A Missouri chiropractor who sold custom orthotic boots to nursing home residents claiming they would reduce falls was sentenced to more than four years in federal prison Wednesday.

Donald Havey sold the boots to nursing homes in Missouri, Texas, Alabama, California, Georgia, Illinois, Kentucky, Massachusetts, Mississippi, Oklahoma, Rhode Island and Tennessee through a “fall prevention program.” Havey and his associates said the boots would improve residents’ quality of life and reduce falls by 20%.

Authorities with the Department of Health and Human Services Office of Inspector General visited some of the facilities that purchased boots from Havey, and found staff had taken many away from residents because they were heavy and, in some cases, caused more falls, the St. Louis Post-Dispatch reported. Some residents also developed ulcers on their ankles from the boots.

Havey sold an estimated 600 pairs of boots between 2009 and 2014, authorities said. Each pair cost Medicare $2,400 to $2,600, and could cost residents up to $500 if they did not have supplemental insurance — a fact Havey left out when he was selling residents on the boots, according to the U.S. Attorney’s Office for the Eastern District of Missouri.

Havey’s wife and billing assistant Susan Reno was sentenced to five years of probation in January, and ordered to repay $10,571 to Medicare. The two pleaded guilty to one felony count of healthcare fraud and one misdemeanor count of submitting false reimbursement claims to Medicare, respectively, in October.

In addition to the prison sentence Havey must also repay close to $2.3 million to Medicare, Medicaid and private insurance companies.