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Inpatient Rehab After Knee Surgery – a Rort?

Why are Australians having rehabilitation as an inpatient after their total knee replacements rather than as an outpatient at a rate higher than any other country in the world?

And why are our rates of inpatient rehabilitation as opposed to community or home-based rehab increasing?

That’s what researchers were investigating in a study just published in the MJA.

Could it be inpatient rehab was associated with better health outcomes for the patient than the other options? Or were patients too complex, lived too far away or needed greater supervision to allow them to have their rehab off-site?

As it turns out, the reason inpatient rehabilitation rates are increasing has much more to do with private hospitals being able to access funding than any patient factors.

According to the study authors, more than 50,000 total knee replacement operations were performed in Australia in 2016, about 70% of which took place in a private hospital.

In that year, 2016, 45% of patients underwent inpatient rehabilitation following surgery. This represents a substantial increase from the 31% who had the same inpatient service back in 2009. This bucks an international trend.

“Inpatient rehabilitation rates in the United States decreased from a peak of 35% in 2003 to 11% in 2009, with a mean rate during 2009-2014 of 15%,” the researchers said.

Randomised controlled trials have failed to show the functional improvements achieved through inpatient rehabilitation are superior to those achieved with home- or community-based rehabilitation. However, the cost was significantly more. A recent analysis including almost 260 privately insured patients at 12 Australian hospitals put the cost differential at an average of $9500.

And even though the mean age for patients undergoing inpatient rehab was slightly higher than for those who did not (71.0 vs 67.3 years), and they were more likely to have comorbidities and live alone, the study authors said the differences didn’t explain the wide variation in admission rates from hospital to hospital.

“Patients in hospitals with high rates of inpatient rehabilitation were similar to those in hospitals with low rates, eliminating patient complexity as the reason,” they said.

It seems the greatest determinant of whether a person had inpatient rehabilitation was the hospital in which the total knee replacement took place.

“This factor was substantially more important than the clinical profile of the patient,” the study authors said.

They suggested some private hospitals were encouraging inpatient rehabilitation because they were able to access funding on a per day basis for the rehab, in addition to the payment received for the knee surgery.

The study authors concede it is an attractive business model, but while these hospitals may be offering excellent rehab in terms of services and facilities, it all comes at a cost ‘that, for many patients, is not justified by better outcomes.’

They suggest the proportion of patients receiving inpatient rehabilitation after a total knee replacement could be reduced, improving health care efficiency without harming health outcomes.

“Reducing low value care will require system-level changes to guidelines and incentives for hospitals, as hospital-related factors are the major driver of variation in inpatient rehabilitation practices,” they concluded.



Schilling C, Keating C, Barker A, Wilson SF, Petrie D,  Predictors of inpatient rehabilitation after total knee replacement: an analysis of private hospital claims data. Med J Aust. 2018 August 27. 209(5): 222-7. Available from: https://www.mja.com.au/journal/2018/209/5/predictors-inpatient-rehabilitation-after-total-knee-replacement-analysis doi:10.5694/mja17.01231