Traumatic anterior tibiofemoral dislocation of mobile-bearing total knee arthroplasty: Two cases

Background: Anterior tibiofemoral dislocation is a severe complication of a total knee arthroplasty. It is rare, and it is distinctly different from bearing spinout. Most tibiofemoral dislocations are posterior. Anterior dislocation has previously been described in various prosthesis designs, but not in mobile-bearing prostheses. We present two cases and provide recommendations for the management of this rare and severe injury. Case description: Two cases of complete anterior tibiofemoral dislocation were brought on by trauma, fifteen and eight years after initial implantation of mobile-bearing total knee arthroplasties in 71-year-old and 73-year-old female patients. One was managed with closed reduction and made a full recovery. In the other, closed reduction failed, open reduction was performed, and there was a need for revision surgery for instability after her initial recovery. There were no neurovascular complications. Follow-up was 23 and 14 months respectively. Conclusion: Anterior tibiofemoral dislocation is a severe injury with a risk of concomitant complications. Early management should include prompt reduction, serial neurovascular exams and CT angiography for all cases. Late management should include assessment of joint stability.