Distraction osteogenesis for knee arthrodesis in infected tumor prostheses.

Three patients had distraction osteogenesis as a salvage method for infected endoprostheses. At the first operation, the infected prosthesis was removed and stabilization was achieved with an external fixator to preserve limb length. An additional external fixator was applied later for distraction osteogenesis after ensuring that there was no infection. Osteotomy was done at two sites on the femur, or tibia and femur, respectively, as a second operation. A third surgery was done at the docking site at the edge of the transported bone fragments. Curettage, refreshing, and soft tissue release were done to enhance bone union. The healing index was 18.3 days/cm in Patient 1, 17.7 days/cm in Patient 2, and 33.0 days/cm in Patient 3. All patients walk without a cane. It has been shown that patients can obtain a long-lasting and weight-bearable leg with our method, because their viable bone establishes biomechanical stability. Loss of knee function, a longer treatment period, and pin site treatment are the weaknesses of our method. Our method is indicated for patients in whom systemic disease can be controlled well and who have longer life expectancy.

Correction of tibial deformity in adults.

This report from five hospitals in Japan describes the results of correcting adult tibial deformities using external fixation. There were 49 patients with 59 lower limb deformities, with trauma being the most common cause of the deformity. Varus angulation was the most common deformity, and the most common magnitude was 11 degrees -30 degrees. Twenty-two patients had a leg-length discrepancy. The aim of the correction was to normalize both the mechanical axis and the inclination of the knee and ankle joints. In 63% of the patients corrections were performed gradually during bone lengthening or acutely after bone lengthening. Altogether, 71% of the patients were completely corrected, and no leg-length discrepancies remained after correction in 47%. Complications were encountered in 22 patients, about half of which were pin tract infections, 28% refractures, and the remainder delayed consolidation or fixator failure. There were no neurological or circulatory complications. The average fixation duration was 9 months. The average hospital charges were 3,740,000 yen in bilateral correction patients and 1,940,000 yen in unilateral correction patients. External fixation can correct not only the mechanical axis and joint inclination but also leg-length discrepancy simultaneously.