An acetabular instrument has a handle portion having one or more solid nonflexible drive shaft elements therethrough. The shaft elements are connected by a U-joint at one of both ends to form a flexible curved drive shaft. One end of a solid shaft element is connected to a knob so that rotation of the knob drives the flexible shaft. The flexible shaft is housed within a hollow curved body preferably made of stainless steel. One end of the curved body it is connected to the handle portion and at the other end to an acetabular cup or acetabular reamer holder. The reamer holder is rotatably driven by the flexible drive shaft. The knob may be made so that it may receive blows from a mallet allowing the instrument to be used as an impactor. The drive shaft may be used to actuate a locking mechanism within the cup or reamer holder which connects the reamer cup to the instrument.