Ankle arthroplasty systems and methods
An ankle arthroplasty system may have a talar prosthesis and a tibial prosthesis, each of which has an articular surface and a bone engagement surface. Each bone engagement surface may have an anterior-posterior curvature and a medial-lateral curvature with a convex shape. A burr with a rotatable cutting element may be used to form a prepared surface on the talus or the tibia to receive the corresponding prosthesis. A cutting guide may be used to guide motion of the burr; the cutting guide may include a base and an arm movably coupled to the base. One of the base and the arm may have a guide surface, and the other may have a follower that slides along the guide surface to constrain motion of the burr such that the prepared surface has at least one concave curvature and one convex curvature.
1. A method for performing ankle arthroplasty on an ankle joint comprising a talus and a tibia, the method comprising:
exposing an anterior aspect of the ankle joint;
securing a first cutting guide to a first bone comprising the talus or the tibia;
inserting a first cutting tool into the ankle joint from along an anterior approach;
with the first cutting guide, guiding motion of the first cutting tool relative to the first bone to cause the first cutting tool to form a first prepared surface on the first bone, the first prepared surface comprising a first anterior-posterior curvature along a sagittal plane; and
placing a first prosthesis on the first prepared surface, the first prosthesis comprising a first articular surface shaped to replace a first natural articular surface of the first bone.
2. The method of claim 1 , wherein:
the first prosthesis comprises a keel;
the method further comprises:
inserting a second cutting tool into the ankle joint from along an anterior approach; and
with the first cutting guide, guiding motion of the second cutting tool relative to the first bone to cause the second cutting tool to form a slot in the first bone, wherein the slot is oriented anterior-posteriorly; and
placing the first prosthesis on the first prepared surface comprises inserting the keel into the slot.
3. The method of claim 1 , wherein:
the first bone comprises the tibia;
the first anterior-posterior curvature comprises a concave curvature along the sagittal plane;
the first prosthesis comprises a convex bone engagement surface; and
placing the first prosthesis on the first prepared surface comprises inserting the convex bone engagement surface into the concave curvature.
4. The method of claim 1 , wherein:
the first bone comprises the talus;
the first anterior-posterior curvature comprises a convex curvature along the sagittal plane;
the first prosthesis comprises a concave bone engagement surface; and
placing the first prosthesis on the first prepared surface comprises positioning the convex curvature in the concave bone engagement surface.
5. The method of claim 4 , further comprising:
exposing an anterior aspect of the ankle joint;
securing a second cutting guide to the tibia;
inserting the first cutting tool or a second cutting tool into the ankle joint from along an anterior approach;
with the second cutting guide, guiding motion of the first cutting tool or the second cutting tool relative to the tibia to cause the first cutting tool or the second cutting tool to form a second prepared surface on the tibia, the second prepared surface comprising a second anterior-posterior curvature comprising a concave curvature along the sagittal plane; and
placing a second prosthesis on the second prepared surface, the second prosthesis comprising:
a convex bone engagement surface; and
a second articular surface shaped to replace a second natural articular surface of the tibia;
wherein placing the second prosthesis on the second prepared surface comprises inserting the convex bone engagement surface into the concave curvature.
6. The method of claim 4 , wherein:
the first cutting guide comprises:
a talar foundation comprising a talar bone attachment interface and a talar tool holder interface; and
a talar tool holder comprising a talar tool attachment interface and a talar foundation interface;
securing the first cutting guide to the first bone comprises securing the talar bone attachment interface to the talus;
the method further comprises, prior to guiding motion of the first cutting tool with the first cutting guide:
coupling the talar foundation to the talar tool holder by coupling the talar tool holder interface to the talar foundation interface; and
attaching the first cutting tool to the talar tool attachment interface.
7. The method of claim 6 , further comprising, prior to securing the talar foundation to the talus:
positioning a trial on the talus, wherein the trial is coupled to a distal end of a column;
using the column to align the trial with the talus, by aligning a proximal end of the column with a landmark on portion of a patient's leg proximal to the talus; and
aligning the talar foundation with the trial.
