Abstract: Illustrative embodiments of impact tools with impact mechanisms rigidly coupled to electric motors are disclosed. In at least one illustrative embodiment, an impact tool may comprise an impact mechanism, an electric motor, and a control circuit. The impact mechanism may comprise a hammer and an anvil, the hammer being configured to rotate about a first axis and to periodically impact the anvil to drive rotation of the anvil about the first axis. The electric motor may comprise a rotor that is rigidly coupled to the impact mechanism, the electric motor being configured to drive rotation of the hammer about the first axis. The control circuit may be configured to supply a current to the electric motor and to prevent the current from exceeding a threshold in response to the hammer impacting the anvil.

Abstract: Illustrative embodiments of impact tools with impact mechanisms rigidly coupled to electric motors are disclosed. In at least one illustrative embodiment, an impact tool may comprise an impact mechanism, an electric motor, and a control circuit. The impact mechanism may comprise a hammer and an anvil, the hammer being configured to rotate about a first axis and to periodically impact the anvil to drive rotation of the anvil about the first axis. The electric motor may comprise a rotor that is rigidly coupled to the impact mechanism, the electric motor being configured to drive rotation of the hammer about the first axis. The control circuit may be configured to supply a current to the electric motor and to prevent the current from exceeding a threshold in response to the hammer impacting the anvil.

Abstract: A patellar trial and drill guide for use during knee replacement surgery comprising an articular surface member and a fixation peg drill guide. The articular surface member is the exact geometry as the artificial patellar implant, and the drill guide aligns the holes for the fixation pegs of the artificial patellar implant. The patellar trial is placed on the resected patella in the desired position, a patellar clamp is used to temporary fix the patellar trial to the patella. The patella is then returned to its normal position and a trial reduction of the total knee replacement is completed. If the placement and/or size of the patellar trial is unacceptable, the patella is inverted, the patellar trial removed, and a different sized trial or new location is determined. The new patellar trial is secured to the resected patella, and another trial reduction of the total knee replacement is completed. This procedure can be repeated until the patellar trial is the correct size and in the proper location.