Assessment of Range of Motion and Contact Zones with Commonly Performed Physical Exam Manoeuvers for Femoroacetabular Impingement (FAI): What do These Tests Mean?

Abstract

Recognition of the magnitude and location of mechanical conflicts is critical to reliably and reproducibly improve functional range of motion and outcomes after surgical treatment of femoroacetabular impingement (FAI). The purpose of this study was to assess the ROM and location of intra-articular and extra-articular mechanical conflict with seven commonly performed physical exam manoeuvers in a cohort of hips with symptomatic FAI. Internal rotation in flexion results in mechanical contact between the anterolateral and anterior femoral head-neck junction with the acetabulum, most commonly at a 1:15 o'clock position. Associated adduction, however, significantly reduces the available internal rotation secondary to contact in the same locations. Straight abduction results in mechanical conflict between the superior femoral head-neck junction and the 12:00 o'clock position of the acetabulum. With external rotation of the hip in various degrees of hip flexion, the potential mechanical impingement is extra-articular between the greater trochanter and ischium or pubic ramus. The zones of proximal femoral and acetabular contact are not intuitive, and may extend significantly more laterally and distally on the femoral head-neck junction than previously appreciated.

In-vivo hip arthrokinematics during supine clinical exams: Application to the study of femoroacetabular impingement

“…In another simulation of 18 cam FAI patients, maximum internal rotation in 85° flexion and 20° adduction was 5.7 ±15.7°. Despite less flexion and more adduction, this estimate of internal rotation is similar to the restrictions identified in the three patients in the present study (Bedi et al, 2013). However, in the study by Bedi et al, maximum external rotation in neutral flexion was 52.7 ± 15.9°, almost 20° greater than all participants in our study herein (Bedi et al, 2013).…”

“…Despite less flexion and more adduction, this estimate of internal rotation is similar to the restrictions identified in the three patients in the present study (Bedi et al, 2013). However, in the study by Bedi et al, maximum external rotation in neutral flexion was 52.7 ± 15.9°, almost 20° greater than all participants in our study herein (Bedi et al, 2013). Also, in the simulation by Bedi et al, maximum range of motion was estimated from bone on bone collision; in external rotation this resulted in direct collision between the greater trochanter and ischium.…”

Clinical tests to determine femoral version category in people with chronic hip joint pain and asymptomatic controls

“…Our findings are important when considering the activities in which people participate. For example, IR creates a mechanical abutment between the anterolateral femoral head-neck junction and the anterior acetabular rim, thus resulting in stresses being placed on the anterior acetabular labrum and articular cartilage (Bedi, et al, 2013). A patient with femoral retroversion and thus decreased hip internal rotation, will experience this mechanical abutment earlier in the limb motion.…”

“…(Mesgarzadeh, et al, 1987;Silveira and Piedade, 2014;Avila, et al, 2016). Conversely, ER creates a mechanical abutment between the posterolateral femoral head-neck junction and the posterior acetabular rim, potentially resulting in repetitive stresses on the posterior acetabular labrum and articular cartilage (Bedi, et al, 2013).…”

Editorial Commentary: What Exactly Is Impingement—Can Dynamic Magnetic Resonance Imaging “See” Impingement in Femoroacetabular Impingement?

“…Femoral head and acetabular sphericity and age associated with higher femoral head translation. There was greater femoral head translation in 45 flexion (3 AE 0.9 mm M; 2.8 AE 0.9 mm F) and FABER (3.2 AE 0.9 mm M; 3.2 AE 0.7 mm F) vs 15 extension (1.7 AE 0.5 mm M; 1.7 AE 0.4 mm F) Bedi et al 11 2013 CT-based 3D motion analysis in 18 symptomatic FAI hips. 12 2012 CT-based 3D motion analysis in 8 symptomatic FAI hips.…”