Trends in Anterior Cruciate Ligament Repair: A Bibliometric and Visualized Analysis

Editorial Commentary: Primary Repair of the Anterior Cruciate Ligament Shows Positive Midterm Outcomes When Properly Indicated

Anatomic anterior cruciate ligament (ACL) reconstruction is the gold standard treatment for ACL injury and has been shown to restore the 3-dimensional joint laxity. Recently, however, there is renewed interest in primary repair of the injured ACL in selected cases. Research shows that, in some cases, short- and midterm outcomes of ACL repair are favorable, albeit with greater failure rates than ACL reconstruction. No long-term outcomes are yet available, which could address whether repair reduces risk of osteoarthritis relative to reconstruction with a graft. Historically, primary repair showed poor outcomes, but for proximal and acute injuries with good vascularity, innovations such as suture anchors, dynamic intraligamentary stabilization, and suture tape augmentation show promise, particularly in paediatric patients. The old orthopaedic dogma that "ACL cannot heal" is not entirely correct.

Multiligamentous Knee Injury: A Scientometric Assessment of Global Publications During 2008-2023

Background

Research and clinical studies on multiligamentous knee injuries (MLKI) have recently gained interest with several clinical studies reported recently. This study aims to identify, visualize, and characterize the MLKI research, to analyze the knowledge structure of MLKI during 2008-2023 and to identify the emerging research trends from a bibliometric perspective.

Methods

All articles reporting MLKI from 2008 to 2023 were curated from the Scopus database, on 1st January 2024. VOS viewer and Microsoft Excel were used to analyze the publications including the participating countries, authors, organizations, journals and research focus. These data were used to generate visual knowledge maps of the outputs.

Results

406 papers on MLKI were published in 115 journals by 483 authors. There has been a slow publication growth in the past 16 years. The United States had more than 50% share in global publications. Knee Surgery Sports Traumatology Arthroscopy, Orthopaedic Journal of Sports Medicine and American Journal of Sports Medicine published the most papers. The three USA institutions, namely Mayo Clinic, Hospital for Special Surgery-New York and Twin Cities Orthopedics contributed the largest number of publications. B.A. Levy (Mayo Clinic, USA) (n = 66) and M.J. Stuart (Mayo Clinic, USA) (n = 63) have registered the highest collaborative links with other authors.

Conclusions

This study is the first comprehensive bibliometric study to analyze MLKI. The findings shed light on the growth trajectory of publications, the extent of international collaborations, the influence of highly cited articles, and the key countries, institutions, journals, and authors contributing to the field.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-024-01149-9.

Anterior cruciate ligament primary repair revision rates are increased in skeletally mature patients under the age of 21 compared to reconstruction, while adults (>21 years) show no significant difference: A systematic review and meta-analysis

PURPOSE

To evaluate the impact of age as a risk factor on the revision rates of anterior cruciate ligament (ACL) primary repair (ACLPR), dynamic intraligamentary stabilization (DIS) and bridge-enhanced ACL restoration (BEAR) compared to ACL reconstruction (ACLR).

METHODS

A systematic literature search was performed for comparative studies comparing outcomes for ACLPR, DIS or BEAR to ACLR. A random-effects meta-analysis was performed to assess nondifferentiated and age-differentiated (skeletally mature patients ≤21 and >21 years) ACL revision and reoperation risk, as well as results for subjective outcomes. Methodological study quality was assessed using the Risk of Bias Tool 2.0c and Methodological Index for Nonrandomized Studies tools.

RESULTS

A total of 12 studies (n = 1277) were included. ACLR demonstrated a lower nonage-stratified revision risk at 2 years versus ACLPR, DIS and BEAR, but a similar revision risk at 5 years when compared to DIS. However, an age-stratified analysis demonstrated a significantly increased ACLPR revision risk as compared to ACLR in skeletally mature patients ≤21 years of age (risk ratios [RR], 6.33; 95% confidence interval [CI], 1.18-33.87, p = 0.03), while adults (>21 years) showed no significant difference between groups (RR, 1.48; 95% CI, 0.25-8.91, n.s.). Furthermore, DIS reoperation rates were significantly higher than respective ACLR rates (RR, 2.22; 95% CI, 1.35-3.65, p = 0.002), whereas BEAR (RR, 1.07; 95% CI, 0.41-2.75, n.s.) and ACLPR (RR, 0.81; 95% CI, 0.21-3.09, n.s.) showed no differences. IKDC scores were equivalent for all techniques. However, ACLPR exhibited significantly better FJS (mean difference, 11.93; 95% CI, 6.36-17.51, p < 0.0001) and Knee injury and Osteoarthritis Outcome Score Symptoms (mean difference, 3.01; 95% CI, 0.42-5.60, p = 0.02), along with a lower Tegner activity reduction.

