Biomechanical Analysis of Tibial Motion and ACL Graft Forces After ACLR With and Without LET at Varying Tibial Slopes

Increased Posterior Tibial Slope is a Risk Factor for Anterior Cruciate Ligament Injury and Graft Failure After Reconstruction: A Systematic Review

IMPORTANCE

Anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) graft failure are important clinical concerns that result in long recovery periods, potential long-term knee instability and poor patient outcomes. Identifying risk factors such as posterior tibial slope (PTS), meniscal slope (MS) and meniscal bone angle (MBA) is important for improving risk stratification, guiding management decisions and reducing the incidence of both ACL injury and ACLR graft failure.

OBJECTIVE

This systematic review and meta-analysis aims to determine whether increased PTS, increased MS and decreased MBA serve as independent predictors of both ACL injury and ACLR graft failure.

EVIDENCE REVIEW

A comprehensive search of the literature was conducted following PRISMA guidelines. For evaluating ACL injury, the review included comparative studies measuring PTS, MS, or MBA between ACL injury patients and ACL-intact controls. For ACLR graft failure, studies comparing these measurements between patients with ACLR graft failures and those with successful ACLR outcomes were included. Data was pooled using a random-effects model to calculate the overall mean difference (MD) between groups.

FINDINGS

Out of 1,683 initially identified studies, 75 studies were selected for detailed analysis, 53 analyzing ACL injury and 24 studies analyzing ACLR graft failure. The meta-analysis revealed that increased PTS significantly increases the risk of both ACL injury (MD 1.64°; 95%CI 1.08-2.20, p<0.01) and ACLR graft failure (MD 1.76°; 95%CI 1.03-2.48, p<0.01). This is statistically significant for both lateral and medial PTS, and across both radiograph and MRI. A higher lateral MS (MD 3.25°; 95%CI 1.70-4.80, p<0.01) and a lower lateral MBA (MD -3.85°; 95%CI -6.38--1.32, p<0.01) were also significantly associated with an increased risk of ACL injury. However, no statistically significant differences were observed for MS or MBA between ACLR graft failure and successful ACLR groups.

CONCLUSION

and Relevance: The findings indicate that increased PTS, whether measured medially or laterally, is a statistically significant risk factor for both ACL injury and ACLR graft failure. Additionally, increased lateral MS and decreased lateral MBA are associated with ACL injury. This evidence supports the consideration of tibial slope in risk assessment, preoperative planning, and surgical decision-making for both prevention of ACL injury and ACLR procedures. Further research is necessary to fully understand the role of MS and MBA in ACL injury.

LEVEL OF EVIDENCE

Level IV; systematic review of level III-IV studies.

Anterior Cruciate Ligament Reconstruction With Lateral Extra-articular Tenodesis Is Associated With Reduced Risk for Revision Anterior Cruciate Ligament Reconstruction in an Insurance Claims Database

PURPOSE

To analyze a large, cross-sectional sample of patients from an administrative database for trends in the yearly utilization of either isolated anterior cruciate ligament (ACL) reconstruction or concomitant ACL reconstruction with lateral extra-articular tenodesis (ACLR/LET) for the treatment of ACL injury and to compare the cumulative incidence of 5-year reoperations and 90-day emergency visits for each treatment modality.

METHODS

International Classification of Diseases, Tenth Revision and Current Procedural Terminology codes were used to query the PearlDiver database between October 2015 and October 2022 to identify patients with a diagnosis of ACL injury undergoing either isolated ACLR or ACLR/LET. Propensity score matching was performed on the basis of age, sex, Charlson Comorbidity Index, overweight or obesity (body mass index >25.0), and tobacco use. Kaplan-Meier survival analysis was used to estimate the 5-year cumulative incidence of reoperations (revision ACLR, meniscus debridement/repair, adhesion lysis, knee joint manipulation, total knee arthroplasty) for each group.

RESULTS

In total, 1,022 patients underwent ACLR/LET, and 64,504 patients underwent ACLR for a diagnosis of ACL injury; following 1:1 propensity matching, 1,022 patients remained in each group. Patient counts for ACLR/LET increased yearly during the study period for every year except 2020, with greater than 20% increases annually after 2017. Kaplan-Meier analysis of revision ACLR in propensity-matched groups showed a 5-year cumulative incidence of 2.6% for patients undergoing ACLR/LET and 4.9% for ACLR (hazard ratio, 0.37; 95% confidence interval, 0.18-0.74; P = .005). There were no significant differences between groups and any other secondary event or postoperative complications.

CONCLUSIONS

ACLR/LET is increasingly utilized to treat patients with ACL tears and shows a decreased risk for revision ACLR without an increased risk for complications compared to patients treated with isolated ACLR.

LEVEL OF EVIDENCE

Level III, retrospective matched comparative series.

