2015 ISAKOS Biennial Congress ePoster #904

Femoroacetabular Impingement Syndrome is Associated With Alterations in Foot Mechanics: A 3-Dimensional Gait Analysis Study

Iftach Hetsroni, MD, Tel Aviv ISRAEL
Shany Funk, MA, Netanya ISRAEL
David Ben-Sira, PhD, Netanya ISRAEL
Ezequiel Palmanovich, MD, Kfar Saba ISRAEL
Meir Nyska, MD, Prof., Kfar Saba ISRAEL
Moshe Ayalon, PhD, Netanya, Wingate Institute ISRAEL

Meir General Hospital, Kfar Saba, Israel, and Biomechanics Laboratory at Zinman College for Sports Sciences, Wingate, Israel, Kfar Saba , ISRAEL

FDA Status Not Applicable

Summary: Patients with cam-type FAI are characterized by alterations in foot mechanics which include out-toeing foot with inverted subtalar joint position at heel strike, and reduction in maximum subtalar joint eversion during the stance

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Abstract:

Objective

Femoroacetabular impingement syndrome (FAI) is reportedly associated with abnormalities in hip mechanics. This may be associated with abnormalities in foot mechanics as a consequence of a closed kinematic chain mechanism during the stance as suggested by some investigators, but it has never been investigated in patients with FAI. The purpose of this study was therefore to investigate whether FAI syndrome is associated with alterations in foot mechanics.

Methods

Fifteen symptomatic limbs of 15 male patients (age, 21-45 years) with cam-type FAI (alpha angle 72°±8°) were compared to 30 limbs of 15 normal control male subjects (age, 21-37 years). All subjects had a physical examination, followed by level walking 3-dimensional (3D) gait analysis from foot to hip level, using 6 camera optical stereometric system (Vicon) sampling at 120Hz.

Results

Tegner score before symptoms appearance in the FAI population was similar to the control group (range, 5-10 vs. 5-9, respectively, p=ns). During the study examination, Tegner score was 1-7 in the FAI group and Hip Outcome Sports-subset score was 59±25, compared to 100 in the control group. On physical examination, hip flexion was 122°±14° and hip internal rotation was 18°±9° in the FAI hips, compared to 140°±7° and 33°±6°, respectively, in the normal control hips (p<0.01). Three-dimensional gait analysis demonstrated similar walking speed, cadence, and stance time in the groups. At heel strike, subtalar joint angle was 3°±3° inversion in the FAI group, and 0°±4° in the normal control group (p=0.01). During the stance, maximum subtalar joint angle was 3°±3° eversion in the FAI group, and 6°±4° eversion in the normal control group (p=0.04). Foot out-toeing angle at heel strike was 16°±8° in the FAI group, and 12°±6° in the normal control group (p=0.05). At the hip level, FAI patients demonstrated a more adducted position compared to control subjects (p=0.01) and a slightly further anterior tilted pelvis (p=0.01).

Conclusions

During level walking, patients with cam-type FAI are characterized by alterations not only in hip mechanics, but also in foot mechanics. These include out-toeing foot with inverted subtalar joint position at heel strike, and reduction in maximum subtalar joint eversion during the stance. The observed alterations in foot mechanics may be related to alterations observed in hip mechanics, corresponding to a closed kinematic chain mechanism. This observation may further contribute to our understanding of patho-mechanisms in this challenging syndrome and may also assist for planning optimal treatment strategies for these young patients in the future.