Acute compartment syndrome after restarting warfarin therapy following polyethylene exchange in unicompartmental knee arthroplasty: case report

BACKGROUND: Acute compartment syndrome (ACS) is one of the true emergencies in orthopedics and traumatology. It can lead to permanent damage to skeletal muscles and neurovascular structures if not promptly treated. Although ACS usually occur after major trauma or invasive surgery, it can develop without trauma or after minimally invasive operation in anticoagulated patients. CASE REPORT: A 76-year-old woman underwent a polyethylene exchange in unicompartmental knee arthroplasty (UKA). She had had undergone mitral valve replacement and tricuspid valve annuloplasty, and a pacemaker insertion. She was on warfarin therapy at a dose of 3.5 mg daily. For surgical preparation, she discontinued warfarin for 7 days prior to the surgery, and administered enoxaparin sodium at a dose of 120 mg/day. Warfarin was re-administered at a dose of 3.5 mg/day on POD #7, and no postoperative complications were observed until the sutures were removed on POD #14. However, ACS, caused by arterial branch bleeding, occurred on POD #16, 10 days after restarting warfarin therapy. Emergency fasciotomy was performed to decompress the anterior and posterior compartments of left thigh. Finally, she had minimal neurologic deficits, with a left knee ROM of 0°–100° after 6 months. CONCLUSION: Presented case showed that arterial branch bleeding of the surgical site could occur more than 1 week after restarting warfarin therapy, which in turn may leaded to fatal complications such as ACS. Moreover, in anticoagulated patients, postoperative arterial branch bleeding and compartment syndrome can occur following considerably less invasive surgical procedures, such as polyethylene exchange in UKA. Therefore, surgeons should be aware of the possibility of surgical site bleeding and compartment syndrome for more than a week in patients who restarted warfarin therapy postoperatively, regardless of the invasiveness of surgical procedure.