Fusion of the septic knee with external hybrid fixator

Arthrodesis is a well-recognized salvage procedure in patients with septic destruction of knee joints. It offers the opportunity for restoring weight bearing capability and significant pain relief as well as eradication of infection, but at the expense of joint motion. However, arthrodesis in order to joint sepsis may be difficult to achieve because of poor bone stock, persistent infection and soft tissue compromise. From 2000 to June 2004, in 70 consecutive patients arthrodesis of the knee was indicated. Nineteen patients were considered to have external hybrid fixator (EHF) and were therefore included to the prospective study protocol. Forty-three stabilisations of destructed knee joints were done by a modular titanium rod. In these cases bony fusion was very unlikely to be achieved because of devastating defects due to infected total knee arthroplasties. Eight patients were treated by compression nailing. In these situations EHF was not indicated. In three patients minor complication occurred. In two out of 17 patients fusion failed because of primary underestimated bony defects (11.8%). The use of EHF for arthrodeses after septic destruction of knee joints can be recommended according to our results. However, EHF will not be successful or applicable in each case. Therefore, physicians and institutions that offer this special method should have not only experiences with EHF but also with arthrodeses and alternative procedures.