Cornelis Nicolas "Niek" van Dijk is an orthopaedic surgeon, a specialist in sports traumatology and arthroscopic surgery of the ankle and knee.

His operative techniques have spread throughout the world, and have benefitted leading athletes, as well as ordinary people suffering from ankle problems.

He began his residency at Utrecht's Centraal Military Hospital, and continued at Wilhelmina Gasthuis Department of Experimental Surgery, in Amsterdam.

His thesis was entitled “Diagnostic strategies in patients with severe ankle sprain”, and his promoter was Professor Dr. R.K. Marti, the former head of Orthopaedic Surgery at AMC.

He has written more than 100 book chapters and presents on average 25 international invited lectures a year.