Patient-specific bone fracture prostheses and methods of making the same
Provided is a method for manufacturing a prosthesis for a fractured long bone of a patient. The method includes: providing data representative of the fractured long bone of the patient, the fractured long bone comprising a diaphyseal fragment comprising a medullary cavity; based on the data provided, designing the prosthesis specifically to the patient, wherein the prosthesis comprising a stem part configured to be inserted into the medullary cavity for securing the stem part to the diaphyseal fragment.
1 . A method for manufacturing a prosthesis for a fractured long bone of a patient, the method comprising the steps of:
providing data representative of the fractured long bone of the patient, the fractured long bone comprising a diaphyseal fragment comprising a medullary cavity;
based on the data provided, designing the prosthesis specifically to the patient, wherein the prosthesis comprising a stem part configured to be inserted into the medullary cavity for securing the stem part to the diaphyseal fragment, wherein designing the prosthesis further comprises:
selecting, specifically to the patient, at least one contact zone of the medullary cavity onto which a respective chosen mechanical stress is planned to be applied by the stem part, when the stem part is inserted into the medullary cavity and designing the stem part so that the stem part may be inserted into the medullary cavity and thus apply the chosen mechanical stress to said at least one contact zone; and
manufacturing the prosthesis including the stem part as designed.
2 . The method according to claim 1 , wherein said at least one contact zone of the medullary cavity continuously covers a circumference of the medullary cavity.
3 . The method according to claim 1 , wherein the chosen mechanical stress is evenly distributed onto each of said at least one contact zone of the medullary cavity.
4 . The method according to claim 1 , wherein based on the data provided, designing the stem part that comprises, specifically to the patient:
a coverable diaphyseal portion, configured to be covered by the diaphyseal fragment when the stem part is secured to the diaphyseal fragment, whereas remainder of the stem part is left uncovered by the diaphyseal fragment; and
a first visible mark, visually delimiting the coverable diaphyseal portion from the remainder of the stem part.
5 . The method according to claim 1 , wherein:
providing the data representative of the fractured long bone includes providing data representative of epiphyseal fragments of the fractured long bone; and
based on the data so provided, designing the prosthesis so that the stem part is configured for securing at least one of the epiphyseal fragments to the stem part.
6 . The method according to claim 5 , further comprising:
selecting, specifically to the patient, respective securing positions of the epiphyseal fragments relative to each other, representative of how the epiphyseal fragments are planned to be positioned relative to each other when secured to the stem part, the securing positions being chosen so that a respective chosen mechanical stress is applied onto each epiphyseal fragment by at least one of the other epiphyseal fragments, when the epiphyseal fragments are secured at the respective chosen securing positions of the stem part, and
designing the stem part so that the stem part is configured for securing the epiphyseal fragments at the respective chosen securing positions.
7 . The method according to claim 6 , further comprising designing the stem part so that the stem part comprises a second visible mark indicating the respective securing positions of the epiphyseal fragments on the stem part.
8 . The method according to claim 7 , further comprising designing the stem part based on the data provided, so that the stem part comprises, specifically to the patient, coverable epiphyseal portions, being configured for being covered respectively by the epiphyseal fragments when the epiphyseal fragments are secured to the stem part at the respective securing positions; wherein the second visible mark is designed so as to visually delimit the coverable epiphyseal portions from each other.
9 . The method according to claim 1 , wherein:
the epiphyseal fragments comprise:
at least one viable tuberosity fragment, secured to a muscle of the patient, the muscle being attached to said at least one viable tuberosity fragment by means of a tendon of the muscle and a damaged articular fragment, initially being part of a damaged joint of the patient, for articulating the long bone with an auxiliary bone of the patient;
wherein the stem part is designed to be configured for securing said at least one viable tuberosity fragment to the stem part, and the prosthesis further comprises a head part, being configured to be secured to the stem part in replacement for the damaged articular fragment of the fractured long bone of the patient,
wherein selecting, specifically to the patient, respective securing positions of said at least one viable tuberosity fragment and of the head part relative to each other, representative of how said at least one viable tuberosity fragment and head part are planned to be positioned relative to each other when secured to the stem part, the securing positions being selected so that a respective chosen mechanical stress is applied to each of said at least one viable tuberosity fragment by the head part, when said at least one viable tuberosity fragment and the head part are secured at the respective selected securing positions of the stem part, and designing the stem part so that said at least one viable tuberosity fragment and the head part may be secured to the stem part at the respective selected securing positions; and
the method further comprises providing or manufacturing the head part of the prosthesis.
10 . The method according to claim 9 , wherein the head part comprises:
a standard cap that includes:
an articular surface of concave or convex shape for forming a prosthetic joint for replacement of the damaged joint of the patient; and
a securing surface opposed to the articular surface, wherein the standard cap being secured to the stem part by means of the securing surface; and
a patient-specific insert, configured to be interposed between the standard cap and the stem part, and apply the respective mechanical stress onto each of said at least one viable tuberosity fragment.
11 . The method according to claim 1 , wherein providing the data representative of the fractured long bone of the patient includes using CT scans of the patient; and manufacturing the prosthesis includes additive manufacturing of at least a part of the prosthesis.
12 . The method according to claim 1 , wherein the fractured long bone is a fractured humerus, the prosthesis being a shoulder prosthesis.
13 . A method of surgery on a specific patient's joint that has a fractured long bone, the method comprising:
accessing the joint of the specific patient, the fractured long bone having a first articular surface and an auxiliary articular surface on a bone opposite the first articular surface;
providing a stem part of a prosthesis, the stem part being configured for the specific patient to have a diaphyseal surface configured to apply a chosen stress to bone matter in a medullary canal of the fractured long bone; and
advancing the diaphyseal portion into the medullary canal of the fractured long bone to apply the chosen stress to the bone matter in the medullary canal of the fractured long bone.