Steps toward the validation of the Trendelenburg test: the effect of experimentally reduced hip abductor muscle function on frontal plane mechanics.
OBJECTIVE
To investigate the validity of the Trendelenburg test (TT) using an ultrasound-guided nerve block (UNB) of the superior gluteal nerve and determine whether the reduction in hip abductor muscle (HABD) strength would result in the theorized mechanical compensatory strategies measured during the TT.


METHODS
Quasi-experimental.


METHODS
Hospital.


METHODS
Convenience sample of 9 healthy men. Only participants with no current or previous injury to the lumbar spine, pelvis, or lower extremities, and no previous surgeries were included.


METHODS
Ultrasound-guided nerve block.


METHODS
Hip abductor muscle strength (percent body weight [%BW]), contralateral pelvic drop (cPD), change in contralateral pelvic drop (ΔcPD), ipsilateral hip adduction, and ipsilateral trunk sway (TRUNK) measured in degrees.


RESULTS
The median age and weight of the participants were 31 years (interquartile range [IQR], 22-32 years) and 73 kg (IQR, 67-81 kg), respectively. An average 52% reduction of HABD strength (z = 2.36, P = 0.02) resulted after the UNB. No differences were found in cPD or ΔcPD (z = 0.01, P = 0.99, z = -0.67, P = 0.49, respectively). Individual changes in biomechanics showed no consistency between participants and nonsystematic changes across the group. One participant demonstrated the mechanical compensations described by Trendelenburg.


CONCLUSIONS
The TT should not be used as a screening measure for HABD strength in populations demonstrating strength greater than 30%BW but should be reserved for use with populations with marked HABD weakness.


CONCLUSIONS
This study presents data regarding a critical level of HABD strength required to support the pelvis during the TT.
Faculty of Kinesiology, Running Injury Clinic, University of Calgary, Calgary, Alberta, Canada. kdkendal@ucalgary.ca
Karen D
KD
Kendall
Chirag
C
Patel
J Preston
JP
Wiley
Michael B
MB
Pohl
Carolyn A
CA
Emery
Reed
R
Ferber
D000328:Adult; D001696:Biomechanical Phenomena; D002081:Buttocks; D020233:Gait Disorders, Neurologic / Q000175:diagnosis*; D006615:Hip / Q000000981:diagnostic imaging / Q000294:innervation / Q000503:physiopathology*; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000294:innervation / Q000503:physiopathology*; D009407:Nerve Block; D010384:Pelvic Bones / Q000503:physiopathology*; D018084:Ultrasonography, Interventional; D014741:Video Recording