The examiner grasps the affected leg near the heel with one hand and at the knee with the other and passively flexes the hip and knee.
Then the hip is hyper flexed, internally rotated, and adducted.
What does a positive FADDIR Test mean?
The FADDIR Test is positive if groin pain with limitation of flexion and internal rotation is elected.
The forced movement combining flexion, adduction, and internal rotation brings the femoral neck into contact with the anterolateral acetabular rim .
Impingement occurs when bony prominences at the junction of the femoral head and neck (cam impingement) and/or at the anterior rim of the acetabulum (pincer impingement) cause the femoral neck to contact the anterior rim of the acetabulum earlier than normal. The same occurs also in the case of deep acetabular sockets.
This impingement causes lesions of the acetabular labrum and joint cartilage, especially in young and physically active individuals, who clinically experience groin pain when sitting and when involved in sports activities.
The symptoms are usually partially or completely relieved by the movement combining flexion and external rotation, during which the femoral neck moves laterally by the anterior acetabular roof without impingement.
Restrictions of internal rotation and of flexion occur in multiple other disorders that must be considered in the differential diagnosis, including Legg Calvé Perthes disease, epiphysiolysis, and decreased anteversion.
Sensitivity & Specificity
The FADDIR Test (Flexion ADDuction Internal Rotation) accuracy for screening cam and pincer morphology (Femoroacetabular impingement) according to Nicola C Casartelli in his study 1:
Sensitivity: 41-60 %
Specificity: 47-52 %
Another study by Burnett et al 2 found that Sensitivity of FADDIR Test was 95 % (Specificity not calculated).
Forced passive hyperextension and external rotation can cause a painful anterior subluxation of the femoral head, in which the femoral head contacts the labrum , which is partially or completely torn (in hip dysplasia).
If a labral lesion is present, forcing the movement combination of hip flexion, abduction, and internal rotation will lead to pain due to contact of the femoral neck with the anterolateral acetabular rim (impingement test).
Nicola C Casartelli, Romana Brunner, Nicola A Maffiuletti, Mario Bizzini, Michael Leunig, Christian W Pfirrmann, Reto Sutter. The FADIR test accuracy for screening cam and pincer morphology in youth ice hockey players. J Sci Med Sport. 2018 Feb;21(2):134-138. doi: 10.1016/ j.jsams.2017.06.011. Epub 2017 Jun 21. PMID: 28669665
Clinical presentation of patients with tears of the acetabular labrum. Burnett RS, Della Rocca GJ, Prather H, Curry M, Maloney WJ, Clohisy JCJ Bone Joint Surg Am. 2006 Jul; 88(7):1448-57. [PubMed].
Clinical Tests for the Musculoskeletal System, Third Edition.