Acetabular Cup Fixation

Abstract

An acetabular cup system includes an acetabular cup having a wall with an inner surface and an outer surface. The acetabular cup includes a fixation opening through the wall, the fixation opening including a first wall portion adjacent to the inner surface and a second wall portion adjacent to the outer surface. The acetabular cup system also includes a fixation fastener including a head and a shaft with a bone-anchoring portion. The fastener can be inserted though the fixation opening. The head includes a first head portion engageable with the first wall portion and a second head portion engageable with the second wall portion.

1 . An acetabular cup system comprising:
 an acetabular cup having a wall with an inner surface and an outer surface, the acetabular cup including a fixation opening through the wall, the fixation opening including a first wall portion adjacent to the inner surface and a second wall portion adjacent to the outer surface; and   a fixation fastener including a head and a shaft with a bone-anchoring portion, the fastener insertable though the fixation opening, the head including a first head portion engageable with the first wall portion and a second head portion engageable with the second wall portion.   
     
     
         2 . The acetabular cup system of  claim 1 , wherein the first head portion is externally threaded and the first wall portion is internally threaded. 
     
     
         3 . The acetabular cup system of  claim 2 , wherein the second head portion is unthreaded and tapered and the second wall portion is unthreaded and tapered forming a taper lock connection with the second head portion, and wherein the first head portion is contiguous to the second head portion. 
     
     
         4 . The acetabular cup system of  claim 3 , wherein the first head portion is cylindrical and the first wall portion is cylindrical. 
     
     
         5 . The acetabular cup system of  claim 3 , wherein the first head portion is tapered and the first wall portion is tapered. 
     
     
         6 . The acetabular cup system of  claim 1 , wherein the second head portion is externally threaded and the second wall portion is internally threaded. 
     
     
         7 . The acetabular cup system of  claim 6 , wherein the first head portion is unthreaded and the first wall portion is unthreaded. 
     
     
         8 . The acetabular cup system of  claim 7 , wherein the first head portion is tapered and the first wall portion is tapered. 
     
     
         9 . The acetabular cup system of  claim 1 , wherein the first head portion is substantially spherical and unthreaded and the second head portion is cylindrical and threaded with self-tapping threads. 
     
     
         10 . The acetabular cup system of  claim 9 , wherein the fixation opening is unthreaded and the first wall portion is substantially spherical and the second wall portion is substantially cylindrical. 
     
     
         11 . The acetabular cup system of  claim 1 , wherein the first head portion is substantially spherical. 
     
     
         12 . The acetabular cup system of  claim 11 , wherein the first head portion is externally threaded. 
     
     
         13 . The acetabular cup system of  claim 12 , wherein the first wall portion is substantially spherical and threaded. 
     
     
         14 . An acetabular cup system comprising:
 an acetabular cup having a wall with an inner surface and an outer surface, the acetabular cup including a fixation opening through the wall, the fixation opening including a first wall portion adjacent to the inner surface and a second wall portion adjacent to the outer surface, the first wall portion being internally threaded and the second wall portion being unthreaded and tapered; and   a fixation fastener including a head and a shaft with a bone anchoring portion, the fastener insertable though the fixation opening, the head including a first head portion threadably engageable with the first wall portion and a second head portion tapered for taper lock connection with the second wall portion.   
     
     
         15 . The acetabular cup system of  claim 14 , wherein the first head portion is substantially cylindrical and the first wall portion is substantially cylindrical. 
     
     
         16 . The acetabular cup system of  claim 14 , wherein the first head portion is tapered and the first wall portion is tapered. 
     
     
         17 . An acetabular cup system comprising:
 an acetabular cup having a wall with an inner surface and an outer surface, the acetabular cup including a fixation opening through the wall, the fixation opening having an unthreaded surface; and   a fixation fastener including a head and a shaft with a bone anchoring portion, the fastener insertable though the fixation opening, the head including a threaded portion with self-tapping threads threadably engageable with the fixation opening.   
     
     
         18 . The acetabular cup system of  claim 17 , wherein the threaded portion of the fixation fastener is tapered. 
     
     
         19 . The acetabular cup system of  claim 17 , wherein the fixation opening is tapered. 
     
     
         20 . An acetabular cup system comprising:
 an acetabular cup having a wall with an inner surface and an outer surface, the acetabular cup including a fixation opening through the wall, the fixation opening having a threaded portion; and   a fixation fastener including an inner head attached to a bone-anchoring shaft and an outer head pivotably coupled to the inner head, the outer head including a threaded portion threadably engageable with the fixation opening, the inner head including a driver engagement recess.