MRI-determined anterolateral capsule injury did not affect the pivot-shift in anterior cruciate ligament-injured knees

All-Onlay Anterolateral Ligament Reconstruction Technique of the Knee

The anterolateral ligament has gained attention as a secondary stabilizer of anterolateral rotatory stability of the knee. This has had implications among sports medicine specialists as an adjunct procedure with anterior cruciate ligament reconstruction to improve stability. As indications have evolved for its use as an anterior cruciate ligament reconstruction augment, so have the techniques for reconstruction. As such, we present a simple, efficient, and reproducible technique for all-onlay reconstruction with low-profile instrumentation that mitigates concerns for tunnel convergence.

Injuries to both anterolateral ligament and Kaplan fiber of the iliotibial band do not increase preoperative pivot-shift phenomenon in ACL injury

Background

To assess the incidence of anterolateral ligament (ALL) and Kaplan fiber of the iliotibial band (KF) injuries in patients with acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI), and to investigate the association between these injuries and the magnitude of preoperative pivot-shift test.

Method

One-hundred and five patients with primary ACL injury were retrospectively reviewed. ALL injury and KF injury were assessed by preoperative MRI, and subjects were allocated into four groups: Group A, neither injury; Group B, only ALL injury; Group C, only KF injury; Group D, simultaneous ALL and KF injuries. Before ACL reconstruction, tibial acceleration during the pivot-shift test was measured by an electromagnetic measurement system, and manual grading was recorded according to the International Knee Documentation Committee (IKDC) guideline.

Results

In MRI, the ALL was identified in 104 patients (99.1%) and KF in 99 patients (94.3%). ALL and KF injuries were observed in 43 patients (43.9%) and 23 patients (23.5%), respectively. Patient distribution to each group was as follows; Group A: 43 patients (43.9%), Group B: 32 patients (32.7%), Group C: 12 patients (12.2%), Group D: 11 patients (11.2%). No significant differences were observed in tibial acceleration, and manual grading among the four groups.

Conclusion

Simultaneous injury to both ALL and KF was uncommon, and preoperative pivot-shift phenomenon did not increase even in those patients. The finding suggests that the role of ALL and KF in controlling anterolateral rotatory knee laxity may be less evident in the clinical setting compared to a biomechanical test setting.

Impacts of Segond Fractures on Anterior Cruciate Ligament Reconstruction Outcomes

INTRODUCTION

Segond fractures, characterized by avulsion injuries at the lateral tibial condyle's anterolateral structure (ALS) attachment, often coincide with anterior cruciate ligament (ACL) injuries, potentially leading to knee instability. However, the influence of Segond fractures on knee stability after ACL reconstruction remains uncertain. Despite documented ALS reconstructions, there is a lack of consensus regarding the assessment of ALS failure and the criteria for surgical interventions. This study aimed to determine if Segond fracture presence impacts ACL reconstruction outcomes, utilizing patient-reported subjective assessments and healthcare providers' objective evaluations.

MATERIALS AND METHODS

This retrospective study encompassed 639 patients (328 males, 311 females; mean age 26.9 years) who underwent ACL reconstruction, with a follow-up of at least one year. Subjects were divided into two groups: Segond fractures diagnosed through radiographic findings (Group S+, n = 17) and no Segond fractures (Group S-, n = 622). Clinical evaluation included the 36-item Short Form Survey (SF-36), Lysholm score, visual analog scale (VAS) for knee pain, knee injury and osteoarthritis outcome score (KOOS), and knee instability assessment via Telos SE (Telos Japan, Tokyo, Japan). Statistical comparisons were performed between the two groups.

RESULTS

At the final follow-up, all SF-36 subscales improved in all eight subscales compared to before surgery, reaching national standard scores; no significant inter-group differences were evident. Lysholm scores were 93.0 ± 12.1 (Group S+) and 91.7 ± 10.9 (Group S-) (P = 0.62), VAS for knee pain was 10.0 ± 18.0 (Group S+) and 11.9 ± 16.9 (Group S-) (P = 0.62), total KOOS was 89.0 ± 17.4 (Group S+) and 90.7 ± 9.9 (Group S-) (P = 0.39), and anterior tibial translation differences were 2.8 ± 3.0 mm (Group S+) and 2.7 ± 2.9 mm (Group S-) (P = 0.73). All these values represent postoperative measurements. No significant discrepancies existed between groups across evaluation methods.

