Proximal tibiofibular joint instability in multiligamentous injury of the knee.

We present a case of a man in his 40s with a proximal tibiofibular joint dislocation, anterior cruciate ligament (ACL) tear and posterolateral corner (PLC) injury sustained after a cycling accident. Physical examination and MRI confirmed the diagnosis. He was treated with reconstruction of the ACL, PLC and proximal tibiofibular joint. Postoperative treatment included physical therapy to improve knee range of motion and full weight-bearing after 6 weeks. He was able to return to full activities including completing a marathon after 1 year. Identifying proximal tibiofibular joint instability is essential in patients with multiligamentous knee injury as it is often missed. The use of a single tunnel for PLC and proximal tibiofibular joint reconstruction can reduce risk of tunnel convergence.