Towards a validated musculoskeletal knee model to estimate tibiofemoral kinematics and ligament strains: comparison of different anterolateral augmentation procedures combined with isolated ACL reconstructions

Background: Persistent clinical instability after anterior cruciate ligament (ACL) reconstruction may be associated with injury to the anterolateral structures and has led to renewed interest in anterolateral extra-articular procedures. The influence of these procedures on knee kinematics is controversial. Purpose/Hypothesis: The purpose was to investigate the biomechanical properties of anatomic anterolateral ligament (ALL) reconstruction and a modified Lemaire procedure (lateral extra-articular tenodesis [LET]) in combination with ACL reconstruction as compared with isolated ACL reconstruction in the setting of deficient anterolateral structures (ALL and Kaplan fibers). It was hypothesized that both techniques would reduce tibial internal rotation when combined with ACL reconstruction in the setting of anterolateral structure deficiency. Study Design: Controlled laboratory study. Methods: A 6 degrees of freedom robotic system was used to assess tibial internal rotation, a simulated pivot-shift test, and anterior tibial translation in 10 paired fresh-frozen cadaveric knees. The following states were tested: intact; sectioned ACL, ALL, and Kaplan fibers; ACL reconstruction; and an anterolateral extra-articular procedure (various configurations of ALL reconstruction and LET). Knees within a pair were randomly assigned to either ALL reconstruction or LET with a graft tension of 20 N and a randomly assigned fixation angle (30° or 70°). ALL reconstruction was then repeated and secured with a graft tension of 40 N. Results: In the setting of deficient anterolateral structures, ACL reconstruction was associated with significantly increased residual laxity for tibial internal rotation (up to 4°) and anterior translation (up to 2 mm) laxity as compared with the intact state. The addition of ALL reconstruction or LET after ACL reconstruction significantly reduced tibial internal rotation in most testing scenarios to values lower than the intact state (ie, overconstraint). Significantly greater reduction in laxity with internal rotation and pivot-shift testing was found with the LET procedure than ALL reconstruction when compared with the intact state. Combined with ACL reconstruction alone, both extra-articular procedures restored anterior tibial translation to values not significantly different from the intact state with most testing scenarios (usually within 1 mm). Conclusion: Residual laxity was identified after isolated ACL reconstruction in the setting of ALL and Kaplan fiber deficiency, and the combination of ACL reconstruction in this setting with either ALL reconstruction or the modified Lemaire LET procedure resulted in significant reductions in tibiofemoral motion at most knee flexion angles, although overconstraint was also identified. ALL reconstruction and LET restored anterior tibial translation to intact values with most testing states. Clinical Relevance: ALL reconstruction and lateral extra-articular tenodesis have been described in combination with intra-articular ACL reconstruction to address rotational laxity. This study demonstrated that both procedures resulted in significant reductions of tibial internal rotation versus the intact state independent of graft tension or fixation angle, although anterior tibial translation was generally restored to intact values. The influence of overconstraint with anterolateral knee reconstruction procedures has not been fully evaluated in the clinical setting and warrants continued evaluation based on the findings of this biomechanical study.