CONCLUSIONS

This study's results suggest that Segond fractures have minimal impact on clinical ACL reconstruction outcomes, as assessed through both patient-reported subjective evaluations and objective healthcare provider evaluations. Segond fractures' significance in postoperative outcomes questions the necessity of ALS 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.

Association of Concomitant MRI-Determined Anterolateral Complex Injury With Quantitative Measurements of Altered Rotational Tibiofemoral Position on MRI in Patients With ACL Injury

Background

Reduced graft failure rates have been reported after anterior cruciate ligament (ACL) reconstruction combined with anterolateral complex (ALC) augmentation. However, the preoperative diagnosis of concomitant ALC injury remains a clinical challenge.

Purpose

To identify the altered rotational tibiofemoral position on magnetic resonance imaging (MRI) in ACL-injured patients with concomitant ALC injury.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Based on the evaluation of ALC abnormalities on MRI scans by experienced surgeons, 123 patients with nonchronic (<3 months) ACL injury confirmed by arthroscopy were included. The patients were divided into 2 groups-an ALC-injured group (n = 57) and an ALC-intact group (n = 66). The altered rotational tibiofemoral position was evaluated and compared by quantitatively measuring internal rotational tibial subluxation (IRTS) and axial internal tibial rotation (ITRa) on MRI. Multivariate logistic regression and receiver operating characteristic (ROC) analyses were performed to identify the factors associated with concomitant MRI-determined ALC injury.

Results

The ALC-injured group showed significantly increased IRTS (P < .001), ITRa (P < .001), lateral anterior tibial subluxation (ATS) (P < .001), and global ATS (GATS) (P = .002) compared with the ALC-intact group, while no significant difference in medial ATS (P = .810) was observed. A strong positive correlation was identified between IRTS and ITRa (rP = 0.809; P < .001). Multivariate analyses revealed that IRTS (P < .001) and GATS (P = .016) were associated factors for the presence of concomitant MRI-determined ALC injury. IRTS (area under the curve [AUC] = 0.734) was more strongly associated with the outcome than GATS (AUC = 0.658) in ROC analyses, suggesting a more significant internal rotational subluxation than anterior subluxation of the tibia. An IRTS threshold of 3.1 mm demonstrated a specificity of 84.2% for indicating the presence of concomitant MRI-determined ALC injury.

Conclusion

The presence of concomitant MRI-determined ALC injury in ACL-injured patients was associated with a significant increase in IRTS and ITRa compared with those with intact ALC, indicating that these MRI measurements of the altered rotational tibiofemoral position could serve as potential quantifiable indicators for identifying concomitant ALC injury in clinical practice.

Greater Knee Rotatory Instability After Posterior Meniscocapsular Injury Versus Anterolateral Ligament Injury: A Proposed Mechanism of High-Grade Pivot Shift

Background

For anterolateral rotatory instability as a result of secondary soft tissue injuries in anterior cruciate ligament (ACL)-deficient knees, there is increasing interest in secondary stabilizers to prevent internal rotation (IR) of the tibia.

Purpose

To determine which secondary stabilizer is more important in anterolateral rotatory instability in ACL-deficient knees.

Study Design

Controlled laboratory study.

Methods

The lower extremities of 10 fresh-frozen cadavers (20 extremities) without anterior-posterior or rotational instability were included. Matched-pair randomization was performed, with each side per specimen assigned to 1 of 2 groups. In group 1, the ACL was sectioned, followed by the anterolateral ligament (ALL); in group 2, the ACL was sectioned, followed by sequential sectioning of the posterolateral meniscocapsular complex (PLMCC) and posteromedial meniscocapsular complex (PMMCC). The primary outcome was the change in relative tibial IR during a simulated pivot-shift test with 5 N·m of IR torque and 8.9 N of valgus force. The secondary outcomes were the International Knee Documentation Committee grade in the pivot-shift test and the incidence of the grade 3 pivot shift.

