The biomechanical function of the anterolateral ligament of the knee

It is challenging to reproduce both anatomical and functional aspects of anterolateral reconstruction: postoperative 3D-CT analysis of the femoral tunnel position

BACKGROUND

This study aimed to evaluate the femoral tunnel position and fiber length of the anterolateral ligament (ALL) reconstruction compared with the natural anatomy of the ALL. We also evaluated whether the femoral tunnel position would affect residual pivot shift.

METHODS

This study was a retrospective review of 55 knees that underwent ALL reconstruction considering the anatomical and functional aspects, during primary anterior cruciate ligament (ACL) reconstruction in the presence of a high-grade pivot shift or revisional ACL reconstruction. We determined the position of the femoral tunnel and the length of graft using a three-dimensional (3D)-computed tomography (CT) model after ALL reconstruction. We also measured graft excursion during surgery and examined pivot shift 2 years after surgery. We conducted a subgroup analysis of femoral tunnel position, fiber length, isometricity, and residual pivot shift depending on whether the tunnel was anterior or posterior to the lateral epicondyle (LE). We also performed a subgroup analysis depending on whether the ACL reconstruction was primary or revisional.

RESULTS

The mean femoral tunnel position was 2.04 mm posterior and 14.5 mm proximal from the center of the LE. The mean lengths of the anterior and posterior fibers were 66.6 and 63.4 mm, respectively. The femoral tunnel was positioned more proximally than the anatomical position, and both anterior and posterior ALL fibers were longer than the natural anatomy. The anteroposterior femoral tunnel position was significantly correlated with anterior (p = 0.045) and posterior (p = 0.037) fiber excursion. In the subgroup analysis, there was no significant difference in the residual pivot shift between the posterior and anterior tunnel positions. However, there were significant differences for proximal position (p < 0.001) and fiber length (p = 0.006). There was no significant difference between primary and revisional ACL regarding femoral tunnel position and fiber lengths.

CONCLUSION

It is challenging to reproduce both anatomical and functional aspects of ALL reconstruction in both primary and revision ACL reconstruction. Especially for functional reconstruction, the femoral tunnel tended to be positioned more proximally than the anatomical position. However, the femoral tunnel position did not affect functional clinical outcomes at the 2-year follow-up.

LEVEL OF EVIDENCE

Level IV Case series.

Combined Anterolateral Ligament Reconstruction Results in Better Knee Stability and More Satisfactory Subjective Outcomes in Non-Athlete Patients Undergoing Revision Anterior Cruciate Ligament Reconstruction

Background: Consensus has not yet been reached regarding combined anterior cruciate ligament reconstruction (ALLR) with revisional anterior cruciate ligament reconstruction (RACLR). We aimed to compare the clinical outcomes between patients who underwent isolated RACLR and those who underwent RACLR combined with ALLR. Methods: Between June 2010 and June 2021, 49 patients who underwent RACLR were retrospectively reviewed over a 24-month follow-up. Patients were categorized into the isolated RACLR (n = 37, group 1) or combined ALLR group (n = 12, group 2). Clinical outcomes were evaluated with several patient-reported outcome measures (PROMs) and minimal clinically important differences (MCIDs) for each PROM. The side-to-side difference (SSD) of the anterior instability was measured. The pivot-shift test was performed. Results: Baseline characteristics showed no differences between the groups. PROMs showed no significant differences between the groups at the 2-year follow-up. Group 2 was superior to group 1 in the MCID achievement rate for Lysholm knee and International Knee Documentation Committee (IKDC) subjective scores at 24 months postoperatively. At the final follow-up, the proportion of IKDC grade A in SSD for anterior laxity was higher in group 2 than in group 1 (58.3% versus [vs.] 18.3%, p = 0.009), and the proportion of pivot-shift grade 0 was also higher in group 2 (66.7% vs. 27.0%, p = 0.013). The "near return to activity" rate was also higher in group 2 than in group 1 (83.3% vs. 45.9%, p = 0.043). Conclusions: Combining ALLR with RACLR in non-athletes results in a higher proportion of patients with less mechanical graft failure and satisfactory clinical outcomes.

Combined ACLR and lateral extra-articular tenodesis with a continuous iliotibial band autograft is a viable option in a population of athletes who participate in pivoting sports

PURPOSE

The aim of this study was to evaluate the clinical results, return to sport and complications after anterior cruciate ligament reconstruction (ACLR) associated with lateral extra-articular tenodesis using continuous plasty with an iliotibial band.

METHODS

This was a prospective multicentre study involving 186 patients who had surgery for anterior cruciate ligament (ACL) rupture. Patients with multiligament ruptures and revision surgery were excluded from the study. All patients included were involved in pivoting sports and wished to resume their activity after surgery. Patients were assessed at a minimum 2-year follow-up using functional and psychological questionnaires (subjective International Knee Documentation Committee [IKDC], Tegner, Lysholm and ACL-RSI scores), ligament assessment including instrumented laxity measurement (Rolimeter), Lachman test and pivot shift and isokinetic testing. Return to sport was assessed using a questionnaire, and complications and repeat surgeries were recorded.

RESULTS

At a mean follow-up of 43.1 months, the subjective IKDC, Lysholm, ACL-RSI and objective IKDC scores were significantly improved (59.8 vs. 94.5 p < 0.0001, 75 vs. 99 p < 0.0001, 60 vs. 93 p < 0.0001, IKDC A 0% vs. 72%, B 12% vs. 27%, C 60% vs. 1% D 28% vs. 0% p < 0.0001). The Tegner activity level was 9 (3-10) before the accident and 9 (3-10) at the last review. Seventy-six percent of the patients had returned to sports at the same level. The differential laxity was 6.6 mm (±1.7) preoperatively and 1.1 mm (±1.4) postoperatively. Additionally, 97% were equal in pivot shift at the last follow-up. At the 6-month isokinetic assessment, the muscle strength recovery for the quadriceps and hamstring was over 85% compared with the healthy side for 79% and 70% of the patients, respectively. Ten patients had graft rupture (5.6%). Four (2.4%) patients had a contralateral ACL rupture, and seven (4%) underwent a reoperation with meniscectomy.

CONCLUSION

Anterior ligament reconstruction with lateral extra-articular tenodesis using a continuous strip of iliotibial band enables 76% of patients in a population with a high demand for sports to resume their activities at the same level. The clinical results and complication rates, particularly reruptures (5.6%), were similar to those of other techniques involving lateral extra-articular tenodesis.

LEVEL OF EVIDENCE

Level II.

The Anterolateral Ligament of the Knee Is a Nonisometric Thin Ligament With High Prevalence and Almost Constant Attachment to the Lateral Meniscus: A Systematic Review With Meta-analysis

PURPOSE

To provide comprehensive information about the anterolateral ligament (ALL) prevalence, morphometry, isometry, insertions, histology, and its relationship with the lateral meniscus (LM).

METHODS

The study was performed, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Eligible cadaveric studies investigating the frequency of the ALL presence, and anatomical features were identified through an online search of the PubMed, Scopus, and Cochrane Central databases from inception to June 2022. Statistical analysis was conducted with the open-source R programming language using the "meta" package. The Higgins I2 statistic was used for quantifying heterogeneity.

RESULTS

Thirty-three studies (1,478 cadaveric knees) were included. The ALL had a 79% prevalence. It was attached to the LM periphery in 97% of studies. Most studies reported a femoral insertion of the ALL, just proximal and posterior to the lateral epicondyle. Tibial attachment is constant at the midpoint between Gerdy's tubercle and fibular head. The mean ALL thickness at the joint line was 1.6 [1.2; 2.0] mm. The ALL length was found to significantly change across the knee flexion (P < .01). It was increased from 0° to 60° and decreased after 60° flexion. Seven histological studies demonstrated a typical ligamentous microstructure.

CONCLUSION

The ALL is a thin ligament, distinct to the knee capsule, which may be found in 79% of the knees having an almost constant attachment to the LM. The ALL is not isometric. It becomes tense during internal rotation and between 30° and 60° knee flexion. Pooled results should be interpreted with caution due to the high heterogeneity among the included studies.

CLINICAL RELEVANCE

This study sheds light on controversial issues and provides comprehensive and accurate information about the essential anatomical knowledge on ALL, which may contribute to optimizing ALL reconstruction surgical techniques and biomechanical settings.

A lateral extra-articular tenodesis without additional hardware: Surgical technique and biomechanical comparison with an anatomic anterolateral ligament reconstruction in the augmentation of anterior cruciate ligament reconstruction

BACKGROUND

The aims of this study were to describe a lateral extra-articular tenodesis (LET) using no additional hardware and compare the tibiofemoral kinematics of anterior cruciate ligament (ACL) reconstruction augmented with either the LET or a standard anatomic anterolateral ligament (ALL) reconstruction using intra-tunnel fixation.

METHODS

Ten cadaveric knees were mounted on a robotic testing system and underwent a kinematic assessment of anterior tibial translation and internal tibial rotation under a simulated pivot-shift in the following states: ACL-intact, ACL-sectioned, ACL-sectioned/anterolateral complex (ALC)-sectioned, ACL-reconstructed/ALC-sectioned, ACL-reconstructed/ALL-reconstructed, and ACL-reconstructed/LET. For the LET, an iliotibial autograft was passed under the fibular collateral ligament and secured to the femur with the pull sutures of the ACL reconstruction femoral cortical suspensory fixation device, positioned at the distal ridge of Kaplan's fibers.

RESULTS

Anterior tibial translation was restored to normal by ACL reconstruction without meaningful benefit of augmentation with LET or ALL. ACL reconstruction restored internal tibial rotation close to normal between 0° and 30°, but increased internal tibial rotation persisted between 45° and 90°. Augmentation of ACL reconstruction with the LET reduced internal rotation close to normal between 45° and 90°, whereas increased internal rotation persisted after ALL reconstruction.

CONCLUSION

ACL reconstruction and LET are complementary in controlling tibiofemoral kinematics of knees with a combined ACL and ALC injury: ACL reconstruction restored native tibiofemoral kinematics except for internal rotation at flexion greater than 30°. The increased internal rotation at flexion greater than 30° was restored to normal with an LET, but not with an ALL reconstruction.

Anterolateral Ligament and Kaplan Fiber Injury Both Occur Frequently in Acute Anterior Cruciate Ligament-Injured Knees

BACKGROUND AND OBJECTIVES

The association of ALL and KF injuries in anterior cruciate ligament (ACL)-deficient knees remain topics of conflicting research despite improved magnetic resonance imaging (MRI). We aimed to evaluate the rate of the anterolateral ligament (ALL) and Kaplan fibers (KF) injuries in adults with acute ACL injuries using MRI.

METHODS

We retrospectively reviewed 64 patients with clinical and MRI diagnoses of acute ACL tears. Two radiologists analyzed and categorized the status of the ALL and KF in all patients as intact, partially injured, or completely injured. Interobserver agreement was assessed. Injuries to the collateral ligaments, ITB and posterior cruciate ligament (PCL) were also evaluated.