Graft failure and secondary meniscal tears are major concerns after anterior cruciate ligament (ACL) reconstruction in young athletes. The aim was to evaluate the link between ACL reconstruction with and without anterolateral ligament (ALL) reconstruction and outcomes in young patients participating in pivoting sports. This was a retrospective study of data collected prospectively. Patients less than 20years, involved in pivoting sports and undergoing primary ACL reconstruction with a quadruple hamstring tendon (4HT) graft or 4HT graft combined with anterolateral ligament reconstruction (4HT + ALL) were included. Survival analysis was performed to identify the prognostic indicators for reoperation due to graft failure or secondary meniscal lesions. Knee laxity was assessed and patient reported outcome measures (PROMs) were collected. A total of 203 patients (mean (± SD) age: 16.3 ± 2years) with a mean follow-up of 4.8 ± 0.9 (range: 3.3‒6.8) years were included. There were 101 4HT and 102 4HT + ALL grafts. Graft rupture rates were 11.9% for 4HT grafts and 5.8% for 4HT + ALL grafts (n.s.). There were 9.9% secondary meniscal procedures for 4HT grafts vs. 1.9% for 4HT + ALL grafts (p = 0.02). With reoperation for graft failure or secondary meniscal lesions at final follow-up as the endpoint, survival was better in the 4HT + ALL group (91.4% vs. 77.8%, respectively; p = 0.03). Absence of ALL reconstruction (HR = 4.9 [95%CI: 1.4-17.9]; p = 0.01) and preoperative side-to-side laxity > 3mm (HR = 3.1 [95%CI: 1.03-9.1]; p = 0.04) were independently associated with an increased rate of reoperations. Mean (± SD) side-to-side laxity was 1.3 ± 1.3mm (range: -2 to 5) for 4HT grafts vs. 0.9 ± 1.3mm (range: -6 to 4.8) for 4HT + ALL grafts (n.s.) 6months post-surgery. The rate of return to the same sport at the same level was 42.2% for 4HT grafts vs. 52% for 4HT + ALL grafts (n.s.). There was no significant difference in subjective outcomes including PROMs between the two groups. Combined ALL + ACL reconstruction reduced the rate of graft failure and secondary meniscal injury in young athletes when compared to ACL reconstruction alone. Subjective results were comparable, with a similar rate of complications. Combined reconstruction should be preferred in this young population. Level IV.

Is the anterolateral ligament the smoking gun to explain rotational knee laxity or just vaporware?

Graft failure rates after anterior cruciate ligament reconstruction (ACLR) in children and adolescents are higher compared to adults. Anterolateral augmentation procedures have recently generated increased focus regarding their ability to reduce graft failure rates. Concerns in skeletally immatures are potential growth disturbances and overconstraint after anterolateral augmentation. The aim of this scoping review is to provide an overview of all current anterolateral augmentation procedures in skeletally immature patients and to discuss surgical techniques, clinical and biomechanical outcomes. This scoping review was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement extension for scoping reviews. On 22December 2022, an information specialist performed a systematic literature search in Cochrane, PubMed (Medline) and EMBASE databases. Inclusion criteria were anterolateral augmentation procedures, including lateral extra-articular tenodesis (LET) and anterolateral ligament reconstruction (ALLR), in combination with ACLR in skeletally immatures. Twenty studies were included after screening 1.485 abstracts. Seventeen studies describe LET techniques, four studies ALLR techniques and one study both techniques. Biomechanical data is scarce and shows conflicting results. Two studies compared ACLR with LET to ACLR in skeletally immatures with promising results in favour of the combined procedure. There were no differences in outcomes between LET and ALLR. Several LET and ALLR techniques have been described for skeletally immature patients and the first clinical data on LET and ALLR is available, which showed promising results. Further research is necessary to evaluate the risk of growth disturbances and overconstraint in skeletally immatures. Level IV.

Background:Anterolateral ligament reconstruction (ALLR) and lateral extra-articular tenodesis (LET) show promise in lowering the risk of rerupture after anterior cruciate ligament reconstruction (ACLR), but there are little data on surgeon practices and preferences in children and adolescents.Purpose:To quantify surgeon practices regarding ALLR and LET in the pediatric population.Study Design:Cross-sectional study.Methods:An electronic survey was administered to 87 surgeons in the Pediatric Research in Sports Medicine society. The questionnaire asked several questions about surgeon and practice characteristics as well as indications, preferences, and techniques for ALLR or LET in the context of primary and revision pediatric ACLR. Chi-square and Fisher exact tests were used to evaluate factors that affect surgical preferences.Results:A total of 63 surgeons completed the survey, of whom 62% performed ≥50 pediatric ACLRs annually; 56% sometimes performed anterolateral augmentation with primary ACLR, and 79% with revision ACLR. The most common indications for ALLR or LET in the primary setting were high-grade pivot shift, knee hyperextension, generalized laxity, and type of sports participation. Surgeons whose practice was >75% sports medicine were more likely to perform ALLR or LET with both primary and revision ACLR (P = .005 and P < .001, respectively). Those who had completed a sports medicine fellowship were more likely to perform these procedures than those with only pediatric orthopaedic training, in both primary (68% vs 36%; P = .01) and revision scenarios (92% vs 60%; P = .002). Of the 28 respondents who did not perform ALLR or LET with primary ACLR, 75% cited insufficient evidence as the reason. However, 96% of surgeons who did perform these procedures expressed interest in studying them prospectively, and 87% were willing to randomize patients.Conclusion:Findings indicated that 56% of pediatric sports surgeons sometimes perform anterolateral augmentation with primary ACLR and 79% with revision ACLR. Surgeons with sports medicine fellowship training or a mostly sports practice were more likely to perform these procedures. Insufficient evidence was the most common reason given by surgeons who did not perform anterolateral augmentation. However, there was substantial willingness to prospectively study and even randomize pediatric patients to assess the impact of ALLR or LET in this population.