Results

In group 1, compared with baseline, the change in relative tibial IR at 0° of knee flexion was 1.4° (95% CI, -0.1° to 2.9°; P = .052) after ALL release. In group 2, it was 2.5° (95% CI, 0.4° to 4.8°; P = .007) after PLMCC release and 4.1° (95% CI, 0.5° to 7.8°; P = .017) after combined PLMCC and PMMCC release. Combined PLMCC and PMMCC release resulted in greater change of tibial IR with statistical significance at 0°, 15°, and 30° of knee flexion (P = .008, .057, and .004, respectively) compared with ALL release. The incidence of grade 3 pivot shifts was 10% in group 1 and 90% in group 2.

Conclusion

Posterior meniscocapsular laxity caused an increase in relative tibial IR as much as ALL injury in ACL-deficient knees in our simulated laboratory test, and greater anterolateral rotatory instability occurred with posterior meniscocapsular injury compared with ALL injury.

Clinical Relevance

Repair of the injured posterior meniscocapsular complex may be an important treatment option for reducing anterolateral rotatory instability in the ACL-deficient knee.

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.

Risk factors of residual pivot-shift after anatomic double-bundle anterior cruciate ligament reconstruction

INTRODUCTION

Although anterior cruciate ligament reconstruction (ACLR) is considered a successful procedure, residual pivot-shift after surgery remains to be solved. The purpose of this study was to comprehensively evaluate the risk factors of residual pivot-shift after anatomic double-bundle (DB) ACLR.

MATERIALS AND METHODS

A total of 164 patients who underwent primary anatomic DB-ACLR between January 2014 and December 2019 and screw removal after the index ACLR in our hospital were included in this retrospective case-control study. The manual pivot-shift test was performed under general anesthesia during screw removal surgery, and patients with grade 1 or higher pivot-shift were classified as the positive pivot-shift group, and those with grade 0 were defined as the negative pivot-shift group. Univariate and logistic regression analyses were performed to identify the factors associated with postoperative residual pivot-shift. Assessment included sex, age, time to surgery, preoperative Tegner activity scale, preoperative pivot-shift grade, preoperative anterior tibial translation by the KT-2000 arthrometer measurement, meniscus injury and its surgical procedure, knee hyperextension, cartilage damage, Segond fracture, medial and lateral posterior tibial slope, lateral-medial slope asymmetry, participation in pivoting sport/activity at the time of injury, and return to sports at postoperative one year line.

RESULTS

Postoperative positive pivot-shift was observed in 14 (8.5%) of 164 patients. The KT-2000 measurement at 1-year postoperatively was significantly higher in the residual pivot-shift-positive group than in the negative group (P < 0.05). Logistic regression analysis revealed that age of patients < 20 years [P < 0.05, odds ratio (OR): 6.1)], preoperative pivot-shift grade (P < 0.05, OR: 4.4), and hyperextended knee (P < 0.05, OR: 11.8) were risk factors of postoperative pivot-shift. There were no statistically significant differences between other variables.

CONCLUSIONS

Patients < 20 years of age, with high-grade preoperative pivot-shift, or hyperextended knees had a higher risk of residual postoperative pivot-shift.

Anterolateral ligament MRI of the knee in ACL injuries: MRI abnormalities association with instability

OBJECTIVE

To evaluate anterolateral ligament abnormalities (ALL) at MRI scans and correlate with data from clinical instability tests (Lachman and pivot shift) performed under anesthesia in patients with acute anterior cruciate ligament (ACL) tears. Furthermore, perform multivariate analysis with other variables to isolate the ALL contribution to instability from other abnormalities.

