A Cherry Hill doctor and his chiropractor son pleaded guilty Tuesday in U.S. District Court in Camden to conspiring to defraud Medicare.

Federal prosecutors said Robert Claude McGrath, 65, and his son, Robert Christopher McGrath, 47, also of Cherry Hill, operated Atlantic Spine & Joint Institute in Westmont, N.J., and Wayne, Pa., and from January 2011 through April 2016, they used unqualified people to perform physical therapy on Medicare patients and then fraudulently identified the elder McGrath in Medicare billings as having done the work.

The McGraths and their practice have agreed to pay $1.78 million as part of a civil settlement of their case. The father and son each face a maximum 10 years in prison. They are scheduled to be sentenced on Sept. 19.

"Elderly patients who need physical therapy deserve properly licensed and supervised caregivers," said Acting U.S. Attorney William E. Fitzpatrick.