CONCLUSIONS

ACLPR in skeletally mature patients ≤21 years of age is associated with up to a six-fold risk increase for ACL revision surgery compared to ACLR; however, adults (>21 years) present no significant difference. Based on the current data, age emerges as a crucial risk factor and should be considered when deciding on the appropriate treatment option in proximal ACL tears.

LEVEL OF EVIDENCE

Level III.

Italian research on anterior cruciate ligament: a bibliometric analysis

INTRODUCTION

This study analysed the trend of publications on anterior cruciate ligament (ACL) in Italy. It was hypothesised that publications on this topic have quickly increased in recent years due to increased knowledge of both clinical and radiological pathology.

METHODS

PubMed and Scopus were accessed on 29/11/2023. This retrieved 838 articles from PubMed and 1050 from Scopus. We analysed the top 10 authors, and journals in publication numbers, citation numbers, and citations per year. We have also looked at the top 10 institutions publishing on anterior cruciate ligament from Scopus as PubMed does not give this information in the output. Data mining was performed using the Orange software, Mac version 3.32.0 ( https://orangedatamining.com/ ) from the titles of all articles. A word cloud analysis of titles, authors, journals and universities was performed.

RESULTS

The peak of citations was in 2017 with 1529, whilst the peak of publications was in 2019 with 59 articles published. Analysing the number of publications and citations for the journal, the most impacted journal is Knee Surgery, Sports Traumatology, Arthroscopy with 5472 citations and 183 articles, followed by The American Journal of Sports Medicine, with 2722 citations and 56 articles and Arthroscopy with 1990 citations and 62 articles. Considering also international collaborations, the most cited author is Della Villa F. in 2020 with 43.67 citations per year. The Italian author with the major number of publications is Zaffagnini S. with 39 articles, whilst the author with the higher number of citations is Aglietti P. with 1612 citations.

CONCLUSIONS

ACL reconstruction has gained growing interest amongst the scientific community. Publications and citations presented a rising trend, the majority of the highly cited papers were contributed by few centres, and clinical trials were the most cited study designs. The long-term outcomes of ACL lesions have attracted interest. The authors hypothesised that shortly there will be an increase in articles analysing the results of ACL revisions, the use of lateral extra-articular tenodesis, and meniscus transplants.

LEVEL OF EVIDENCE IV

Cross-Sectional Study.

Acute anterior cruciate ligament rupture: can repair become an alternative to reconstruction: a meta-analysis of randomized controlled trials and cohort studies

PURPOSE

To perform a meta-analysis to compare clinical outcomes of anterior cruciate ligament (ACL) repair and ACL reconstruction for acute ACL rupture.

METHOD

We searched Pubmed, Embase, the Cochrane Library, and Web of Science databases to seek relevant studies. Clinical outcomes included failure rate, hardware removal rate, anteroposterior (AP) knee laxity, and patient-reported outcomes. In addition, subgroup analysis was carried out according to repair techniques, rupture locations, and study designs. Funnel plots were used to detect publication bias. All statistical analysis was performed using STATA (version 14.2, StataCorp).

RESULTS

A total of 10 articles were included in this study, comprising 5 randomized controlled trials (RCTs) and 5 cohort studies, involving a total of 549 patients. We found no statistical differences between the ACL repair and ACL reconstruction in the following outcomes: failure rate, AP knee laxity, International Knee Documentation Committee (IKDC) score, Lysholm score, Knee Injury and Osteoarthritis Outcome (KOOS) Score, and Tegner score. However, the ACL repair group had a higher hardware removal rate. Except for AP knee laxity results on different repair techniques, there was no statistical difference in other subgroup analyses.

