Osseoperception and Osseointegrated Prosthetic Limbs

Abstract

During the last decade, bone anchorage of prosthetic limbs has become a realistic alternative to socket prostheses for patients with amputations due to causes other than severe peripheral vascular disease. The theoretical advantages that could be assumed to exist with an artificial limb attached to the bone as an extension of the residual skeleton, were first described more than 20 years ago (1) and could be summarized as follows: a stable attachment of the prosthetic device with elimination of any movements of a socket, better proprioception due to the stable attachment directly to the bone; elimination of skin and pain problems related to a prosthetic socket; and a better potential to control the prosthetic limb. However, it is through recent clinical research that these advantages have become a reality for patients. The first successful clinical applications of patients treated with bone-anchored amputation prostheses was by the use of the method of osseointegration (2). The discovery that implants made of commercially pure titanium could provide a stable anchorage for an implant in bone tissue was made by the Swedish Professor Per-Ingvar Branemark, during the 1950s. This phenomenon was later named osseointegration (3). Since 1965 the method of osseointegration has been in successful clinical practice for dental applications (4,5) and to date there have been more than two million patients who have been treated with dental implants due to edentulousness worldwide. Currently the same method is, for example, also used for treatment with bone-anchored hearing aids, for anchorage of prostheses due to other defects in the head and neck area (6), for finger joint prostheses (7,8), and for thumb amputation prostheses (9). Treatment with an osseointegrated (OI) transfemoral amputation prosthesis was performed for the very first time in 1990 in Sweden (2). Since then, the treatment has continued to be performed in Sweden and more recently also in the United Kingdom (10,11). Until today, most patients treated have had a transfemoral amputation, but individuals with amputations on the upper extremity, that is, transhumeral, transradial, and thumb amputations, have also been treated with OI prostheses. To date, more than 120 patients have been treated with OI prostheses worldwide, with most patients treated at the Sahlgrenska University Hospital in Gothenburg, Sweden. The treatment includes two surgical sessions. At the first surgery (S1), a titanium implant (fixture) is inserted in the residual bone and left unloaded for 3 to 6 months. At the second surgery (S2), a titanium rod (abutment) is inserted into the distal end of the fixture and then penetrates out of the skin on the residual limb (Fig. 10.1). Prosthetic suspension is obtained by connecting the OI prosthesis to the abutment with a specific attachment device (Figs. 10.2 and 10.3). After the second surgery, the patient undergoes a period of rehabilitation. For