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Surgical Instruments for Revision THR


- Company Specific Products:
     - Innomed Products:
     - Biomet® Flexible Osteotome System

 - Screw Drivers:

     - manufacturer specific screw drivers are necessary to remove the acetabular screws;

- High-Speed Drills:
     - disadvantage: these drills remove bone more easily than they do harder cement;
     - may be needed to remove distal cement plug;

- High Speed Burrs:
     - creates a space as thin column of bone is removed at the prosthesis-cement or the cement-bone interface;
     - ask to have several metal cutting tips available (tungsten-carbide), which may be required for collar removal or notch of the femoral stem;
     - advantage: less likely to cause fracture than osteotomes;
     - disadvantage: because cement is harder than bone, the burr will tend to cut into softer bone;
           - if burr is used as the primary means of cement removal, then consider use of flouroscopy to reduce chances of femoral perforation;
           - also consider use of multiple controlled anterior cortical windows, inorder to better visualize the canal during insertion of burr;
                  - attempt to keep these windows as proximal as possible;
     - it is prudent to ensure that metal cutting burrs are available before the case begins;

- Osteotomes:
    - these instrument will have a wedging effect at the prosthesis bone or the prosthesis cement interface which can cause fracture;
    - osteotomes tend to work well in cancellous bone, but may split the femur in diaphyseal bone;
    - long, narrow handled osteotomes and chisels:
           - are essential for removing cement from femoral canal;
           - offset handled osteotomes assist w/ cement removal deep in the canal;
           - these should have both straight and curved tips and both positive & negative cutting angles;
           - negative cutting angle provides protection against penetration of bone cortex;
           - positive angle allows precision in cutting between cement & bone;
    - flexible osteotomes:
           - helpful in curved areas of proximal femur (metaphyseal bone);
           - disadvantage: little driving force can be applied;
           - may be used in diaphyseal bone if the stem is undersized;

- Moreland Cement Hook:
     - used to remove distal cement plug;
     - this is curved on one side and flattended on the other;
     - curved end is placed against the wall distally, w/ flattended side facing the femur;
     - it is gently tapped with a hammer until it bypasses the cement;
     - hook is then turned to face cement, and the handle is struck sharply with a slap hammer;

- Punch:
     - if cement stem is a smooth stem model, it can be tapped out w/ a punch applied to the head or collar;

- Universal Extractor:
     - used once component has been loosened;
     - loops over prosthetic femoral head or a ledge under the Morris taper prosthetic neck;
     - as the name implies, this extractor was developed to remove femoral stems, which have differing sizes of femoral neck tapers;
     - modular stem extractor is applied to the neck taper (after head is removed), using a specific matching sleeve;
     - matching sleeves:
            - can be fitted for the following specific company tapers:
                   - Zimmer, Depuy, Biomet, Richards, Osteonics, Intermedics, Howmedica, Dow-Corning, Wright modular femoral stems, Kirschner,
                          Johnson and Johnson, and Joint Medical Products;
     - the matching sleeve is then inserted and bolted into the extractor;
     - stem is extracted w/ slap hammer;

- Bone Hook:
      - may be slid into stem hole (if one is present)