Non cemented hip implants. Failures of biologically fixed devices: causes and treatment

Complications of cementless prostheses are similar to those presented by the cemented ones. They are all the consequence of a failure (lack) of the bony fixation, which may be primary (the components never become fixed) or secondary (the components lose their bony attachments that were initially achieved). The bony fixation is often very difficult to assess, and a localized radiolucent line is always a bad indication. Failure of fixation may be partial or total for one or both components. Removal of distal broken cementless stems is much more difficult than for the cemented ones. Loosening may damage the bone at least as much as a mobile cemented mantle, and bone grafting at revision is often needed. Revisions for loosening of uncemented prostheses are at least as difficult as for the cemented ones. The lifetime of the Judet prosthesis has been shortened by an initially poor manufacturing process. Perhaps this has allowed us to get information about the outcome of uncemented prostheses in a shorter period. Finally, I believe in the concept of uncemented prostheses because their possible fixation by bony ingrowth is proved, but the definitive solutions have to be found and improvements are needed: A screwed socket appears to be good. A better plastic than HDP with less wearability and better mechanical properties is needed. A stem better adapted to the shape of the medullary canal bedding would probably facilitate bony ingrowth. The kind of porosity does not affect many things in my experience. Failures of prostheses that are no longer commonly used today have been reported. These were state-of-the-art devices 10 years ago--perhaps that is good food for thought.