Medicare’s readmission reduction is program is helping reduce the number of seniors readmitted to the hospital following joint replacement surgery, a new report from AARP has found.

The report, which examined hospital readmission rates between 2009 and 2013, suggests falling readmission rates for hip and knee replacements can be attributed to the Centers for Medicare & Medicaid Service’s Hospital Readmissions Reduction Program. The program fines hospitals that have “excessive” readmission rates for Medicare beneficiaries with specific conditions, including heart attacks, pneumonia and joint replacements.

In that five-year timespan, readmission rates for hip replacements in adults between the ages 50 and 84 fell by 20%, the report found. The rates for knee replacements in the same age group dropped by 23%.

The readmission reductions come despite the increasing number of joint replacement surgeries in the 50 to 84 age group. Between 2009 and 2013, the number of seniors who had hip replacements increased by 73%; the number of knee replacements rose 46% in the same time period.