US-12616488-B2 - Patient specific instruments and methods for joint prosthesis

US12616488B2US 12616488 B2US12616488 B2US 12616488B2US-12616488-B2

Abstract

A system for preparing an ankle bone to receive an ankle prosthesis is provided. The system includes a patient specific cutting guide that has an anterior surface, a posterior surface, and at least one cutting feature extending through the guide from the anterior surface. The posterior surface comprising a first protrusion or other member that extends from a first end fixed to the posterior surface to a second end disposed away from the first end of the first protrusion. The posterior surface has a second protrusion or other member that extends from a first end fixed to the posterior surface to a second end disposed away from the first end of the second protrusion. The first and second protrusions are spaced apart and have a length such that when the patient specific cutting guide is coupled with first and second bone references, which can include bushings implantable in bones, a clearance gap is provided between the posterior surface and the ankle bone.

Inventors

Richard Garret Mauldin
Thomas Anthony Flanagan
Emmanuel Francois Marie Lizee

Assignees

HOWMEDICA OSTEONICS CORP.

Dates

Publication Date: 20260505
Application Date: 20240411

Claims (20)

1 . A patient specific surgical guide, comprising: a first surface, a second surface opposite the first surface, and at least one cutting tool engagement surface extending from the first surface to the second surface, the second surface having a first bone interface portion and a second bone interface portion, at least one of the first bone interface portion and the second bone interface portion forming an outwardly projecting protrusion configured so as to provide a gap between the patient specific guide and at least one of the first bone interface portion and a second bone interface portion thereby providing isolated contact with a bone; whereby when the patient specific surgery cutting guide is applied to the patient so as to be in contact with an ankle bone, a clearance gap is provided between the ankle bone and regions of the second surface.
2 . The patient specific surgical guide of claim 1 , wherein the second surface comprises a first portion configured to be disposed in spaced close proximity to a neck of a talus and a second portion configured to be disposed in spaced close proximity to an anterior face of a tibia.
3 . The patient specific surgical guide of claim 2 , wherein the first portion of the second surface is generally planar and the second portion of the second surface is generally planar, the first portion of the second surface being disposed at an angle to the second portion of the second surface.
4 . The patient specific surgical guide of claim 3 comprising a third bone interface portion disposed on the first portion of the second surface.
5 . The patient specific surgical guide of claim 4 , further comprising a fourth bone interface portion disposed on the first portion of the second surface.
6 . The patient specific surgery cutting guide of claim 3 , further comprising a third bone interface portion disposed on the second portion of the second surface.
7 . A method for manufacturing a patient specific guide, comprising: receiving location and orientation information including a position of at least two bushings disposed in at least two bone locations; receiving location and orientation information including the position of at least two bone locations; based upon the location and orientation information, manufacturing a patient specific guide configured to position at least one tool guide surface relative to at least one of the bone locations, the manufacturing including forming a first member to mate with the first bushing and forming a second member to mate with the second bushing, the first and second members having a length sufficient to create clearance from the bone when the first and second members are so mated.
8 . The method of claim 7 , wherein the clearance created from the bone is sufficient to accommodate soft tissues normally disposed over the bone such that the patient specific guide is adapted to preserve such soft tissue without requiring dissection.
9 . A system for preparing an ankle bone to receive an ankle prosthesis, comprising: a patient specific cutting guide having an anterior surface, a posterior surface, and at least one tool engaging surface extending through the cutting guide from the anterior surface, the posterior surface comprising a first protrusion extending from a first end fixed to the posterior surface to a second end disposed away from the first end of the first protrusion; the posterior surface comprising a second protrusion extending from a first end fixed to the posterior surface to a second end disposed away from the first end of the second protrusion; wherein the first and second protrusion are spaced apart and have a length such that when the patient specific cutting guide is coupled with at least one ankle bone a clearance gap is provided between the posterior surface and the ankle bone.
10 . A surgical method, comprising: advancing a first bushing into a tibia adjacent to an ankle joint of a patient; advancing a second bushing into a talus adjacent to the ankle joint; obtaining three dimensional spatial location information of the first bushing and a portion of the tibia around the first bushing and of the second bushing and a portion of the talus around the second bushing; and coupling a patient specific cutting guide to the first bushing and to the second bushing so that a gap is provided between the patient specific guide and at least one of the tibia and the talus; wherein the first and second bushings are engaged with the patient specific cutting guide each at a location that is based upon the three dimensional spatial location information.
11 . The surgical method of claim 10 wherein one the first bushing and the second bushing each have a smooth tapered distal portion.
12 . The surgical method of claim 10 , comprising advancing a third bushing into the tibia and advancing a fourth bushing into the talus.
13 . The surgical method of claim 10 wherein obtaining spatial location information comprises performing a CT scan of the first and second bushings positioned in the tibia and the talus.
14 . The surgical method of claim 10 , wherein the patient specific cutting comprises a first reference configured to contact the first bushing and a second reference configured to contact the second bushing, wherein when the patient specific cutting guide is connected to the first and second bushings, a posterior surface of the patient specific cutting guide extends from the first reference to the second reference without tibial or talar contact between the first bushing and second bushing.
15 . The surgical method of claim 10 , wherein when the patient specific cutting guide contacts the first and second bushings, the patient specific cutting guide contacts the bushings in the absence of tibial or talar contact.
16 . The surgical method of claim 10 , wherein when the patient specific cutting guide contacts the first and second bushings, the patient specific cutting guide is spaced apart from the tibia.
17 . The surgical method of claim 10 , wherein when the patient specific cutting guide contacts the first and second bushings the patient specific cutting guide is spaced apart from the talus.
18 . The surgical method of claim 10 , further comprising: placing a first cannula through a first incision such that a distal end of the first cannula is adjacent to the anterior surface of the tibia and a proximal end of the first cannula is outside of the skin of the patient; placing a second cannula through a second incision such that a distal end of the second cannula is adjacent to a neck of the talus and a proximal end of the second cannula is outside of the skin of the patient; and advancing the first bushing through the first cannula and advancing the second bushing through the second cannula.
19 . The surgical method of claim 10 , wherein prior to connecting the second reference with the second bushing, the ankle joint is placed in plantar flexion and while the ankle joint is in plantar flexion, the patient specific cutting guide is rigidly connected to the talus.
20 . The surgical method of claim 19 , wherein coupling the first reference of the patient specific cutting guide to the first bushing comprises rotating the ankle joint out of plantar flexion after the patient specific cutting guide is rigidly attached to the talus.