METHODS

Retrospective analysis of MRI and instability tests of 95 patients with ACL tears. The ALL was classified as no abnormality, abnormality without discontinuity, and discontinuity. Injuries in other knee ligament structures and menisci were also assessed. Results of instability tests (pivot shift and Lachman) with the patient anesthetized for arthroscopic ACL reconstruction were obtained from the patient database. Statistical analysis was performed using the IBM SPSS 22.

RESULTS

ALL abnormalities and iliotibial band (ITB), lateral (LCL), and medial (MCL) collateral ligament injuries showed a statistically significant correlation with the pivot shift test. The ALL MRI abnormalities were associated with the high-grade pivot shift results (p < 0.0005), with an odds ratio of 55.9 for high degrees of pivot shift in patients with abnormal ALL. The logistic model for all variables analyzed with the results of the pivot shift test demonstrated that the ALL was the only variable with a statistically significant correlation in the model (p < 0.0005).

CONCLUSION

MRI ALL abnormalities in patients with ACL injuries have a significant association with pivot shift test results in patients under anesthesia. The logistic model for high - grade pivot shift test results demonstrated that ALL abnormalities were the only variable with significant correlation.

KEY POINTS

• Evaluating the anterolateral ligament with MRI in acute anterior cruciate ligament injuries is useful to predict higher grades of pivot shift test in the moment of the arthroscopic reconstruction. • An abnormal anterolateral ligament presented an odds ratio of 55 for high degrees of pivot shift. • ALL MRI abnormalities association with knee instability is independent from other internal knee injuries.

Steeper lateral posterior tibial slope and greater lateral-medial slope asymmetry correlate with greater preoperative pivot-shift in anterior cruciate ligament injury

PURPOSE

To investigate the association between posterior tibial slope (PTS) and preoperative pivot-shift phenomenon in anterior cruciate ligament (ACL)-injured knees.

METHODS

Fifty unilateral ACL-injured patients (mean age: 28.0 ± 11.4 years, 29 males) who underwent ACL reconstruction were retrospectively included. Patients with a history of injury to the ipsilateral knee joint, concomitant ligament injuries with ACL injury, and/or more than one year from injury to surgery, were excluded. Pivot-shift tests were performed preoperatively under general anaesthesia using an electromagnetic measurement system, and tibial acceleration (m/s²) during the posterior reduction of the tibia was measured. Medial and lateral PTS (°) were measured respectively using high-resolution CT images taken two weeks after surgery. Lateral-medial slope asymmetry was calculated by subtracting medial PTS from lateral PTS (lateral-medial PTS) and we evaluated the correlation between each PTS parameter (medial PTS, lateral PTS, and lateral-medial slope asymmetry) and tibial acceleration during the pivot-shift test. The level of significance was set at p < 0.05.

RESULTS

Medial PTS was 4.9 ± 2.0°, and lateral PTS was 5.2 ± 1.9°. The lateral-medial slope asymmetry was 0.3 ± 1.6° (range: -2.9 to 3.8). Tibial acceleration during the pivot-shift test in the ACL-injured knee was 1.6 ± 0.1 m/s². Preoperative tibial acceleration was positively correlated with lateral PTS (r = 0.436, p < 0.01), and lateral-medial slope asymmetry (r = 0.443, p < 0.01), while no significant correlation was found between preoperative tibial acceleration and medial PTS (r = 0.06, p = 0.70).

CONCLUSION

Preoperative greater tibial acceleration during the pivot-shift test was associated with steeper lateral PTS and greater lateral-medial slope asymmetry in ACL-injured knees. These findings improve our understanding of anterolateral rotatory knee laxity by linking tibial bony morphology to quantitative measurement of pivot-shift phenomenon. Surgeons should be aware that not only lateral PTS but also lateral-medial slope asymmetry are the factors associated with preoperative pivot-shift.

LEVEL OF EVIDENCE

Level IV.