8. The method of claim 6 , further comprising:
attaching a talar foundation interface of an alignment block to the talar foundation;
attaching a tibial foundation interface of the alignment block to a tibial foundation, the tibial foundation comprising a tibial bone attachment interface and a tibial tool holder interface;
securing the tibial bone attachment interface to the tibia; and
coupling a tibial tool holder to the tibial foundation by coupling the tibial tool holder interface to a tibial foundation interface of the tibial tool holder, wherein the tibial foundation and the tibial tool holder constitute a second cutting guide.
9. The method of claim 8 , further comprising:
attaching the first cutting tool or a second cutting tool to a tibial tool attachment interface of the tibial tool holder;
inserting the first cutting tool or the second cutting tool into the ankle joint from along an anterior approach; and
with the second cutting guide, guiding motion of the first cutting tool or the second cutting tool relative to the tibia in a medial-lateral direction to cause the first cutting tool or the second cutting tool to form a second prepared surface on the tibia, the second prepared surface comprising a second anterior-posterior curvature comprising a concave curvature along the sagittal plane.
10. The method of claim 4 , wherein guiding motion of the first cutting tool relative to the first bone to form the first prepared surface comprises moving the first cutting tool in a medial-lateral direction.
11. The method of claim 10 , wherein guiding motion of the first cutting tool relative to the first bone to form the first prepared surface further comprises rotating the first cutting tool relative to the first bone about an axis extending medial-laterally to cause the first cutting tool to move anterior-posteriorly.
12. A method for performing ankle arthroplasty on an ankle joint comprising a talus and a tibia, the method comprising:
exposing an anterior aspect of the ankle joint;
securing a talar cutting guide to the talus;
inserting a first cutting tool into the ankle joint from along an anterior approach;
with the talar cutting guide, guiding motion of the first cutting tool relative to the talus to rotate the first cutting tool relative to the talus about an axis extending medial-laterally to cause the first cutting tool to move anterior-posteriorly to form a first prepared surface on the talus, the first prepared surface comprising a first anterior-posterior curvature extending anterior-posteriorly; and
placing a talar prosthesis on the first prepared surface, the talar prosthesis comprising a talar articular surface shaped to replace a natural talar articular surface of the talus.
13. The method of claim 12 , wherein:
the talar prosthesis comprises a keel;
the method further comprises:
inserting the first cutting tool or a second cutting tool into the ankle joint from along an anterior approach; and
with the talar cutting guide, guiding motion of the first cutting tool or the second cutting tool relative to the talus to cause the first cutting tool or the second cutting tool to form a slot in the talus, wherein the slot is oriented anterior-posteriorly; and
placing the talar prosthesis on the first prepared surface comprises inserting the keel into the slot.
14. The method of claim 12 , wherein guiding motion of the first cutting tool relative to the talus to form the first prepared surface further comprises moving the first cutting tool in a medial-lateral direction.
15. The method of claim 14 , further comprising:
securing a tibial cutting guide to the tibia;
inserting the first cutting tool or a second cutting tool into the ankle joint from along an anterior approach;
with the tibial cutting guide, guiding motion of the first cutting tool relative to the tibia to move the first cutting tool or a second cutting tool medial-laterally to form a second prepared surface on the tibia, the second prepared surface comprising a second anterior-posterior curvature extending anterior-posteriorly; and
placing a tibial prosthesis on the second prepared surface, the tibial prosthesis comprising a tibial articular surface shaped to replace a natural tibial articular surface of the tibia.
16. The method of claim 12 , wherein:
the talar cutting guide comprises:
a talar foundation comprising a talar bone attachment interface and a talar tool holder interface; and
a talar tool holder comprising a talar tool attachment interface and a talar foundation interface;
securing the talar cutting guide to the talus comprises securing the talar bone attachment interface to the talus;
the method further comprises, prior to guiding motion of the first cutting tool with the talar cutting guide:
coupling the talar foundation to the talar tool holder by coupling the talar tool holder interface to the talar foundation interface; and
attaching the first cutting tool to the talar tool attachment interface.