Combined anterior cruciate ligament and anterolateral ligament reconstruction using an adjustable-loop device provides similar short-term clinical outcomes compared with isolated reconstruction.

The role of concomitant extra-articular procedures in improving the outcome of ACL reconstruction has experienced a recent resurgence in interest. The aim of this article is to highlight the differences in philosophies and outcomes of historical lateral extra-articular tenodesis (LET) and contemporary, anterolateral reconstruction. A narrative review was performed using PubMed/MEDLINE using the keywords "lateral extra-articular tenodesis" and "anterolateral ligament reconstruction". Results of search strategy: Thirty-seven studies [13 reporting clinical outcomes of isolated LET in ACL deficient knees and 24 comparing isolated anterior cruciate ligament reconstruction (ACLR) with ACLR+LET] and 1 study on anterolateral ligament (ALL) reconstruction were identified as relevant and included in the review. Results of literature review: Isolated extra-articular reconstructions are rarely performed in contemporary practice. They are associated with a high rate of persistent anterior instability and early degenerative change. Combined ACL reconstruction and lateral extra-articular tenodeses results in a significant reduction in the prevalence of residual pivot shift, but the majority of the studies do not demonstrate any significant difference with respect to patient-reported outcome measures and return to sport. Although several authors report a trend towards decreased graft rupture rates, significant differences were not demonstrated in most studies. In a single clinical study, combined anatomic ACL and anterolateral ligament reconstruction was reported to be associated with a threefold reduction in graft rupture rates and improved return to sport compared to isolated ACL graft choices. Historically performed, combined ACL reconstruction and lateral extra-articular tenodeses are associated with improved knee kinematics. Although trends towards decreased graft rupture rates are reported by several authors, the majority did not demonstrate a significant difference, likely as a result of small and underpowered studies using post-operative immobilisation and delayed rehabilitation protocols. More recently, combined ACLR and ALL reconstruction has been shown to be associated with significant improvements in graft failure and return to sport rates when compared to isolated ACLR. However, these results are from a single clinical series with only medium-term follow-up. IV.

BACKGROUNDAnterior cruciate ligament (ACL) reconstruction has been a successful treatment for ACL rupture. However ongoing rotational instability can be an issue. Several surgical techniques have been recommended to overcome this including lateral extra-articular tenodesis (LET) and more recently anterolateral ligament reconstruction (ALLR). AIMTo compare the clinical outcomes following ACL reconstruction (ACLR) alone or ACLR with either LET or ALLR. METHODSA systematic review was conducted by means of four databases (MEDLINE, EMBASE, Cochrane and Clinical.Trials.Gov), and the Reference Citaion Analysis (https://www.referencecitationanalysis.com/) to identify all studies investigating either or both of LET and ALLR. The Critical Appraisal Skills Programme checklist for cohort studies was employed for critical appraisal and evaluation of all twenty-four studies which met the inclusion criteria. RESULTSPooled meta-analyses illustrated that ACLR with additional LET or ALLR results in improved pivot shift test scores, compared to isolated ACLR. There was no statistically significant difference in International Knee Documentation Committee (IKDC) clinical scores with addition of either LET or ALLR. ACL re-rupture rates were compared between LET and ALLR techniques. There was a statistically significant difference between techniques, with a 1.14% rupture rate in ACLR +ALLR, and 4.03% rupture rate in ACLR + LET. Isolated ACLR re-rupture rates were 12.59%, significantly higher than when augmented with either ALLR or LET (P < 0.0001 for both groups). There were no statistical differences in pivot shift test or IKDC scores between LET and ALLR techniques. CONCLUSIONThis meta-analysis has found that use of either LET or ALLR in addition to ACLR results in improved mechanical outcomes suggesting surgeons should consider augmenting ACLR with an extra-articular procedure in patients with rotatory instability. Furthermore, both anterolateral extra articular procedures in addition to ACLR lead to reduced ACL re-rupture rates compared to isolated ACLR. Moreover, ALLR results in reduced ACL re-rupture rates, compared to LET. More research is needed to compare the two respective extra-articular procedures.

