Dr Hirner is a fellowship trained Orthopaedic surgeon. He specialises in musculoskeletal problems affecting the knee and shoulder.

Dr Hirner undertook his medical training at the University of the Witwatersrand in Johannesburg South Africa. Following this Dr Hirner obtained a Master Degree in Sports Science from Sheffield University, United Kingdom and then completed his Orthopaedic training in South Africa.

After completing his Orthopaedic training, he underwent sub specialist fellowship training in knee and shoulder reconstruction at the Orthopaedic and Arthritic Hospital in Toronto, Canada. During this time Dr Hirner gained experience treating elite athletes from the NBA Toronto Raptors in addition to managing complex degenerative knee and shoulder problems

Dr Hirner has been living and working in New Zealand since 2000 and currently works at the Northland DHB, Northland Orthopaedic Center and Allevia Kensington Hospital. He is currently involved in several research projects and takes an active role in training Orthopaedic registrars.