17. The method of claim 16 , further comprising:
attaching a talar foundation interface of an alignment block to the talar foundation;
attaching a tibial foundation interface of the alignment block to a tibial foundation, the tibial foundation comprising a tibial bone attachment interface and a tibial tool holder interface;
securing the tibial bone attachment interface to the tibia; and
coupling a tibial tool holder to the tibial foundation by coupling the tibial tool holder interface to a tibial foundation interface of the tibial tool holder, wherein the tibial foundation and the tibial tool holder constitute a second cutting guide.
18. A method for performing ankle arthroplasty on an ankle joint comprising a talus and a tibia, the method comprising:
exposing an anterior aspect of the ankle joint;
securing a talar cutting guide to the talus;
inserting a first cutting tool into the ankle joint from along an anterior approach;
with the talar cutting guide, guiding motion of the first cutting tool relative to the talus to cause the first cutting tool to form a first prepared surface on the talus, the first prepared surface comprising a first anterior-posterior curvature extending anterior-posteriorly;
securing a tibial cutting guide to the tibia;
inserting the first cutting tool or a second cutting tool into the ankle joint from along the anterior approach;
with the tibial cutting guide, guiding motion of the first cutting tool or the second cutting tool relative to the tibia to cause the first cutting tool or the second cutting tool to form a second prepared surface on the tibia, the second prepared surface comprising a second anterior-posterior curvature extending anterior-posteriorly;
placing a talar prosthesis on the first prepared surface, the talar prosthesis comprising a talar articular surface shaped to replace a first natural articular surface of the talus; and
placing a tibial prosthesis on the second prepared surface, the tibial prosthesis comprising a tibial articular surface shaped to replace a second natural articular surface of the tibia.
19. The method of claim 18 , wherein:
the talar prosthesis comprises a talar keel;
the tibial prosthesis comprises a tibial keel;
the method further comprises:
with the talar cutting guide, guiding motion of the first cutting tool, the second cutting tool, or a third cutting tool relative to the talus to form a first slot in the talus, wherein the first slot is oriented anterior-posteriorly; and
with the tibial cutting guide, guiding motion of the first cutting tool, the second cutting tool, the third cutting tool, or a fourth cutting tool relative to the tibia to form a second slot in the tibia, wherein the second slot is oriented anterior-posteriorly;
placing the talar prosthesis on the first prepared surface comprises inserting the talar keel into the first slot; and
placing the tibial prosthesis on the second prepared surface comprises inserting the tibial keel into the second slot.
20. The method of claim 18 , wherein:
the talar cutting guide comprises:
a talar foundation; and
a talar tool holder;
the tibial cutting guide comprises:
a tibial foundation; and
a tibial tool holder;
securing the talar cutting guide to the talus comprises securing the talar foundation to the talus;
the method further comprises, prior to guiding motion of the first cutting tool or the second cutting tool with the tibial cutting guide:
attaching a talar foundation interface of an alignment block to the talar foundation; and
attaching a tibial foundation interface of the alignment block to the tibial foundation; and
securing the tibial cutting guide to the tibia comprises securing the tibial foundation to the tibia with the talar foundation interface attached to the talar foundation and the tibial foundation interface attached to the tibial foundation.
21. A method for performing ankle arthroplasty on an ankle joint comprising a talus and a tibia, the method comprising:
exposing an anterior aspect of the ankle joint;
securing a first cutting guide to a first bone comprising the talus or the tibia;
inserting a first cutting tool into the ankle joint from along an anterior approach, the first cutting tool having an axis of rotation about which the first cutting tool rotates to cut tissue;
with the first cutting guide, guiding motion of the first cutting tool along a direction nonparallel to the axis of rotation, relative to the first bone to cause the first cutting tool to form a first prepared surface on the first bone, the first prepared surface comprising a first anterior-posterior curvature extending anterior-posteriorly; and
placing a first prosthesis on the first prepared surface, the first prosthesis comprising a first articular surface shaped to replace a first natural articular surface of the first bone.