The anterolateral capsule is infrequently damaged as evaluated arthroscopically in patients undergoing anatomic ACL reconstruction

OBJECTIVES

Concomitant anterolateral complex (ALC) injury may contribute to persistent rotatory knee instability following anterior cruciate ligament (ACL) reconstruction. There is no consensus on how to best identify concomitant ALC injury preoperatively, nor how well ALC injury identified on imaging modalities correlates with clinical examination of knee instability. The purpose of this retrospective study was to determine the incidence of concomitant ALC injury in ACL-injured knees, as determined by arthroscopy to preoperative radiography, ultrasound, and MRI.

METHODS

A total of 117 patients with a unilateral primary ACL injury who underwent individualized anatomic ACLR between June 2016 and May 2019 were enrolled. Preoperative imaging modalities, including X-ray, ultrasound, and MRI, were evaluated for concomitant ALC injury. Clinical examination under anesthesia, including the anterior drawer, Lachman, and pivot shift tests were performed. Anterolateral capsule injury, as defined by hemorrhage and/or capsular tearing on diagnostic arthroscopy, was also determined. Correlative analyses of ALC injury incidence and severity were performed across imaging modalities and against clinical examination grades.

RESULTS

ALC injury incidence across imaging modalities was as follows: X-ray (3%), arthroscopy (19%), MRI (53%), and US (63%). The ALC injury rate on arthroscopy was significantly less than MRI (p < 0.001) or ultrasound (p < 0.001). ALC injury incidence and severity were significantly correlated between MRI and US grading scales (p = 0.02), but no correlations among other imaging modalities were found. Similarly, no imaging modality meaningfully correlated with physical examination maneuvers.

CONCLUSION

The incidence of ALC injury varies across imaging modalities, with lower injury rates found on arthroscopy (19%) compared to MRI (53%) and US (63%). Increasing ALC injury severity grades on imaging does not predict increasing anterolateral knee laxity on clinical examination.

LEVEL OF EVIDENCE

V, retrospective case series.

Preoperative quantitative pivot shift does not correlate with in vivo kinematics following ACL reconstruction with or without lateral extraarticular tenodesis

PURPOSE

Quantitative pivot shift (QPS) testing using PIVOT technology can detect high- and low-grade rotatory knee instability following anterior cruciate ligament injury or reconstruction (ACLR). The aim of this project was to determine if preoperative QPS correlates with postoperative knee kinematics in the operative and contralateral, healthy extremity following ACLR with or without lateral extraarticular tenodesis (LET) using a highly precise in vivo analysis system. A positive correlation between preoperative QPS and postoperative tibial translation and rotation following ACLR with or without LET in the operative and healthy, contralateral extremity was hypothesized.

METHODS

Twenty patients with ACL injury and high-grade rotatory knee instability were randomized to undergo anatomic ACLR with or without LET as part of a prospective randomized trial. At 6 and 12 months postoperatively, in vivo kinematic data were collected using dynamic biplanar radiography superimposed with high-resolution computed tomography scans of patients' knees during downhill running. Total anterior-posterior (AP) tibial translation and internal-external tibial rotation were measured during the gait cycle. Spearman's rho was calculated for preoperative QPS and postoperative kinematics.

RESULTS

In the contralateral, healthy extremity, a significant positive correlation was seen between preoperative QPS and total AP tibial translation at 12 months postoperatively (r_s = 0.6, p < 0.05). There were no additional significant correlations observed between preoperative QPS and postoperative knee kinematics at 6 and 12 months postoperatively in the operative and contralateral, healthy extremity for combined isolated ACLR and ACLR with LET patients as well as isolated ACLR patients or ACLR with LET patients analyzed separately.

DISCUSSION

The main finding of this study was that there was a significant positive correlation between preoperative QPS and total AP tibial translation at 12 months postoperatively in the contralateral, healthy extremity. There were no significant correlations between preoperative QPS and postoperative in vivo kinematics at 6 and 12 months following ACLR with or without LET. This suggests that QPS as measured with PIVOT technology does correlate with healthy in vivo knee kinematics, but QPS does not correlate with in vivo kinematics following ACLR with or without LET.

