US 2019/0239903 A1 · PATIENT-SPECIFIC, MECHANICAL SELF-LOCKING, FEMORAL AND TIBIAL SURGICAL CUTTING JIGS

Abstract

Surgical jigs for guiding bone resectioning in knee replacement surgery, one for the femur and another for the tibia, contain both the various bone-jig contact surfaces and the cutting guide as a single unitary piece. The contact surfaces are curvilinear surfaces formed into ends of planar fins that project from the jig base or substrate. Each jig has three (3) pairs of contact surfaces selected to abut low-wear, lateral and medial, articular surface features, such that the jig has one and only one possible self-locking position against the bone (or cartilage) and so the jig's integral cutting guide will define one and only one cut plane for the bone resectioning. The presence of osteophytes generally does not adversely impact the proper fit of the jigs. An improved rotational transformation method for converting the scan views into the desired proper axes is based not only on planar rotations, but also on a projection of the rotated coordinates onto the plane of rotation and produces parameters that correspond much more closely to the joint surfaces in the desired jig coordinates.

Claims14

Dependent claims

A surgical jig for bone resection in a tibio-femoral joint region, comprising:

a single unitary piece combining a set of bone-jig contact surfaces and a bone cutting guide defining a cut plane, the set of contact surfaces being curvilinear surfaces formed onto ends of planar fins projecting from a jig substrate, the curvilinear surfaces positioned to abut respective lateral and medial articular surface features in the tibio-femoral joint region such that the unitary piece has one and only one mechanical self-locking position,
the curvilinear surfaces further characterized by custom patient-specific parameters derived from measurements from selected coronal, axial and sagittal magnetic resonance imaging (MRI) image slices of the tibio-femoral joint, the image slices having been subject to a set, of rotational transformations onto orthogonal jig coordinates, wherein each transformation in some specified plane of rotation is accompanied by a projection of rotated coordinates onto that plane of rotation.

A method of manufacture of a patient-specific surgical jig for bone resection in a tibio-femoral joint region, comprising:

obtaining a series of coronal, axial and sagittal magnetic resonance imaging (MRI) image slices of a tibio-femoral joint region of a patient;
selecting MRI image slices showing specified lateral and medial articular surface features in the tibio-femoral joint region;
performing a set of rotational transformations of the selected coronal, axial and sagittal MRI image slices onto orthogonal jig coordinates, each transformation in some specified plane of rotation being accompanied by a projection of rotated coordinates onto that plane of rotation;
characterizing patient-specific parameters for the specified lateral and medial articular surface features in the tibio-femoral joint region to specify a set of bone-jig contact surfaces and a cut plane;
and
manufacturing a jig in the form of a single unitary piece combining a bone cutting guide and a set of curvilinear surfaces formed onto ends of planar fins projecting from a jig substrate, the curvilinear positioned according to the specified bone-jig contact surfaces derived from the selected and transformed MRI image slices so as to abut respective lateral and medial articular surface features in the tibio-femoral joint region of the patient such that the jig has one and only one mechanical self-locking position and the bone cutting guide defines the specified cut plane.

3 more elements

Dependencies are inferred from the claim text.

Patient-specific, mechanical self-locking, femoral and tibial surgical cutting jigs

Life of this patent

Patient-specific, mechanical self-locking, femoral and tibial surgical cutting jigs

Life of this patent

Abstract

Claims14