European Journal of Cardiovascular Medicine

The knee is the largest joint in the body and is a common site of injury. It is a complex ‘hinge’ joint made up of the lower end of the femur, the upper end of the tibia, and the patella, which slides in a groove on the end of the femur. The knee joint has three components, the lateral tibiofemoral, medial tibiofemoral, and patellofemoral joints. Four bands of tissue, the anterior and posterior cruciate ligaments, and the medial and lateral collateral ligaments connect the femur and the tibia and provide joint stability.

A key component in stabilising knee motion is the anterior cruciate ligament (ACL). An ACL injury results in significant impairment. In both the short- and long-term, patient management depends on an accurate diagnosis of ACL injury [1]. MRI (magnetic resonance imaging) has emerged as the preferred method of assessing the condition of the ACL and other related knee structures. [1,2,3, 4]. An assessment of the ACL has traditionally made use of sagittal MR images. Coronal and axial imaging provide a better understanding of ACL injuries, while multiplanar imaging easily reveals meniscal and other ligamentous and bone marrow injuries. These findings increase diagnostic confidence and accuracy for meniscal and other injuries [1, 5] Meniscal tears and damage to other ligamentous structures surrounding the knee are frequently associated with anterior cruciate ligament tears, which are a common sports injury [5]. Planning surgical interventions and selecting appropriate treatments are crucial when it comes to acute knee injuries, and magnetic resonance imaging is essential for this assessment [1, 5]. An ACL tear is strongly linked to peripheral meniscal tears, especially when the posterior horn is involved. Upon identifying an ACL tear on knee MR imaging, it is crucial to closely examine the menisci for signs of damage [6].

Individuals with ACL injuries may exhibit varying meniscal tear patterns due to different demographic and historical risk factors, such as gender, age, body weight, and injury method. When diagnosing patients with significant meniscal tears in the early posttraumatic period, doctors may find it easier if they are aware of these risk factors [7, 8]. Anterior cruciate ligament (ACL) injuries are common in sportsmen and physically active people, often as a result of trauma encountered during sports. Meniscal tears and ACL injuries often occur together, and the ACL is essential for knee stability. It is essential to understand the connection between meniscal tears and ACL injuries in order to optimise therapeutic approaches. [9, 10,11] Using MRI as a diagnostic tool, this study looks into the forms, patterns, and prevalence of meniscal tears linked to ACL injuries.

AIMS

To study the meniscal tears in patients with anterior cruciate ligament injury using magnetic resonance imaging

Objectives:

1. To estimate the frequency of meniscal tear and the location of tear associated with an anterior cruciate ligament injury and grading of Anterior Cruciate ligament using MRI
2. To study the association of meniscal tears in patients presenting with an anterior cruciate ligament injury.

Study Design:  Observational study.

Place of study: Department of Radiodiagnosis at Manipal hospital, Bangalore. It is a hospital-based study. Data for the study was collected from patients with ACL injury undergoing MRI knee at Manipal Hospital.

Sample size: Minimum of 40 cases subjected to MR knee.

Inclusion criteria:

1. Patients with clinical suspicious of anterior cruciate ligament injuries.
2. Patients who are already diagnosed and are under conservative treatment for anterior cruciate ligament injury.

Exclusion Criteria:

1. Patients with cardiac pacemakers & metallic implants will not be subjected to MRI.
2. Motion disorder and claustrophobia, if severe may make the examination difficult.
3. Patients presenting with degenerative changes.
4. Patients with a history of knee surgery.

Study period

The study was carried out for 1 year from months of April 2018 to May 2019

Data Collection:

Before enrolling patients in the study, we obtained their written and informed consent. Once the patient meets the study's inclusion requirements, the doctor explains the procedure to the patient. Before undergoing an MRI, the doctor obtained the patient's demographic and clinical information. The patient was informed about the noise produced by gradient coils (heard once the patient was inside the magnet's bore) and the importance of limiting body movement during the scanning process.

All the MRI scans in this study was performed using

1. General Electric Medical systems, 1.5T strength.
2. Philips Medical systems, 3T strength.
3. Sagittal FS PD FSE

Study procedure (Sequences):

1. Axial T1 or PD FSE
2. Sagittal T1 or PD FSE
3. Sagittal FS PD FSE
4. Coronal FS PD FSE
5. Axial FS PD FSE
6. Coronal T1
7. Sagittal T2 GRE.

Data analysis:

The data was double-checked and entered on Microsoft Excel-2019, and the final data analysis was done with the help of the statistical software SPSS 21. Continuous data was represented as mean and standard deviation, whereas categorical data was represented in proportions and frequencies. The data was tabulated and graphically represented. The Pearson Chi-square test was used to assess the associations for categorical variables. P < 0.05 considered significant. 

Ethical approval:

The study was approved by Manipal Hospital Institutional Ethics Committee, Bangalore.