The coronal lateral collateral ligament sign in the anterior cruciate ligament-injured knees was observed regardless of the knee laxity based on the quantitative measurements

PURPOSE

The coronal lateral collateral ligament (LCL) sign has been reported to be associated with deviated position of the tibia on MRI due to anterior cruciate ligament (ACL) injuries. However, the relationships between LCL sign and clinical knee laxity evaluations are still unclear. The purpose of the study was to investigate the relationship between the coronal LCL sign and knee laxity measurements.

METHODS

A retrospective review of unilateral ACL injured patients who underwent ACL reconstruction was performed. The coronal LCL sign was determined using magnetic resonance imaging (MRI). Clinical grading of the pivot-shift test, KT-1000 measurements, and quantitative measurements of the Lachman test and the pivot-shift test using an electromagnetic system, were compared between patients with positive and negative coronal LCL sign. A subgroup analysis of different age groups was then performed, dividing patients to adolescent (age ≤ 18 years) and adult (age > 18 years) groups.

RESULTS

A total of 85 patients were enrolled, of which 45 patients had coronal LCL signs. The coronal LCL sign was not associated with the pivot-shift test clinical grading (n.s), KT-1000 measurement (n.s), the tibial translation during the Lachman test (n.s), or with tibia acceleration (n.s) and translation (n.s) during the pivot-shift test. The subgroup analysis also showed that the aforementioned parameters were not associated with the coronal LCL sign in either adolescent or adult subgroups.

CONCLUSION

The occurrence of coronal LCL sign in MRI did not imply greater clinical knee laxity evaluations in patients with ACL tears. The knee laxity should routinely be evaluated regardless the coronal LCL sign.

LEVEL OF EVIDENCE

Level III.

Three-Dimensional Reconstruction Algorithm-Based Magnetic Resonance Imaging Evaluation of Biomechanical Changes in Articular Cartilage in Patients after Anterior Cruciate Ligament Reconstruction

This study aimed to investigate the evaluation of biomechanical changes in articular cartilage in patients after anterior cruciate ligament (ACL) reconstruction by magnetic resonance imaging (MRI) based on a three-dimensional (3D) finite element model. The data of 90 patients undergoing arthroscopic ACL reconstruction in the hospital were collected and divided into the stable group (54 cases) and the unstable group (36 cases). A load of up to 134N was applied to the 3D finite element model, and the kinematics of knee flexion at 0°, 30°, 60°, and 90° were examined. The tibial anteversion, tibial rotation, and ACL/graft tension were recorded in the 3D finite element model, which was randomly divided into the normal group (intact group, n = 30), the ACL rupture group (deficient group, n = 30), and the anatomical reconstruction group (anatomical group, n = 30). When the graft was fixed at 0°, the anterior tibial translation at 30°, 60°, and 90° in the anatomic group was 8-19% higher than the normal value under 134 N anterior load. The tibial internal rotation in the anatomic group was 18% and 28% higher than the normal value at 30° and 90°. When the graft was fixed at 30°, the anterior tibial translation at 60° and 90° of the anatomic group was 15% higher than the normal value. The tibial internal rotation at 90° of the anatomic group was 16% higher than the normal value, and the above differences had statistical significance (P < 0.05). MRI images were used to assess the bone tunnel angle, and the statistical analysis by the independent-samples t-test showed that there were significant differences in the bone tunnel angle between the stable group and the unstable group (P < 0.05). Currently, based on the 3D finite element model, MRI can accurately evaluate the postoperative effect of anatomical ACL reconstruction in the position, diameter, and angle of tibial and femoral bone tunnels, which can be applied to clinical promotion.

