Modular prosthesis and use thereof for replacing a radial head

Abstract

A modular prosthesis system for replacement of a head portion of a proximal radius includes a monolithic stem component, a head component, and a locking mechanism formed by the stem and head components. The stem component defines a stem anchoring portion having a longitudinal axis and configured to couple to the proximal radius, and a dovetail-shaped first mounting portion on a first end face that extends in a first direction transverse to the longitudinal axis. The head component has a dovetail-shaped second mounting portion on a second end face opposite the first end face slidably engaged with the first mounting portion along the first direction. One of the first and second mounting portions intersects the longitudinal axis. The locking mechanism is formed at an interface between the stem and head components and is engaged through relative translational movement between the stem and head components. A related method is provided.

1 . A prosthesis system for replacement of a head portion of a proximal radius, comprising:
 a monolithic stem component defining a stem anchoring portion having a longitudinal axis and configured to couple to the proximal radius, and a dovetail-shaped first mounting portion on a first end face that extends in a first direction transverse to the longitudinal axis;   a head component having a dovetail-shaped second mounting portion on a second end face opposite the first end face slidably engaged with the first mounting portion along the first direction; and   a locking element formed by the monolithic stem component and the head component at an interface between the stem component and the head component, wherein one of the first and second mounting portions intersects the longitudinal axis and the locking element is engaged through relative translational movement between the stem component and the head component along the first direction.   
     
     
         2 . The prosthesis system of  claim 1  wherein the locking element is engaged through relative translational movement between the monolithic stem component and the head component along a single axis. 
     
     
         3 . The prosthesis system of  claim 1  wherein the locking element is formed by a protrusion and a complementary recess that define a pair of complementary faces that engage along a second direction perpendicular to the first direction when the stem component and the head component are connected. 
     
     
         4 . The prosthesis system of  claim 3  wherein the protrusion is deformable. 
     
     
         5 . The prosthesis system of  claim 3  wherein the protrusion is formed on a mounting surface defined by one of the first mounting portion and the second mounting portion. 
     
     
         6 . The prosthesis system of  claim 3  wherein the recess is formed on a mounting surface defined by one of the first mounting portion and the second mounting portion. 
     
     
         7 . The prosthesis system of  claim 1  wherein the locking element is formed by a female connection portion of the stem component and a male connection portion of a flange of the head component that engage along a second direction perpendicular to the first direction when the stem component and the head component are connected. 
     
     
         8 . The prosthesis system of  claim 7  wherein the female connection portion and the male connection portion are brought into engagement through relative translational movement between the stem component and the head component along a single axis. 
     
     
         9 . The prosthesis system of  claim 7  wherein the flange of the head component is deformable. 
     
     
         10 . The prosthesis system of  claim 1  wherein the first and second mounting portions define a pair of complementary bearing surfaces and one of the pair of complementary bearing surfaces intersects the longitudinal axis. 
     
     
         11 . The prosthesis system of  claim 10  wherein the one of the pair of complementary bearing surfaces intersects the longitudinal axis at an angle of 90 degrees. 
     
     
         12 . The prosthesis system of  claim 10  wherein the pair of complementary bearing surfaces has an area of contact that intersects the longitudinal axis. 
     
     
         13 . The prosthesis system of  claim 1  wherein the first and second mounting portions form an assembly plane that is normal to the longitudinal axis. 
     
     
         14 . The prosthesis system of  claim 1  wherein the head component is a monolithic component. 
     
     
         15 . The prosthesis system of  claim 1  wherein the head component includes an articulating surface that is formed to slidably engage a native capitellum. 
     
     
         16 . A method of use for a modular prosthesis for replacement of a head portion of a proximal radius, comprising:
 coupling a stem anchoring portion of a monolithic stem component having a longitudinal axis to a resected portion of the proximal radius; and   coupling a dovetail-shaped first mounting portion on a first end face of a head component that extends in a first direction transverse to the longitudinal axis to a dovetail-shaped second mounting portion on a second end face of the monolithic stem component that extends in the first direction, wherein coupling a dovetail-shaped first mounting portion includes:   slidably engaging the first mounting portion with the second mounting portion by moving the head component in the first direction, and   coupling the head component and the stem component by moving the head component in the first direction after the slidably engaging until a locking mechanism formed by the stem component and the head component at an interface is engaged, wherein the first and second mounting portions intersect the longitudinal axis.   
     
     
         17 . The method of  claim 16  wherein the locking mechanism is formed by a protrusion and a complementary recess that define a pair of complementary faces, and the connecting the head component and the stem component further includes engaging the pair of complementary faces along a second direction perpendicular to the first direction. 
     
     
         18 . The method of  claim 16  further comprising determining in-situ a prosthetic length and selecting in-situ one of a plurality of head components, and one of a plurality of stem components to achieve a prosthetic length.