RESULTS

The mean age of the patients was 33 years. ALL injuries were observed in 46 (71%) patients, among whom 33 (71%) had partial and 13 (28%) had complete injuries. KF injuries were identified in 32 (50%) patients, with 28 (87.5%) of them having partial and 4 (12.5%) having complete injuries. Combined injuries of both ALL and KF were found in 25 (32.4%) patients (p-value of 0.266). The agreement between the examiners ranged from moderate to substantial (Kappa between 0.55 and 0.75), with the highest agreement observed in cases of KF injuries (Kappa = 0.75).

CONCLUSIONS

ALL and KF injuries were prevalent in acute ACL-injured knees with rates of injury of 71% and 50%, respectively. ALL injuries were more frequent and more frequently severe compared to KF injuries.

The Role of Anterolateral Ligament Reconstruction or Lateral Extra-articular Tenodesis for Revision Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Comparative Clinical Studies

BACKGROUND

After its success in restoring rotational stability and reducing failure rates in primary anterior cruciate ligament reconstruction (ACLR), lateral extra-articular tenodesis (LET) or anterolateral ligament reconstruction (ALLR) has been endorsed for use in revision ACLR surgery, where failure rates are historically higher.

PURPOSE

To perform a systematic review and meta-analysis on whether the addition of a LET or ALLR results in superior clinical outcomes and stability compared with isolated revision ACLR (iACLR).

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

The Cochrane Controlled Register of Trials, PubMed, Medline, and Embase were used to perform a systematic review and meta-analysis of comparative studies using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria with the following search terms: ("extra-articular" OR "tenodesis" OR "anterolateral ligament" OR "iliotibial") AND ("anterior cruciate ligament") AND ("revision" OR "re-operation"). Data pertaining to all patient-reported outcome measures (PROMs), rotational stability, and postoperative complications were extracted from each study.

RESULTS

After abstract and full-text screening, 10 clinical comparative studies were included. There were 793 patients, of whom 390 had an iACLR while 403 had an ACLR augmented with a LET or an ALLR (augmented ACLR [aACLR]). The mean time for assessment of PROMs was 35 months. The aACLR group had superior International Knee Documentation Committee (IKDC) scores (standardized mean difference [SMD], 0.27; 95% CI, 0.01 to 0.54; P = .04), rotational stability (odds ratio [OR], 2.77; 95% CI, 1.91 to 4.01; P < .00001), and lower side-to-side difference (OR, -0.53; 95% CI, -0.81 to -0.24; P = .0003) than those without the augmentation. Furthermore, they were less likely to fail (OR, 0.44; 95% CI, 0.24 to 0.80; P = .007). Subgroup analysis in the higher-grade laxity cohort (grade ≥2) revealed an even greater IKDC score (SMD, 0.51; 95% CI, 0.16 to 0.86; P = .005) and an improved Lysholm score (SMD, 0.45; 95% CI, 0.24 to 0.67; P < .0001) in the aACLR group.

CONCLUSION

Revision aACLR with a LET or an ALLR can improve subjective IKDC scores, restore rotational stability, and reduce failure rates compared with iACLR. Although controversy remains on the necessity of augmenting all revision ACLRs, the present meta-analysis advocates adding a lateral procedure, particularly in those with a higher-grade pivot shift.

The Anterolateral Ligament of the Knee in Pediatric Patients: What Do We Know? A Scoping Review

The knowledge on the anatomy, function and biomechanics and the role of surgical procedures on the anterolateral ligament (ALL) of the knee is still controversial. Only a few papers have examined the ALL in children. The aim of this review is to analyze all the available literature about ALL in the pediatric population. Following the PRISMA criteria, the literature was systematically reviewed, examining all the articles about ALL in pediatric patients. Eight articles were involved in this study. Five cadaveric studies, two diagnostic studies, and one cross-sectional study were found. The identification of the ALL is not always possible in diagnostic studies using magnetic resonance (MRI) or in dissecting specimens. A high variability in the presence of the ligament and in its origin and insertion were found among the studies. It is more difficult to identify the ligament in younger patients than in older children, suggesting that its presence may develop at some point during the growth. Further studies are needed for a detailed knowledge of the ALL.

Localizing the position of the Segond fracture bed under CT measurements to determine the functional tibial insertion of an anterolateral ligament

Background

Many studies have confirmed the existence of ligament structures in the anterolateral region of the knee that maintain rotational stability of the knee joint, namely, the anterolateral ligament (ALL). Most scholars believe that knee joint reconstruction should be considered during revision surgery and a high level of pivot displacement test (stage 2 or 3). During ALL reconstruction, the choice of ligament reconstruction sites affects the success rate and prognosis of the operation. Therefore, the choice of ligament reconstruction sites is particularly important. There is little research on the lateral ALL tibia insertion point, and most clinicians use the midpoint Gerdy's tubercle and fibular head as insertion points. However, the reconstruction effect is not ideal.

Objective

This study aims to measure the position of the Segond fracture bed on CT images to determine the ALL position of the tibia.

Method

To determine the position of the Segond fracture bone bed, the CT AM Volume Share 2 system was used to manually measure the position of bone fragments in 23 Segond fracture patients. Using the highest point of Gerdy's tubercle in the CT axial slices and the outermost point of the fibular head in the CT axial slices as reference points, the direction and angle of the CT slices were adjusted to ensure that the highest point of the Gerdy tubercle, the outermost point of the fibular head, and the center of Segond fracture bed were in the same sagittal slice. A CT sagittal slice measures the vertical distance from the center of the Segond fracture bed to the Gerdy-fibular line segment (G-F line segment), which is the line connecting the highest point of the segment to the outermost point of the fibula. The distance from the vertical point at the center of the Segond fracture bed of the G-F line to the highest point of the Gerdy tubercle was measured. All measurements were performed using the same measurement standard and were expressed as a percentage of the length of the G-F line. The measured results were statistically analyzed using SPSS 25.0 descriptive statistical research methods.

Results

The average length of the G-F segment measured on CT images was 39.6 ± 2.0 mm, and the average vertical length from the center of the Segond fracture bed to the G-F segment was 13.1 ± 1.1 mm, accounting for 33.2% ± 2.1% of the length of the G-F segment. The length from the vertical point of the fracture bed on the G-F line segment to the highest point of the Gerdy tubercle was 14.7 ± 1.3 mm, accounting for 37.1% ± 2.9% of the length of the G-F segment.

Conclusion

Through the study of the CT measurement of the Segond fracture location, we obtained the location of the functional tibial insertion of ALL, which is different from the anatomical insertion of ALL and is more inclined to the Gerdy tubercle and above, which has reference value for the treatment of recovering the function of anterolateral ligament after reconstruction.

Association of medial collateral ligament complex injuries with anterior cruciate ligament ruptures based on posterolateral tibial plateau injuries

BACKGROUND

The combined injury of the medial collateral ligament complex and the anterior cruciate ligament (ACL) is the most common two ligament injury of the knee. Additional injuries to the medial capsuloligamentous structures are associated with rotational instability and a high failure rate of ACL reconstruction. The study aimed to analyze the specific pattern of medial injuries and their associated risk factors, with the goal of enabling early diagnosis and initiating appropriate therapeutic interventions, if necessary.

RESULTS

Between January 2017 and December 2018, 151 patients with acute ACL ruptures with a mean age of 32 ± 12 years were included in this study. The MRIs performed during the acute phase were analyzed by four independent investigators-two radiologists and two orthopedic surgeons. The trauma impact on the posterolateral tibial plateau and associated injuries to the medial complex (POL, dMCL, and sMCL) were examined and revealed an injury to the medial collateral ligament complex in 34.4% of the patients. The dMCL was the most frequently injured structure (92.2%). A dMCL injury was significantly associated with an increase in trauma severity at the posterolateral tibial plateau (p < 0.02) and additional injuries to the sMCL (OR 4.702, 95% CL 1.3-133.3, p = 0.03) and POL (OR 20.818, 95% CL 5.9-84.4, p < 0.0001). Isolated injuries to the sMCL were not observed. Significant risk factors for acquiring an sMCL injury were age (p < 0.01) and injury to the lateral meniscus (p < 0.01).

CONCLUSION

In about one-third of acute ACL ruptures the medial collateral ligament complex is also injured. This might be associated with an increased knee laxity as well as anteromedial rotational instability. Also, this might be associated with an increased risk for failure of revision ACL reconstruction. In addition, we show risk factors and predictors that point to an injury of medial structures and facilitate their diagnosis. This should help physicians and surgeons to precisely diagnose and to assess its scope in order to initiate proper therapies. With this in mind, we would like to draw attention to a frequently occurring combination injury, the so-called "unlucky triad" (ACL, MCL, and lateral meniscus). Level of evidence Level III Retrospective cohort study.

Sharing of proximal fibers by the anterolateral and lateral collateral ligaments in the human knee: a cadaveric study

Literature is highly inconsistent in describing the proximal attachment of the anterolateral ligament (ALL) and its relationship with the lateral collateral ligament (LCL) in human knees. This observational study aims to investigate that lacuna. The gross dissection was performed in the lower limbs (n = 83) from the donated adult-age (> 18 years) embalmed cadavers from medical institutions in the north and east India. The dissected knee specimens were first examined macroscopically. Further routine and special staining and microscopic examinations were performed. The ALL was absent in approximately 20.4% of the studied knee specimens (17/83). In remaining, the sharing of ALL and LCL proximal fibers was observed as a consistent finding (~ 97%) with rare exceptions. The mean length of the tibial and meniscal limbs of ALL was 1.57 ± 0.8 cm [Range (R) 0.5-4 cm] and 0.73 ± 0.47 cm [Range (R) 0.1-1.6 cm], respectively. In addition, multiple variations in its presentation were observed. We propose that the proximal sharing of LCL-ALL fibers is a dominant feature in the studied population. The sharing of the fibers may impact the biomechanics and injury mechanisms for both ligaments. The possibility of ethnic variations in the ALL morphology should be a concern during reconstruction surgery.

Additional Anterolateral Ligament Reconstruction Helps Patients Improve Dynamic Postural Stability in Revision Anterior Cruciate Ligament Reconstruction

Background and Objectives: The goal in treating anterior cruciate ligament (ACL) injury especially in revision cases is return to sports activity by regaining dynamic postural stability. Among various methods to achieve this goal, additional anterolateral ligament reconstruction (ALLR) is gaining attention. The purpose of this study was to evaluate the effects of additional ALLR in revision ACL reconstruction (RACLR). Materials and Methods: Patients who underwent RACLR between July 2015 and June 2018 were enrolled. The exclusion criteria were less than 1-year follow-up, age older than 45 years, concomitant multiple ligament injuries, contralateral knee injury, subtotal or total meniscectomized state, and articular cartilage lesions worse than Outerbridge grade 3. Thirty-nine patients (20 patients; RACLR only (Group A), 19 patients; RACLR with additional ALLR (Group B)) were included. Clinical scores (Lysholm score, subjective International Knee Documentation Committee (IKDC) score, Tegner activity scale), isokinetic strength test, single-leg-hop for distance test (SLHDT), Y-balance test (YBT) were checked preoperatively and 1-year postoperatively. Results: Limb symmetry index values in YBT showed significantly better result in Group B 1-year postoperatively (Group A: 97.2 ± 4.0, Group B: 100.3 ± 2.9, p = 0.010), although there were no differences preoperatively between groups (Group A: 90.4 ± 6.7, Group B: 89.3 ± 5.5, p = 0.594). Regarding clinical scores, isokinetic strength tests, and SLHDT, there were no differences between groups preoperatively nor 1-year postoperatively. Conclusions: Additional ALLR in RACLR helped patients gain better dynamic postural stability at 1-year postoperative follow-up.

