Patella reference device
In order to conduct navigation-assisted knee operations in a simple and optimum manner, a patella reference device is proposed for the determination of the spatial position of a patella of a human knee joint during a navigation-assisted surgical procedure, comprising a base unit that can be secured on the patella, a reference element that can be detected by a detection device and a connecting device for the detachable connection of the base unit and the reference element in a first reference position and in at least one further second reference position differing from the first reference position.
1 . Patella reference device for the determination of the spatial position of a patella of a human knee joint during a navigation-assisted surgical procedure, comprising a base unit that can be secured on the patella, a reference element that can be detected by a detection device and a connecting device for the detachable connection of the base unit and the reference element in a first reference position and in at least one further second reference position differing from the first reference position.
2 . Reference device according to claim 1 , wherein the base unit has a first frame element and at least one second frame element, wherein in a release position the at least one second frame element is movable relative to the first frame element, and wherein in a securing position the first frame element and the at least one second frame element are immovably secured on one another.
3 . Reference device according to claim 2 , wherein the first frame element and/or the at least one second frame element comprise a guide means for the respective other frame element for guidance of a relative movement of the first and the at least one second frame element in the release position.
4 . Reference device according to claim 2 , wherein the first frame element is displaceable relative to the at least one second frame element.
5 . Reference device according to claim 3 , wherein the guide means defines a curved path for a relative movement of the first and the at least one second frame element in the release position.
6 . Reference device according to claim 2 , wherein a locking device is provided for the detachable connection of the first frame element to the at least one second frame element in the securing position.
7 . Reference device according to claim 6 , wherein the locking device comprises an operating element for moving the locking device from the release position into the securing position and vice versa.
8 . Reference device according to claim 7 , wherein the locking device assumes the securing position in a normal position.
9 . Reference device according to claim 8 , wherein the locking device comprises a biasing element for automatically moving the operating element into the normal position.
10 . Reference device according to claim 1 , wherein at least three application points are provided on the base unit for placement on the patella, wherein the at least three application points define a base plane.
11 . Reference device according to claim 10 , wherein at least one of the application points is defined by a point of a spike.
12 . Reference device according to claim 11 , wherein all the application points are defined by a point of a spike.
13 . Reference device according to claim 11 , wherein the first frame element and the at least second frame element respectively bear at least one spike.
14 . Reference device according to claim 11 , wherein at least one spike is adjustably arranged relative to a frame element.
15 . Reference device according to claim 10 , wherein the application points essentially point towards one another.
16 . Reference device according to claim 1 , wherein the reference element bears at least three transmission elements detectable by the detection device.
17 . Reference device according to claim 16 , wherein the at least three transmission elements are passive transmission elements.
18 . Reference device according to claim 16 , wherein the transmission elements are spheres reflecting electromagnetic radiation.
19 . Reference device according to claim 16 , wherein the at least three transmission elements define a reference element plane.
20 . Reference device according to claim 19 , wherein in the first reference position the reference element plane runs parallel to the reference element plane in the at least one second reference position.
21 . Reference device according to claim 16 , wherein the reference element has a reference element base unit and the at least three transmission elements are held on the reference element base unit.
22 . Reference device according to claim 21 , wherein the at least three transmission elements are detachably held on the reference element base unit.
23 . Reference device according to claim 21 , wherein the reference element base unit has the form of a plane, flat ring.
24 . Reference device according to claim 1 , wherein the connecting device comprises a first coupling element and a second coupling element, wherein the first coupling element is arranged on the reference element and the second coupling element is arranged on the base unit.
25 . Reference device according to claim 10 , wherein the connecting device comprises a first coupling element and a second coupling element, wherein the first coupling element is arranged on the reference element and the second coupling element is arranged on the base unit.
26 . Reference device according to claim 16 , wherein the connecting device comprises a first coupling element and a second coupling element, wherein the first coupling element is arranged on the reference element and the second coupling element is arranged on the base unit.
27 . Reference device according to claim 24 , wherein the first coupling element and the second coupling element positively intermesh when the reference device assumes the first and/or the at least one second reference position.
28 . Reference device according to claim 24 , wherein the first coupling element is arranged on the reference element base unit and the second coupling element is arranged on the first frame element.
29 . Reference device according to claim 24 , wherein the first coupling element is movable relative to the second coupling element in a coupling direction for movement of the first and the second coupling element from a decoupling position, in which the first and the second coupling element are separated from one another, into a coupling position, in which the reference device assumes the first and/or the at least one second reference position.
30 . Reference device according to claim 29 , wherein the coupling direction runs parallel to the base plane and/or parallel to the reference element plane.
31 . Reference device according to claim 24 , wherein the first coupling element comprises a recess and the second coupling element comprises a projection that can be inserted into the recess.
32 . Reference device according to claim 24 , wherein a locking element is provided for locking the first and the second coupling element in the coupling position.
33 . Reference device according to claim 31 , wherein the projection is provided with a thread and the locking element is a nut with an internal thread corresponding to the thread.