Delayed femoral fracture through a tracker pin site after navigated total knee arthroplasty.

Femoral shaft fractures through a tracker pin site after computer navigated total knee arthroplasty are being increasingly reported. All previously reported fractures have occurred within 3 months of surgery, and thus, any patient with an unexpected thigh pain during the early postoperative period should be carefully monitored for a potential fracture and receive appropriate follow-up care. However, unlike these fractures, we encountered a navigation pin-associated delayed femoral shaft fracture during the late postoperative period (at 12 months postoperatively), which we believe, might be associated with transcortical drilling marks.