Untreated Injuries to the Anterolateral Capsular Structures Do Not Affect Outcomes and Kinematics after Anatomic Anterior Cruciate Ligament Reconstruction

BACKGROUND

Injuries to the anterolateral complex (ALC) may contribute to increased rotatory knee laxity. However, it has not been evaluated whether such injuries affect in vivo kinematics when treated in situ. The purpose of this study was to determine the grade of ALC injury and its effect on kinematic and clinical outcomes of ACL-injured patients 24 months after anatomic ACL reconstruction. It was hypothesized that injury to the ALC would be significantly related to patient-reported outcomes (PROs) and in vivo knee kinematics during downhill running.

METHODS

Thirty-five subjects (mean age: 22.8 ± 8.5 years) participating in a randomized clinical trial to compare single- and double-bundle ACL reconstruction were included in the study. Subjects were divided into two groups based on the presence or absence of injury to the ALC, as determined on MRI scans performed within 6 weeks of injury. None of the patients underwent treatment for these ALC injuries. At 24 months, PROs, including the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), Knee injury and Osteoarthritis Outcome Score (KOOS) and in vivo knee kinematics during downhill running, were obtained. Pivot-shift test results, PROs and in vivo knee kinematics were compared between groups with and without ALC injury using the Pearson's Chi Squared test and Mann-Whitney U test with significance set at p < 0.05.

RESULTS

The average interval between injury and performing the MRI scans was 9.5 ± 10 days. ALC injury was observed in 17 (49%) study participants. No significant differences were detected in PROs and in vivo kinematics between subjects with and without ALC injury (n.s.).

CONCLUSION

The findings of this study demonstrate that MRI evidence of an ALC injury does not significantly affect in vivo knee kinematics and PROs even in individuals with a high-grade ALC injury. Injuries to the ALC as observed on MRI might not be a useful indication for an anterolateral procedure.

Radiographic Incidence of Knee Osteoarthritis After Isolated ACL Reconstruction Versus Combined ACL and ALL Reconstruction: A Prospective Matched Study From the SANTI Study Group

BACKGROUND

Combined anterior cruciate ligament (ACL) reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) have demonstrated reduced risk of graft rerupture as compared with isolated ACLR. However, concerns remain that the risk of osteoarthritis (OA) may be increased by the addition of ALLR.

PURPOSE/HYPOTHESIS

The aim of this study was to evaluate the incidence of OA with isolated ACLR in comparison with ACLR + ALLR at medium-term follow-up. We hypothesized that there would be no differences between the groups.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent ACLR + ALLR with hamstring tendon autograft between January 2011 and March 2012 were propensity matched to patients who underwent isolated ACLR with bone-patellar tendon-bone (BPTB) or hamstring tendon autograft in the same period. Medium-term radiographic evaluation was performed using the International Knee Documentation Committee (IKDC) radiographic OA grading scale, modified Kellgren-Lawrence grade, and the surface fit method to assess percentage of joint space narrowing. Clinical outcomes were assessed with the following measures: IKDC, Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm, Tegner, and ACL Return to Sport after Injury.

RESULTS

A total of 80 patients (42 ACLR + ALLR and 38 isolated ACLR) were analyzed with a mean follow-up of 104 months. There was no significant difference between groups for joint space narrowing in the medial or lateral tibiofemoral or lateral patellofemoral (PF) compartment. However, 36.8% in the isolated ACLR group versus 11.9% in the ACLR + ALLR group had narrowing of the medial PF compartment (P = .0118). A lateral meniscal tear increased the risk of lateral tibiofemoral narrowing by nearly 5 times (odds ratio, 4.9; 95% CI, 1.547-19.367; P = .0123). The risk of medial PF narrowing was >4-fold with an isolated ACLR (odds ratio, 4.8; 95% CI, 1.44-19.05; P = .0179). Between the isolated ACLR group and the ACLR + ALLR group, the secondary meniscectomy rate was 13.2% versus 11.9% (not significantly different). There was no difference between groups in KOOS, Tegner, or IKDC scores. There was also no difference between groups for grades of osteoarthritic change for any classification system. Patients who received a BPTB graft had medial PF joint narrowing in 66.7% of cases as compared with 11.9% in those who received ACLR + ALLR (P = 0.118).

CONCLUSION

ACLR + ALLR did not increase the risk of OA in the lateral tibiofemoral compartment when compared with an isolated ACLR at medium-term follow-up. Isolated ACLR using BPTB was associated with a significantly increased risk of medial PF joint space narrowing.

REGISTRATION

NCT05123456 (ClinicalTrials.gov identifier).

Characterizing the viscoelastic properties of the anterolateral ligament and grafts commonly used in its reconstruction

BACKGROUND

Current anatomic anterolateral ligament reconstruction is typically performed using either a gracilis tendon or an iliotibial band graft based on their quasi-static behavior. However, there is limited knowledge about their viscoelastic behaviors. This study aimed to characterize the viscoelastic properties of the anterolateral ligament, distal iliotibial band, distal gracilis tendon and proximal gracilis tendon for graft material choice in anterolateral ligament reconstruction.

METHODS

All the tissues were harvested from thirteen fresh-frozen cadaveric knees and subjected to preconditioning (3-6 MPa), sinusoidal cycle (1.2-12 MPa), dwell at constant load (12 MPa), and load to failure (3%/s). The quasi-static and viscoelastic properties of the soft tissues were computed and compared using a linear mixed model (p < 0.05).

FINDINGS

The hysteresis of anterolateral ligament (mean:0.4 Nm) was comparable with gracilis halves (p > 0.85) but iliotibial band (6 Nm) was significantly higher (p < 0.001,ES = 6.5). In contrast, the dynamic creep of anterolateral ligament (0.5 mm) was similar to iliotibial band (0.7 mm, p > 0.82) whereas both gracilis halves were significantly lower (p < 0.007,ES > 1.4). The elastic modulus of anterolateral ligament (181.4 MPa, p < 0.001,ES > 2.1) was the lowest compared to the grafts materials (distal gracilis tendon:835 MPa, distal gracilis tendon:726 MPa, iliotibial band:910 MPa). Additionally, the failure load of the anterolateral ligament (124.5 N, p < 0.001,ES > 2.9) was also the lowest.

INTERPRETATION

The mechanical properties of the gracilis halves and iliotibial band were significantly different from anterolateral ligament, except for hysteresis and dynamic creep, respectively. Our findings showed that the gracilis halves may be a more appropriate graft choice for anterolateral ligament reconstruction due to its low energy dissipation and permanent deformation under dynamic loads.

Surgical Treatment for Avulsion Fractures of the Anterolateral Ligament Associated with Periarticular Fractures of the Knee

The existence and anatomy of the anterolateral ligament (ALL) of the knee are a somewhat controversial topic in orthopaedic surgery. The fixation of the avulsion fracture of the ALL (Segond fracture), associated with periarticular knee fractures, is rarely given much consideration while the major fracture fragments are reconstructed. This study aims to confirm the existence of ALL and evaluate the clinical outcomes of surgical management for avulsion fractures, involving its insertion, when associated with periarticular knee fractures. Twenty-three patients (16 males and 7 females) with avulsion fractures of the ALL associated with periarticular knee fractures were fixed with a spider plate, cannulated screw, or suture anchor. Eight patients were diagnosed with distal femoral fracture, 10 with tibial plateau fracture, and 5 with tibial eminence avulsion fracture. All patients underwent X-rays at follow-up. Clinical and functional outcomes were assessed with the pivot-shift test, objective and subjective International Knee Documentation Committee (IKDC) score, Lysholm score, and Tegner activity scale. The ALL was found and identified as a distinct ligamentous structure in all patients. Prior to Segond repair, patients had significantly more instability, as determined by pivot-shift test, than seen postoperatively (p < 0.0001). At final follow-up, the mean subjective IKDC score was 83.2 ± 10.3. Fourteen patients were graded A, 6 were graded B, and 3 was graded C on the IKDC objective score. The mean Lysholm score was 85.4 ± 12.2. The mean Tegner score was 7.5 ± 1.2. This study confirmed that the ALL is a distinct structure in the anterolateral portion of the knee. The fixation of the avulsion fracture of the ALL associated with periarticular knee fractures can be an effective procedure without specific complications. Long-term and comparative follow-up studies are necessary to confirm the effects.

Comparison of Anterior Cruciate Ligament Reconstruction With Versus Without Anterolateral Augmentation: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

It is clear that the anterolateral ligament has an important role in rotational knee stability. However, whether patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) can benefit from anterolateral augmentation (ALA) is still controversial.

Purpose

To compare the effects of isolated ACLR versus ACLR combined with ALA (ACLR+ALA) on clinical outcomes and knee stability.

Study Design

Systematic review; Level of evidence, 1.

Methods

The methodology followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A literature search of the PubMed, Embase, and Cochrane Library Central Register of Controlled Trials databases was undertaken to identify all randomized controlled trials (RCTs) comparing isolated ACLR with ACLR+ALA for the treatment of ACL injuries in the last 15 years. The Cochrane Collaboration risk-of-bias tool and the revised Jadad scale were utilized by 2 independent reviewers to determine the quality of RCTs. Relevant data were extracted and compared between procedures, and heterogeneity across the RCTs was assessed using the I ² statistic.

Results

The initial search yielded 849 articles. A total of 14 studies (1850 patients; 941 ACLR and 909 ACLR+ALA) satisfied the eligibility criteria for the meta-analysis. There were no significant differences between the procedures in terms of patient-reported outcomes (International Knee Documentation Committee score, Tegner score, Knee injury and Osteoarthritis Outcome Score) or return-to-sport rates. However, patients who underwent ACLR+ALA had better knee stability based on the pivot-shift test (risk ratio [RR], 1.06 [95% CI, 1.02 to 1.10]; P = .0008), Lachman test (RR, 1.03 [95% CI, 1.00 to 1.07]; P = .04), and side-to-side difference in anterior laxity (standardized mean difference, -0.55 [95% CI, -0.98 to -0.12]; P = .01) as well as a lower incidence of graft failure (RR, 0.30 [95% CI, 0.19 to 0.45]; P < .01) compared with patients who underwent isolated ACLR.

