Revisions
Revision is the replacement of a prosthesis. This means that a prosthesis previously implanted in the body is removed and replaced by a new prosthesis. Compared to the initial operation revisions are often more complex and more difficult, because every revision involves the loss of healthy bone substance. Revision operations are also more expensive for a satisfactory result. The most important goal is therefore to avoid revisions by using a good surgical procedure and using products with good (long-term) results.
Unfortunately, it is not always possible to avoid revisions. There can also be different reasons for revisions and there is a distinction between septic or aseptic revision. If it is necessary to replace an implant without confirmation of an infection - i.e. aseptic - now the cement is not necessarily removed completely. However, if the implant has loosened for septic reasons, the cement must be fully removed. In the current state of knowledge it is easier to remove cement than to release a well-anchored cement-free prosthesis from the bone site. Ultimately it is important for the stability of the revised prosthesis to detect possible loosening of the initial implant early to be able to retain as much healthy bone as possible.
A prosthesis fixed with bone cement offers very high primary stability combined with fast remobilization of patients. The cemented-in prosthesis can be fully loaded very soon after the operation. The necessary rehabilitation is comparatively simple for patients who have had a cemented-in prosthesis implanted. The joints can be loaded again very soon after the operation, but the use of crutches is still required for a reasonable period for safety reasons.
Bone cement has proven particularly useful because specific active substances, e.g. antibiotics, can be added to the powder component. The active substances are released locally after implant placement of the new joint, i.e. in the immediate vicinity of the new prosthesis and have been confirmed to reduce the danger of infection. The antibiotics act against bacteria precisely at the site where they are required in the open wound without subjecting the body in general to unnecessarily high antibiotic levels. This makes bone cement a modern drug delivery system that delivers the required drugs directly to the surgical site. The important factor is not how much active substance is in the cement matrix but how much of the active substance is actually released locally. Too much active substance in the bone cement would actually be detrimental, because the mechanical stability of the fixed prosthesis is weakened by a high proportion of active substance in the cement. The local active substance levels of industrially manufactured bone cements that are formed by the use of bone cements that contain active substances are approximate (assuming that there is no incompatibility) and are significantly below the clinical routine dosages for systemic single injections.
Read more about this topic: Bone Cement
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