22. The method of claim 21 , wherein:
the first bone comprises the tibia;
the first anterior-posterior curvature comprises a concave curvature extending anterior-posteriorly;
the first prosthesis comprises a convex bone engagement surface; and
placing the first prosthesis on the first prepared surface comprises inserting the convex bone engagement surface into the concave curvature.
23. The method of claim 21 , wherein:
the first bone comprises the talus;
the first anterior-posterior curvature comprises a convex curvature extending anterior-posteriorly;
the first prosthesis comprises a concave bone engagement surface; and
placing the first prosthesis on the first prepared surface comprises positioning the convex curvature in the concave bone engagement surface.
24. The method of claim 23 , further comprising:
exposing an anterior aspect of the ankle joint;
securing a second cutting guide to the tibia;
inserting the first cutting tool or a second cutting tool having the axis of rotation into the ankle joint from along an anterior approach;
with the second cutting guide, guiding motion of the first cutting tool or the second cutting tool along a direction nonparallel to the axis of rotation, relative to the tibia to cause the first cutting tool or the second cutting tool to form a second prepared surface on the tibia, the second prepared surface comprising a second anterior-posterior curvature comprising a concave curvature extending anterior-posteriorly; and
placing a second prosthesis on the second prepared surface, the second prosthesis comprising:
a convex bone engagement surface; and
a second articular surface shaped to replace a second natural articular surface of the tibia;
wherein placing the second prosthesis on the second prepared surface comprises inserting the convex bone engagement surface into the concave curvature.
25. A method for performing ankle arthroplasty on an ankle joint comprising a talus and a tibia, the method comprising:
exposing an anterior aspect of the ankle joint;
securing a first cutting guide to a first bone comprising the talus or the tibia;
inserting a first cutting tool into the ankle joint from along an anterior approach;
with the first cutting guide, guiding motion of the first cutting tool relative to the first bone to cause the first cutting tool to form a first prepared surface on the first bone, the first prepared surface comprising a first anterior-posterior curvature extending anterior-posteriorly; and
placing a first prosthesis on the first prepared surface, the first prosthesis comprising a first articular surface shaped to replace a first natural articular surface of the first bone, such that a curvature of the first articular surface is parallel to the first anterior-posterior curvature.
26. The method of claim 25 , wherein:
the first bone comprises the tibia;
the first anterior-posterior curvature comprises a concave curvature extending anterior-posteriorly;
the first prosthesis comprises a convex bone engagement surface having a shape that matches the concave curvature; and
placing the first prosthesis on the first prepared surface comprises inserting the convex bone engagement surface into the concave curvature.
27. The method of claim 25 , wherein:
the first bone comprises the talus;
the first anterior-posterior curvature comprises a convex curvature extending anterior-posteriorly;
the first prosthesis comprises a concave bone engagement surface having a shape that matches the convex curvature; and
placing the first prosthesis on the first prepared surface comprises positioning the convex curvature in the concave bone engagement surface.
28. The method of claim 25 , further comprising:
exposing an anterior aspect of the ankle joint;
securing a second cutting guide to the tibia;
inserting the first cutting tool or a second cutting tool into the ankle joint from along an anterior approach;
with the second cutting guide, guiding motion of the first cutting tool or the second cutting tool relative to the tibia to cause the first cutting tool or the second cutting tool to form a second prepared surface on the tibia, the second prepared surface comprising a second anterior-posterior curvature comprising a concave curvature extending anterior-posteriorly; and
placing a second prosthesis on the second prepared surface, the second prosthesis comprising:
a convex bone engagement surface having a shape that matches the concave curvature; and
a second articular surface shaped to replace a second natural articular surface of the tibia;
wherein placing the second prosthesis on the second prepared surface comprises inserting the convex bone engagement surface into the concave curvature.