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Am J Sports Med. 2012
May;40(5):1113-8. Epub 2012 Mar 5.
The effect of dynamic
femoroacetabular impingement on pubic symphysis motion: a cadaveric
study.
Birmingham PM, Kelly BT,
Jacobs R, McGrady L, Wang M.
Source
Department of Orthopaedic
Surgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
[email protected]
Abstract
BACKGROUND:
A link between
femoroacetabular impingement and athletic pubalgia has been reported clinically.
One proposed origin of athletic pubalgia is secondary to repetitive loading of
the pubic symphysis, leading to instability and parasymphyseal tendon and
ligament injury. Hypothesis/
PURPOSE:
The purpose of this study
was to investigate the effect of simulated femoral-based femoroacetabular
impingement on rotational motion at the pubic symphysis. The authors hypothesize
that the presence of a cam lesion leads to increased relative symphyseal
motion.
STUDY DESIGN:
Controlled laboratory
study.
METHODS:
Twelve hips from 6
fresh-frozen human cadaveric pelvises were used to simulate cam-type
femoroacetabular impingement. The hips were held in a custom jig and maximally
internally rotated at 90° of flexion and neutral adduction. Three-dimensional
motion of the pubic symphysis was measured by a motion-tracking system for 2
states: native and simulated cam. Load-displacement plots were generated between
the internal rotational torque applied to the hip and the responding motion in 3
anatomic planes of the pubic symphysis.
RESULTS:
As the hip was internally
rotated, the motion at the pubic symphysis increased proportionally with the
degrees of the rotation as well as the applied torque measured at the distal
femur for both states. The primary rotation of the symphysis was in the
transverse plane and on average accounted for more than 60% of the total
rotation. This primary motion caused the anterior aspect of the symphyseal joint
to open or widen, whereas the posterior aspect narrowed. At the torque level of
18.0 N·m, the mean transverse rotation in degrees was 0.89° ± 0.35° for the
native state and 1.20° ± 0.41° for cam state. The difference between cam and the
native groups was statistically significant (P <
.03).
CONCLUSION:
Dynamic femoroacetabular
impingement as caused by the presence of a cam lesion causes increased
rotational motion at the pubic
symphysis.
CLINICAL RELEVANCE:
Repetitive loading of the
symphysis by cam impingement is thought to lead to increased symphyseal motion,
which is one possible precursor to athletic
pubalgia.
PMID: 22392561 [PubMed -
indexed for MEDLIN
Am J Sports Med. 2012
May;40(5):1113-8. Epub 2012 Mar 5.
The effect of dynamic
femoroacetabular impingement on pubic symphysis motion: a cadaveric
study.
Birmingham PM, Kelly BT,
Jacobs R, McGrady L, Wang M.
Source
Department of Orthopaedic
Surgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
[email protected]
Abstract
BACKGROUND:
A link between
femoroacetabular impingement and athletic pubalgia has been reported clinically.
One proposed origin of athletic pubalgia is secondary to repetitive loading of
the pubic symphysis, leading to instability and parasymphyseal tendon and
ligament injury. Hypothesis/
PURPOSE:
The purpose of this study
was to investigate the effect of simulated femoral-based femoroacetabular
impingement on rotational motion at the pubic symphysis. The authors hypothesize
that the presence of a cam lesion leads to increased relative symphyseal
motion.
STUDY DESIGN:
Controlled laboratory
study.
METHODS:
Twelve hips from 6
fresh-frozen human cadaveric pelvises were used to simulate cam-type
femoroacetabular impingement. The hips were held in a custom jig and maximally
internally rotated at 90° of flexion and neutral adduction. Three-dimensional
motion of the pubic symphysis was measured by a motion-tracking system for 2
states: native and simulated cam. Load-displacement plots were generated between
the internal rotational torque applied to the hip and the responding motion in 3
anatomic planes of the pubic symphysis.
RESULTS:
As the hip was internally
rotated, the motion at the pubic symphysis increased proportionally with the
degrees of the rotation as well as the applied torque measured at the distal
femur for both states. The primary rotation of the symphysis was in the
transverse plane and on average accounted for more than 60% of the total
rotation. This primary motion caused the anterior aspect of the symphyseal joint
to open or widen, whereas the posterior aspect narrowed. At the torque level of
18.0 N·m, the mean transverse rotation in degrees was 0.89° ± 0.35° for the
native state and 1.20° ± 0.41° for cam state. The difference between cam and the
native groups was statistically significant (P <
.03).
CONCLUSION:
Dynamic femoroacetabular
impingement as caused by the presence of a cam lesion causes increased
rotational motion at the pubic
symphysis.
CLINICAL RELEVANCE:
Repetitive loading of the
symphysis by cam impingement is thought to lead to increased symphyseal motion,
which is one possible precursor to athletic
pubalgia.
PMID: 22392561 [PubMed -
indexed for MEDLIN
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