Evaluation of Trendelenburg and Duchenne signs by experimentally induced gluteal muscle paralysis.

Abstract

The Trendelenburg and Duchenne signs are commonly used to clinically assess hip abductor function. Previous studies, however, have shown only a partial reduction of functional abduction force after paralyzing the gluteus medius and minimus. This study aimed to investigate the effects of experimentally induced sequential paralysis of the tensor fasciae latae, gluteus medius and minimus, and gluteus maximus on the Trendelenburg and Duchenne signs. Ten healthy adults received sequential nerve blocks of the branch of the superior gluteal nerve to the tensor fasciae latae, the branch of the superior gluteal nerve to the gluteus medius and minimus, and the inferior gluteal nerve supplying the gluteus maximus. After each block, participants performed a ten-second single-leg stance recorded with 56 skin markers and 27 cameras. Pelvic drop and spinal obliquity were analyzed to determine the presence of a Trendelenburg or Duchenne sign. Paralysis of the tensor fasciae latae resulted in compensatory mechanisms in 2 of 10 participants. Following paralysis of the gluteus medius and minimus, 5 of 10 could not maintain single-leg stance for ten seconds and one exhibited a Trendelenburg sign. Gluteus maximus paralysis led to failure in 5 of 10 participants, with two showing a Duchenne sign. Our study demonstrates that the Trendelenburg and Duchenne signs lack both sensitivity and specificity and should not be solely attributed to gluteus medius and minimus weakness. Importantly, impairment of the gluteus maximus may also produce similar compensatory patterns or mask abductor deficits.