Dr Chang graduated from from the National University of Singapore Faculty of Medicine in 1994. He was admitted as a Fellow to the Royal College of Surgeons of Edinburgh and the Royal College of Surgeons and Physicians of Glasgow in 1998. The same year, he obtained his Master of Medicine in General Surgery from the National University of Singapore. In 2001, Dr Chang became the first orthopaedic trainee from Singapore to obtain the FRCS Edin (Orth) when it was made a requirement for exit certification for orthopaedic training in Singapore. He was then awarded the Ministry of Health HMDP Scholarship in 2003 to train at the University of Louisville, Kentucky, USA as a Clinical Fellow in Orthopaedic Sports Medicine. He was mentored by Professor David NM Caborn, a leading sports orthopaedic surgeon in the USA, with a special interest in the use of allograft tissues for sports reconstructive surgeries and in meniscus transplantations.
Dr Chang served as a Consultant Orthopaedic Surgeon in Changi General Hospital and as Deputy-Head of the Changi Sports Medicine Center (CSMC). He was instrumental in developing the Orthopaedic Sports Service in CSMC, eventually becoming the Director of Orthopaedic Sports Service in 2007. Among his many achievements was the setting up of the CSMC Anterior Cruciate Ligament (ACL) Programme in 2004, which has treated over 250 patients with anterior cruciate ligament injuries annually. Among his patients were National football players and S-League football players.
A firm believer in the need to contribute to teaching and training, Dr Chang is a Clinical Lecturer with the National University of Singapore. For his contribution to undergraduate medical teaching of orthopaedic surgery, he was awarded the "Best Orthopaedic Teacher" award for consecutive terms of 2003-2004 and 2005-2006. As the Director of the Orthopaedic Sports Medicine at Changi General Hospital, he has trained surgeons from the Asian region in Orthopaedic Sports Medicine. He has also organized cadaveric workshops in Shoulder Arthroscopy, Knee Double-Bundle Anterior Cruciate Ligament Reconstruction as well as Autologous Chondrocyte Transplantation to train both local and international orthopaedic surgeons in these advanced techniques.
Dr HC Chang performed the first Robotic Assisted Partial Knee Replacement (MAKOplasty) surgery at Mount Elizabeth Novena Hospital in 2013.
An avid researcher, Dr Chang has published over 20 peer-reviewed papers, a majority on Orthopaedic Sports Medicine in prestigious Sports Medicine journals such as the American Journal of Sports Medicine and the Arthroscopy Journal. Dr Chang has contributed a book chapter on "Allograft Anterior Cruciate Ligament Reconstruction" in the 4th edition of Insall and Scott Surgery of the knee, a "bible" for knee surgeons. He also co-authored a new surgical technique in double-bundle anterior cruciate ligament reconstruction. He has been invited to speak on many issues related to sports medicine, at local and international meetings. Dr Chang also serve in the Editorial Board of the Singapore Medical Journal.