Shoulder prosthesis with anatomic reattachment features

Abstract

A humeral prosthesis features improved anatomic attachment areas for tendon or bone. In the preferred embodiment, in contrast to existing devices, at least one set of tendon/bone attachment points are provided along a line, at least a portion of which is divergent with respect to the axis of the stem. One or more sets of attachment points may be further be provided along a line which is substantially parallel to the axis of the stem, resulting in a “T” “L” or “U” shape. Alternatively, attachment points having a changing degree of diversion with respect to the axis of the stem may be provided along a common, curved line. The attachment points may simply be apertures formed through the body of the implant though, in the preferred embodiment, the apertures are provided on raised tabs. An area of bone-ingrowth material may be provided adjacent the attachment points, and may include a separate fastening mechanism such as a threaded hole to receive a screw. A groove may also be provided in any embodiment to receive the biceps tendon. Particularly with respect to fractures, including multi- and ‘four-part’ fractures, means specifically intended for the rigid reattachment of the greater or lesser tuberosities may be provided separately or in conjunction with other sets of reattachment configurations.

I claim:  
     
         1 . A humeral prosthesis with anatomic tendon or bone reattachment features, comprising: 
 an elongated body having a proximal end and a distal end terminating in a stem with an axis, the stem being configured for placement within an intramedullary canal of a humerus such that a portion of the proximal end remains exposed; and    a set of tendon or bone reattachment points on the exposed portion of the proximal end, the points being arranged along a line, wherein at least a portion of the line is divergent relative to the axis of the stem.    
     
     
         2 . The prosthesis of  claim 1 , further including at least one set of attachment points arranged along a line which is substantially parallel to the axis of the stem.  
     
     
         3 . The prosthesis of  claim 2 , wherein the set of divergent attachment points and those arranged along a line which is substantially parallel to the axis of the stem form a “T” shape.  
     
     
         4 . The prosthesis of  claim 2 , wherein the set of divergent attachment points and those arranged along a line which is substantially parallel to the axis of the stem forms an upright or inverted, forward or backward “L” shape.  
     
     
         5 . The prosthesis of  claim 2 , wherein the set of divergent attachment points and those arranged along a line which is substantially parallel to the axis of the stem both lie along the same curved line.  
     
     
         6 . The prosthesis of  claim 1 , further including two sets of attachment points, each arranged along a separate line is substantially parallel to the axis of the stem.  
     
     
         7 . The prosthesis of  claim 6 , wherein the set of divergent attachment points and those arranged along a line which is substantially parallel to the axis of the stem form an upright or inverted “U” shape.  
     
     
         8 . The prosthesis of  claim 6 , wherein the set of divergent attachment points and those arranged along the two lines which are substantially parallel to the axis of the stem all lie along the same curved line.  
     
     
         9 . The prosthesis of  claim 1 , where at least some of the attachment points are disposed on a raised tab.  
     
     
         10 . The prosthesis of  claim 1 , further including an area of bone-ingrowth material adjacent to the set of attachment points.  
     
     
         11 . The prosthesis of  claim 1 , further including a groove to receive a biceps tendon.  
     
     
         12 . The prosthesis of  claim 1 , wherein the set of attachment points is arranged along a line which is substantially perpendicular to the axis of the stem.  
     
     
         13 . The prosthesis of  claim 1 , wherein: 
 the bone to be attached includes the greater or lesser tuberosity; and    the prosthesis further includes a feature specifically intended to reattach the greater or lesser tuberosity.    
     
     
         14 . The prosthesis of  claim 13 , wherein: 
 the feature specifically intended to reattach greater or lesser tuberosity includes a fastener-receiving aperture.    
     
     
         15 . The prosthesis of  claim 13 , wherein: 
 the feature specifically intended to reattach greater or lesser tuberosity includes a bone-ingrowth surface.    
     
     
         16 . The prosthesis of  claim 13 , wherein: 
 the feature specifically intended to reattach greater or lesser tuberosity includes a recess.    
     
     
         17 . A prosthesis applicable to fractures of the humerus, including multi-part fractures wherein the greater or lesser tuberosities require reattachment, the prosthesis comprising: 
 an elongated body having a proximal end and a distal end terminating in a stem configured for placement within an intramedullary canal of a humerus, such that a portion of the proximal end remains exposed following installation; and    one or more features on the exposed portion of the proximal end, the position of each feature being specifically intended for the reattachment of one of the greater or lesser tuberosities.    
     
     
         18 . The prosthesis of  claim 17 , wherein: 
 the feature specifically intended for the reattachment of the greater or lesser tuberosity includes a fastener-receiving aperture.    
     
     
         19 . The prosthesis of  claim 17 , wherein: 
 the feature specifically intended for the reattachment of the greater or lesser tuberosity includes a bone-ingrowth surface.    
     
     
         20 . The prosthesis of  claim 17 , wherein: 
 the feature specifically intended for the reattachment of the greater or lesser tuberosity includes a recess.    
     
     
         21 . The prosthesis of  claim 17 , wherein two separate distinct regions are provided for reattachment of the greater and lesser tuberosities, respectively.  
     
     
         22 . The prosthesis of  claim 21 , wherein the distinct regions include a bone ingrowth or outgrowth surface.  
     
     
         23 . The prosthesis of  claim 22 , wherein the bone ingrowth or ongrowth surfaces include a biologic enhancement material.