Many knee replacement surgeries are unwarranted, researchers say.

The Centers for Medicare & Medicaid Services released two proposals last week that may change where beneficiaries receive joint replacements, and how accountable care organizations deal with the agency’s three-day stay rule waiver.

The first proposal, contained within a proposed rule concerning hospital outpatient prospective payments, would allow Medicare to cover knee replacement surgeries in outpatient facilities.

Research on conducting the procedures in outpatient settings has shown outpatients did not experience higher complication or readmission rates than inpatients, CMS said. If the rule were to be enacted, beneficiaries would still be able to undergo the procedures in an inpatient setting “based on the beneficiary’s individual clinical needs and preferences,” the agency said.

CMS also is soliciting public comment on possibly doing the same with hip replacements.

Allowing Medicare coverage of the procedures in an outpatient setting calls into question the future of CMS’ bundled payment initiatives for joint replacements, Modern Healthcare reported Friday, noting “the CMS rule appears to undermine that initiative.”

In a second proposal posted Thursday, CMS suggested changes to the three-day stay requirement waiver for patients receiving care from an ACO.

The changes would allow ACOs to apply for the SNF three-day rule waiver without having to submit documents describing any financial relationships between the organization, skilled nursing affiliates and acute care hospitals.

The proposal would still require that SNFs have three stars or more on the Five-Star Rating scale to receive patients as part of the waiver, but they would no longer have to submit documentation showing it.

The agency said its initial experiences reviewing applications to waive the rule showed those two requirements “impose an unnecessary burden on applicants, without a sufficient benefit to the administration of the Shared Savings Program to justify the burden.”

Comments on both of CMS’s proposed rules must be received by Sept. 11, 2017.