Pelvic posture and kinematics in femoroacetabular impingement: a systematic review.
BACKGROUND
Pelvic posture and kinematics influence acetabular orientation and are therefore expected to be involved in the pathomechanics of femoroacetabular impingement (FAI). This systematic review aims to determine whether FAI patients show pelvic postures or patterns of motion contributing to impingement or, conversely, develop compensatory postures and patterns of motion preventing it.


METHODS
PubMed/MEDLINE, Embase, Google Scholar and the Cochrane Library were systematically searched to find all the studies that measured pelvic positional and/or kinematic data in humans (patients or cadaveric specimens) affected by FAI.


RESULTS
Twelve items were selected and grouped according to the main field of investigation. No quantitative data synthesis was allowed due to methodological heterogeneity. Pelvic posture and kinematics seem to play a relevant role in FAI. The patients, especially if symptomatic, show a paradoxical lack of pelvic back tilt in standing hip flexions, i.e., in squatting, that enhances femoroacetabular engagement. Such an aberrant pattern might depend on a lower pelvic incidence. On the contrary, active hip flexion in decubitus elicits a compensatory, more pronounced back tilt to facilitate hip flexion without impingement. Stair climbing shows a compensatory pattern of augmented pelvic axial rotation and augmented peak forward tilt to reduce painful hip motions, namely internal rotation and extension.


CONCLUSIONS
In FAI patients, pelvic posture and kinematics are sometimes an expression of compensatory mechanisms developed to reduce pain and discomfort, and sometimes an expression of paradoxical responses that further enhance the impingement pathomechanism.


METHODS
IV.
Gaetano Pini Orthopedic Institute, P.zza C. Ferrari, 1, 20122, Milan, Italy. LMCPierannunzii@hotmail.com.
Luca
http://orcid.org/0000-0002-7962-1496
L
Pierannunzii
D000077:Acetabulum / Q000503:physiopathology; D001696:Biomechanical Phenomena; D057925:Femoracetabular Impingement / Q000503:physiopathology*; D005270:Femur Head / Q000503:physiopathology; D005272:Femur Neck / Q000503:physiopathology; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D010384:Pelvic Bones / Q000503:physiopathology*; D011187:Posture / Q000502:physiology*; D013131:Spine / Q000503:physiopathology*
Femoroacetabular impingement; Gait analysis; Pelvic kinematics; Pelvic posture; Pelvic tilt