He joined the PGIMER in 1987 as a senior resident,and went on to become one of the longest serving Heads of the Orthopaedics Department. He also headed the Physical Medicine and Rehab department from 2009 to 2024.

He was instrumental in starting a Sports Medicine Clinic in the 1990s, a Foot and Ankle clinic in 2000s, Regenerative Orthopaedics Facility in the 2010s and an Amputee Rehab clinic in the 2020s, all of which were first of their kind patient care facilities in the country.

During his tenure the Orthopaedic department expanded tremendously and he has mentored many youngsters into super specialists in their own right, as the department now offers all types of treatments ranging from arthroplasty to sports medicine to spinal surgery and paediatric orthopaedics.

Professor Dhillon was one of the first sports medicine specialists in North India and was the first one to start arthroscopy and ACL reconstructions in North India, as early as 1990.He went on to become the President of the Indian Assn of Sports Medicine and was associated with many National and International sports teams, like the Indian Hockey team, SriLanka Cricket team, regional Cricket teams and all the regional sports associations, being a consultant to BCCI, Sports authority of India, Indian Gymnastic association etc.

Dr Dhillon is a pioneer in Regenerative Orthopaedics and was one of the first surgeons to start using PRP and other kind of orthobiological substances as early as 2009. He founded, and became President of, the Indian Ortho Biologics Society, and has represented India in many conferences on regenerative medicine around the world.

Prof Dhillon went on to become the President of many OrthopaedicAssociations in India including the Indian Orthopaedic Association, the Indian Foot and Ankle society, the Indian Arthroplasty Association among others.