Patent ID: 7879043

Claim:
A method for monitoring impaction of a femoral component of a hip prosthesis into a femur, comprising: receiving impaction data generated during the impaction of the femoral component into the femur from at least one accelerometer attached to the femoral component; normalizing the impaction data into a usable format as normalized impaction data; calculating a total norm of an acceleration signal including the normalized impaction data based on the following equation: Norm Total = ∑ i = 1 N ⁢ a i 2 where N is a number of points in a time interval to be analyzed and a is an acceleration measurement taken at an i th point by the accelerometer; calculating an impaction monitoring metric E j for a femoral component impaction hit as a fraction of the total norm of the acceleration signal during the time interval at a j th point based on the following equation: E j = ∑ i = 1 j ⁢ a i 2 Norm Total determining a time t(j) corresponding to a fractional value E j within a predetermined range indicative of the femoral component being fully seated for each of a plurality of femoral component impaction hits that is equal to a length of time required for E j to reach a predetermined fractional value indicative of femoral component fit and stability after the impaction hit; and generating an output based on the time t(j) for the femoral component impaction hit, the output being indicative of the femoral component fit and stability.