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

Abstract

Visualization of hip articulation relative to the underlying anatomy (i.e., arthrokinematics) is required to understand hip dysfunction in femoroacetabular (FAI) patients. In this exploratory study, we quantified in-vivo arthrokinematics of a small cohort of asymptomatic volunteers and three symptomatic patients with varying FAI deformities during the passive impingement, FABER, and rotational profile exams using dual fluoroscopy and model-based tracking. Joint angles, joint translations, and relative pelvic angles were calculated. Compared to the 95% CI of the asymptomatic cohort, FAI patients appeared to have decreased adduction and internal rotation during the impingement exam and greater flexion and less abduction/external rotation in the FABER exam. During the rotational profile, only one patient (most severe deformities) demonstrated considerable rotation deficits. Contact between the labrum and femoral head/neck limited motion during the impingement exam, but not the rotational profile, in all participants. Substantial pelvic motion was measured during the impingement exam and FABER test in all participants. Femoral translation along any given anatomical direction ranged between 0.69–4.1 mm. These results suggest that hip articulation during clinical exams is complex in asymptomatic hips and hips with FAI, incorporating pelvic motion and femur translation. Range of motion appears to be governed by femur-labrum contact and other soft tissue constraints, suggesting that current computer simulations that reply on direct bone contact to predict impingement may be unrealistic. Additional research is necessary to confirm these preliminary results. Still, dual fluoroscopy data may serve to validate existing software platforms or create new programs that better-represent hip arthrokinematics.

Physical impairments in symptomatic femoroacetabular impingement: a systematic review of the evidence

“…Recent studies investigating the effect of FAI-related bony deformities in athletic populations have also reported a non-significant influence of cam on hip rotation ROM53 54 and all other directions of movement 54. It is possible that computer simulations or X-ray studies that rely on direct bone contact to predict impingement may be unrealistic 45. It might also reflect that some studies evaluated participants postsurgery, which may have influenced the results.…”

Dynamic radiostereometric analysis for evaluation of hip joint pathomechanics

“…The mean adduction found in this study was comparable to the results of the symptomatic group found by Kapron et al Roach et al have investigated digital inclinometer and goniometer for measuring passive hip motion and found these methods to be associated with errors up to 5° (Roach et al 2013). Hence, these methods would not be feasible for measuring the differences in ROM found in this study nor for measuring the differences between subjects (Kapron et al 2015). …”

Physical impairments in symptomatic femoroacetabular impingement: A Systematic review of the evidence

“…54 It is possible that computer simulations or X-ray studies that rely on direct bone contact to predict impingement may be unrealistic. 45 It might also reflect that some studies evaluated participants postsurgery, which may have influenced the results. Surgical interventions had no significant effect on hip ROM.…”