Summary

We made an articulating cement spacer loaded with antibiotics just same size and shape as infected implant. Due to perfect congruity, good range of motion and stability were maintained after installment of the spacer.

Abstract

INSTRUCTION
The standard treatment for infected total knee arthroplasty (TKA) is a two-stage replantation with a temporally articulating spacer. However, no ideal method had been reported by technical and economic point of view. Using with dental silicon, we made a mold for ideal articulating bone cement spacer.

Material And Method

We treated 14 cases of infected TKA. Using with same type and same size implant or trial component as infected implant in the knee, we made molds for cement spacer. We used two packs of Simplex bone cement including 2g of Vancomycin and 500 mg Amicamycin sulfate in each pack for 1 pair of cement spacer. Six to 8 weeks after installment of cement spacer, we performed revision TKA.

RESULT
Except one case resulted into arthrodesis, in 13 cases the infection were successfully controlled. Mean range of motion before implant removal was 4 to 110 degrees, 2 to 111 degrees during installment of articulating spacer, and 1 to 109 one year after revision TKA.

Discussion

Cost for one pair of molds was approximately 20 USD. On the contrary, the prices of commercially available one were approximately 1000 USD in Japan. Due to same size and shape as infected implant, the congruity to the femur and tibia was perfect, and also we could avoid the difficulty at wound closure due to overstuff bulky cement spacers. In addition, the cement spacer made by our mold had good patellofemoral motion unlike those of commercially available mold. Thus, a hand-made mold made with dental silicon was very beneficial to produce the ideal bone cement spacer for infected total knee arthroplasty.