Summary

A weak correlation was found between the MRI total score and bone marrow edema and medial meniscal extrusion. Medial meniscal extrusion may affect the pathology of early knee osteoarthritis.

Abstract

Introduction

Osteoarthritis of the knee (knee OA) has a very high prevalence, and interest in "early knee OA" as a clue to early detection and treatment is growing. Although the onset mechanism and pathology remain largely unknown, it has been suggested that the synovio-enthesial complex (SEC) is important in the pathology of osteoarthritis, and it is known that the medial collateral ligament functions as an SEC in the knee joint. As

Method

for evaluating SEC in early knee OA, we focused on the Tenosynovitis scoring proposed by The OMERACT MRI in Enthesitis Initiative. The purpose of this study is to investigate the correlation between ultrasound findings and Tenosynovitis MRI score in cases of early knee OA.

Materials And Methods

The subjects were 162 knees with early knee OA (64 men, 98 women; 60.3±11.5 years) investigated in a multicenter collaborative study. The parameters were MRI score: signal changes within and around the ligament, size of bone marrow edema, size of bursa, degree of ligament thickening, size of bone formation, size of bone lesion (0-3), total score (0-21), and ultrasound findings: synovial hyperplasia, joint effusion, horizontal meniscus tear, and osteophytes(femoral and tibial), synovial blood flow signal (0-3), medial meniscus (MM) extrusion (mm), MM extrusion (90° flexion) (mm), medial collateral ligament (MCL) bursa blood flow signal (0-3), patellofemoral joint (IPFP) blood flow signal (0-3), standing MM extrusion (mm), and stress MM extrusion (mm), and the correlation between each item was examined.

Results

The correlation analysis of each parameter between MRI score and ultrasound findings showed a weak positive correlation between total score and medial meniscus extrusion (mm) (r=0.232, p<0.01), total score and standing medial meniscus extrusion (mm) (r=0.296, p<0.01), bone marrow edema and medial meniscus extrusion (mm) with knee flexion at 90° (r=0.352, p<0.01), and bone marrow edema and standing medial meniscus extrusion (mm) (r=0.258, p<0.01).
The results of the Cochran-Armitage test showed a significant correlation between joint effusion and periligamentous signals, bone marrow edema, synovitis, ligament thickening, and total score (p<0.05).
Furthermore, a significant correlation was observed between femoral osteophytes, bone marrow edema, and total score(p<0.05).

Conclusion

A weak correlation was observed between MRI total score, bone marrow edema and medial meniscus extrusion (mm).
Furthermore, a significant correlation was observed between joint effusion, femoral osteophytes, and MRI score. Medial meniscus extrusion, joint effusion, and femoral osteophytes in ultrasound findings may affect the pathology of early knee OA.