Knee MRI Underestimates the Grade of Cartilage Lesions

Przemysław Krakowski,Józef Jonak,Agata Nogalska,Mariusz Jojczuk,Robert Karpiński

doi:10.3390/app11041552

Przemysław Krakowski, Józef Jonak + Show 3 more

Open Access

https://doi.org/10.3390/app11041552

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Abstract

Purpose: This study was conducted in order to evaluate the clinical utility of MRI in detecting cartilage lesions and its dependence on anatomical location and lesion grade. Methods: A retrospective analysis of MRI reports and arthroscopic findings was performed on 190 consecutive patients treated in one orthopaedic department. MRI protocols were prepared by 18 radiologists from 10 different MRI centers with the use of 1.5 T magnets. The image protocols were selected by reading radiologists. Four hundred and fifty-three chondral lesions in five anatomic locations were identified during this study and graded according to the ICRS classification. Sensitivity, specificity, receiver operating characteristic (ROC), and Bangdiwala’s observer agreement charts were utilized to evaluate the diagnostic performance. Results: Only approximately 30% of MRI showed an adequate cartilage status in all anatomical locations. The sensitivity ranged from 92% in healthy cartilage to 5% in grade I lesions. The specificity differed also grossly depending on the lesion grade, reaching 96.5% in grade four lesions and 38% in healthy cartilage. The medial compartment Bangdiwala’s observer agreement charts show a gross underestimation of cartilage lesions, and the area under the curve (AUC) of ROC surpasses 0.7 only in the medial femoral condyle and patella-femoral joint. Overall, the medial compartment accuracy was significantly higher than the lateral compartment. The MRI showed correspondence of its diagnostic performance with cartilage lesion severity. Conclusion: MRI underestimates the extent of cartilage injury and evaluation of cartilage defects based on MRI should be taken with caution by orthopaedic surgeons in planning surgery. Surgical planning on MRI should take cartilage lesions under consideration, even if no cartilage lesions are reported on the MRI.

Highlights

Chondral defects are a common cause of knee dysfunction found in over 60% of patients requiring arthroscopy [1]
If no information on the cartilage defects was given, the cartilage was regarded as a grade O as per the International Cartilage Repair Society (ICRS) [21,22]
Chondral lesions were diagnosed in 139 knees, out of which 112 had concomitant injuries such as meniscal lesions or ACL tears

Summary

Introduction

Chondral defects are a common cause of knee dysfunction found in over 60% of patients requiring arthroscopy [1]. In pursuit of a better cartilage evaluation, new imaging techniques based on MRI have been introduced in recent years These techniques include sodium imaging, delayed gadoliniumenhanced MRI of cartilage (dGEMRIC), glycosaminioglycan specific chemical exchange saturation transfer (gagCEST), diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), and relaxometry measurements [7]. Such techniques enable the differentiation between a healthy and repaired cartilage [8], can correspond with glycosaminoglycans concentration [9,10,11], or enable the quantitative monitoring of macromolecules in early osteoarthritis [12]. Joint effusion can interfere with the gagCEST evaluation due to the presence of glycosaminoglycans in the synovial fluid [14]

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