Acetabular cup impacting using patient-specific instrumentation

Abstract

A cup impactor assembly comprises a shaft. A cup coupler is at a cup end of the shaft and is releasably connecting a cup in fixed relation. A handle is at an impacting end of the shaft. A visual guide is mounted to at least one of the shaft and the handle, the visual guide producing visual guidance for pointing at at least two landmarks of the pelvis or fixed relative to the pelvis, based on a pre-planned patient-specific relation between the at least two landmarks and a desired acetabular cup orientation relative to the landmarks. A method for orienting an acetabular cup prior to impacting in an acetabulum of a pelvis is also provided.

1 . A cup impactor assembly comprising:
 a shaft;   a cup coupler at a cup end of the shaft adapted to releasably connect a cup in fixed relation;   a handle at an impacting end of the shaft; and   a visual guide mounted to at least one of the shaft and the handle, the visual guide producing visual guidance for pointing at at least two landmarks of the pelvis or fixed relative to the pelvis, based on a pre-planned patient-specific relation between the at least two landmarks and a desired acetabular cup orientation relative to the landmarks.   
     
     
         2 . The cup impactor assembly according to  claim 1 , wherein the visual guide comprises a body supporting light sources emitting at least two visible light beams. 
     
     
         3 . The cup impactor assembly according to  claim 2 , wherein the body of the visual guide has a patient specific shape resulting from the pre-planned patient-specific relation between the at least two landmarks and a desired acetabular cup orientation relative to the landmarks. 
     
     
         4 . The cup impactor assembly according to  claim 1 , further comprising a translational joint between the visual guide and the shaft or handle. 
     
     
         5 . The cup impactor assembly according to  claim 1 , further comprising a patient specific block having a shape resulting from the pre-planned patient-specific relation between the at least two landmarks and a desired acetabular cup orientation relative to the landmarks, the patient specific block configured to create the at least two landmarks. 
     
     
         6 . The cup impactor assembly according to  claim 5 , wherein the patient specific block is configured to be received in the acetabulum in a single possible orientation. 
     
     
         7 . The cup impactor assembly according to  claim 6 , wherein the patient specific block is configured to be secured to the cup coupler, whereby the visual guide is used with the patient specific block to create the at least two landmarks. 
     
     
         8 . The cup impactor assembly according to  claim 6 , wherein the patient specific block has at least one pin guide for positioning at least one pin for subsequent use in aligning the visual guide. 
     
     
         9 . The cup impactor assembly according to  claim 8 , further comprising a target board configured to be fixed to the at least one pin, the target board having the at least two landmarks. 
     
     
         10 . The cup impactor assembly according to  claim 8 , wherein the visual guide comprises a sleeve through which the pin is threaded for visual guidance. 
     
     
         11 . The cup impactor assembly according to  claim 1 , further comprising a file comprising the patient-specific relation between the at least two landmarks and a desired acetabular cup orientation relative to the landmarks used for the fabrication of a patient-specific portion of the cup impactor assembly.