Background:Graft failure remains a challenging complication after anterior cruciate ligament reconstruction (ACLR) in children and adolescents. Anterolateral ligament reconstruction (ALLR) and lateral extra-articular tenodesis (LET) show promise in lowering the risk of ACL graft failure, but there is little data on surgeon practices and preferences in the pediatric population. An improved understanding can help determine the feasibility of future research, identify questions of interest, and ultimately design clinical studies.Hypothesis/Purpose:The purpose of this study is to quantify surgeon practices regarding ALLR and LET in children and adolescents.Methods:An electronic survey was administered to surgeons in the Pediatric Research in Sports Medicine (PRiSM) society. Surgeon and practice demographic information was collected. The survey then asked several questions about indications, preferences, and techniques for ALLR or LET in the context of primary and revision pediatric ACLR. Chi-square and Fisher exact tests were used to evaluate factors that impact surgical preferences.Results:A total of 63 surgeons completed the survey, of which 62% performed ≥50 pediatric ACLR annually. In the setting of primary ACLR, 35/63 (56%) sometimes perform ALLR or LET. The frequency increased to 50/63 (79%) with revision ACLR. The most common indications for ALLR/LET in the primary setting were high-grade pivot shift, knee hyperextension, generalized laxity, and type of sports participation. Surgeons whose practice was >75% sports medicine were more likely to perform ALLR/LET with both primary and revision ACLR (p=0.005 and <0.001, respectively). Those that completed a sports medicine fellowship were more likely to perform these procedures than those with only pediatric orthopaedic training in both primary (68% vs. 36%, p=0.01) and revision scenarios (92% vs. 60%, p=0.002). Of the 28 respondents that do not perform ALLR/LET with primary ACLR, 75% cited insufficient evidence as the reason. However, 95% of surgeons that do perform these procedures expressed interest in studying them prospectively and 86% were willing to randomize patients.Conclusion:In this study of pediatric sports surgeons, 56% sometimes perform ALLR or LET with primary ACLR and 79% with revision ACLR. Surgeons with sports medicine fellowship training or a mostly sports practice were more likely to perform these procedures. Insufficient evidence was the most common reason given by those that do not perform ALLR or LET. However, there was substantial willingness to prospectively study and even randomize pediatric patients to assess the impact of ALLR/LET in this population.

