When the man saw that he did not prevail against Jacob: did not prevail means that he could not beat Jacob, could not throw him down. See Good News Translation “he was not winning.” Jacob’s opponent was unable to defeat him by using ordinary wrestling methods, and, in order to escape before dawn, he threw Jacob’s hip out of joint.

He touched the hollow of his thigh: the verb rendered touched may also mean to strike or hit. Hollow refers to the hip socket. The ball of the thigh bone fits into the hip socket. It is clearer to say, for example, “he hit him on the hip.” See Good News Translation.

Put out of joint means the thigh bone was pulled loose from the hip socket.

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .