There remains some confusion around Medicare’s coverage of maintenance physical therapy. The general idea is that if a skilled service is required to prevent decline in a person’s condition, then the service is now covered under Medicare.
The following is from the Center for Medicare Advocacy website:

SERVICES FOR BENEFICIARIES WITH CHRONIC CONDITIONS

A chronic condition requiring skilled care services can take many forms and is not limited to a particular set of disease, diagnosis, or disabling conditions.

COVERAGE REQUIREMENTS

The Medicare program recognizes the need for skilled care and related services for chronic, long-term conditions.  For care to be covered, the patient must require skilled services which may be designed to:

  • Maintain the status of a medical condition or the functioning of a body part; or
  • Slow or prevent the deterioration of a medical condition or body part.

WHERE ARE SERVICES PROVIDED?

Services can be provided in a variety of settings – at home, through Medicare certified home health agencies, in Medicare certified outpatient facilities, rehabilitation hospitals and centers, and in Medicare certified skilled nursing facilities.

WHO PROVIDES SKILLED SERVICES?

Skilled services are those services provided by (or under the supervision of) technical or professional personnel such as registered nurses, licensed practical nurses, physical therapists, occupational therapists, speech pathologists, and audiologists. Services must be a type that are not ordinarily performed by non-skilled personnel.

More information may be found at

http://www.medicareadvocacy.org/medicare-info/chronic-conditions/#Coverage%20Requirements