Socket and prosthesis for joint replacement

Abstract

A joint replacement prosthesis and procedure reduce the number of steps to complete a joint replacement. The joint replacement prosthesis comprises a ball and socket unit that fixes the ball in the socket prior to surgery. The unit is coupled to a bone structure in the patient and is coupled with a prosthesis that is fixed to another bone of the patient, such as a femoral implant fixed in a femur and providing a coupling at the end of a neck portion that is easily fit into a femoral head and acetabulum unit. A tether may be used to retain the ball in the socket and/or the ball may be retained by extension in the socket that do not restrict patient motion.

1 . A method of assembling a joint prosthesis, comprising:
 installing a joint head prosthesis pre-assembled with a shell prosthesis as a unit without separating the joint head prosthesis and the shell prosthesis during installation; shaping a pre-existing bone of a patient such that the joint head prosthesis fits onto the pre-existing bone after the step of shaping; disposing the joint head prosthesis pre-assembled with the shell prosthesis as a unit onto the pre-existing bone after the step of shaping; fixing the joint head prosthesis onto the pre-existing bone after the step of shaping by connecting the joint head prosthesis to an opposite side of the pre-existing bone using a coupling device comprising a cannulated member and a fixing device, the cannulated member having a first end and a second end, opposite of the first end, and ridges extending from an exterior surface of the cannulated member, the fixing device having a contact surface such that the contact surface of the fixing device operatively contacts a surface of the pre-existing bone of the patient opposite of the joint head prosthesis; and tensioning the cannulated member between the first end of the cannulated member joined to the joint head prosthesis and the second end of the cannulated member joined to the fixing device.   
     
     
         2 . The method of  claim 1 , wherein the fixing device is joined to the second end of the cannulated member by a ratchet mechanism. 
     
     
         3 . The method of  claim 2 , wherein the ratchet mechanism applies tension to the cannulated member until a preset tension is applied by ratcheting the ratchet mechanism. 
     
     
         4 . The method of  claim 3 , wherein, once the present tension is applied, a tensioning tool no longer ratchets the ratchet mechanism. 
     
     
         5 . A system for assembling a joint prosthesis, comprising a tensioning tool;
 a joint head prosthesis and shell prosthesis unit,   a fixing device; and   a cannulated member, wherein the joint head prosthesis and shell prosthesis unit is pre-assembled prior to insertion of the unit into a patient, and the unit has a shaped surface formed on the joint head prosthesis having a shape designed for fitting onto a pre-prepared bone of a patient such that the unit fits on one side of the bone of the patient, and the fixing device has a contact surface fitting on an opposite surface of the bone of the patient, the cannulated member extending through a hole in the bone of the patient such that the head is joined to the fixing device by the cannulated member, the cannulated member being placed under tension using the tensioning tool.   
     
     
         6 . The system of  claim 5 , wherein the cannulated member and the fixing device are joined by a ratchet mechanism. 
     
     
         7 . The system of  claim 6 , wherein the tensioning tool applies tension to the cannulated member by ratcheting the ratchet mechanism. 
     
     
         8 . The system of  claim 7 , wherein, once a preset tension is applied to the cannulated mechanism, the tensioning tool no longer ratchets the ratchet mechanism.