There has been increased interest in lateral extra-articular procedures, such as anterolateral ligament reconstruction (ALLR) or lateral extra-articular tenodesis (LET), to reduce anterolateral rotation instability of the knee after anterior cruciate ligament reconstruction (ACLR). Despite promising surgical outcomes with these techniques, their impact on knee strength recovery is unknown. Patients undergoing lateral extra-articular procedures at the time of ACLR would have impaired thigh muscle strength at 6 to 9 months after surgery. Cohort study; Level of evidence, 3. Adolescent patients who had undergone primary unilateral ACLR with lateral extra-articular augmentation between 2017 and 2023 were identified. Patients were included if they were aged between 12 and 20 years at the time of surgery and had completed an isokinetic strength assessment at 6 to 9 months after surgery. A total of 104 participants (mean age, 16.5 ± 1.7 years; 63 female) were included in this analysis: 25 who underwent ACLR+ALLR, 17 who underwent ACLR+LET, and 62 who underwent isolated ACLR. Isokinetic knee extension and flexion strength normalized to body weight, as well as the bilateral limb symmetry index (LSI), were assessed. One-way analysis of variance and analysis of covariance were used to compare differences between surgical techniques. After adjusting for age, graft type, and time since surgery, the ACLR+LET (1.36 ± 0.52 N·m/kg) and ACLR+ALLR (1.61 ± 0.53 N·m/kg) groups had significantly less involved limb knee extension strength (P = .025), uninvolved limb knee extension strength (P = .046), and LSI for knee extension strength (P = .040) compared to the isolated ACLR group. There were no differences between the 3 groups regarding involved limb knee flexion strength (P = .222) or uninvolved limb knee flexion strength (P = .984), but the isolated ACLR group displayed a greater LSI for knee flexion strength (96.6% ± 17.8%; P = .012). The addition of lateral extra-articular procedures at the time of ACLR was associated with decreased quadriceps strength at 6 to 9 months after ACLR. While lateral extra-articular procedures may enhance knee rotary stability after ACLR, prolonged rehabilitation may be needed to re-establish adequate quadriceps strength before return to sports.

The attachment locations of anterior cruciate ligament (ACL) grafts during reconstruction have been reported to influence knee joint function. However, there are controversial opinions on femoral ACL attachment locations for restoring normal knee kinematics. The knee stability and ACL force by different ACL attachment locations could be predicted using the musculoskeletal model simulation. The objectives of this study are to develop a detailed musculoskeletal knee model and to quantify the effect of ACL graft attachment locations on knee kinematics and graft force. Five normal subjects walked at a self-selected speed, and motion data were captured. A detailed knee model including 14 ligaments was developed for dynamics simulation using cadaveric specimen data, which were previously published and are open to public access. The ACL bundles of the model were removed and replaced with ACL grafts to develop anatomical and isometric ACL-reconstructed knee models; the femoral anatomical footprint and isometric locations were used, respectively. After the knee models were embedded in a full-body template model from the AnyBody Managed Model Repository, the full-body musculoskeletal model was simulated using the measured gait data. The isometric reconstruction model had significantly large anterior translation and internal rotation than the intact and anatomical reconstruction model. The average differences between the isometric reconstruction and intact models were 4.5 mm and 3.0° for tibial anterior translation and internal rotation, respectively. The ACL tensional force in the isometric reconstruction model was significantly lower than that in the intact model. Anatomical reconstruction could closely restore the normal knee kinematics.

Clinical outcomes after anterior cruciate ligament reconstruction (ACLR) have improved remarkably. However, residual rotational instability of the knee joint remains a major concern. The anterolateral ligament (ALL) has recently gained interest as a secondary stabilizer of knee joint rotatory instability, and this has led to the attempt of ALL reconstruction (ALLR) in combination with ACLR to restore rotational stability in patients with anterior cruciate ligament (ACL) injury. Although several techniques for ALLR have recently been introduced, the ideal graft type and surgical technique for combined ACLR and ALLR are yet to be established. This technical note therefore aimed at introducing a novel surgical procedure involving the use of a single Achilles tendon allograft as a relatively simple and minimally invasive procedure for combined ALL and ACL reconstruction.

