Patent ID: 8900246

Claim:
A surgical instrument assembly for use during a surgical procedure to implant an orthopaedic hip prosthesis, comprising: a trial shaft having (i) a cylindrically-shaped stem, and (ii) a locking screw having a number of threads formed in a distal end thereof, the locking screw being rotatable relative to the cylindrically-shaped stem, and a discrete trial neck removably secured to the trial shaft, the trial neck having (i) a bore formed therein, with the stem of the trial shaft being received into the bore so as to allow for rotation of the trial neck relative to the trial shaft, and (ii) a locking mechanism operable to selectively lock the rotational position of trial neck relative to the trial shaft, wherein the stem of the trial shaft has a number of grooves formed therein, and the locking mechanism of the trial neck has a locking pawl that is selectively positionable in the number of grooves to selectively lock the rotational position of trial neck relative to the trial shaft.