Conclusion

ALA can be considered as a reinforcement of ACLR to improve anteroposterior and anterolateral rotational stability of the knee and reduce the risk of failure. The patient-reported outcomes of isolated ACLR were similar to those of ACLR+ALA, and both procedures provided improved knee function.

Particularities on Anatomy and Normal Postsurgical Appearances of the Knee

Detailed knowledge of anatomy helps to understand pathologic processes. This article focuses on the anatomy and functionality of the knee, with emphasis on recently studied concepts and anatomic features that have an association with the development of pathology. The most common anatomic variants posing a challenge for diagnosis and other common findings in asymptomatic patients are reviewed. Good understanding of the different surgical procedures helps in providing as much information as possible to guarantee a positive outcome, improving prognosis. We review what are the commonly expected postsurgical appearances and the most common postsurgical complications.

Anatomical and Biomechanical Characteristics of the Anterolateral Ligament: A Descriptive Korean Cadaveric Study Using a Triaxial Accelerometer

Background and Objectives: The anterolateral ligament (ALL) could be the potential anatomical structure responsible for rotational instability after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate the anatomical and biomechanical characteristics of the ALL in Korean cadaveric knee joints. Materials and Methods: Twenty fresh-frozen cadaveric knees were dissected and tested. Femoral and tibial footprints of the ALL were recorded. Pivot shift and Lachman tests were measured with KiRA. Results: The prevalence of ALL was 100%. The average distance of the tibial footprint to the tip of the fibular head was 19.85 ± 3.41 mm; from the tibial footprint to Gerdy's tubercle (GT) was 18.3 ± 4.19 mm; from the femoral footprint to the lateral femoral epicondyle was 10.25 ± 2.97 mm. ALL's footprint distance was the longest at 30° of flexion (47.83 ± 8.05 mm, p < 0.01) in a knee with intact ALL-ACL and neutral rotation. During internal rotation, the footprint distance was the longest at 30° of flexion (50.05 ± 8.88 mm, p < 0.01). Internal rotation produced a significant increase at all three angles after ACL-ALL were transected (p = 0.022), where the footprint distance was the longest at 30° of flexion (52.05 ± 7.60 mm). No significant difference was observed in KiRA measurements between intact ALL-ACL and ALL-transected knees for pivot shift and Lachman tests. However, ACL-ALL-transected knees showed significant differences compared to the intact ALL-ACL and ALL-transected knees (p < 0.01). Conclusions: The ALL was identified as a distinct ligament structure with a 100% prevalence in this cadaveric study. The ALL plays a protective role in internal rotational stability. An isolated ALL transection did not significantly affect the ALL footprint distances or functional stability tests. Therefore, the ALL is thought to act as a secondary supportive stabilizer for rotational stability of the knee joint in conjunction with the ACL.

Outcomes of Combined Anterior Cruciate Ligament and Anterolateral Ligament Reconstruction According to GNRB Arthrometer Measurement

Background and Objectives: To investigate the prognosis of combined anterior cruciate ligament (ACL) and anterolateral ligament (ALL) reconstruction, we used a GNRB (Genourob, Laval, France) arthrometer to measure surgical outcomes. Materials and Methods: This retrospective study reviewed patients who underwent combined ACL and ALL reconstruction and had a minimum follow-up of 2 years. Subjective outcomes, namely the International Knee Documentation Committee (IKDC) evaluation form scale scores and Lysholm scores, were evaluated preoperatively and postoperatively. We used a GNRB arthrometer to test the side-to-side laxity under pressures of 134 and 200 N, and we calculated the differential of the slope of the curves. We also recorded complications. Results: Our study examined 18 patients (mean age: 30.56 ± 8.9 years, range: 19-53) with a mean follow-up of 27.37 ± 3.4 months (range: 24-36). Both Lysholm and IKDC scores were significantly improved following the operation. The GNRB arthrometer measured mean anteroposterior laxity side-to-side as 0.76 ± 0.78 mm and 0.82 ± 0.8 mm under pressures of 134 and 200 N, respectively. The mean side-to-side differential slope under 200 N was 3.52 ± 2.17 μm/N. These values indicated that patients displayed no graft tear or low functional knee instability. All patients had a grade 3 pivot shift preoperatively; only two patients had a grade 1 pivot shift postoperatively, with the rest having a negative pivot shift. Conclusions: Our study revealed that combined ACL and ALL reconstruction has an excellent prognosis. GNRB measurement demonstrated excellent stability, and most patients had no residual pivot shift.

Anatomic Combined Anterior Cruciate Ligament and Antero-Lateral Ligament Reconstruction Using Autologous Gracilis and Semitendinosus Graft With Single Tibial and Femoral Tunnel

Anterior cruciate ligament (ACL) injuries are among the most common lesions in orthopaedics practice, but still today, rates up to 24% of unsatisfactory results are reported. Unaddressed anterolateral complex (ALC) injuries have been claimed to be responsible for residual anterolateral rotatory instability (ALRI) after isolate ACL reconstruction and have demonstrated to increase graft failure. In this article, we present our technique for reconstruction of the ACL and anterolateral (ALL) ligament combining the advantages of the anatomical position and the intraosseous femoral fixation to ensure anteroposterior and anterolateral rotational stability.

ACL surgical trends evolve in the last five years for young European surgeons: results of the survey among the U45 ESSKA members

PURPOSE

Although the outcomes of ACL reconstruction are generally satisfying, there are several patients who do not regain their pre-injury sporting level and suffer persistent symptoms. Orthopaedic practice has evolved significantly over the last five years to address these drawbacks. The aim of the present survey was to analyze the changes in the approach to ACL reconstruction among a population of young ESSKA surgeons dedicated to ACL surgery.

METHODS

The survey was uploaded on the ESSKA website and was accessible to members under the age of 45. The ESSKA society has 1035 U45 members involved in multiple aspects of Orthopaedic practice. One hundred and forty questionnaires were returned. Several aspects of ACL surgery were investigated at baseline and 5 years prior. They included general details such as the volume of ACL reconstructions per surgeon per year, the graft choice in cases of low and high demanding patients, the technique for femoral tunnel drilling and the preferred device for femoral fixation. The approach to the management of damage to peripheral structures, as well as meniscal ramp and root tears were also investigated.

RESULTS

Hamstrings and quadrupled semitendinosus were the preferred graft choice in low-demanding patients (92.9%) while quadriceps tendon is gaining popularity in contact sport practitioners (from 4.3 to 10.7%). The percentage of surgeons using femoral screws had decreased from 37.9 to 29.3 while the percentage of those who used buttons increased from 52.9 to 69.3%. Extra-articular procedures (antero-lateral ligament (ALL) or lateral tenodesis have become popular. The percentage of surgeons who perform an additional peripheral reconstruction rose from 28.5 to 71.5%. Of those who perform the meniscal repair more than 50% of patients rose from 14.3 to 27.9%. Similarly, the percentage of surgeons who performed a medial meniscus ramp lesion repair rose from 29.4 to 54.7%. While the percentage of those who choose to perform a transtibial pull-out repair of lateral meniscus root tears significantly rose from 17.9 to 59.3%.

CONCLUSIONS

The present survey among under 45 years old ESSKA surgeons yields some notable findings. The new evidence on the impact of injuries on peripheral structures and menisci is stimulating surgeons towards a more anatomic approach if identified at the time of ACL reconstruction. This evidence will probably influence future research and decision-making.

LEVEL OF EVIDENCE

IV.

Extent of posterolateral tibial plateau impaction fracture correlates with anterolateral complex injury and has an impact on functional outcome after ACL reconstruction

PURPOSE

The impact of posterolateral tibial plateau impaction fractures (TPIF) on posttraumatic knee stability in the setting of primary anterior cruciate ligament (ACL) tear is unknown. The main objective was to determine whether increased bone loss of the posterolateral tibial plateau is associated with residual rotational instability and impaired functional outcome after ACL reconstruction.

METHODS

A cohort was identified in a prospective enrolled study of patients suffering acute ACL injury who underwent preoperative standard radiographic diagnostics and clinical evaluation. Patients were included when scheduled for isolated single-bundle hamstring autograft ACL reconstruction. Exclusion criteria were concurrent anterolateral complex (ALC) reconstruction (anterolateral tenodesis), previous surgery or symptoms in the affected knee, partial ACL tear, multi-ligament injury with an indication for additional surgical intervention, and extensive cartilage wear. On MRI, bony (TPIF, tibial plateau, and femoral condyle morphology) and ligament status (ALC, concomitant collateral ligament, and meniscus injuries) were assessed by a musculoskeletal radiologist. Clinical evaluation consisted of KT-1000, pivot-shift, and Lachman testing, as well as Tegner activity and IKDC scores.

RESULTS

Fifty-eight patients were included with a minimum follow-up of 12 months. TPIF was identified in 85% of ACL injuries (n = 49). The ALC was found to be injured in 31 of 58 (53.4%) cases. Pearson analysis showed a positive correlation between TPIF and the degree of concomitant ALC injury (p < 0.001). Multiple regression analysis revealed an increased association of high-grade TPIF with increased lateral tibial convexity (p = 0.010). The high-grade TPIF group showed worse postoperative Tegner scores 12 months postoperatively (p = 0.035).

CONCLUSION

Higher degrees of TPIFs are suggestive of a combined ACL/ALC injury. Moreover, patients with increased posterolateral tibial plateau bone loss showed lower Tegner activity scores 12 months after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Percutaneous Lateral Collateral Ligament Release for Arthroscopic Procedures of the Knee: The "Lateral Pie-Crusting"

Arthroscopy of the knee is among the most frequent procedures worldwide in orthopaedic surgery. To avoid iatrogenic cartilage injury, adequate visualization and working space are mandatory to perform complex procedures. Narrow femorotibial joint space is often encountered, and it is challenging to obtain consistent satisfactory results. Medial collateral ligament release is safe and reliable for facilitating medial joint widening. Current clinical studies support lateral collateral ligament (LCL) healing capacity in isolated injuries. This article describes a simple, safe, and reproducible technique of LCL release through a multiple-puncture method to facilitate lateral compartment visualization and instrumentation, the so-called lateral pie-crusting.

The orientation of the ALL femoral tunnel to minimize collision with the ACL tunnel depends on the need or not of far-cortex drilling

PURPOSE

To (1) evaluate the optimal drill orientation of the anterolateral ligament (ALL) femoral tunnel to minimize collision with the anterior cruciate ligament (ACL) femoral tunnel during anatomical ACL reconstruction according to the need for far-cortex drilling and (2) investigate the geometric factors that affect tunnel collision secondary to drill orientation of the ALL femoral tunnel.

METHODS

A three-dimensional femoral model of patients who underwent anatomical single-bundle ACL reconstruction between 2015 and 2016 was constructed, and the geometric factors were evaluated. Virtual ALL femoral tunnels were created to simulate 45 drilling conditions. For each condition, whether the virtual ALL femoral tunnel and its trajectory violated the femoral cortex and the minimum distance between tunnels was investigated.