Background: Failure, persistent knee instability, and reinjury rates after anterior cruciate ligament (ACL) reconstruction are still concerns. Biomechanical investigations have highlighted the role of the anterolateral ligament (ALL) as a crucial knee stabilizer, and clinical outcomes after combined ACL and ALL reconstruction appear to indicate the success of the procedure. Purpose: To compare the functional outcomes, return-to-sport (RTS) rate, and complications between combined ACL and ALL reconstruction and isolated ACL reconstruction. Study Design: Meta-analysis; Level of evidence, 4. Methods: The PubMed/MEDLINE, Scopus, and Cochrane Central databases were used to search keywords, and a total of 16 studies were included. The data extracted for quantitative analysis included the Tegner activity scale score, Lysholm knee score, International Knee Documentation Committee (IKDC) score, laxity measured using the KT-1000 knee arthrometer, number and types of complications, RTS rate, and survival rate. Random- and fixed-effects models were used for the meta-analysis of pooled mean differences and odds ratios. Results: A total of 2329 patients were identified, 1116 of whom underwent combined ACL and ALL reconstruction and 1213 of whom underwent isolated ACL reconstruction. The mean ages were 25.4 ± 7.2 years and 26.5 ± 7.8 years for the combined ACL and ALL reconstruction and isolated ACL reconstruction groups, respectively. The mean follow-ups were 40.3 ± 21.4 months and 42.5 ± 21.6 months, respectively. Comparable Tegner activity scale (P = .16), Lysholm knee (P = .13), and IKDC (P = .83) scores were found between groups. Significantly greater postoperative knee laxity was found in the isolated ACL reconstruction group (mean difference, –0.44; 95% CI, –0.85 to −0.04; P = .03). The combined ACL and ALL reconstruction group showed a significantly lower rate of graft failure (odds ratio [OR], 0.37; 95% CI, 0.18-0.77; P = .008), a higher RTS rate (OR, 1.41; 95% CI, 1.11-1.80; P = .005), and a higher survival rate (OR, 2.94; 95% CI, 1.97-4.37; P < .001). Conclusion: Compared with isolated ACL reconstruction, combined ACL and ALL reconstruction yielded comparable functional outcomes but significantly less residual knee laxity and a lower graft failure rate. Patients who underwent combined ACL and ALL reconstruction also had higher RTS and survival rates.

SummaryBackgroundAnterior Cruciate Ligament (ACL) rupture is common knee injury. Although ACL reconstruction (ACLR) is standard, graft failure rates remain high in young active patients. This study investigated whether combining ACLR with anterolateral ligament (ALL) reconstruction (ALLR) reduces grafts failure compared with ACLR.MethodsIn this prospective, single-centre, randomised controlled trial conducted at the Santy Orthopedic Center in Lyon, France, patients aged 18–35 years with symptomatic ACL rupture were randomly allocated (1:1) to ACL + ALL reconstruction using hamstring tendon autograft (ACLR + ALLR) or ACLR with bone-patellar tendon-bone autograft (ACLR). Randomisation was performed with a block size of four using telematic software by an independent study coordinator, with concealed allocation. Surgeons were informed of the assigned procedure on the morning of surgery. Outcome assessors were not blinded. The primary outcome was graft failure at 5 years, assessed clinically and by magnetic resonance imaging (MRI) by an independent sports medicine physicians not involved in the index surgery. Efficacy analyses were performed on the Full Analysis Set in accordance with the intention-to-treat principle, while safety analyses were conducted on the Safety Set. Trial registration: ClinicalTrials.gov, ID NCT03740022. The trial has been completed.FindingsBetween November 11, 2016, and January 20, 2020, 593 patients were randomized (297 assigned to ACLR + ALLR and 296 to ACLR). The mean age was 25.0 years (SD 4.5); 447 (75%) participants were male and 146 (25%) female. Of these 593 patients, 556 (94%) completed a mean 5-year follow-up. Graft failure occurred in 12/283 (4.2%) with ACLR + ALLR versus 28/273 (10.3%) with ACLR (p = 0.006; adjusted odds ratio 2.54 [95% CI 1.27; 5.36]—p = 0.008). The number needed to treat was 17 overall, and 9 in patients younger than 25 years.InterpretationIn our study of young, active adults with ACL rupture, who are considered high-risk for graft failure, combining ACL reconstruction with anterolateral ligament reconstruction (ACLR + ALLR) significantly decreased graft failure compared with ACLR. These results suggest that ACLR + ALLR might be beneficial for young or highly active individuals and provide a basis for future research to refine patient selection, evaluate long-term outcomes beyond five years, and explore benefits in other subgroups of patients with ACL injuries.FundingGCS Ramsay Santé pour l'Enseignement et la Recherche funds the scientific activity at the Santy center.

Anterolateral Ligament Reconstruction Does Not Delay Functional Recovery, Rehabilitation, and Return to Sport After Anterior Cruciate Ligament Reconstruction: A Matched-Pair Analysis From the SANTI (Scientific ACL Network International) Study Group