2015 ISAKOS Biennial Congress ePoster #1112

MRI Study of the Anterolateral Ligament and its Association With Knee Injury

Shreyash M. Gajjar, MS, FRCSEd, FRCSEd (Orth), Mumbai, Maharashtra INDIA
Mohammad Salim, MBBS, D.Orth, MS (Orth), MCh (Orth), Stockton-On-Tees, N/A UNITED KINGDOM
Shafiq Mohammed, D'Orth, Mumbai INDIA
Amol Sanap, MS (Orth), Mumbai INDIA
Kokilaben D. Ambani Hospital & Medical Research Institute, Mumbai, INDIA

FDA Status Not Applicable

Summary: ALL visible on 3T MRI

Abstract:

Introduction

Recent Anatomic & Biomechanical knee studies, have identified & described an Anterolateral ligament (ALL) as an important additional lateral stabiliser of the knee. One MRI study, has also reported a high incidence of tear of this ligament in ACL ruptured knees.

Objectives:
1) To determine the ease in identifying the ALL on routine knee MRI scans.
2) To determine any association of tear of the ALL with other intra-articular knee injuries.

Materials & Method:
In a retrospective study, 138 knee MRI scans (3 Tesla) of 136 patients done for evaluation of their knee injury were included in the study. We excluded patients with previous knee surgery, knee dislocation, signs of Osteoarthritis > Kellegren - Lawrence grade II, inflammatory arthritis, haemophilia, knee tumours. The scans included MRI knee protocol with T1 weighted sequences, T2 weighted sequences with fat saturation & Proton density (PD)- weighted fast spin echo sequences. All MRI scans were examined as per a standard pre- described protocol by 2 trained independent observers to evaluate inter observer reliability. The ALL was divided into 3 portions for analysis: femoral (proximal), mid-portion & tibial (distal) as described in recent studies. The presence or absence of a tear of the ALL in isolation or in association with other intra-articular injuries was noted.

Results

Atleast some portion of the ALL was identified by both observers in all 138 knee MRI scans (100%). The ALL was visualised best on Coronal plane T2 weighted sequences with fat saturation, and proton density (PD)- weighted fast spin echo sequences. Observer 1 reported tear of ALL in 22 out of 138 knee MRIs (16%) whilst Observer 2 reported in 23 out of 138 knee MRIs (16%). Observer 1 reported associated tear of ALL in 15 out of 55 knees he identified as having associated ACL rupture (27%). Observer 2 reported associated tear of ALL in 15 out of 54 knees he identified as having associated ACL rupture (27%). The association of ALL tear with ACL rupture was 65%. The inter-rater agreement according to kappa test (95% CI) ranged from 0.896 to 1.000.

Conclusion

The results of our study showed that ALL was identified by our trained Observers in 100% of 3 Tesla knee MRI scans. Only a small proportion of knee injury patients in our study group were noted to have a tear of the ALL on MRI. The association of ALL tear with ACL rupture was 65%.