[Principles of OSG arthrodesis in cases of joint infection]

A chronic empyema of the ankle joint often develops after an open fracture or surgery. In the case of the destruction of the joint due to an infection, an arthrodesis should be performed. Normally we use an external fixator with two bone-nails placed into the calcaneus and two into the tibia. The arthrodesis is distracted and Septopal is permanently implemented. At 4-6 weeks after surgery the Septopal is removed, with distraction being reduced and a cancellous bone-graft taken from the dorsal iliac crest is performed to fill the bony defect. After bone healing, the external fixator is removed and the patient mobilized in a brace. Initially, weight-bearing is limited to 10 kg but is increased gradually to full weight. The brace is used for 6-9 months; later the patient is mobilized in orthopaedic shoes. In difficult cases, also in combination with a malposition which has to be corrected or a lengthening of the lower limb, we use the Ilizarov fixator. From 1993 to 2003 we performed arthrodeses of the ankle joint due to infectious destruction in 107 cases. In 82.2%, the empyema was caused by a fracture of the ankle joint and the following treatment. In 58% of the patients, we saw associated diseases such as obesity, alcohol abuse, diabetes and malposition of the foot. In 55% we found Staphylococcus aureus. In 86%, we used the external AO-fixator, in 14% the Ilizarov fixator. The patient retained the fixator for an average of 128 days. In our study, 92.1% of the 101 patients who had completed therapy showed a good stability an average of 4.5 years after the arthrodesis. In 5% we found partial stability, while three patients had to be amputated. In 57 patients (56.4), an arthrosis of the tarsal bones was found, and 38 patients (54.3%) of the 70 patients who at the time of the arthrodesis were still working could return to work.