We all know the end goal of a total knee arthroplasty (TKA)—pain relief and improved quality of life. But with the total price tag of the surgery and subsequent costs exceeding $57, 000, are patients really getting their money’s worth? Research led by Elena Losina, Ph.D., and colleagues at Brigham and Women’s Hospital and the Boston University of Public Health shows that, yes, the end result of a TKA is actually worth every penny, but the deciding variable in determining cost-effectiveness may have more to do with location than the actual patient.
Physicians use total knee arthroplasty to replace diseased or damaged surfaces of the knee joint using implants designed to retain motion of the knee. The most common cause of such damage is degenerative arthritis—chiefly osteoarthritis. As of 2007, according to PearlDiver research estimates, over 6.5 million patients suffer from osteoarthritis of the knee—of whom 4.1 million are over the age of 65. In addition, over 560, 000 TKA procedures were performed in the United States in 2007.
Each one of the patients who received a total knee arthroplasty expected to have an improved quality of life. According to the report titled “Cost-effectiveness of Total Knee Arthroplasty in the United States” published in the June 22 issue of Archives of Internal Medicine, researchers used a computer simulation model populated with Medicare claims data and cost and outcomes data to study projected lifetime costs and quality-adjusted life expectancy. From this model, the results indicated:
- Patients who received a TKA lived over one year longer in good health than those patients who did not receive a knee replacement.
- Lifetime costs for TKA patients increased $20, 800 over those patients who did not receive a TKA from $37, 100 to $57, 900.
- The cost per year of increased quality of life was $18, 300.
- Cost and effectiveness was directly related to the volume of knee arthroplasties performed by the facility.
The results lead Losina and colleagues to the conclusion that TKA is cost effective in the Medicare patient population across all risk groups. The one caveat mentioned with this conclusion is that the higher the procedure volume of the hospital, the better the expected results will be.
Further details available through PearlDiver research shed some light on these conclusions. Counter to expectations, the total charges for a TKA in 2007 on average showed no statistical difference between patients diagnosed with comorbidities such as diabetes or hypertension prior to the procedure and those who were not. Despite the increased chance of complications resulting from comorbidities during and after the procedure—the average total charges are seemingly not affected.
In addition, TKA procedures within the Medicare population are indeed impacted by the volume of procedures done by provider, and this impact is evident even on a macro-level. As shown in Table 1, the procedure volume ranking by state clearly reflects the relationship of volume and success. Nationwide, the highest incidence rate for revision of knee replacement in the Medicare population is 2.3% in the state of Hawaii. The second highest rate is in Delaware, which is slightly below 2.0%. Neither of these states is ranked in the top five by volume for TKA. Of the top states by volume for TKA, only one is even in the top 15 by rank of revision volumes. This story also holds true for knee implant failure.
Table1: State TKA Rank by Volume
|
State |
National Rank by Volume of Knee Replacements |
National Rank by Volume of Knee Revisions |
National Rank by Volume of Implant Failure |
|
Texas |
1 |
25 |
20 |
|
Florida |
2 |
13 |
9 |
|
California |
3 |
19 |
33 |
|
Ohio |
4 |
28 |
15 |
|
Pennsylvania |
5 |
21 |
30 |
|
Hawaii |
49 |
1 |
6 |
|
Delaware |
43 |
2 |
11 |
|
West Virginia |
36 |
3 |
1 |
|
Maryland |
17 |
4 |
8 |
|
Idaho |
38 |
5 |
2 |
|
West Virginia |
36 |
3 |
1 |
|
Idaho |
38 |
5 |
2 |
|
Wyoming |
51 |
44 |
3 |
|
Mississippi |
34 |
12 |
4 |
|
Virginia |
14 |
17 |
5 |
Source: PearlDiver Medpar Statistics, 2008 – Includes District of Columbia, Puerto Rico, and Virgin Islands
This week, PearlDiver is releasing the results of a study that studies the variability of charges by region of the country.
The most expensive region in the United States for a total knee replacement procedure is the West. According to PearlDiver data, the average insurance charge for a total knee replacement is $59, 000 as compared to, for example, $44, 000 in the Midwest.
This regional variability was also documented by PearlDiver for total hip replacements and partial hip replacements.
The variability of regional charges is becoming a significant public policy debating point since such variability appears to be disconnected from patient outcomes. In other words, more spending does NOT correlate with better patient outcomes. Indeed, evidence has emerged that the link between spending and patient outcomes is not only tenuous, at best, but may be random. In a seminal article in the New Yorker magazine “The Cost Conundrum” by Dr. Atal Gawande, which appeared this past May, Dr. Gawande visited McAllen, Texas, where he documented that higher rates of spending on diagnostic tests and procedures resulted in comparatively worse patient outcomes!
For copies of the soon to be published PearlDiver White Paper on this subject please email a request for a copy to meg@pearldiverinc.com.
The study further notes that policy decisions on TKA should be made based on locality. PearlDiver research data couldn’t agree more. So when deciding whether or not TKA is worth the hefty price tag, the real variable for cost-effectiveness is not who you are, but where you are.
