Before choosing the more costly in-patient option for rehabilitation after knee replacement surgery, consider out-patient rehab, which delivers results just as quickly, Justine Naylor wrote.

Most private patients who have had knee replacement surgery recover just as well with a cheaper form of rehabilitation than many are currently offered, research published in the Medical Journal of Australia showed.

The researchers found people who have had uncomplicated total knee arthroplasty recover just as fast and with similar outcomes after out-patient rehab – which involves people leaving hospital and having regular visits to a physiotherapist – rather than the costly in-patient option, where patients stay in hospital for their rehab.

In the public system, in-patient rehab is generally reserved for patients who are too frail to go home, who have no support at home, or have had complications after surgery. Most public patients attend rehab as an out-patient.

But in-patient rehab is more common for private patients, whose surgeon may offer it as an option.

While physiotherapy is the mainstay of formal rehab for both public and private patients, those who attend as an in-patient can also see other health professionals like rehab physicians, occupational therapists and nurses.

Private patients who choose in-patient rehab after knee surgery typically stay in hospital for seven to 14 days. This adds another A$9,500 or so to the median A$22,000 bill for the surgery itself. By comparison, we found rehab as an out-patient costs just a median A$374.

To find out which option gave private patients the best outcomes, the researchers conducted a national study involving privately insured people who had undergone uncomplicated total knee arthroplasty. We then compared the outcomes between people who had in-patient therapy with those who went straight home.

People with significant complications following surgery, who progressed slowly in the early days after surgery, and people with limited help at home, were excluded from our study.

To ensure we compared apples with apples, we matched people who went to in-patient rehab with those who did not on many characteristics including age, gender, body-mass index, and the severity of disease before surgery.

We phoned people 35, 90 and 365 days after surgery and asked for details about their recovery and the types of rehabilitation they had.

People who received in-patient therapy reported similar knee-joint pain, and similar function and quality of life. Patients and their carers also took the same time off work regardless of the rehab option.

Median rehab costs for those who had in-patient therapy (A$9,978) were also much higher than costs for those who did not (A$374). The higher costs were due to the in-patient component, but, interestingly, also slightly more community-based therapy.

The main implication of the study is, given the cost difference between rehabilitation options, community-based (non-inpatient) alternatives seem to be better value.