If you need a medical procedure (e.g. hip or knee replacement) you are entitled to have this done in any EU country and have the fee reimbursed promptly by the HSE. This applies to almost any medical procedure approved in Ireland. At present, there can be long waiting lists for many procedures.
In December 2014, there were almost 400,000 people on the outpatients waiting list. Of this figure 60,000 patients were waiting longer than 12 months. For Inpatient treatment, there are almost 70,000 people waiting, with 10,000 waiting longer than 6 months. Source of above data: http://www.ntpf.ie/home/outpatient.htm
You don’t need to be on a waiting list or to wait for years to have this done.
“The freedom to receive health services throughout the European Union must be accompanied by guarantees of quality and security. In order to make an informed choice, patients must be able to access all the information they require on the conditions under which they will receive healthcare in another EU Member State and the conditions under which they will be reimbursed once they return home”.