Editorial Commentary: Increased Tibial Slope and Decreased Medial Proximal Tibial Angle Negatively Affect Anterior Cruciate Ligament Graft Maturation: Objective Evidence on When to Add a Lateral Extra-Articular Augmentation Procedure to a Soft-Tissue Anterior Cruciate Ligament Reconstruction

Recent anterior cruciate ligament (ACL) research focuses on risk factors for ACL graft failure and techniques and augmentations to limit failure. One of the most recognized risk factors is sagittal malalignment in the form of high posterior tibial slope (PTS), especially PTS ≥12°, which leads to increased force through the ACL and ACL graft. To reduce the risk associated with increased PTS, lateral augmentation techniques, typically either a lateral extra-articular tenodesis or an anterolateral ligament reconstruction, improve clinical outcomes, and the authors preferred graft choice, particularly in such cases, is bone-patellar tendon-bone autograft. Furthermore, in revision cases, there exists a strong argument to perform a slope reducing osteotomy to correct bony malalignment which, if left untreated, could lead to ACL graft failure. Slope-reducing osteotomies are reported to significantly decrease anterior tibial translation and forces on the ACL graft. Coronal malalignment is also a risk factor for ACL failure (although not as extensively studied as sagittal alignment). Both varus and valgus alignment of the knee can lead to increased forces through the ACL or ACL graft compared with knees in neutral alignment, and workup requires proper lateral and long-leg anteroposterior radiographs to determine sagittal and coronal alignment and guide treatment algorithms. Recent research shows that decreased medial proximal tibial angle of the knee (increasing varus alignment of the tibia) may delay graft maturation. However, there is yet to be a consensus about what exactly contributes to ACL graft failure in the coronal plane and what is the best treatment option, especially in the primary setting when an osteotomy is not indicated. Again, we recommend bone-patellar tendon-bone autograft as our preferred graft choice unless contraindicated by skeletal immaturity.

Around-the-knee osteotomies part 1: definitions, rationale and planning-state of the art

Knee osteotomies are essential orthopedic procedures with the ability to preserve the joint and correct ligament instabilities. Literature supports the correlation between lower limb malalignment and outcomes after knee ligament reconstruction and cartilage procedures. Concepts such as joint line obliquity, posterior tibial slope angle, and intra-articular deformity correction are integral components of both preoperative planning and postoperative evaluations. The concept of preserving and/or restoring joint line congruence during simultaneous correction of varus or valgus deformity can be achieved through several different approaches. With advancements in osteotomy research and surgical planning technology, the surgical decision-making has increased in complexity. Based upon a patient's specific deformity, decisions need to be made whether to perform a single-level (proximal tibia or distal femur) versus double-level (both proximal tibia and distal femur) osteotomy, and whether to correct deformity in a single plane (coronal or sagittal) or perform a biplanar osteotomy, correcting two of the malalignments in either coronal, sagittal, or axial planes. Osteotomy procedures prioritize safety, reproducibility, precision, and meticulous planning. Equally important is the proactive management of possible complications and the implementation of preventive strategies for complications such as hinge fractures and unintentional changes to alignment in other planes. This review navigates the intricate landscape of lower limb alignment, commencing with foundational definitions and rationale for performing osteotomies, progressing through the planning phase, and addressing the critical aspect of complication prevention, all while looking ahead to anticipate future advancements in this field. However, rotational osteotomies and tibial tubercle osteotomies in isolation or as an adjunct procedure are beyond the scope of this review.

Finite element graft stress for anteromedial portal, transtibial, and hybrid transtibial femoral drillings under anterior translation and medial rotation: an exploratory study

Stress concentration on the Anterior Cruciate Ligament Reconstruction (ACLr) for femoral drillings is crucial to understanding failures. Therefore, we described the graft stress for transtibial (TT), the anteromedial portal (AM), and hybrid transtibial (HTT) techniques during the anterior tibial translation and medial knee rotation in a finite element model. A healthy participant with a non-medical record of Anterior Cruciate Ligament rupture with regular sports practice underwent finite element analysis. We modeled TT, HTT, AM drillings, and the ACLr as hyperelastic isotropic material. The maximum Von Mises principal stresses and distributions were obtained from anterior tibial translation and medial rotation. During the anterior tibia translation, the HTT, TT, and AM drilling were 31.5 MPa, 34.6 Mpa, and 35.0 MPa, respectively. During the medial knee rotation, the AM, TT, and HTT drilling were 17.3 MPa, 20.3 Mpa, and 21.6 MPa, respectively. The stress was concentrated at the lateral aspect of ACLr,near the femoral tunnel for all techniques independent of the knee movement. Meanwhile, the AM tunnel concentrates the stress at the medial aspect of the ACLr body under medial rotation. The HTT better constrains the anterior tibia translation than AM and TT drillings, while AM does for medial knee rotation.

Over-the-Top Double-Bundle Revision Anterior Cruciate Ligament Reconstruction Technique With Hybrid Hamstring Tendon Autograft-Allograft and Associated Lateral Extra-articular Tenodesis

Revision anterior cruciate ligament (ACL) presents many technical challenges that are not commonly seen in primary ACL reconstruction. The purpose of this article is to describe an alternative technique consisting of over-the-top double-bundle ACL revision combined with lateral extra-articular tenodesis using hybrid hamstring tendon autograft-allograft. This technique provides a valid treatment option in ACL revision surgery.

Why Your Patient May Need an ACL Reconstruction Plus Lateral Extra-Articular Tenodesis Procedure

Anterior cruciate ligament (ACL) tears are one of the most common knee injuries experienced by active individuals engaging in cutting sports. Despite improved surgical techniques and rehabilitation, the return to sport rate and re-tear rates remain unsatisfactory. Lateral extra-articular tenodesis (LET) is a procedure that has been growing in interest when performed in conjunction with ACL reconstruction. The benefits of adding an LET procedure to an ACL surgery may include greater rotational stability, decreased re-tear rates, and improved return to play. Level of evidence: V.