Hansen specializes in reconstructive, replacement and revision surgery of the hip and knee, and has expertise in the direct anterior hip approach for hip joint replacement. In his research, he focuses on the diagnosis, treatment and prevention of periprosthetic joint infection. Hansen earned a medical degree and completed an orthopedic surgery residency at UCSF. He served as a fellow in adult reconstructive surgery at the Rothman Institute at Thomas Jefferson University in Philadelphia. Hansen directs a total joint database and a periprosthetic infection database, and is an assistant professor in residence of orthopedic surgery.