A recent multi-country study might suggest so. Researchers compared the results of total knee replacement (TKR) in patients across three countries. This included the United Kingdom (UK), United States, and Australia. They found that patients in the UK waited an average of two years longer than patients anywhere else.
The delay may keep patients from getting the best results possible. Patients are treated on a first-come, first-served basis, not on the basis of severity of disease and symptoms. Another important factor in the UK is the lack of rehab. Most patients go home without rehab at the hospital or after discharge.
Before making this decision, check on finances. Your sister will need to know if her insurance will cover the cost of the care needed. There are many parts to this figure: doctor's fees (surgeon and anesthesiologist), hospital fees, rehab costs, and of course, travel.