Patient-specific acetabular alignment guides

Abstract

An acetabular device includes a patient-specific acetabular alignment guide including a bone engagement surface. The bone engagement surface has a first portion configured and shaped to be conforming and complementary to an acetabular rim surface and a second portion configured and shaped to be conforming and complementary to a periacetabular area of an acetabulum of a patient. The acetabular alignment guide includes a plurality of guiding formations extending through the second portion for guiding a plurality of alignment pins therethrough. The bone engagement surface and the plurality of guiding formations are prepared from a three-dimensional model of the acetabulum of the specific patient reconstructed pre-operatively from a scan of the patient.

1 .- 20 . (canceled) 
     
     
         21 . A method for inserting an acetabular implant into an acetabulum of a patient, the method comprising:
 engaging a patient-specific side of an acetabular alignment guide to a complementary rim surface and periacetabular area of a pelvis outside the acetabulum of the patient;   inserting a plurality of alignment pins through corresponding alignment apertures of the acetabular alignment guide and into the periacetabular area of the pelvis outside the acetabulum of the patient;   removing the acetabular alignment guide without removing the plurality of alignment pins from the periacetabular area of the pelvis of the patient;   coupling an acetabular instrument to a patient-specific alignment adapter having a plurality of openings located at patient-specific locations, each of the plurality of openings configured to align with one of the plurality of alignment pins; and   guiding the patient-specific alignment adapter along the plurality of alignment pins to engage the acetabular instrument with the acetabulum.   
     
     
         22 . The method of  claim 21 , wherein engagement of the acetabular instrument with the acetabulum comprises reaming the acetabulum with a reamer. 
     
     
         23 . The method of  claim 21 , wherein guiding the patient-specific alignment adapter along the plurality of alignment pins comprises adjusting arms of the patient-specific alignment adapter to move the plurality of openings to the patient-specific locations. 
     
     
         24 . The method of  claim 23 , wherein adjusting arms of the patient-specific alignment adapter comprises adjusting a position of a pair of parallel arms in a plane. 
     
     
         25 . The method of  claim 21 , further comprising coupling an instrument shaft to the acetabular instrument. 
     
     
         26 . The method of  claim 25 , wherein the patient-specific alignment adapter includes a quick-connect coupler for connecting to the instrument shaft. 
     
     
         27 . The method of  claim 25 , further comprising:
 slidably attaching a scale to one of the plurality of alignment pins; and   determining a size of an implant for the acetabulum using the scale.   
     
     
         28 . The method of  claim 27 , further comprising attaching an acetabular implant to the acetabulum using an inserter coupled to another patient-specific alignment adapter mounted to at least one of the plurality of alignment pins. 
     
     
         29 . A method of preparing an acetabulum of a patient for receiving an acetabular implant, the method comprising:
 positioning a patient-specific acetabular alignment guide against bone adjacent to the acetabulum, the patient-specific acetabular alignment guide including first and second alignment apertures;   inserting first and second alignment pins through the first and second alignment apertures, respectively;   coupling a patient-specific alignment adapter to the first and second alignment pins, the patient-specific alignment adapter comprising:
 first and second arms including first and second openings, respectively, for receiving the first and second alignment pins, respectively; 
 a reaming head supported by the first and second arms; and 
 a quick-connect coupler connected to the reaming head for receiving a drive shaft; 
   connecting the drive shaft to the quick-connect coupler; and   reaming the acetabulum with the reaming head.   
     
     
         30 . The method of  claim 29 , wherein positioning the patient-specific acetabular alignment guide against bone adjacent to the acetabulum comprises locating the first and second alignment apertures at patient-specific locations on an acetabular rim surface of the acetabulum. 
     
     
         31 . The method of  claim 29 , wherein coupling the patient-specific alignment adapter to the first and second alignment pins comprises adjusting a location of the first and second arms relative to each other within a plane to align the first and second openings with the first and second alignment pins. 
     
     
         32 . The method of  claim 29 , wherein reaming the acetabulum with the reaming head comprises transmitting rotational force from the drive shaft to the reaming head through the quick-connect coupler. 
     
     
         33 . The method of  claim 29 , wherein positioning the patient-specific acetabular alignment guide against bone adjacent to the acetabulum comprises:
 positioning a first portion configured and shaped to be conforming and complimentary to an acetabular rim surface of the patient against the acetabular rim surface of the patient, the first portion configured to extend around the entire acetabulum to form an opening through which the acetabulum is accessible; and   positioning a second portion configured and shaped to be conforming and complementary to a periacetabular area of an acetabulum of the patient against the periacetabular area of the acetabulum of the patient, the second portion configured to extend around the entire periacetabular area of the acetabulum to provide locations for the first and second alignment apertures.   
     
     
         34 . The method of  claim 33 , further comprising shaping the first portion and the second portion of the patient-specific acetabular alignment guide in accordance with a three-dimensional model of the acetabulum of the patient reconstructed pre-operatively from an image scan of the patient. 
     
     
         35 . The method of  claim 29 , further comprising removing the patient-specific acetabular alignment guide from the bone adjacent to the acetabulum before coupling the patient-specific alignment adapter to the first and second alignment pins. 
     
     
         36 . The method of  claim 29 , further comprising:
 removing the patient-specific alignment adapter from the first and second guide pins;   coupling an inserter to the first and second guide pins with a patient-specific inserter adapter to insert an acetabular implant into the acetabulum;   removing the inserter from the patient-specific inserter adapter;   coupling an impactor to the patient-specific inserter adapter; and   impacting the acetabular implant with the impactor.   
     
     
         37 . A method of preparing an acetabulum of a patient for receiving an implant, the method comprising:
 positioning a patient-specific acetabular alignment guide against the acetabulum, the patient-specific acetabular alignment guide including:
 a closed-loop body configured to three-dimensionally conform and complement the acetabulum of the patient in only one position, the closed-loop body defining an opening to access the acetabulum and an acetabular centering axis; and 
 first and second alignment apertures extending through the closed-loop body outside of the opening; 
   inserting first and second alignment pins through the first and second alignment apertures, respectively;   adjusting a patient-specific alignment adapter to receive the first and second alignment pins, the patient-specific alignment adapter comprising:
 first and second arms including first and second openings, respectively, the first and second arms rotatable about the acetabular centering axis; 
 a reaming head supported by the first and second arms; and 
 a quick-connect coupler connected to the reaming head for receiving a drive shaft; 
   connecting the drive shaft to the quick-connect coupling; and   reaming the acetabulum with the reaming head.   
     
     
         38 . The method of  claim 37 , wherein adjusting the patient-specific alignment adapter to receive the first and second alignment pins comprises adjusting a location of the first and second arms relative to each other within a plane to align the first and second openings with the first and second alignment pins, respectively. 
     
     
         39 . The method of  claim 37 , wherein reaming the acetabulum with the reaming head comprises transmitting rotational force from the drive shaft to the reaming head through the quick-connect coupler. 
     
     
         40 . The method of  claim 37 , further comprising:
 slidably attaching a scale to at least one of the first and second alignment pins; and   determining a size of an implant for the acetabulum using the scale.