Biodegradable implants in orthopaedic surgery--a review on the state-of-the-art.

Until recently, internal fixation of fractured bones and joints has been managed by metal implants. Certain disadvantages of the metal implants are: the properties of the materials are stiffer than those of cortical bone and removal of the implants requires a second operation. About 40 different biodegradable polymers, copolymers and composites have been developed in order to substitute the metal implants for internal fracture fixation. First experimental and clinical results demonstrate the limitations of these new methods. The main problem of the material is the loss of mechanical strength within a time interval not long enough to guarantee bone healing. The development of sterile sinus at the site of implantation is also a problem reported by various groups. Despite some drawbacks, there are indications for the isolated or the adjuvant implantation of biodegradable materials.