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

## TL;DR

This paper reports two rare cases of anterior tibiofemoral dislocation in mobile-bearing total knee replacements caused by trauma and outlines management strategies.

## Contribution

The paper presents the first reported cases of anterior dislocation in mobile-bearing total knee arthroplasties.

## Key findings

- Low-energy trauma can cause complete tibiofemoral dislocation in total knee arthroplasty.
- Anterior dislocation in mobile-bearing prostheses differs from bearing spinout and requires prompt reduction.
- Long-term outcomes may involve instability and the need for revision surgery.

## Abstract

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.

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.

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.

•Low-energy trauma can cause complete tibiofemoral dislocation of total knee arthroplasty.•Complete dislocation in mobile-bearing knee arthroplasty is different from bearing spinout.•Anterior tibiofemoral dislocation requires prompt reduction.•Clinical assessment and imaging are indicated to rule out concomitant neurological or vascular injury.•Long term sequelae may include persistent instability and the need for revision surgery.

Low-energy trauma can cause complete tibiofemoral dislocation of total knee arthroplasty.

Complete dislocation in mobile-bearing knee arthroplasty is different from bearing spinout.

Anterior tibiofemoral dislocation requires prompt reduction.

Clinical assessment and imaging are indicated to rule out concomitant neurological or vascular injury.

Long term sequelae may include persistent instability and the need for revision surgery.