RESULTS

Thirty-nine subjects were included. Overall violation rates of the femoral cortex by the ALL tunnels and its trajectories were 11.1% (195 of 1755 conditions) and 40.7% (714 of 1755 conditions), respectively. A drilling angle of axial 0° and coronal - 40° showed the longest minimum distance between tunnels without femoral cortex violation by the ALL tunnel (6.3 ± 4.0 mm; collision rate 2.6% [1 of 39 subjects]). With simultaneous consideration of the ALL tunnel's trajectory representing far-cortex drilling, a drill angle of axial 40° and coronal 10° showed the longest minimum distance between tunnels without femoral cortex violation (0.6 ± 3.9 mm; collision rate 38.5% [15 of 39 subjects]). For surgical techniques requiring far-cortex drilling, regression analyses were performed on geometric factors that could affect tunnel collision, which revealed that the sagittal inclination angle of the ACL and the distance between the ACL femoral tunnel's outlet and ALL's femoral attachment were associated with tunnel collision.

CONCLUSION

The optimal drill orientations of the ALL femoral tunnel to minimize collision with the ACL femoral tunnel were axial 0° and coronal - 40° for surgical techniques not requiring far-cortex drilling and axial 40° and coronal 10° for techniques requiring far-cortex drilling. For techniques requiring far-cortex drilling, additional adjustment for orientation of the ACL femoral tunnel is required to reduce the risk of tunnel collision. Therefore, an individualized surgical strategy should be applied according to the graft fixation method of the ALL femoral tunnel.

Minimally invasive anatomic reconstruction of the anterolateral ligament with ipsilateral gracilis tendon: a kinematic in-vitro study

Purpose

The anterolateral ligament (ALL) has been defined as a key stabilizer of internal tibial rotation at 35° or more of knee flexion, with a minimal primary or secondary stabilizing role in the AP direction. This study aimed to demonstrate that anatomical reconstruction of the ALL confers rotational stability equal to that of the uninjured knee. Hypothesis: anteroposterior (AP) and rotatory laxity will significantly vary after ALL tenotomy and ALL reconstruction with the author’s previously described technique.

Methods

After ultrasound (US) ALL identification, different kinematic measurements were performed with an image-less Computer-Assisted Navigation System with dedicated software for Laxity Analysis in 5 knee specimens. Anteroposterior (AP) translations and varus/valgus (VV) and Internal-External (IE) rotations were evaluated by two trained orthopedic surgeons before ALL section, after ALL section, and after ALL anatomical reconstruction with doubled ipsilateral autologous gracilis tendon.

Results

ALL resection significantly increased laxity in IE rotations with knee 90° flexed (IE90) and AP translation with tibia internally rotated and the knee 30° flexed (APlat) (p < 0.05). ALL reconstruction significantly reduced laxity in IE90 and APlat (p < 0.05) and reduced VV rotations at 30° of flexion (VV30) (p < 0.05).

There were no statistically significant elongation differences between native ALL and reconstructed ALL (graft) during laxity tests. The inter-operator repeatability of the tests was excellent for each measurement.

Conclusions

ALL acted as an important internal tibial rotation restrain at 90° and a significant (secondary) AP stabilizer at 30° of knee flexion. The presented ALL reconstruction technique significantly restored the increase of knee laxity produced by the ALL section.

Scientific level

Case-Controlled Laboratory Study, Level III.

Anterior cruciate ligament rupture and associated Segond fracture: Incidence and effect on associated ligamentous and meniscal injuries

Introduction

The Segond fracture is an avulsion fracture of the lateral tibial plateau and is widely considered to be pathognomonic of anterior cruciate ligament (ACL) rupture. In addition to ACL rupture, Segond fractures have also been noted to be associated with significant intra-articular pathology such as meniscal injuries as well as extra-articular pathology such as collateral ligament injuries. This is likely due to the fact that the presence of a Segond fracture may represent increased rotatory instability. Whilst several studies have demonstrated the association of a Segond fracture with significant intra-articular pathology, there is a paucity of literature assessing if the combination of an ACL rupture and Segond fracture gives rise to higher rates of concomitant ligamentous and meniscal injuries. The primary objective of this study is to determine if patients with ACL ruptures associated with Segond fractures have higher rates of concomitant ligamentous and meniscal injury, when compared to patients with ACL ruptures without a Segond fracture.

Methods

A retrospective review of all patients who underwent ACL reconstruction in a single institution between 2014 to 2018 was conducted. A review of the patients’ demographics, operative notes, and radiographs was performed. X-rays and MRI scans were double-read by a board-certified radiologist and Orthopaedic surgeon.

Results

A total of 414 subjects were included. The incidence of Segond fracture was 2.4%. The mean age was 24.7±7.4 (range 16 to 60) years and 26.7±7.6 (range 16 to 38) years in patients with and without Segond fractures respectively. 89.9% of patients suffered a non-contact mechanism of injury, with sports injuries being most common (79.5%). There was a significantly higher rate of isolated lateral meniscus tears in patients with Segond fractures compared to those without (50% v.s. 20.8%) based on pre-operative MRI. (p<0.05) There were no other significant differences in associated ligamentous injuries.

Conclusion

The incidence of Segond fracture associated with ACL rupture is 2.4%. There is a significantly higher risk of a concomitant isolated lateral meniscus tear in ACL ruptures associated with a Segond fracture. There is no significantly higher risk of concomitant ligamentous injuries in ACL ruptures associated with a Segond fracture.

Graft choices for anterolateral ligament knee reconstruction surgery: Current concepts

The anterolateral ligament (ALL) is a primary structure of the anterolateral complex of the knee that contributes to internal rotational stability of the joint. Injury of the ALL is commonly associated with rupture of the anterior cruciate ligament. If left untreated, ALL lesions may lead to residual anterolateral rotational instability of the knee after anterior cruciate ligament reconstruction, which is a common cause of anterior cruciate ligament graft failure. The function of the ALL can be restored by lateral extraarticular tenodesis or anterolateral ligament reconstruction (ALLR). In the lateral extraarticular tenodesis procedure, a strip of the iliotibial band is placed in a non-anatomical position to restrain the internal rotation of the tibia, while in ALLR, a free graft is fixed at the insertion points of the native ALL. Gracilis and semitendinosus grafts have mainly been utilized for ALLR, but other autografts have also been suggested. Furthermore, allografts and synthetic grafts have been applied to minimize donor-site morbidity and maximize the size and strength of the graft. Nevertheless, there has been no strong evidence to fully support one method over another thus far. The present review presents a detailed description of the graft choices for ALLR and the current literature available in regard to the effectiveness and outcomes of published surgical techniques.

Anterolateral complex of the knee: State of the art

Rotatory instability of the knee represents the main reason for failure and poor clinical outcomes regarding anterior cruciate ligament (ACL) reconstruction techniques. It is now clear that the anterolateral complex (ALC) of the knee possesses a fundamental role, in association with the ACL, in controlling internal rotation. Over the past decade, ever since the anterolateral ligament has been identified and described as a distinct structure, there has been a renewed interest in the scientific community about the whole ALC: Lateral extra-articular tenodesis have made a comeback in association with ACL reconstructions to improve functional outcomes, reducing the risks of graft failure and associated injuries. Modern ACL reconstruction surgery must therefore investigate residual instability and proceed, when necessary, to extra-articular techniques, whether functional tenodesis or anatomical reconstruction.This review aims to investigate the latest anatomical and histological descriptions, and the role in rotational control and knee biomechanics of the ALC and its components. The diagnostic tools for its identification, different reconstruction techniques, and possible surgical indications are described.. In addition, clinical and functional results available in the literature are reported.

Anatomy, Biomechanics, and Reconstruction of the Anterolateral Ligament of the Knee Joint

Despite remarkable advances in the clinical outcomes after anterior cruciate ligament reconstructions (ACLRs), residual rotational instability of the knee joint remains a major concern. Since the anterolateral ligament (ALL) on the knee joint has been “rediscovered”, the role of anterolateral structures, including ALL and deep iliotibial band, as secondary stabilizers of anterolateral rotatory instability has gained interest. This interest has led to the resurgence of anterolateral procedures combined with ACLRs to restore rotational stability in patients with anterior cruciate ligament (ACL) deficiencies. However, the difference in concepts between anterolateral ligament reconstructions (ALLRs) as anatomical reconstruction and lateral extra-articular tenodesis (LETs) as non-anatomical reinforcement has been conflicting in present literature. This study aimed to review the anatomy and biomechanics of anterolateral structures, surgical techniques, and the clinical outcomes of anterolateral procedures, including LET and ALLR, in patients with ACL deficiencies.

Association between a Concomitant Anterolateral Ligament Tear and Pivot Shift Before and After Single-Bundle Anterior Cruciate Ligament Reconstruction: A Retrospective Cohort Study

BACKGROUND: Regardless of the type of intra-articular anterior cruciate ligament (ACL) reconstruction performed, a certain degree of rotatory instability is often seen after surgery. Recent studies suggest that the anterolateral ligament (ALL) plays a significant role in maintaining stability during internal rotation of the tibia at high knee flexion angles. Unrecognized damage to the ALL may potentially be associated with a positive pivot shift despite a surgically reconstructed ACL being done. AIM: The primary objective of this study was to determine whether a concomitant ALL tear is associated with a high-grade pivot shift before and after ACL reconstruction. METHODS: This study was a retrospective cohort study of patients that underwent single-bundle ACL reconstruction surgery in our institution from October 2014 to March 2017. One hundred and forty-four patients were included in this study. All data were extracted from the department of ACL registry. All knee MRIs were reviewed by the author and coauthor to determine the integrity of the ALL. Subjects were divided into two groups based on the grade of pivot shift before surgery. The prevalence of ALL tear based on MRI was further compared between high-grade and low-grade pivot-shift groups. RESULTS: Overall, the prevalence of a concomitant ALL tear was 70.83%. Comparing the prevalence of concomitant ALL tear between the high-grade pivot-shift group (73.11%) and low-grade pivot-shift group (60%), we had insufficient evidence to demonstrate an association between pre-surgery high-grade pivot shift and concomitant ALL tear. After surgery, none of the patients had a high-grade pivot shift or was positive for Lachman’s test. CONCLUSION: There is a high prevalence of concomitant ALL tear in patients with torn ACL. We have insufficient evidence to demonstrate an association between the presence of a torn ALL and high-grade pivot shift before and after single-bundle ACL reconstruction.

Effects of the Anterolateral Ligament and Anterior Cruciate Ligament on Knee Joint Mechanics: A Biomechanical Study Using Computational Modeling

Background:

Recent studies on lateral knee anatomy have reported the presence of a true ligament structure, the anterolateral ligament (ALL), in the anterolateral region of the knee joint. However, its biomechanical effects have not been fully elucidated.

Purpose:

To investigate, by using computer simulation, the association between the ALL and anterior cruciate ligament (ACL) under dynamic loading conditions.

Study Design:

Descriptive laboratory study; Level of evidence, 5.

