- 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)