Description

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 C.F.R. § 1.57. BACKGROUND OF THE INVENTION Field of the Invention This application is directed to methods and apparatuses used to install a joint prosthesis using patient specific instruments. Description of the Related Art Patient specific instruments (PSI) refer to specially manufactured instruments that incorporate the patient's own bone geometry data. The instruments can be accurately positioned because they are formed with reference to the patient's bone data and when formed in this manner have features that engage selected landmarks on the bone to assure proper positioning. An imaging technology, such as computerized tomography (CT) scanning, is used to acquire the bone data prior to surgery. Three dimensional (3D) models of bone are used to align a 3D model of a prosthesis. These models are provided to a system that constructs the patient specific instruments such that when applied to the bone the patient specific instruments produce the bone cuts needed for installing the prosthesis accurately. One advantage of patient specific instruments is that they may include planning software that allows a surgeon or technician to manipulate the 3D models of the bones. Here the surgeon or technician can correct deformities in the relationship of the bones, e.g., the relationship of the talus to the tibia. These deformities can include one or more of varus/valgus alignment, anterior/posterior or medial/lateral subluxation, subsidence and/or distractions. Once the bones are aligned properly, the surgeon may select the appropriate size prosthesis and align it to and place it in its desired position. The position of the bones to the prosthesis in the absence of deformity is an input to the design of the patient specific instruments in order to make accurate cuts in the bone. Thus, deformities can be corrected with the help of the patient specific instruments in surgery. SUMMARY OF THE INVENTION While patient specific instruments can be formed with reference to bony landmarks as discussed above, this approach is in need of improvement. Bony landmarks are disposed under soft tissue and vary from patient to patient in location and size. This variation introduces complexity in exposing and consistently locating a landmark to be used as a registration point. While landmarks can be exposed by dissecting the soft tissue, dissection is time consuming, not always effective, and is invasive. It would be faster and less invasive to place an instrument that includes a patient specific component, without dissecting away the soft tissue. Further, patient specific guides placed against soft tissue may compress the soft tissue and the location of the guide can vary when placed against soft tissue. Therefore, it would be an advance to provide methods and structures that can provide a consistent, easy to access registration structure across a wide range of patients. Methods herein to form a patient specific instrument can include three parts or phases: (1) installing reference bushing(s) and gathering 3D spatial location information including the location of the bushings; (b) designing and manufacturing patient specific cutting guides based on the spatial location information (e.g., based on the 3D data) of reference bushing, bone geometry and desired implant location; and (c) performing surgery using reference bushing(s) and patient specific cutting guides. In an example method, one or more reference bushings are advanced into a tibia adjacent to an ankle joint of a patient. One or more reference bushings are advanced into a talus adjacent to the ankle joint. After the reference bushings are advanced into the tibia and talus, information of the spatial location of the reference bushings and a portion of the tibia and talus around the reference bushings is obtained. The spatial location information can include imaging and/or three-dimensional spatial location information. From the information (e.g., the 3D data), cutting guides are designed taking into account the specific location of the reference bushings, the specific bone geometries, and the proposed location of joint replacement implant. Patient specific cutting guides are manufactured in preparation for joint replacement surgery. Thereafter, in surgery, a patient specific cutting guide is connected to the reference bushings. First, second, and/or more reference bushings are located on, and can be connected to, the patient specific cutting guide based upon the spatial location information. When the patient specific cutting guide is coupled to the patient, a gap is provided between the patient specific guide and at least one of the tibia and the talus. In one embodiment, a surgical method is provided. A first reference bushing