desai N
      • Andernord D
      • Sundemo D
      • et al.
      Revision surgery in anterior cruciate ligament reconstruction: a cohort study of 17,682 patients from the Swedish national knee ligament register.
      likely due to the greater in situ graft forces experienced following anatomical graft placement.
      • Araujo PH
      • Asai S
      • Pinto M
      • et al.
      Acl graft position affects in situ graft force following ACL reconstruction.
      More recent studies have found similar overall failure rates between techniques,
      • Eysturoy NH
      • Nielsen TG
      • Lind MC
      Anteromedial portal drilling Yielded better survivorship of anterior cruciate ligament reconstructions when comparing recent versus early surgeries with this technique.
      ,
      • Suomalainen P
      • Moisala A-S
      • Paakkala A
      • et al.
      Comparison of tunnel placements and clinical results of single-bundle anterior cruciate ligament reconstruction before and after starting the use of double-bundle technique.
      suggesting a learning curve following anatomical ACLR adoption and/or refinement of postoperative rehabilitation and return-to-sport protocols. This study also found a similar overall failure rate in the anatomical (6.5%) and non-anatomical (5.8%) groups, but a higher proportion of failures in the anatomical group were due to traumatic graft rupture (64.9%), as compared with the non-anatomical group (37.7%), which is consistent with higher in situ graft forces following anatomical ACLR. Furthermore, higher in situ graft forces and traumatic ruptures warrant the delay in return-to-sport following anatomical ACLR.
      • Beischer S
      • Gustavsson L
      • Senorski EH
      • et al.
      Young athletes who return to sport before 9 months after anterior cruciate ligament reconstruction have a rate of new injury 7 times that of those who delay return.
      Nevertheless, the categorisation of the mechanism of graft rerupture was performed for only 60.2% of the total failures; the definition of failure was heterogeneous and, the time of failure after surgery was inconsistently reported, thereby limiting additional conclusions.
      Given that anatomical graft placement produces higher in situ forces, one study found the degree of in situ forces also depends on knee flexion angles.
      • Araujo PH
      • Asai S
      • Pinto M
      • et al.
      Acl graft position affects in situ graft force following ACL reconstruction.
      At flexion angles of >30°, the in situ forces were greater in the non-anatomically placed graft exposing the graft to a potentially higher risk of atraumatic, i.e., technical failures.
      • Koga H
      • Nakamae A
      • Shima Y
      • et al.
      Mechanisms for noncontact anterior cruciate ligament injuries: knee joint kinematics in 10 injury situations from female team handball and basketball.
      Another study found a significant correlation between non-anatomical ACLR techniques such as TT femoral tunnel positioning and femoral transfixation techniques and atraumatic failures due to tibial tunnel mispositioning.
      • Jaecker V
      • Zapf T
      • Naendrup J-H
      • et al.
      Differences between traumatic and non-traumatic causes of ACL revision surgery.
      Multiple other risk factors related to bone morphology, such as intercondylar notch stenosis and variations in sagittal condylar shape, may contribute to atraumatic graft rupture.
      • Koga H
      • Nakamae A
      • Shima Y
      • et al.
      Mechanisms for noncontact anterior cruciate ligament injuries: knee joint kinematics in 10 injury situations from female team handball and basketball.
      ,
      • Bayer S
      • Meredith SJ
      • Wilson K
      • et al.
      Knee morphological risk factors for anterior cruciate ligament injury.
      These findings were consistent with our results, and we were the first to reveal that the anatomical ACLR failures were mostly traumatic; however, future studies are required to better understand the association between graft placement and atraumatic failures.
      Of the further controversy, it has been argued that the magnitude of improvement in postoperative knee stability achieved through anatomical ACLR, while often statistically significant, is not clinically meaningful.
      • Riboh JC
      • Hasselblad V
      • Godin JA
      • et al.
      Transtibial versus independent drilling techniques for anterior cruciate ligament reconstruction: a systematic review, meta-analysis, and meta-regression.
