Dr Ryan's research interests have been varied down the years, underlying his surgical training and anatomical expertise. Previously, his interests have centred on the use of ileal conduits in patients with bladder cancer and the epidemiology of peptic ulcer disease. He has also assessed the incidence of physical abnormalities in long stay psychiatric patients.
More recently, Dr Ryan's research is linked with sports medicine. He has performed a prospective study of injuries sustained by rugby players over two years. He has also analysed the prevalence of injuries to the zygomatic arch, related to dentistry.
Dr Ryan also maintains an interest in the pathology of nerve compression syndromes at the head of the fibula. He is currently initiating a study on the anterior compartment of the leg to assess the role of the tibialis anterior muscle in compartment syndromes.