Deep Learning-Based Magnetic Resonance Imaging Image Features for Diagnosis of Anterior Cruciate Ligament Injury

To study and explore the adoption value of magnetic resonance imaging (MRI) in the diagnosis of anterior cruciate ligament (ACL) injuries, a multimodal feature fusion model based on deep learning was proposed for MRI diagnosis. After the related performance of the proposed algorithm was evaluated, it was utilized in the diagnosis of knee joint injuries. Thirty patients with knee joint injuries who came to our hospital for treatment were selected, and all patients were diagnosed with MRI based on deep learning multimodal feature fusion model (MRI group) and arthroscopy (arthroscopy group). The results showed that deep learning-based MRI sagittal plane detection had a great advantage and a high accuracy of 96.28% in the prediction task of ACL tearing. The sensitivity, specificity, and accuracy of MRI in the diagnosis of ACL injury was 96.78%, 90.62%, and 92.17%, respectively, and there was no considerable difference in contrast to the results obtained through arthroscopy (P > 0.05). The positive rate of acute ACL patients with bone contusion and medial collateral ligament injury was substantially superior to that of chronic injury. Moreover, the incidence of chronic injury ACL injury with meniscus tear and cartilage injury was notably higher than that of acute injury, with remarkable differences (P < 0.05). In summary, MRI images based on deep learning improved the sensitivity, specificity, and accuracy of ACL injury diagnosis and can accurately determined the type of ACL injury. In addition, it can provide reference information for clinical treatment plan selection and surgery and can be applied and promoted in clinical diagnosis.

The quantitative evaluation of anterior drawer test using an electromagnetic measurement system

The anterior drawer test (ADT) is the gold standard examination for the diagnosis of anterior talofibular ligamentinsufficiency,although there is noquantitative evaluation of ADT that is generally usable and reliable.An electromagnetic sensor (EMS)has been used to quantitatively evaluate joint kinematics, and has a high potential to be applied to the ankle joint. The aim of this study was to validatethe EMS measurement of the ADTin comparison to the fluoroscopic evaluationand to evaluate the reproducibility of the EMS measurement.Six feet were included,and an examinerperformed the ADT5 times for each foot while the anterior translation of the ankle jointwas quantitative evaluatedusing EMS and fluoroscope simultaneously. The anterior translation of the ankle joint during the ADT in EMS and in fluoroscope was 8.1 ± 5.7 mm and 3.6 ± 2.4 mm.Astrong correlation was observed between the measurements using EMS and fluoroscope (p < 0.01, the correlation coefficient = 0.91). Another 20 feet were included, and three examiners performed the ADT five times for each foot with the EMS measurement. The intra and inter-examiner reliability was 0.99 and 0.89.The EMS could quantify the anterior translation during the ADT which corresponds to fluoroscopic evaluation.

Association Between Radiological Evidence of Kaplan Fiber Injury, Intraoperative Findings, and Pivot-Shift Grade in the Setting of Acute Anterior Cruciate Ligament Injury

BACKGROUND

Biomechanical studies have suggested that the Kaplan fibers (KFs) of the iliotibial band play a role in controlling anterolateral rotation of the knee. There is a paucity of clinical information on whether injury to the KF in the setting of anterior cruciate ligament (ACL) rupture contributes to increased rotatory laxity of the knee.

PURPOSE/HYPOTHESIS

The purpose was to evaluate the association among radiological evidence of KF injury, intraoperative arthroscopic findings, and grade of pivot shift at the time of ACL reconstruction (ACLR). It was hypothesized that KF injury would be associated with increased injury to the lateral compartment of the knee and a higher grade of pivot shift.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective magnetic resonance imaging (MRI) analysis was conducted on 267 patients with ACL-injured knees who underwent primary ACLR. Patients who had MRI and surgery within 60 days of injury were included (mean age, 23.6 years); there were 158 (59.2%) male patients. MRI was performed using standard knee protocols, and diagnostic criteria were applied to identify KF injury. Associations were made among MRI findings, intraoperative findings, and grade of pivot shift with the patient examined under anesthesia at the time of ACLR. A comparison was made between patients with and without radiological evidence of KF injury.

RESULTS

The prevalence of KF injury was 17.6% (47/267 patients). Arthroscopic evidence of lateral meniscal injury was associated with KF injury (KF intact, 31%; KF injured, 55%; P = .010). The majority of patients in the intact and injured KF groups had a grade 2 pivot shift (75% and 70%, respectively). A minority had grade 3 pivot shift: 5% in the intact group versus 6.4% in the injured group. There was no association between radiological evidence of KF injury and pivot-shift grade (P = .600).

