Charcot Fracture in the Calcaneus after Total Knee Arthroplasty: A Case Report

INTRODUCTION Only a few reports have described calcaneus fractures after total knee arthroplasty (TKA). Therefore, in this report, we describe a case of calcaneal avulsion fracture that occurred 5 weeks after a TKA in a relatively young male patient with syphilis. CASE REPORT A 63-year-old man with syphilis had Charcot joint of the right knee. The patient developed severe varus deformity and contracture and experienced severe pain in the knee. TKA was performed to alleviate the pain and improve the patient's gait. The patient noticed slight heel pain 4 weeks after the TKA, and a calcaneus avulsion fracture in the ipsilateral foot was diagnosed without any trauma 1 week later. Open reduction internal fixation was performed with cannulated cancellous screws and a cerclage wire. 3 weeks after the surgery, partial weight bearing was permitted in an orthotic device. Full weight-bearing was allowed at 7 weeks after surgery. The surgical wounds healed without complications. The calcaneus fracture successfully achieved bone union with appropriate surgical intervention and aftercare. CONCLUSION The previous studies have shown that calcaneus stress fracture may occur in elderly osteoporotic women after TKA. Patients with peripheral neuropathy may develop a Charcot fracture after minimal trauma because of decreased protective sensation, even if the patient is a relatively young man without osteoporosis. Charcot joint disease is also considered to be a risk factor for calcaneal stress fracture and Charcot fracture after TKA.