A total of 40 patients were participated in the study, out of which 28 (70%) were males and the rest 12(30%) were females. The mean age of the study participants was 35± 9.4 years. Among the 40 participants regarding the distribution of meniscal injury, majority 17 (42.5%) had medical meniscal injury, followed by both medial and lateral meniscus in 15  (37.5 %),  least affected was lateral meniscus alone (2.5 %) and 7 (17.5 %) has no meniscal injury. In patients with ACL tears, male sex, age <40 and grade of ACL tear are independent risk factors for concomitant major meniscal tears.

Anterior cruciate ligament injury grading was done using MRI imaging. Out of 40 participants, majority 52.5% has Grade III injury followed by grade II in 32.5% and grade I was observed in only 15%. 

Table I Distribution of Study subjects according to Lateral Meniscus injury

Table II Distribution of Study subjects according to Lateral Meniscus injury

Table III: Study Subjects according to association between Medial Meniscus injury and  age

Meniscal injuries are more in the active age group, that is 21 to 30 years and 31 to years age group and the difference is not found to be statically significant. ( P : 0.607 ).

Figure 1 ; Distribution of study subjects according to Gender

Anterior cruciate ligament (ACL), as a primary stabilizing structure of the knee and is the most common disrupted ligament in acute trauma. Magnetic resonance imaging (MRI) is a valuable tool, preferred than diagnostic arthroscopy in most patients with ligamentous and meniscal tears because it avoids the surgical risks of arthroscopy, with better accuracy in the medial and lateral meniscus and ACL, and plays an important role in deciding treatment options and planning surgical intervention.

Different tear patterns of the menisci in ACL-injured subjects may be associated with different demographic and historical risk factors such as gender, age, the grade of ACL injury, and injury mechanism. Knowledge about such risk factors may help physicians to identify patients with major meniscal tears in the early posttraumatic phase.

The overall incidence of meniscal tears in the present study was 82.5% (42.5% for medial meniscus, 2.5% for lateral meniscus and 37.5% for both menisci). The tear occurrence of medial meniscus tears is higher than lateral meniscal tears due to the firm attachment of the meniscus to the tibia, particularly at the posterior horn, which acts as a knee stabilizer in ACL deficient knees. Similar findings were observed by study conducted by Sagar Venkataraman at Jalappa Hospital & Research Centre, Kolar, from January 2012 to December 2019. Where in ACL tears medial meniscus tear was more frequent followed by both lateral and medical meniscus and least in lateral meniscus.

This is consistent with research conducted by Al Saran Y[13], which aimed to identify the most prevalent kind of meniscus damage in a population linked to an ACL tear and to ascertain the patterns of meniscus damage related with ACL rupture. Of the 294 patients in that study, 175 (59.7%) had a meniscal tear in the middle, 91 (30.9%) had a tear in the side, and 28 patients (9.5%) had a rupture in both the medial and lateral regions. According to the study, tears to the medial meniscus seemed to occur more frequently in cases of ACL rupture.

In another study conducted by Tetsuo Hagino to investigate the frequency of meniscal tear and the location of tear associated with anterior cruciate ligament (ACL) injury, the incidence of meniscal tear associated with ACL injury was higher in patients with chronic than in those with acute ACL deficiency. In particular, there was an increase in medial meniscal tears, most of which were treated by meniscectomy [9,10,11]

The loss of ACL function increases tibial translation, allowing the meniscus to “engage” the femoral condyle and act as a wedge against the tibia, while some studies have suggested that mechanical trauma causes the medial meniscal tears in this setting [13].

This study was conducted to determine the location, patterns, and grade of meniscus damage associated with ACL rupture and identify the commonest type of meniscus damage in our population that is associated with an ACL tear.

The most common tear location in the medial meniscus in our study was posterior horn, with the most common tear types being horizontal (40.63%), followed by complex (25%) and bucket handle type (12.5%)

In Lateral meniscal tears, the most common site for the tears was also the posterior horns. The most common tear types were complex (43.75%) and horizontal (18.75%)

This study highlights the significant prevalence of meniscal injuries in patients with ACL tears, with a notable focus on medial meniscal involvement. The grading of ACL injuries suggests a majority of severe cases, underscoring the need for comprehensive imaging and careful management strategies in this population. These findings of imaging using MRI emphasize the importance of a thorough assessment of knee injuries to inform clinical decisions and optimize patient outcomes.

Limitations:

While this study provides valuable insights into the association between ACL injuries and meniscal tears using MRI imaging, it is not without limitations. The relatively small sample size may restrict the generalizability of the findings. Future studies with larger cohorts and a more diverse demographic could provide deeper insights into the patterns of knee injuries. Furthermore, long-term follow-up could elucidate the outcomes of different treatment approaches in patients with concurrent ACL and meniscal injuries.

Acknowledgement: I am thankful to all the participants for their cooperation and all the staff department of radiology for their immense support and valuable inputs throughout the study.

Funding: The study did not receive any financial support from external sources.

Conflict of interest: No conflicts of interest have been declared.

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