Orthopedic device delivering a controlled, repeatable impact
In an illustrative embodiment, a motor-driven orthopedic impacting tool for orthopedic impacting in the hips, knees, shoulders and the like may be capable of holding a surgical implement such as a broach, chisel, or other end effector, which when gently tapped in a cavity with controlled percussive impacts, can expand the size or volume of an opening of the cavity or facilitate removal of the surgical implement from the opening. A stored-energy drive mechanism may store potential energy and then release it to launch a launched mass or striker to communicate a striking force to an adapter in either a forward or reverse direction. The tool may further include a combination anvil and adapter and an energy adjustment mechanism to adjust the striking force the launched mass delivers to the adapter.
1. A surgical impacting tool, comprising:
a first mechanical spring configured to release energy stored therein to drive a surgical implement in a forward direction;
a second mechanical spring configured to release energy stored therein to drive the surgical implement in a rearward direction;
an electronic controller configured to control the energy storage and release such that energy is alternately 1) stored in and released from the first mechanical spring and 2) stored in and released from the second mechanical spring;
an adapter configured to secure to the surgical implement;
a means for delivering an impact force responsive to the energy released by the first mechanical spring and the energy released by the second mechanical spring to the surgical implement secured to the adapter, the means being independent from the adapter, being located between the first and second mechanical springs, and being linearly aligned with the adapter and the first and second mechanical springs along a longitudinal axis extending forward and rearward along the forward and rearward directions; and
a cam configured to rotate and thereby compress and release the mechanical springs to generate the impact force;
wherein a cam follower is disposed between the first and second mechanical springs, and
the rotation of the cam is configured to push the cam follower toward the first mechanical spring and then move the cam follower away from the first mechanical spring and thereafter to push the cam follower toward the second mechanical spring and then move the cam follower away from the second mechanical spring.
2. The surgical impacting tool of claim 1 , wherein:
the cam includes a worm protruding from a cylindrical portion of the cam; and
the worm includes a helicoid surface extending between a first worm end and a second worm end, wherein the cam follower is configured to slide on the helicoid surface from the first worm end to the second worm end as the cam rotates so as to compress the first mechanical spring, and the cam follower is configured to slide on the helicoid surface from the second worm end to the first worm end as the cam rotates so as to compress the second mechanical spring.
3. The surgical impacting tool of claim 1 , wherein at least one of the first and second mechanical springs has a compression ratio of less than 50% of a free length of the at least one of the first and second mechanical springs.
4. The surgical impacting tool of claim 1 , wherein the controller, after the delivery of the impact force, is configured to stop the cam in a position where at least part of the energy has been stored by the first mechanical spring, thereby providing a latency upon activation of the surgical impacting tool of up to about 100 milliseconds.
5. The surgical impacting tool of claim 1 , wherein the means for delivering the impact force comprises a means for delivering both a forward impact force and a reverse impact force, wherein the reverse impact force is equal or greater to the forward impact force.
6. The surgical impacting tool of claim 1 , further comprising first and second pistons;
wherein the means for delivering the impact force comprises a striker configured to be activated by the first piston and by the second piston;
the first piston, the second piston, the first mechanical spring, and the second mechanical spring are linearly aligned;
the first piston is configured to be actuated by the first spring; and
the second piston is configured to be actuated by the second spring.
7. The surgical impacting tool of claim 6 , further comprising a bumper element;
wherein the piston, upon actuation, is configured to come to rest on the bumper element.
8. A surgical impacting tool, comprising:
a first mechanical spring configured to release energy stored therein to drive a surgical implement in a forward direction;
a second mechanical spring configured to release energy stored therein to drive the surgical implement in a rearward direction;
an electronic controller configured to control the energy storage of the first and second mechanical springs and the release of the energy of the first and second mechanical springs such that energy is alternately 1) stored in and released from the first mechanical spring and 2) stored in and released from the second mechanical spring;
an adapter configured to secure to the surgical implement;
a thrown mass configured to deliver an impact force responsive to the released energy to the surgical implement secured to the adapter, the thrown mass being independent from the adapter, being located between the first and second mechanical springs, and being linearly aligned with the adapter and the first and second mechanical springs along a longitudinal axis extending forward and rearward along the forward and rearward directions; and
a can configured to rotate and thereby compress and release the mechanical springs to displace the thrown mass and generate the impact force;
wherein a cam follower is disposed between the first and second mechanical springs; and
the rotation of the cam is configured to push the cam follower toward the first mechanical spring and then move the cam follower away from the first mechanical spring and thereafter to push the cam follower toward the second mechanical spring and then move the cam follower away from the second mechanical spring.
