Tensor Fasciae Latae and Gluteus Maximus Muscles: Do They Contribute to Hip Abduction?

Hip abductors are essential for hip function. To understand abduction weakness, it is important to know which muscles contribute to abduction force. Our aim was to investigate the effects of an experimentally induced weakness of the different muscles (tensor fasciae latae TFL, gluteus medius and minimus (Gmed/min), gluteus maximus Gmax) on the abduction force. Ten participants received sequential nerve blocks of the TFL, the Gmed/min, and the Gmax. Subsequently, abduction force was measured in the lateral decubitus position in three sagittal positions of the hip (30° flexion, neutral, 30° extension). In 30° flexion, the average abduction force was 220 N without block, 187 N with block of the TFL, 83 N with block of the Gmed/min, and 97 N with block of the Gmax, respectively. In neutral position, average abduction force was 213 N without block, 200 N with block of the TFL, 82 N with block of the Gmed/min, and 115 N with block of the Gmax, respectively. In 30° extension, average abduction force was 116 N without block, 146 N with block of TFL, 61 N with block of the Gmed/min, and 94 N with block of the Gmax, respectively. An induced weakness of the TFL reduces abduction force only in 30° of hip flexion by 15%. It is not highly relevant as an abductor. An induced weakness of the Gmax reduces abduction force in flexion by 43%-56%, depending on the position. It is, therefore, highly relevant as an abductor of the hip.