      ,
      • Franceschi F
      • Papalia R
      • Rizzello G
      • et al.
      Anteromedial portal versus transtibial drilling techniques in anterior cruciate ligament reconstruction: any clinical relevance? A retrospective comparative study.
      ,
      • Hamrin Senorski E
      • Sundemo D
      • Murawski CD
      • et al.
      No differences in subjective knee function between surgical techniques of anterior cruciate ligament reconstruction at 2-year follow-up: a cohort study from the Swedish national knee ligament register.
      Namely, both ACLR techniques have heretofore often produced good to excellent clinical results, as defined by scores approaching the upper limits of the most commonly reported clinical outcome measures (eg, Lysholm and IKDC). To that point, this study found that anatomical and non-anatomical ACLR produced similar postoperative Lysholm and objective IKDC scores. In contrast, analysis of Tegner and subjective IKDC scores was deferred due to inconsistent reporting among studies.
      In a study from a group using the Swedish National Knee Ligament Registry, it was found that performance of anatomical ACLR using eight selected items from the AARSC lowered the risk of revision surgery associated with AM portal drilling.
      • Desai N
      • Andernord D
      • Sundemo D
      • et al.
      Revision surgery in anterior cruciate ligament reconstruction: a cohort study of 17,682 patients from the Swedish national knee ligament register.
      Likewise, a recent systematic review comparing long-term (≥10 years) OA prevalence following anatomical vs non-anatomical ACLR, with anatomical defined as a minimum AARSC score of 8, found a nearly 50% reduction in radiographically defined OA with the former compared with the latter.
      • Rothrauff BB
      • Jorge A
      • de Sa D
      • et al.
      Anatomic ACL reconstruction reduces risk of post-traumatic osteoarthritis: a systematic review with minimum 10-year follow-up.
      Absent consensus on what defines anatomical ACLR, but recognising that independent femoral tunnel drilling, is not synonymous with anatomical ACLR, and in light of the aforementioned studies, anatomical ACLR was herein considered an AARSC score of 8 or greater.
      Additional limitations of this study included variability in autograft source (hamstring tendon graft (HS) vs patellar tendon graft (PT)), graft diameter, drilling technique (AM vs OI) and the number of bone tunnels (ie, single bundle (SB) vs double bundle (DB)). Although all included studies used HS and/or PT autograft, subgroup analyses of outcomes between graft source were not performed. Recent systematic reviews have largely reported equivalence between HS and PT autograft in terms of failure rate, knee stability and clinical and functional outcomes while differing in complications (eg, PT autograft more commonly associated with anterior knee pain).
      • Widner M
      • Dunleavy M
      • Lynch S
      Outcomes following ACL reconstruction based on graft type: are all grafts equivalent?.
      ,
      • Ciccotti MC
      • Secrist E
      • Tjoumakaris F
      • et al.
      Anatomic anterior cruciate ligament reconstruction via independent tunnel drilling: a systematic review of randomized controlled trials comparing Patellar tendon and hamstring autografts.
      ,
      • Gabler CM
      • Jacobs CA
      • Howard JS
      • et al.
      Comparison of graft failure rate between autografts placed via an anatomic anterior cruciate ligament reconstruction technique.
      No included study used the quadriceps tendon (QT) autograft, despite its increasing popularity and use in the primary settings.
      • Sheean AJ
      • Musahl V
      • Slone HS
      • et al.
      Quadriceps tendon autograft for arthroscopic knee ligament reconstruction: use it now, use it often.
      As QT autograft use in anatomical ACLR has been associated with both higher
      • Lind M
      • Strauss MJ
      • Nielsen T
      • et al.
      Quadriceps tendon autograft for anterior cruciate ligament reconstruction is associated with high revision rates: results from the Danish knee ligament registry.
      and lower
      • Nyland J
      • Collis P
      • Huffstutler A
      • et al.