CONCLUSION

Compared with ACL reconstruction, ACL repair shows similar results in clinical outcomes, and it is promising to be an effective alternative treatment for acute ACL rupture. Larger samples and higher-quality studies are needed to support our results and further explore the advantages of ACL repair in other aspects.

LEVEL OF EVIDENCE

Level III.

Arthroscopic Anatomic Anterior Cruciate Ligament Primary Repair Restores Anterior Tibial Translation Intraoperatively at Time Zero With No Additional Effect of Suture Augmentation

PURPOSE

To intraoperatively evaluate the ability of anterior cruciate ligament (ACL) primary repair (ACLPR) to restore anterior tibial translation (ATT) at time zero and to assess the influence of additional suture augmentation (SA) on ATT.

METHODS

Patients with proximal ACL tears undergoing arthroscopic ACLPR with dual-suture anchor fixation were included in this time-zero clinical study. Laxity measurements were taken with a digital arthrometer to evaluate ATT stability preoperatively in the office (T0) as a standardized diagnostic tool, preoperatively under anesthesia (T1), at time zero intraoperatively after ACLPR but prior to SA fixation (T2), and after SA fixation (T3).

RESULTS

A total of 27 patients (mean age ± standard deviation [SD], 35.1 ± 12.0 years) with proximal ACL tears and significant preoperative (T0) ATT side-to-side differences (SSDs) (mean ± SD, 4.1 ± 1.5 mm) were evaluated. ACLPR was shown to restore ATT SSD at time zero (mean ± SD, 0.2 ± 1.1 mm) given that a significant reduction in ATT SSD (mean difference ± standard error, -4.7 ± 0.21 mm; P < .001) was achieved when comparing preoperative and intraoperative measurements after separate refixation of both ACL bundles with suture anchors. Additional SA fixation did not further decrease ATT when comparing measurements of the ipsilateral leg after ACL refixation and after SA fixation (mean difference ± SD, 0.03 ± 0.22 mm; P = .496).

CONCLUSIONS

ACLPR with dual-suture anchor fixation restores time-zero ATT laxity in adults with proximal ACL tears. Additional SA fixation in full knee extension does not further decrease ATT.

CLINICAL RELEVANCE

This study provides important information about the effectiveness of ACLPR in restoring ATT. SA with the knee fixed in full knee extension does not further decrease ATT; therefore, augmentation may not lead to overconstraint of the knee or stress shielding of the repaired ACL.

The impact of surgical randomised controlled trials on the management of FAI syndrome: a citation analysis

PURPOSE

To identify and assess the clinical impact of randomised controlled trials (RCTs) assessing the surgical management of femoroacetabular impingement syndrome (FAIS) through a citation analysis.

METHODS

MEDLINE, EMBASE and CENTRAL were searched from inception to April 22, 2023 for RCTs assessing the surgical management of FAIS. Study characteristics were directly abstracted from included trials and citation metrics were obtained from the Clarivate Web of Knowledge database on May 19, 2023. The continuous fragility index (CFI) was calculated for eligible outcomes. Univariate regression models were used to explore correlations between total citations per year and various study characteristics.

RESULTS

Ten studies comprising one thousand two hundred ninetypatients were eligible for analysis. Studies were published from 2013 to 2023. Eight countries were represented across various trials with 91% being either North American or European. The mean journal impact factor of published studies was 39.684 (median 2.982; range 1.31-202.73). The mean citation density was 14.17 (range 0.33-48.67). The median CFI was 4.8 (range 1-32.2). Correlation analysis demonstrated strong and statistically significant correlations to study sample size (R = 0.75, p = 0.012), journal impact factor (R = 0.80, p = 0.006) and continuous fragility index (R = 0.95, p = 0.015).

CONCLUSION

Trials assessing the surgical management of FAIS present with a wide range of clinical uptake based on citation density and are published in journals of broadly variable impact factor. Despite promising citation metrics, high-quality evidence on arthroscopy for FAIS is limited to the United States and Europe with an unclear international impact. Future knowledge translation efforts are warranted to maximise the international uptake of evidence regarding arthroscopic management of FAIS.

