Magnetic Resonance Arthrography, a valuable pre-operative imaging modality in femoro-acetabular impingement

Nevien Ezzat El-Liethy,Ahmed Hazem Abd El-Azeem,Rania Zeitoun,Heba Ahmed Kamal

doi:10.1186/s43055-019-0049-0

Nevien Ezzat El-Liethy, Ahmed Hazem Abd El-Azeem + Show 2 more

Open Access

https://doi.org/10.1186/s43055-019-0049-0

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Abstract

BackgroundThe diagnostic accuracy of MR arthrography in preoperative assessment of labral tears and chondral abnormalities in femoroacetabular impingement patients.A non-randomized control study including 31 FAI patients (17 male and 14 females, mean age 31.9 years). All patients underwent MR arthrography after US-guided intra-articular contrast injection. Conventional and MR arthrography images were evaluated for bone abnormalities (including alpha angle and acetabular depth measurements), labral tears, and chondral abnormalities. The results were correlated to arthroscopy as the gold standard. Sensitivity, specificity, PPV, and NPV in the detection of labral tears and chondral abnormalities were statistically calculated.ResultsThe included FAI patients presented cam (mean age 30.4 years ± 6.8 years), pincer (mean age 33.6 years ± 9.8 years), and mixed (mean age 36.6 years ± 12.9 years) types with the predominance of cam type. Cam type predominated in the male, while pincer and mixed types predominated in female patients. MR arthrography detected 41 labral tears in 23 patients with 87.5%, 71.4%, 91.3%, and 62.5% sensitivity, specificity, PPV, and NPV, respectively, and detected chondral abnormalities in 13 patients with 66.7%, 92.3%, 92.3%, and 66.7% sensitivity, specificity, PPV, and NPV, respectively.ConclusionMR arthrography is a valuable imaging modality in preoperative assessment of FAI patients. Besides identifying the type of impingement through alpha angle and acetabular depth measurements, it detects labral tears with high sensitivity and PPV. Although less sensitive in detection of chondral abnormalities, our results showed high specificity.

Highlights

The diagnostic accuracy of Magnetic resonance (MR) arthrography in preoperative assessment of labral tears and chondral abnormalities in femoroacetabular impingement patients
The purpose of this study is to evaluate the diagnostic value of MR arthrography in preoperative assessment of labral tears and chondral abnormalities in femoroacetabular impingement patients, with reference to hip arthroscopy results as the gold standard
The included 31 patients had Femoroacetabular impingement (FAI) based upon the alpha angle and acetabular depth measurements using axial oblique MR images

Summary

Introduction

The diagnostic accuracy of MR arthrography in preoperative assessment of labral tears and chondral abnormalities in femoroacetabular impingement patients. Femoroacetabular impingement (FAI) is defined as abnormal femoral acetabular contact, within the normal range of motion, and attributed to changes of the anatomical configuration of the acetabulum and/ or the femoral head–neck. It was initially described by Myers et al [1] and was reintroduced by Ganz et al [2] with the recognition that non-united femoral neck fractures healed in retroversion could. Pincer impingement is caused by an acetabular abnormality, usually anterior, resulting in over-coverage of the femoral head It is more common in middle-aged women at an average age of 40 years [5, 7,8,9]. Magnetic resonance (MR) arthrography is considered the best imaging modality for evaluation of the internal hip pathology allowing better visualization of the joint internal structures by the help of better distention and higher contrast resolution obtained by intra-articular gadolinium [13]

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