      Quadriceps tendon autograft ACL reconstruction has less pivot shift laxity and lower failure rates than hamstring tendon autografts.
      revision rates, compared with other autograft options, additional studies are needed to elucidate the relative merits of using the QT autograft, particularly in an anatomical fashion. Furthermore, subgroup analysis of outcomes based on difference in graft diameter (ie, thinner vs thick graft) was not performed due to inconsistent reporting within the included studies. Using New Zealand ACL registry data of 992 patients, the study concluded that failure rate was not influenced by graft diameter.
      • Murgier J
      • Powell A
      • Young S
      • et al.
      Effectiveness of thicker hamstring or patella tendon grafts to reduce graft failure rate in anterior cruciate ligament reconstruction in young patients.
      Both AM and OI drilling of the femoral tunnel is superior to TT drilling in achieving anatomical tunnel placement, with studies finding near equivalence between AM and OI techniques.
      • Tejpal T
      • Gupta A
      • Shanmugaraj A
      • et al.
      Anteromedial portal Double-Bundle anterior cruciate ligament reconstruction yields similar outcomes to Non-AMP femoral drilling Double-Bundle techniques: a systematic review of comparative studies.
      ,
      • Lee D-H
      • Kim H-J
      • Ahn H-S
      • et al.
      Comparison of Femoral Tunnel Length and Obliquity Between Transtibial, Anteromedial Portal, and Outside-In Surgical Techniques in Single-Bundle Anterior Cruciate Ligament Reconstruction: A Meta-analysis.
      ,
      • Osti M
      • Krawinkel A
      • Ostermann M
      • et al.
      Femoral and tibial graft tunnel parameters after transtibial, anteromedial portal, and outside-in Single-Bundle anterior cruciate ligament reconstruction.
      Consequently, AM and OI drilling techniques were not separately analysed. Finally, while DB ACLR techniques were developed to better recapitulate the two-bundle anatomy of the native ACL, DB ACLR should not necessarily be considered equivalent to anatomical ACLR, just as independent femoral tunnel drilling is not synonymous with anatomical reconstruction. Nevertheless, as systematic reviews have failed to find consistent differences in outcomes between anatomical SB and DB ACLR,
      • Järvelä S
      • Kiekara T
      • Suomalainen P
      • et al.
      Double-Bundle versus Single-Bundle anterior cruciate ligament reconstruction: a prospective randomized study with 10-year results.
      ,
      • Hussein M
      • van Eck CF
      • Cretnik A
      • et al.
      Prospective randomized clinical evaluation of conventional single-bundle, anatomic single-bundle, and anatomic double-bundle anterior cruciate ligament reconstruction: 281 cases with 3- to 5-year follow-up.
      ,
      • Desai N
      • Björnsson H
      • Musahl V
      • et al.
      Anatomic single- versus double-bundle ACL reconstruction: a meta-analysis.
      both techniques were pooled in this study.
      While acknowledging these limitations, this is the first systematic review that reports failure rate, knee stability outcomes, and functional and patient-reported outcomes, specifically comparing anatomical versus non-anatomical ACLR. The broad scope of the results, summarising multiple outcomes, as well as capturing 3710 patients, strengthen the findings of this review. The findings contained herein confirm the advantage of anatomical ACLR in restoring knee stability, with similar overall failure rates as compared with non-anatomical ACLR.

      Conclusion

      This systematic review and meta-analysis of studies comparing outcomes following anatomical and non-anatomical ACLR found similar overall failure rates between the two techniques, while anatomical ACLR resulted in a higher proportion of failure due to traumatic mechanisms. Additionally, anatomical ACLR better restored knee stability, as measured by a negative pivot-shift test postoperatively. Non-anatomical ACLR resulted in higher rates of atraumatic graft ruptures and persistent rotatory knee instability. Lysholm and objective IKDC scores were equivalent between techniques, but a comparison of additional outcome measures was limited by inconsistent reporting and study heterogeneity. Surgeons should consider anatomical ACLR when treating rotatory knee stability in patients. Future comparative studies of anatomical ACLR should consistently and comprehensively report outcome measures and surgical details, as detailed in the validated AARSC.

      Supplementary Material

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