Methods:

The authors combined medical imaging from 5 healthy participants with motion capture to create participant-specific knee models that simulated the entire 12 degrees of freedom of tibiofemoral (TF) and patellofemoral (PF) joint behaviors. These dynamic computational models were validated using electromyographic data, muscle activation data, and data from previous experimental studies. Forces exerted on the ALL with ACL deficiency and on the ACL with ALL deficiency, as well as TF and PF contact forces with deficiencies of the ACL, ALL, and the entire ligament structure, were evaluated under gait and squat loading. A single gait cycle and squat cycle were divided into 11 time points (periods 0.0-1.0). Simulated ligament forces and contact forces were compared using nonparametric repeated-measures Friedman tests.

Results:

Force exerted on the ALL significantly increased with ACL deficiency under both gait- and squat-loading conditions. With ACL deficiency, the mean force on the ALL increased by 129.7% under gait loading in the 0.4 period ( P < .05) and increased by 189% under high flexion during the entire cycle of squat loading ( P < .05). A similar trend of significantly increased force on the ACL was observed with ALL deficiency. Contact forces on the TF and PF joints with deficiencies of the ACL, ALL, and entire ligament structure showed a complicated pattern. However, contact force exerted on TF and PF joints with respect to deficiencies of ACL and ALL significantly increased under both gait- and squat-loading conditions.

Conclusion:

The results of this computer simulation study indicate that the ACL and the ALL of the lateral knee joint act as secondary stabilizers to each other under dynamic load conditions.

Tibial internal rotation in combined anterior cruciate ligament and high-grade anterolateral ligament injury and its influence on ACL length

Background

Assessment of combined anterolateral ligament (ALL) and anterior cruciate ligament (ACL) injury remains challenging but of high importance as the ALL is a contributing stabilizer of tibial internal rotation. The effect of preoperative static tibial internal rotation on ACL -length remains unknown. The aim of the study was analyze the effect of tibial internal rotation on ACL length in single-bundle ACL reconstructions and to quantify tibial internal rotation in combined ACL and ALL injuries.

Methods

The effect of tibial internal rotation on ACL length was computed in a three-dimensional (3D) model of 10 healthy knees with 5° increments of tibial internal rotation from 0 to 30° resulting in 70 simulations. For each step ACL length was measured. ALL injury severity was graded by a blinded musculoskeletal radiologist in a retrospective analysis of 61 patients who underwent single-bundle ACL reconstruction. Preoperative tibial internal rotation was measured in magnetic resonance imaging (MRI) and its diagnostic performance was analyzed.

Results

ACL length linearly increased 0.7 ± 0.1 mm (2.1 ± 0.5% of initial length) per 5° of tibial internal rotation from 0 to 30° in each patient.

Seventeen patients (27.9%) had an intact ALL (grade 0), 10 (16.4%) a grade 1, 21 (34.4%) a grade 2 and 13 (21.3%) a grade 3 injury of the ALL. Patients with a combined ACL and ALL injury grade 3 had a median static tibial internal rotation of 8.8° (interquartile range (IQR): 8.3) compared to 5.6° (IQR: 6.6) in patients with an ALL injury (grade 0–2) (p = 0.03). A cut-off > 13.3° of tibial internal rotation predicted a high-grade ALL injury with a specificity of 92%, a sensitivity of 30%; area under the curve (AUC) 0.70 (95% CI: 0.54–0.85) (p = 0.03) and an accuracy of 79%.

Conclusion

ACL length linearly increases with tibial internal rotation from 0 to 30°. A combined ACL and high-grade ALL injury was associated with greater preoperative tibial internal rotation. This potentially contributes to unintentional graft laxity in ACL reconstructed patients, in particular with concomitant high-grade ALL tears.

Study design

Cohort study; Level of evidence, 3.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05218-8.

Does anterolateral ligament internal bracing improve the outcomes of anterior cruciate ligament reconstruction in patients with generalized joint hypermobility?

BACKGROUND

Generalized joint hypermobility (GJH) is a risk factor for anterior cruciate ligament (ACL) injury and ACL graft failure and is considered an indication for anterolateral ligament (ALL) reconstruction. The aim of this retrospective study was to compare functional outcomes, rupture rates, and residual instability in patients with GJH undergoing isolated ACL reconstruction or combined ACL reconstruction and ALL augmentation with internal bracing (ALL-IB).

METHODS

Sixty-eight patients with GJH and unilateral ACL injury were randomly assigned to undergo either isolated ACL reconstruction (Group 1) or combined ACL reconstruction and ALL-IB (Group 2). The patients were evaluated pre- and postoperatively; their medical histories; physical examination results; anterior knee translation, as measured using the KT-1000 arthrometer; and scores of validated knee assessments were recorded.

RESULTS

Groups 1 and 2 consisted of 37 and 31 patients, respectively. The mean follow-up was 30.1±4.1 and 28.1±2.9 months, respectively. In the final evaluation, the patients in Group 2 showed better rotational stability, as evaluated by the pivot-shift test (p=0.013); better anteroposterior stability, as evaluated by KT-1000 arthrometry (p=0.001); similar function (p=0.14 for the Lysholm, p=0.11 for the Cincinnati, and p=0.19 for the International Knee Documentation Committee subjective score); and failure rate (p=0.41).

CONCLUSION

The functional outcomes were similar between the groups. The stability outcomes after combined ACL and ALL-IB were better than those after isolated ACL reconstruction in patients with GJH. However, the technique and its results need to be validated in larger patient series and prospective randomized controlled trials.

Prevalence of anterolateral ligament injuries and lateral meniscus tear on MR imaging in patients with both-bundle tear vs. selective bundle incomplete tear of the anterior cruciate ligament

OBJECTIVES

We investigated the prevalence of anterolateral ligament (ALL) injury and lateral meniscus (LM) tear in cases with both-bundle tear and selective bundle incomplete tear of the anterior cruciate ligament (ACL).

METHODS

A total of 174 cases of magnetic resonance (MR) images that had an ACL tear and underwent arthroscopic ACL reconstruction were retrospectively reviewed. ACL injury was classified into both bundle, anteromedial bundle, and posterolateral bundle (PL) on arthroscopic finding. The ALL was divided into three portions: femoral, meniscal, and tibial. ALL injury was scored into three groups: grade 0 is intact; grade 1 is stranding and edema surrounds the expected location of the ALL; grade 2 is clear discontinuity of the ALL consistent with rupture. Traumatic LM tear was also assessed on MR images.

RESULTS

The total prevalence of ALL injury was 36.2% (reader 1) and 42.0% (reader 2). ALL injury was statistically related to the selective bundle tear (p = 0.002 and 0.004, readers 1 and 2). PL bundle tear was significantly correlated with the ALL injury (p value < 0.001, readers 1 and 2, both). The location and grade of ALL injury were not significantly correlated with the type of ACL injury. LM tear was not significantly related to the types of ACL tear (p = 0.208 and 0.907, readers 1 and 2) and ALL injury (p value = 0.096 and 0.383, readers 1 and 2).

CONCLUSIONS

ALL injury was significantly related to the PL bundle tear of the ACL. LM tear was not significantly correlated with the types of ACL injury and ALL injury.

KEY POINTS

• Anterolateral ligament (ALL) injury was significantly related to the posterolateral bundle (PL) tear of the anterior cruciate ligament (ACL). • Lateral meniscus (LM) tear was not significantly correlated with the types of ACL injury and ALL injury. • Clinicians and radiologists should be aware of these relationships and scrutinize ALL injury in cases with PL bundle tears, even with an incomplete ACL injury.

Injuries to the anterolateral ligament are observed more frequently compared to lesions to the deep iliotibial tract (Kaplan fibers) in anterior cruciate ligamant deficient knees using magnetic resonance imaging

PURPOSE

To determine the accuracy of detection, injury rate and inter- and intrarater reproducibility in visualizing lesions to the anterolateral ligament (ALL) and the deep portion of the iliotibial tract (dITT) in anterior cruciate ligament (ACL) deficient knees.

METHODS

Ninety-one consecutive patients, out of those 25 children (age 14.3 ± 3.5 years), with diagnosed ACL tears were included. Two musculoskeletal radiologists retrospectively reviewed MRI data focusing on accuracy of detection and potential injuries to the ALL or dITT. Lesion were diagnosed in case of discontinued fibers in combination with intra- or peri-ligamentous edema and graded as intact, partial or complete tears. Cohen's Kappa and 95% confidence intervals (95% CI) were determined for inter- and intrarater reliability measures.

RESULTS

The ALL and dITT were visible in 52 (78.8%) and 56 (84.8%) of adult-and 25 (100%) and 19 (76.0%) of pediatric patients, respectively. The ALL was injured in 45 (58.5%; partial: 36.4%, compleate: 22.1%) patients. Partial and comleate tears, where visualized in 21 (40.4%) and 16 (30.8%) adult- and seven (28.0%) and one (4%) peditric patients. A total of 16 (21.3%; partial: 13.3%, compleate: 8.0%) dITT injuries were identified. Partal and complete lesions were seen in seven (12.5%) and five (8.9%) adult- and three (15.8%) and one (5.3%) pediatric patients. Combined injuries were visualized in nine (12.7%) patients. Inter-observer (0.91-0.95) and intra-observer (0.93-0.95) reproducibility was high.

CONCLUSION

In ACL injured knees, tears of the ALL are observed more frequently compared to lesions to the deep iliotibial tract. Combined injuries of both structures are rare. Clinically, the preoperative visualization of potentially injured structures of the anterolateral knee is crucial and is important for a more personalized preoperative planning and tailored anatomical reconstruction. The clinical implication of injuries to the anterolateral complex of the knee needs further investigation.

LEVEL OF EVIDENCE

II.

The Cadaveric Studies and the Definition of the Antero-Lateral Ligament of the Knee: From the Anatomical Features to the Patient-Specific Reconstruction Surgical Techniques

Cadaver studies represented a milestone in surgical orthopaedic research, and still today they play a crucial role in the achievement of new knowledge about joint disease behaviour and treatment. In this review, an overview of the cadaver studies available in the literature about the anatomy, role, and treatment of the antero-lateral ligament (ALL) of the knee was performed. The aim of the review was to describe and gain more insight into the part of in vitro study in understanding knee joint anatomy and biomechanics, and in developing surgical reconstruction techniques. The findings of the review showed that cadaver studies had, and will continue to have, a key role in the research of knee joint biomechanics and surgical reconstruction. Moreover, they represent a powerful tool to develop and test new devices which could be useful in clinical and surgical practice.

Increased lateral femoral condyle ratio is associated with greater risk of ALC injury in non-contact anterior cruciate ligament injury

PURPOSE

To examine whether increased lateral femoral condyle ratio (LFCR) correlates with increased risk of Anterior cruciate ligament (ACL) injury (1) and to evaluate the relationship between the LFCR and anterolateral complex (ALC) injury in non-contact ACL torn knees (2).

