[Endo-exo prostheses following limb-amputation]

Rehabilitation of patients having undergone limb amputation is difficult due to problems related to poor socket fit, which often deteriorates comfort, gait and the ability to take part in everyday life and work. The endo-exo prosthesis has been an alternative provision for people having undergone lower limb amputation for reasons other than diabetes or peripheral vascular disease for more than 10 years. The system consists of an intramedullar, osseointegrated and skin perforating prosthesis, which is implanted in the remaining bone and has an abutment to allow the attachment of the external prosthetic part including the knee joint in the case of a trans-femoral amputation. The idea originates in findings of modern tooth-implantology and involves a two-step operation. This study focuses on one centre's experience with the endo-exo prostheses in Lübeck, Germany, to describe and discuss the reliability of this alternative treatment method after lower limb amputation.

This article presents the results of lower limb amputees operated on in Lübeck, Germany between 1999-2013. It focuses on theoretical aspects of osseointegration and different clinically-based findings using the endo-exo technique over the last decade.

74 lower-limb amputees were treated with an endo-exo prosthesis until December 2013. There were only 4 verified intramedullar infections, yet there were many unplanned surgical revisions secondary to soft-tissue infections in the beginning. They were successfully encountered via clinically-based changes that were made concerning implant design, wound treatment and operative technique.

Since 1990 a few groups have developed an innovative method that provides an alternative to traditional socket-type prostheses. This involves a skeletally anchored device that is inserted into the remaining stump and provides osseointegration into the bone. The distal part of the implant protrudes transcutaneously and allows attachment to a prosthetic limb. This creates a hard point where the forces are transmitted through the skeleton with a more physiological pathway because the bone becomes the force carrier again, closer in biomechanics to an able-bodied person. With long-term numbers that show successful osseointegration for more than 10 years it is evident that obligate bacterial colonization does not necessarily lead to an intramedullar infection. Especially short stumps that are difficult to treat with a socket can be successfully fitted with an endo-exo prosthesis. Amputees who would otherwise be bound to a wheelchair due to their challenging situation should specifically be regarded as potential profiteers of this novel treatment option.