2017 ISAKOS Biennial Congress ePoster #1041

 

Incidence of Anterolateral Ligament Tears Seen on Magnetic Resonance Imaging in Anterior Cruciate Ligament Deficient Knees

Audrey X. Han, MBBS (Singapore), MRCS (Edinburgh), Singapore SINGAPORE
Tien Jin Tan, MBBS, FRCR, Singapore SINGAPORE
Tiep Ngoc Nguyen, MD, Hanoi VIETNAM
Yee-Han Dave Lee, MBBS, FRCS(Ortho), Singapore SINGAPORE

Changi General Hospital, Singapore, Singapore, SINGAPORE

FDA Status Not Applicable

Summary

To evaluate the presence Anterolateral Ligament (ALL), ALL tears as well as characterize ALL injuries in Anterior Cruciate Ligament (ACL) deficient knees with standard 1.5-Tesla Magnetic Resonanace Imaging (MRI). To assess inter-observer reliability variation between a musculoskeletal radiologist and an orthopedic surgeon in the identification of the above.

Abstract

Purpose

To visualize the Anterolateral Ligament (ALL) tears in Anterior Cruciate Ligament (ACL) deficient knees with standard 1.5-Tesla Magnetic Resonance Imaging (MRI). We wanted to identify the location of the ALL tears (femoral, meniscal, tibial) as well as the inter-observer variation between a musculoskeletal radiologist and an orthopedic surgeon in the identification of ALL injuries. We also compared to see if patients with combined ALL and ACL tears had a poorer pre-operative knee score than those with just ACL tears.

Method

This study involves a fellowship-trained musculoskeletal radiologist and an orthopedic surgeon. They reviewed MRI images of all patients who had their MRIs performed within two months of their knee injuries. All patients (n=148) identified had ACL tears confirmed on MRI and arthroscopy, for which they had undergone ACL reconstruction. Patients with concomitant lateral collateral ligament or posterolateral corner injuries were excluded.

Both assessors read the MRI images separately to look for the following (i) presence of ALL (ii) presence of an ALL tear (iii) location of the tear ie, femoral, meniscal and tibial insertions of the ALL . Based on their readings of the ALL, the inter-rater reliability between the two assessors was compared. The pre-surgery Subjective IKDC and Lysholm scores for the patients with ACL tears versus those with combined ACL and ALL tears were compared.

Results

The Anterolateral Ligament (ALL) was identified in 100% of the patients by both assessors.

In group 1(MRI within month of injury) (n= 88), the ALL tear was noted in 92% of patients by the radiologist and 90% of patients by the surgeon. Observed agreement was 0.86 (?=0.176).

In group 2(MRI between 1 to 2 months after injury) (n= 60), the ALL tear was reported in 78% of patients by the radiologist and 92% of patients by the surgeon. Observed agreement was 0.62; (?=-0.14).

There was a discrepancy between 2 to 14% in the detection of ALL tears. Accuracy in detection of presence of a tear on MRI was affected by duration between time of injury and time when the MRI was taken. (p value < 0.01).

In group 1, the observed agreement of identifying the location of the ALL tear at the femoral, meniscal and tibial insertions were 0.53, 0.72 and 0.76 respectively (K= 0.09, 0.28, 0.37). In group 2, the observed agreement was 0.55, 0.52 and 0.57 respectively (K= -0.02, 0.11, 0.12). This indicated that the ALL tears could still be fairly accurately identified on the meniscal and tibial side.

When we compared the pre-surgery Subjective IKDC and Lysholm scores for the patients with ACL tears versus those with combined ACL and ALL tears, we found no statistically significant differences between the two groups.

Conclusion

The Anterolateral Ligament can be accurately identified on MRI. If the MRI is performed within one month of injury, ALL tears can be identified fairly accurately, especially if the tear occurs on the meniscal and tibial side. Duration of the MRI from the injury also affects the accuracy of ALL tears being identified on MRI.