METHODS

Six hundred and seventy-two patients who underwent ACL reconstruction surgery between 2013 and 2019 were retrospectively reviewed, and 120 patients were finally included in the study. Forty patients (ACL + ALC injury) were included in the study group, while forty patients with isolated ACL injury (isolated ACL injury group) and 40 patients who suffered from meniscal tear without ACL or ALC injury were matched in a 1:1 fashion by age, sex, and BMI to the study group (ACL + ALC injury). The LFCR was measured on standard lateral radiographs in a blinded fashion. The differences between the three groups were analyzed by ANOVA. A ROC (Receiver Operating Characteristic) curve was produced to determine risk of ACL injury and risk of concomitant ALC injury in non-contact ACL injury.

RESULTS

The mean LFCR was 71.9% ± 3.1% in the ACL + ALC injury group, 68.4% ± 3.2% in the isolated ACL injury group, and 66.8% ± 2.6% in the control group (patients who suffered from meniscal tear without ACL or ALC injury). Significantly greater LFCR was found in the ACL + ALC injury group than that in the isolated ACL injury group (p < 0.017). Greater LFCR was additionally confirmed in the ACL injury group as compared to the control group (p < 0.05). ROC curve analysis demonstrated that LFCR > 68.3% was predictive for an increased risk of ACL injury in the entire cohort. LFCR > 69.4% was predictive for an increased risk of ALC injury in non-contact ACL ruptured patients.

CONCLUSION

Increased LFCR was found to be associated with greater risk of ALC injury in non-contact ACL ruptured patients. Additionally, increased LFCR was further confirmed to be correlated with increased risk of ACL injury in an Asian population. The data from this study may help recognize patients undergoing ACL reconstruction that could benefit from additional extra-articular tenodesis.

LEVEL OF EVIDENCE

III.

Reconstruction for Chronic ACL Tears with or without Anterolateral Structure Augmentation in Patients at High Risk for Clinical Failure: A Randomized Clinical Trial

BACKGROUND

The purpose of this trial was to determine whether anterior cruciate ligament reconstruction (ACLR) with anterolateral structure augmentation (ALSA) would result in better clinical outcomes in patients with a high risk of clinical failure.

METHODS

From February 2017 to June 2018, 120 young, active adults with chronic anterior cruciate ligament injury and high risk of clinical failure were randomized. The patients were followed for >2 years, with 5 being lost to follow-up and 1 being withdrawn from the study. Clinical characteristics, operative findings, and postoperative clinical outcomes were analyzed.

RESULTS

The analysis included data from 114 patients, including 95 men and 19 women with a mean age (and standard deviation) of 30.1 ± 6.7 years in the ACLR group and 30.1 ± 6.4 years in the ALSA group. The rate of clinical failure was 20.4% (11 of 54 patients) and 3.3% (2 of 60 patients) in the ACLR and ALSA groups, respectively (difference, 17.1%; 95% confidence interval [CI], 5.3% to 29.8%; p = 0.007). Significantly higher rates of return to the preinjury level of sports (48.3% versus 27.8%; difference, 20.5%; 95% CI, 2.7% to 36.6%; p = 0.024) and to a competitive level of play (63.3% versus 42.6%; difference, 22.3%; 95% CI, 4.1% to 38.8%; p = 0.027) was found in the ALSA group.

CONCLUSIONS

Compared with isolated ACLR, combined ACLR and ALSA resulted in a reduction in persistent rotatory laxity and higher rates of return to preinjury and competitive levels of play at 2 years of follow-up in the population studied. Our study suggests that patients with high risk of clinical failure appear to be candidates for the ALSA approach.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Isolated lateral extra-articular tenodesis enhance better rotatory knee joint stability post-primary ACL repair: Four cases report and literature review

INTRODUCTION AND IMPORTANCE

Residual rotatory instability has been reported to occur after primary anterior cruciate ligament reconstruction. The anterolateral ligament complex of the knee has gained attention for its role in rotational instability of the knee, especially in association with anterior cruciate ligament injuries. The role of an isolated lateral extra-articular tenodesis procedure among those patients presenting with residual rotatory instability after primary anterior cruciate ligament reconstruction has not been reported on.

CASE PRESENTATION

Four patients (Tegner level 4) presenting with residual rotatory instability after primary anterior cruciate ligament reconstruction without signs of graft failure, underwent an isolated lateral extra-articular tenodesis with modified Lemaire procedure. Pre- and postoperative outcome scores were assessed. At one-year follow-up, all patients reported functional knee stability. Pivot shift tests were negative and postoperative Lysholm scores were increased with a mean of 19.75 points. Tegner scores equaled the preinjury level.

CLINICAL DISCUSSION

This case report showed that our four patients where successfully treated with an isolated secondary modified Lemaire procedure for residual anterolateral rotatory instability after primary anterior cruciate ligament reconstruction.

CONCLUSION

An isolated secondary lateral extra-articular tenodesis procedure can be a valuable treatment option for moderate active patients with residual rotatory instability after a primary anterior cruciate ligament reconstruction without signs of graft failure.

The Anterolateral Ligament Has Limited Intrinsic Healing Potential: A Serial, 3-Dimensional-Magnetic Resonance Imaging Study of Anterior Cruciate Ligament-Injured Knees From the SANTI Study Group

BACKGROUND

Recent imaging studies demonstrate that the anterolateral ligament (ALL) is frequently injured at the time of anterior cruciate ligament (ACL) rupture. The intrinsic healing potential of these injuries after ACL reconstruction (ACLR) has not been defined.

PURPOSE/HYPOTHESIS

The primary objective was to evaluate the rate and duration of the healing process of injured ALLs after ACLR using serial 3-dimensional magnetic resonance imaging (3D-MRI). The secondary objective was to investigate whether any patient, injury, or surgical factors influenced the healing rate. The hypothesis was that serial imaging would demonstrate that the ALL has limited healing potential.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients enrolled in the study underwent 3D-MRI (slice thickness 0.5 mm) preoperatively and at 1, 6, 12, and 24 months after ACLR. Three observers determined the grade of ALL injury according to the Muramatsu classification. Inter- and intraobserver reliabilities were calculated. The rates of injury and time points for healing were determined. Full healing was defined as a change from a preoperative Muramatsu grade of B or C (indicating partial or complete injury) to grade A (normal). Multivariate analysis was used to investigate the association of aforementioned factors with the risk of incomplete healing.

RESULTS

A total of 44 patients were enrolled in the study. Of them, 71.2% had an ALL injury on preoperative imaging. Overall, full healing of ALL injuries occurred at a rate of 3.2%, 15.2%, and 30.3% at 1, 6, and 12 months, respectively. There were no changes in the Muramatsu grade in any patient beyond 12 months postoperatively. None of the complete lesions demonstrated full healing, but the proportion of patients with a grade C injury decreased from 13.6% preoperatively to 4.5% at 12 months due to an improvement to grade B in 4 of 6 patients (66%). Inter- and intraobserver reliabilities of the classification system were almost perfect at 0.81-0.94 and 0.95-1.00, respectively. None of the potential risk factors investigated were predictive of an increased risk of nonhealing.

CONCLUSION

ALL injuries occurred in the majority of ACL-injured knees. They had limited intrinsic healing potential, with only 30.3% healing by 12 months after ACLR. The process of healing took >6 months in half of the patients in whom it occurred. No new cases of full healing occurred beyond 12 months postoperatively. No significant risk factors for failure of full healing to occur were identified, but it is likely that this aspect of the study was underpowered.

Biomechanical Effects of Combined Anterior Cruciate Ligament Reconstruction and Anterolateral Ligament Reconstruction: A Systematic Review and Meta-analysis

Background:

Combined anterior cruciate ligament (ACL) reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) are performed with the intention to restore native knee kinematics after ACL tears. There continue to be varying results as to the difference in kinematics between combined and isolated procedures, including anterior tibial translation (ATT) and internal tibial rotation (IR).

Purpose:

To perform a systematic review and meta-analysis to evaluate the kinematic changes of a combined ACLR/ALLR versus isolated ACLR and to assess the effects of different fixation techniques.

Study Design:

Systematic review.

Methods:

We conducted a systematic review and meta-analysis of 15 human cadaveric biomechanical studies evaluating combined ACLR/ALLR versus isolated ACLR and their effects on ATT and IR in 149 specimens. The primary outcomes were ATT and IR. Secondary outcomes included graft type and size as well as fixation methods such as type, angle, tension, and position of fixation. Meta-regression was used to examine the effect of various cofactors on the resulting measures.

Results:

Compared with isolated ACLR, combined ACLR/ALLR decreased ATT and IR by 0.01 mm (95% CI, –0.059 to 0.079 mm; P = .777) and 1.64° (95% CI, 1.30°-1.98°; P < .001), respectively. Regarding ACLR/ALLR, increasing the knee flexion angle and applied IR force led to a significant reduction in IR (P < .001 and P = .044, respectively). There was also a significant reduction in IR in combined procedures with semitendinosus ALL graft, higher flexion fixation angles, and tension but no change in IR with differing femoral fixation points (P < .001, P < .001, and P = .268, respectively). Multivariate meta-regression showed that the use of tibial-sided suture anchor fixation significantly reduced IR (P < .001).

Conclusion:

These results suggest that a combined ACLR/ALLR procedure significantly decreases IR compared with isolated ACLR, especially at higher knee flexion angles. Semitendinosus ALL graft, fixation at higher knee flexion, increased tensioning, and tibial-sided interference screw fixation in ALLR may help to further reduce IR.

The deep lateral femoral notch sign: a reliable diagnostic tool in identifying a concomitant anterior cruciate and anterolateral ligament injury

PURPOSE

The aim of the present study was to investigate the validity and reliability of the deep lateral femoral notch sign (DLFNS) in identifying a concomitant anterior cruciate ligament (ACL)/anterolateral ligament (ALL) rupture and predicting the clinical outcomes following an anatomical single-bundle ACL reconstruction. It was hypothesized that patients with a concomitant ACL/ALL rupture would have an increased DLFNS compared to patients without a concomitant ACL/ALL rupture.

METHODS

The lateral preoperative radiographs and MRI images of 100 patients with an ACL rupture and 100 control subjects were evaluated for the presence of a DLFNS and ACL/ALL rupture, respectively. The patients were evaluated clinically preoperatively and at a minimum 1 year following the ACL reconstruction. A receiver operator curve (ROC) analysis was performed to define the optimal cut-off value of the DLFNS for identifying a concomitant ACL/ALL injury. The relative risk (RR) was also calculated to determine whether the presence of the DLFNS was a risk factor for residual instability or ACL graft rupture following an ACL reconstruction.

RESULTS

The prevalence of DLFNS was 52% in the ACL-ruptured patients and 15% in the control group. At a minimum 1-year follow-up, 35% (6/17) of the patients with DLFNS > 1.8 mm complained of persistent instability, and an MRI evaluation demonstrated a graft re-rupture rate of 12% (2/17). In patients with a DLFNS < 1.8 mm, 8% (7/83) reported a residual instability, and the graft rupture rate was 2.4% (2/83). A DLFNS > 1.8 mm demonstrated a sensitivity of 89%, a specificity of 95%, a negative predictive value of 98%, and a positive predictive value of 89% in identifying a concomitant ACL/ALL rupture. Patients with a DLFNS > 1.8 mm had 4.2 times increased risk for residual instability and graft rupture compared to patients with a DLFNS ≤ 1.8 mm.