LEVEL OF EVIDENCE

I.

Ambulatory knee biomechanics and muscle activity 2 years after ACL surgery: InternalBraceTM-augmented ACL repair versus ACL reconstruction versus healthy controls

BACKGROUND

Little is known about knee mechanics and muscle control after augmented ACL repair. Our aim was to compare knee biomechanics and leg muscle activity during walking between the legs of patients 2 years after InternalBraceTM-augmented anterior cruciate ligament repair (ACL-IB) and between patients after ACL-IB and ACL reconstruction (ACL-R), and controls.

METHODS

Twenty-nine ACL-IB, 27 sex- and age-matched ACL-R (hamstring tendon autograft) and 29 matched controls completed an instrumented gait analysis. Knee joint angles, moments, power, and leg muscle activity were compared between the involved and uninvolved leg in ACL-IB (paired t-tests), and between the involved legs in ACL patients and the non-dominant leg in controls (analysis of variance and posthoc Bonferroni tests) using statistical parametric mapping (SPM, P < 0.05). Means and 95% confidence intervals (CI) of differences in discrete parameters (DP; i.e., maximum/minimum) were calculated.

RESULTS

Significant differences were observed in ACL-IB only in minimum knee flexion angle (DP: 2.4°, CI [-4.4;-0.5]; involved > uninvolved) and maximum knee flexion moment during stance (-0.07Nm/kg, CI [-0.13;-0.00]; involved < uninvolved), and differences between ACL-IB and ACL-R only in maximum knee flexion during swing (DP: 3.6°, CI [0.5;7.0]; ACL-IB > ACL-R). Compared to controls, ACL-IB (SPM: 0-3%GC, P = 0.015; 98-100%, P = 0.016; DP: -6.3 mm, CI [-11.7;-0.8]) and ACL-R (DP: -6.0 mm, CI [-11.4;-0.2]) had lower (maximum) anterior tibia position around heel strike. ACL-R also had lower maximum knee extension moment (DP: -0.13Nm/kg, CI [-0.23;-0.02]) and internal knee rotation moment (SPM: 34-41%GC, P < 0.001; DP: -0.03Nm/kg, CI [-0.06;-0.00]) during stance, and greater maximum semitendinosus activity before heel strike (DP: 11.2%maximum voluntary contraction, CI [0.1;21.3]) than controls.

CONCLUSION

Our results suggest comparable ambulatory knee function 2 years after ACL-IB and ACL-R, with ACL-IB showing only small differences between legs. However, the differences between both ACL groups and controls suggest that function in the involved leg is not fully recovered and that ACL tear is not only a mechanical disruption but also affects the sensorimotor integrity, which may not be restored after surgery. The trend toward fewer abnormalities in knee moments and semitendinosus muscle function during walking after ACL-IB warrants further investigation and may underscore the importance of preserving the hamstring muscles as ACL agonists.

LEVEL OF EVIDENCE

Level III, case-control study.

TRIAL REGISTRATION

clinicaltrials.gov, NCT04429165 (12/06/2020).

Anatomic Arthroscopic Primary Repair of Proximal Anterior Cruciate Ligament Tears

Within the last decade, various highly diverse anterior cruciate ligament (ACL) preservation techniques have been proposed, as contemporary selective arthroscopic ACL preservation experienced a resurgence. Among surgical techniques, there are a variety of suturing, fixation, and augmentation methods, whereas a common thread, considering essential anatomic and biomechanical properties, is missing. This technique aims to anatomically reapproximate both the anteromedial (AM) and posterolateral (PL) bundles to their respective femoral footprints. Additionally, a PL compression stitch is performed to increase the ligament-bone contact area and recreate the anatomic vectors of the native bundles, therefore, creating a more anatomic and biomechanical construct. This technique is a minimally invasive procedure, with no graft harvesting nor tunnel drilling, which leads to decreased pain levels, earlier return of full range motion (ROM), and faster rehabilitation, while failure rates seem to be comparable to that of ACL reconstruction. We present an updated surgical technique of anatomic arthroscopic primary repair with suture anchor fixation for patients with proximal ACL tears.