Apparatus and Method for Hip Cup Extraction

Abstract

A hip cup extraction apparatus ( 101 ) comprising a shaft ( 402 ), a handle ( 404 ), a semicircular cutting blade ( 406 ), a spring loaded latching member ( 408 ), and a head ( 100 ) for removing a hip cup ( 405 ) from a pelvic bone ( 401 ). The head ( 100 ) includes a semispherical section ( 102 ) terminating in a substantially planar surface ( 104 ), a hip cup extraction apparatus aperture ( 106 ), a retaining sleeve ( 108 ), and a three sided void ( 110 ). The head ( 100 ) may be configured for selective attachment to the hip cup extraction apparatus ( 101 ). The hip cup extraction apparatus ( 101 ) is inserted into the hip cup extraction apparatus aperture ( 106 ), and an optional spring loaded latching member ( 408 ) retains the head ( 100 ) in place. As the head ( 100 ) is being attached to the hip cup extraction apparatus ( 101 ), the semicircular cutting blade ( 406 ) may pass through the three sided void ( 110 ). Once the head ( 100 ) is attached to the hip cup extraction apparatus ( 101 ), the head ( 100 ) is inserted into the hip cup ( 405 ). Force may then be applied to the hip cup extraction apparatus ( 101 ) in order to drive the semicircular cutting blade ( 406 ) into the pelvic bone ( 401 ). The hip cup extraction apparatus ( 101 ) may then be rotated or pivoted such that the semicircular cutting blade ( 406 ) passes completely around the hip cup ( 405 ).

1 . A head configured for selective attachment to a hip cup extraction apparatus, comprising:
 a semispherical section terminating in a substantially planar surface, the semispherical section having a spherical section diameter of between 39 and 60 millimeters;   a hip cup extraction apparatus aperture disposed centrally along the substantially planar surface;   a retaining sleeve projecting distally from the substantially planar surface about the hip cup extraction apparatus aperture; and   a three sided void disposed along the semispherical section.   
     
     
         2 . The head of  claim 1 , wherein the head is manufactured from one of stainless steel or acetal resin plastic. 
     
     
         3 . The head of  claim 1 , wherein the hip cup extraction apparatus aperture has an aperture diameter of between 12 and 18 millimeters. 
     
     
         4 . The head of  claim 3 , wherein the aperture diameter of the hip cup extraction apparatus aperture is between 15.784 and 16.002 millimeters. 
     
     
         5 . The head of  claim 1 , wherein the three sided void is characterized by a width of between 7 and 12 millimeters. 
     
     
         6 . The head of  claim 1 , wherein the head further comprises a cylindrical détente disposed about the hip cup extraction apparatus aperture. 
     
     
         7 . The head of  claim 6 , wherein the cylindrical détente has a diameter of between 11.296 and 11.557 millimeters. 
     
     
         8 . The head of  claim 1 , wherein the retaining sleeve projects distally from the substantially planar surface by at least 9 millimeters. 
     
     
         9 . The head of  claim 1 , wherein a first side of the three sided void is less than 18 millimeters from a center of the head. 
     
     
         10 . A cutting apparatus for removing a hip cup from a pelvic bone, comprising:
 a shaft having a length of at least 275 millimeters;   a handle extending distally from the shaft;   a semicircular cutting blade coupled to the shaft, wherein the semicircular cutting blade projects outwardly from the shaft;   a spring loaded latching member coupled to the shaft between the semicircular cutting blade and a first end of the shaft; and   a head comprising a semispherical section terminating in a substantially planar surface, and a three sided void disposed along the semispherical section.   
     
     
         11 . The cutting apparatus of  claim 10 , wherein the three sided void is configured such that when the head is coupled to the shaft, a tip of the semicircular blade may pass through the three sided void. 
     
     
         12 . The cutting apparatus of  claim 11 , further comprising an impaction platform disposed at a second end of the shaft. 
     
     
         13 . The cutting apparatus of  claim 12 , wherein the semicircular cutting blade terminates between 17 and 20 millimeters from a radial center of the shaft. 
     
     
         14 . The cutting apparatus of  claim 10 , wherein the shaft is manufactured from metal. 
     
     
         15 . The cutting apparatus of  claim 10 , wherein the semispherical section of the head has a spherical section diameter of between 39 and 60 millimeters. 
     
     
         16 . The cutting apparatus of  claim 10 , wherein one side of the three sided void is within 17.12 millimeters of a center of the shaft when measured along a line normal to the one side. 
     
     
         17 . The cutting apparatus of  claim 16 , wherein the three sided void is characterized by a width of between 7 and 12 millimeters. 
     
     
         18 . The cutting apparatus of  claim 10 , wherein the head is selectively detachable. 
     
     
         19 . A method of removing a hip cup, the method comprising the steps of:
 providing a hip cup removal apparatus comprising a shaft, a semicircular cutting blade and a selectively detachable, semispherical head having a diameter of between 39 and 60 millimeters, and a three-sided void disposed along the semispherical head;   inserting the semispherical head into a cup section of the hip cup;   rotating the hip cup removal apparatus such that the semicircular cutting blade passes about the hip cup; and   removing the hip cup.   
     
     
         20 . The method of  claim 19 , further comprising the step of applying an impaction force to the hip cup removal apparatus to initiate a cutting action by the semicircular cutting blade.