CONCLUSIONS

A DLFNS > 1.8 mm could be a clinically relevant diagnostic tool for identifying a concomitant ACL/ALL rupture with high sensitivity and PPV. Patients with a DLFNS > 1.8 mm should be carefully evaluated for clinical and radiological signs of a concomitant ACL/ALL rupture and treated when needed with a combined intra-articular ACL reconstruction and extra-articular tenodesis to avoid a residual rotational instability and ACL graft rupture.

LEVEL OF EVIDENCE

III.

A Quantifiable Risk Factor for ACL Injury: Applied Mathematics to Model the Posterolateral Tibial Plateau Surface Geometry

Background:

The mechanism for traumatic ruptures of the native anterior cruciate ligament (ACL) is frequently a noncontact injury involving a valgus moment with internal rotation of the tibia. The abnormal rotation and translation of the lateral femoral condyle posteroinferiorly relative to the lateral tibial plateau is thought to be related to the geometry of the tibial plateau.

Purpose/Hypothesis:

The purpose of the study was to mathematically model the posterior tibial plateau geometry in patients with ACL injuries and compare it with that of matched controls. The hypothesis was that increased convexity and steepness of the posterior aspect of the lateral plateau would subject knees to higher forces, leading to a potentially higher risk of ACL injury.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

We mathematically modeled the posterior curvature of the lateral tibial plateau in 64 patients with ACL injuries and 68 matched controls. Using sagittal magnetic resonance imaging scans of the knee, points on the articular cartilage of the posterolateral tibial plateau were selected and curve-fitted to a power function (y = a × xⁿ). For coefficient a and coefficient n, both variables modulated the shape of the curve, where a larger magnitude represented an increase in slope steepness. Groups were compared using a Mann-Whitney test and α < .05.

Results:

There was a significant difference in surface geometry between the patients with ACL injuries and matched controls. The equation coefficients were significantly larger in the patients with ACL injuries: coefficient a (ACL injury, 0.9 vs control, 0.68; P < .0001) and coefficient n (ACL injury, 0.34 vs control, 0.30; P = .07). For coefficient a, there was a 78.9% sensitivity, 77.5% specificity, and odds ratio of 12.6 (95% CI, 5.5-29.0) for ACL injury using a cutoff coefficient a = .78.

Conclusion:

Patients with ACL injuries had a significantly greater posterolateral plateau slope. The steeper drop off may play a role in higher anterior translation forces, coupled with internal rotation torques on the knee in noncontact injury, which could increase ACL strain and predispose to ACL injury.

Isokinetic Strength After ACL Reconstruction: Influence of Concomitant Anterolateral Ligament Reconstruction

BACKGROUND

To reduce the rate of anterior cruciate ligament (ACL) graft rupture, recent surgeries have involved anterolateral ligament reconstruction (ALLR). This reconstruction procedure harvests more knee flexor muscle tendons than isolated ACL reconstruction (ACLR), but its influence on knee muscle strength recovery remains unknown. This study aimed to assess the influence of ALLR with a gracilis graft on the strength of the knee extensor and flexor muscles at 6 months postoperatively.

HYPOTHESIS

The additional amount of knee flexor harvest for ALLR would result in impairment in knee flexor muscle strength at 6 months postoperatively.

STUDY DESIGN

Retrospective cohort study.

LEVEL OF EVIDENCE

Level 2.

METHODS

A total of 186 patients were assigned to 2 groups according to the type of surgery: ACL + ALLR (graft: semitendinosus + gracilis, n = 119) or isolated ACLR (graft: semitendinosus, n = 67). The strength of the knee extensor and flexor muscles was assessed using an isokinetic dynamometer at 90, 180, and 240 deg/s for concentric and 30 deg/s for eccentric contractions and compared between groups using analysis of variance statistical parametric mapping.

RESULTS

Regardless of the surgery and the muscle, the injured leg produced significantly less strength than the uninjured leg throughout knee flexion and extension from 30° to 90° for each angular velocity (30, 90, 180, and 240 deg/s). However, the knee muscle strength was similar between the ACL + ALLR and ACLR groups.

CONCLUSION

The addition of ALLR using the gracilis tendon during ACLR does not alter the muscle recovery observed at 6 months postoperatively.

CLINICAL RELEVANCE

Although more knee flexor muscle tendons were harvested in ACL + ALLR, the postoperative strength recovery was similar to that of isolated ACLR.

A Secondary Injury of the Anterolateral Structure Plays a Minor Role in Anterior and Anterolateral Instability of Anterior Cruciate Ligament-Deficient Knees in the Case of Functional Iliotibial Band

PURPOSE

To analyze the contribution of a secondary anterolateral structure (ALS) deficiency to knee instability based on anterior cruciate ligament (ACL) deficiency, in the condition of a functional iliotibial band (ITB).

METHODS

Nine freshly-frozen cadaveric knees were sectioned sequentially to create ACL deficiency and ACL-ALS deficiency, using intact knees before sectioning as controls. When ITB was tensioned with 30 N, 4 separate aspects of knee instability were tested as follows: anterior translation in 90 N anterior load, isolated internal rotation in 5 N·m internal rotational torque from 0° to 90° in 15° increments, and anterolateral translation and internal rotation during a simulated pivot-shift test at 0°, 15°, 30°, and 45°. The contribution of ACL deficiency alone and additional ALS deficiency to knee instability were evaluated.

RESULTS

The addition of an ALS lesion produced no significant exacerbation of either anterior translational or pivot shift instability in ACL-deficient knees. Additional ALS deficiency in an ACL-deficient knee resulted in a significant increase in isolated internal rotation from 45° to 90° (P = .001 at 45° and P < .001 in other cases). After sequentially sectioning, the contribution to instability of additional ALS deficiency to the entire instability in ACL-ALS-deficient knees was significantly smaller than that of ACL deficiency alone during anterior load and pivot-shift test (P < .001 in all cases), but significantly contributed more to isolated internal rotational instability at 60° (P = .011) and 90° (P = .015).

CONCLUSIONS

When ITB was tensioned, ALS played a minor role in controlling both anterior or pivot shift stability in ACL-deficient knees but a major role in restraining isolated internal rotation from 45° to 90°.

CLINICAL RELEVANCE

In the condition of functional ITB, concomitant ALS injury might not exacerbate anterior and pivot-shift instability after ACL rupture, while affecting isolated internal rotation stability at higher flexion.

Anterolateral ligament reconstruction improves the clinical and functional outcomes of anterior cruciate ligament reconstruction in athletes

PURPOSE

To compare the outcomes of anterior cruciate ligament (ACL) reconstruction with those of combined ACL and anterolateral ligament (ALL) reconstruction in ACL-deficient knees. The objective of this study was to improve knowledge regarding the treatment of ACL-deficient knees with combined ACL and ALL reconstruction. Combined ACL and ALL reconstruction has been hypothesized to result in better clinical and functional outcomes than isolated ACL reconstruction (ACLR).

METHODS

One-hundred and seven adult male athletes with ACL tears and high-grade pivot shifts were randomized into two groups. Those in group A (n = 54) underwent ACLR, while those in group B (n = 53) underwent combined ACL and ALL reconstruction. The median age was 26 (18-40) and 24 (18-33) years in groups A and B, respectively, and the median follow-up was 60 (55-65) months. Physical examination findings, instrumented knee laxity tested using a KT-1000 arthrometer, and International Knee Documentation Committee Scale (IKDC) scores were used to evaluate the outcomes.

RESULTS

One-hundred and two patients were available for follow-up: 52 in group A and 50 in group B. Postoperatively, the pivot shift was normal in 43 (82.7%) and 48 (96%) patients in groups A and B, respectively (p < 0.001). The median instrumented knee laxity was 2.5 ± 0.7 (1.2-6.1) mm in patients in group A and 1.2 ± 0.7 (1.2-3.2) mm in patients in group B (p < 0.001). Additionally, 44 (84.6%) patients in group A had normal IKDC scores and 3 (5.8%) had nearly normal scores, while 48 (96.0%) patients in group B had normal IKDC scores and 2 (4%) had nearly normal scores (p < 0.001).

CONCLUSION

Combined ACL and ALL reconstruction, compared with isolated ACLR resulted in favourable clinical and functional outcomes, as demonstrated by decreased rotational instability and instrumented knee laxity, a lower graft rupture rate and better postoperative IKDC scores.

LEVEL OF EVIDENCE

1.

Effects of Anterolateral Structure Augmentation on the In Vivo Kinematics of Anterior Cruciate Ligament-Reconstructed Knees

BACKGROUND

Double-bundle anterior cruciate ligament (ACL) reconstruction (ACLR) is a well-known treatment that restores the stability of ACL-deficient knees. However, some isolated ACL-reconstructed knees ultimately show rotatory laxity and develop osteoarthritis. Whether combined ACLR with anterolateral structure (ALS) augmentation (ALSA) can provide better improvement in the in vivo knee rotational kinematics remains unknown.

HYPOTHESIS

When compared with isolated double-bundle ACLR, combined double-bundle ACLR with ALSA can improve knee in vivo rotational kinematics and provide better restoration of knee kinematics.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sixteen patients with unilateral ACL injury were randomly divided into 2 groups to receive either combined double-bundle ACLR and ALSA (ALSA group) or isolated double-bundle ACLR (ACLR group). All patients performed a single-leg lunge using the operative and nonoperative/contralateral legs under dual-fluoroscopic imaging system surveillance during a hospital visit at a minimum 1 year (12-13 months) of follow-up to assess the 6 degrees of freedom knee kinematics. Functional evaluation using the Lysholm and Marx rating scales and clinical examinations were also performed.

RESULTS

From full extension to approximately 90° of knee flexion at 5° intervals, the mean ± SD internal rotation of the reconstructed knees in the ALSA group (1.5°± 0.9°) was significantly smaller than that of the contralateral knees (8.2°± 1.9°; P = .008). The ALSA group knees also showed significantly (P = .045) more medial translation than the contralateral knees. In the ACLR group, the mean internal rotation of the reconstructed knee (6.0°± 2.1°) was significantly smaller than that of the contralateral knees (8.9°± 0.6°; P < .001). At full extension, the tibia was significantly more externally rotated than that of the contralateral legs (0.5°± 7.4° vs 7.6°± 3.4°, P = .049).

CONCLUSION

When compared with isolated double-bundle ACLR, double-bundle ACLR augmented with ALS reconstruction resulted in anterolateral rotatory overconstraint during the lunge motion.

CLINICAL RELEVANCE

Additional ALSA of double-bundle ACL-reconstructed knees overconstrained rotatory stability. Therefore, the use of ALSA for ACL-reconstructed knees should be considered with caution for patients with ACL deficiency and anterolateral rotatory instability. Longer-term follow-up to evaluate long-term outcomes and altered kinematics over time is recommended.