CONCLUSION

In acute ACL injury, KF injuries were not very common (17.6%), and the rate of grade 3 pivot shift was low (5.2%). When present, KF injuries were not associated with a higher-grade pivot shift. However, there was an association between KF injury and lateral meniscal tears identified at the time of ACLR. The role of KFS in controlling anterolateral rotatory laxity in the acute ACL injury in the clinical setting may be less evident when compared with the biomechanical setting.

Editorial Commentary: Magnetic Resonance Imaging Evaluation of the Anterolateral Complex-Is Seeing Really Believing?

The anatomic and biomechanical role of the anterolateral complex (ALC) of the knee has gained increased interest in recent years. Specifically, a keen focus has been on magnetic resonance imaging (MRI) evaluation of the ALC in the setting of anterior cruciate ligament injury. Although many of these studies are well designed and conducted, they are based on a foundation of controversial gross anatomy and MRI protocols and scanners not typically used in standard practice. Ultimately, there is a lack of correlation between MRI evidence of injury to the ALC and clinical evaluation of anterolateral rotatory laxity. So, do we believe in what we see or believe in what we feel?

No difference in postoperative rotational laxity after ACL reconstruction in patients with and without anterolateral capsule injury: quantitative evaluation of the pivot-shift test at 1-year follow-up

PURPOSE

To compare rotational laxity in anterior cruciate ligament (ACL)-reconstructed knees retrospectively with and without concomitant anterolateral capsule (ALC) injury confirmed by magnetic resonance imaging (MRI) prior to ACL reconstruction.

METHODS

Sixty-two ACL-reconstructed knees (26 men, 36 women; median age 20 (range 13-59)) were included. Pivot-shift test was performed before ACL reconstruction and 1 year postoperatively under anesthesia with both clinical grading and quantitative measurement simultaneously. Clinical grading was determined according to the International Knee Documentation Committee (IKDC) criteria (none, glide, clunk, or gross), and an electromagnetic measurement system was used to provide tibial acceleration as a quantitative parameter. The resence of concomitant ALC injury was confirmed retrospectively by MRI. The pivot-shift test was compared between ACL-reconstructed knees with and without ALC injury test for clinical grading and the independent t test for quantitative evaluation.

RESULTS

ALC injury was identified in 26 of 62 (42%) knees. Before ACL reconstruction, there was no difference in the pivot-shift test results between the ACL-deficient knees with and without ALC injury in IKDC grading (n.s.) or tibial acceleration (1.1 ± 0.7 m/s² and 1.4 ± 1.1 m/s², respectively, n.s.). At 1 year postoperatively, no difference was observed between groups (IKDC, p = 0.90; tibial acceleration, 0.6 ± 0.3 m/s² and 0.8 ± 0.6 m/s², n.s.).

CONCLUSIONS

Concomitant ALC injury at the time of ACL injury had no effect on the rotational laxity of the knee in the postoperative course after ACL reconstruction. Therefore, additional treatment for ALC injury may not be warranted.

LEVEL OF EVIDENCE

IV.

The anterolateral ligament of the knee joint: a review of the anatomy, biomechanics, and anterolateral ligament surgery

Residual knee instability and low rates of return to previous sport are major concerns after anterior cruciate ligament (ACL) reconstruction. To improve outcomes, surgical methods, such as the anatomical single-bundle technique or the double-bundle technique, were developed. However, these reconstruction techniques failed to adequately overcome these problems, and, therefore, new potential answers continue to be of great interest. Based on recent anatomical and biomechanical studies emphasizing the role of the anterolateral ligament (ALL) in rotational stability, novel surgical methods including ALL reconstruction and anterolateral tenodesis have been introduced with the possibility of resolving residual instability after ACL reconstruction. However, there is still little consensus on many aspects of the ALL, including: several anatomical issues, appropriate indications for ALL surgery, and the optimal surgical method and graft choice for reconstruction surgery. Therefore, further studies are necessary to advance our knowledge of the ALL and its contribution to knee stability.