9. The surgical impacting tool of claim 8 , wherein:
the cam includes a worm protruding from a cylindrical portion of the cam; and
the worm includes a helicoid surface extending between a first worm end and a second worm end, wherein the cam follower is configured to slide on the helicoid surface from the first worm end to the second worm end as the cam rotates so as to compress the first mechanical spring, and the cam follower is configured to slide on the helicoid surface from the second worm end to the first worm end as the cam rotates so as to compress the second mechanical spring.
10. The surgical impacting tool of claim 8 , wherein a ratio of a weight of the thrown mass to a combined weight of the adapter and the surgical implement secured thereto is less than 25%.
11. A surgical impacting tool, comprising:
a first mechanical spring;
a second mechanical spring;
a cam configured to move in a first rotational motion and thereby cause energy to be stored in the first mechanical spring and then to be released from the first mechanical spring and thereafter to move in a second rotational motion and thereby cause energy to be stored in the second mechanical spring and then to be released from the second mechanical spring, the second rotational motion being in an opposite direction to the first rotational motion;
an electronic controller configured to manage the storage of the energy of the first and second mechanical springs and the release of the energy of the first and second mechanical springs;
an adapter configured to secure to a surgical implement; and
a mass configured to deliver an impact force responsive to the released energy to the surgical implement secured to the adapter.
12. The surgical impacting tool of claim 11 , further comprising the surgical implement;
wherein the surgical implement is configured to be positioned relative to a bone of the patient such that the delivered impact force causes the surgical implement to impact the bone.
13. The surgical impacting tool of claim 11 , further comprising first and second pistons each operatively coupled to the cam;
wherein the first piston, the second piston, the first mechanical spring, and the second mechanical spring are linearly aligned;
the movement of the cam in the first rotational motion is configured to cause linear translation of the first piston that causes compression of the first mechanical spring, thereby storing the energy in the first mechanical spring; and
the movement of the cam in the second rotational motion is configured to cause linear translation of the piston that causes compression of the second mechanical spring, thereby storing the energy in the second mechanical spring.
14. The surgical impacting tool of claim 11 , further comprising a cam follower operatively coupled to the cam and disposed between the first and second mechanical springs; and
a protrusion extending helically along the cam;
wherein, in response to the movement of the cam in the first rotational motion, the cam follower is configured to slide in a first direction along the protrusion during the compression of the first mechanical spring;
the cam follower ceasing to slide in the first direction along the protrusion is configured to cause decompression of the first mechanical spring, thereby releasing the energy from the first mechanical spring;
in response to the movement of the cam in the second rotational motion, the cam follower is configured to slide in a second direction along the protrusion during the compression of the second mechanical spring;
the second direction is opposite to the first direction; and
the cam follower ceasing to slide in the second direction along the protrusion is configured to cause decompression of the second mechanical spring, thereby releasing the energy from the second mechanical spring.
15. The surgical impacting tool of claim 11 , wherein the adapter is configured to secure to the surgical implement at a forward end of the surgical impacting tool; and
the controller is configured to control a direction of rotation of the cam, thereby controlling a direction of the impact force in either a forward direction or a rearward direction.
16. The surgical impacting tool of claim 11 , wherein the cam is a singular element configured to move in the first rotational motion and thereafter to move in the second rotational motion; and
the adapter and the mass are independent elements from one another.
17. A surgical impacting tool, comprising:
a first mechanical spring configured to release energy stored therein to drive a surgical implement in a forward direction;
a second mechanical spring configured to release energy stored therein to drive the surgical implement in a rearward direction;
an electronic controller configured to control the energy storage and release such that energy is alternately 1) stored in and released from the first mechanical spring and 2) stored in and released from the second mechanical spring;
an adapter configured to secure to the surgical implement;
a means for delivering an impact force responsive to the energy released by the first mechanical spring and the energy released by the second mechanical spring to the surgical implement secured to the adapter, the means being independent from the adapter, being located between the first and second mechanical springs, and being linearly aligned with the adapter and the first and second mechanical springs along a longitudinal axis extending forward and rearward along the forward and rearward directions; and
first and second pistons;
wherein the means for delivering the impact force comprises a striker configured to be activated by the first piston and by the second piston;
the first piston, the second piston, the first mechanical spring, and the second mechanical spring are linearly aligned;
the first piston is configured to be actuated by the first spring; and
the second piston is configured to be actuated by the second spring.
18. The surgical impacting tool of claim 17 , further comprising a bumper element;
wherein the piston, upon actuation, is configured to come to rest on the bumper element.