**5. The present: current results**

Arthroplasties are currently among the most practiced surgeries in the world. Routinely, thousands of patients undergo this type of intervention daily in almost every country around the world. This is possible thanks to the effective and safe results obtained with the technique and the great impact on the recovery of people's quality of life.

The safety and effectiveness of the technique can be verified through data collected in large cohorts, called registries, available in many countries around the world. There are local, regional, and national registries. Four registries stand out as the main forces behind the effort to popularize the concept of evidence-based medicine: the Mayo Registry and the Harris registry are important institutional registries in the United States; while among national registries, both the Swedish Knee Registry and Hip Registry [10].

A total estimated 630,000 hip replacement procedures were performed in the United States in 2017. For total knee replacement, the increasing incidence of TKA is a universal phenomenon. In 2017, the United States had 911,000 total knee procedures performed [11].
