More than 40 years' follow-up of an unconstrained metal lunate replacement for the treatment of Kienböck's disease.

Kienböck's disease is characterised by avascular necrosis of the lunate bone, and over the years it has been a challenging disease to manage, with differing opinions on the best intervention. We present an interesting case of a metallic unconstrained lunate replacement that is still functioning well in a patient 40 years after surgery. This case report represents the longest follow-up of any such prosthesis.