Jugjiwan Ram Yesudas Ramsaha MD, Abstract Co-Author: Nothing to Disclose

Yue Dong, Presenter: Nothing to Disclose

Kiran Kerbhoo Keedoly MBBS, Abstract Co-Author: Nothing to Disclose

Jacques Michael Marie-Jeanne, Abstract Co-Author: Nothing to Disclose

To prove whether there is significant difference between the readings of two independent readers and repeated readings of the same reader needed to diagnose Femoroacetabular Impingement syndrome (FAI).

This retrospective clinical study was performed with approval from the Institutional Review Board. 233 patients (15-85years old, mean age 42.7) who attended same hospital between March 2010 and March 2011 for hip pain underwent one or more of the following imaging examinations: plain X-ray, CT scan and MRI. A total amount of 466 sides were observed. Diagnosis of FAI was based upon the absence of any other disease and according to the following radiological imaging criteria: From X-ray images – osseous bump, pistol-grip deformity, femoral head-neck offset < 9mm, figure-8 configuration, posterior wall sign together with a lateral centre edge angle >40 degrees, extrusion index <25 together with a lateral centre edge angle >40 degrees. From CT primary axial, reformatted coronal and axial oblique images: osseous bump, pistol-grip deformity, femoral head-neck offset < 9mm, extrusion index < 25 together with a lateral centre edge angle >40 degrees, increased acetabular depth (>5mm). From MR images: osseous bump, pistol-grip deformity, femoral head-neck offset < 9mm, extrusion index < 25 together with a lateral centre edge angle >40 degrees. Readings were taken independently by readers A and B. Reader A took a second reading after a time lapse of one month. Cohen Kappa method was used to determine the agreement between the readings for different FAI signs using SPSS statistical analysis software.

Osseous bump, pistol grip deformity, femoral head neck offset, posterior wall sign with lateral center edge and extrusion index with lateral center edge were the signs which demonstrated the highest agreement in both inter and intra observer readings. Figure of 8 sign showed substantial agreement while the acetabular depth sign proved to have a slight agreement in both inter and intra observer readings.  

Osseus bump, pistol grip deformity, femoral head neck offset, posterior wall sign with lateral center edge and extrusion index with lateral center edge are reliable signs for diagnosis of FAI. Figure of 8 and acetabular depth signs are unreliable for the diagnosis of FAI.

Diagnosis of FAI can be done using reliable signs with best agreement values.

Ramsaha, J, Dong, Y, Kerbhoo Keedoly, K, Marie-Jeanne, J, Inter and Intra Observer Agreement of FAI.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12035805.html