Databyte: A Snapshot of Hip and Knee Replacements and Cost in Utah

By: Laurel Galli-Graves & Brantley Scott

According to the Centers for Medicare and Medicaid Services, hips and knees are the two most commonly replaced joints.[1] Both of these surgeries are done to reduce patient pain and increase mobility. Although it is most common for seniors to require hip and knee replacements, other age groups may also need this type of surgery.

In this DataByte, we examine the prevalence of hip and knee surgeries in Utah over the past three years by various patient demographics. Additionally, we look at the normal/average cost range for these surgeries and compare Utah readmission rates with the national average. Any noticeable trends or differences between years are identified.

Methodology

The cost information in this report comes from three years of data, 2018–2020, from both commercial and Medicare Advantage data in the Utah All Payers Claim Database (APCD). It should be noted that Medicare Fee for Service (FFS), which includes Medicare Part A, is not included in this analysis. As such, the number of procedures included for the senior population is fewer than the total number of hip and knee surgeries performed in the state. Hip and knee replacement claims were identified in the APCD by a Centers for Medicare & Medicaid Services (CMS) Diagnosis Related Group (DRG) code of “470.” The care quality information in this report comes from 2016–2019 CMS Hospital Readmissions Reduction Program (HRRP) data.[2]

More than 10,000 claims for hip and knee surgery were identified in the Utah APCD. Due to the reduction in procedures during the COVID-19 pandemic, about 80% of the claims come from 2018 and 2019; about 20% are from calendar year 2020 (see figure below). There was higher cost variation in 2020 than in other years observed.

Replacement Procedure Demographics

As the following graph depicts, females received more hip and knee replacement surgeries between 2018 and 2020 than males. This was true for every age group except the youngest group (patients ages 0 to 24), who collectively had only 22 surgeries throughout the three-year period. The largest grouping was females between ages 55 to 64, which represented 2,592 surgeries. This figure represents more than 500 more surgeries than males in the same age range.

While not all factors that contribute to this observable difference between males and females are known, these findings are consistent with a study based out of Ontario, Canada which identified that women surveyed had significantly higher rates of hip and knee arthritis.[3] Additionally, an article published by the Syracuse Orthopedic Specialists identified higher rates of knee replacements for females but similar rates of hip replacements for both sexes.[4]

Replacement Procedure Cost

The TRIA Research Institute identifies five key factors that affect the cost of a knee replacement surgery.[5] These include: 1) the patient’s insurance coverage, 2) the type of surgery the patient needs, 3) whether the patient receives inpatient or outpatient care, 4) whether the surgery takes place at a surgery center or hospital, and 5) the patient’s recovery plan. The effect of the first factor referenced, insurance coverage, can be seen in the graph below.

This graph illustrates the 25th percentile, median, and 75th percentile allowed amounts for commercial insurance and Medicare insurance. Commercial insurance has a larger overall interquartile range of allowed amounts, while Medicare insurers have a smaller interquartile range and lower amounts across years. The median of commercial insurance allowed amount trends down over time, while Medicare insurance allowed amounts trend slightly up each year.

Patients may be more concerned with trends in member liability amounts, since this measure reflects the costs patients may ultimately pay themselves. The graph below shows the member liability amounts for the same period and interquartile ranges for payers with Medicare and commercial insurance.

The member liability for commercial insurance has a larger and increasing interquartile range in comparison to the liability for Medicare insurance. This is a similar trend to the interquartile range depicted in the allowed amount graphic. Notably, in 2018, while commercial insurers demonstrated a much higher median allowed amount ($28,145) than their Medicare counterparts ($12,621), the amount their members were liable for was comparable ($572 versus $640). Since 2018, however, median liability amounts for commercial insurers has risen to $919 while it has fallen to $0 for Medicare payers. The 2020 Medicare median of $0 is likely an abnormality due to the COVID-19 pandemic.

Quality Measures for Utah Procedures

Separate from the cost associated with the procedure, another factor prospective hip or knee replacement patients may consider is the quality of outcome. Since the Utah All Payers Claim Database does not contain outcome information for procedures, the Centers for Medicare and Medicaid Services (CMS) Hospital Readmissions Reduction Program database was used to explore how Utah’s rates of readmissions after hip and knee replacements compare with the national average.[6] As depicted below, the Utah rate of readmission after hip and knee replacement was 3.5%, which is slightly lower than the national rate of 4%.

A 2019 study on complications following hip and knee replacement surgeries indicates there may also be a difference in outcomes between sexes.[7] The study found that while women experienced higher complication rates than men in general (especially urinary tract infections), men experienced higher rates of acute complications, including death, kidney injury, and cardiac arrest. Without access to similar statistics for the state of Utah specifically, our analysis is unable to determine whether these findings hold true for Utah patients as well.

Conclusion

Prospective hip and knee replacement patients may consider procedure cost as well as the possibility of readmission when deciding whether and where to have their surgeries. We hope these findings provide valuable information for these individuals, as well as open additional dialogue among stakeholders who find this information relevant. For additional information regarding individual hospital quality measures, please see: https://www.medicare.gov/care-compare/. For additional information regarding individual hospital commercial cost ranges, please see: https://opendata.utah.gov/Health/Common-Medical-Procedure-Prices-in-Utah/6c3e-vvdg.


[1] The Centers for Medicare & Medicaid Services. (2019, January 8). Major Joint Replacement (Hip and Knee). CMS.gov. Retrieved November 18, 2021, from https://www.cms.gov/medicare-coverage-database/view/lcd.aspx?LCDId=33618&ver=23&Date=&DocID=L33618&bc=iAAAABAAAAAA&.

[2] The Centers for Medicare & Medicaid Services. (2020, December 10). Hospital Readmissions Reduction Program. CMS.gov. Retrieved November 18, 2021, from https://data.cms.gov/provider-data/dataset/9n3s-kdb3.

[3] Hawker, G. A., Wright, J. G., Coyte, P. C., Williams, J. I., Harvey, B., Glazier, R., & Badley, E. M. (2000). Differences between men and women in the rate of use of hip and knee arthroplasty. New England Journal of Medicine, 342(14), 1016-1022.

[4] Greenky, B. B. (2015, April 21). Gender Differences in Joint Replacement. Syracuse Orthopedic Specialists. Retrieved November 18, 2021, from https://www.sosbones.com/news/gender-differences-in-joint-replacement/.

[5] The Cost of Knee Replacement Surgery: 5 Key Factors. TRIA. Retrieved November 18, 2021, from https://tria.com/cost-of-a-knee-replacement-surgery/.

[6] The Centers for Medicare & Medicaid Services. (2020, December 10). Hospital Readmissions Reduction Program. CMS.gov. Retrieved November 18, 2021, from https://data.cms.gov/provider-data/dataset/9n3s-kdb3.

[7] Basques, B. A., Bell, J. A., Fillingham, Y. A., Khan, J. M., & Della Valle, C. J. (2019). Gender differences for hip and knee arthroplasty: complications and healthcare utilization. The Journal of arthroplasty, 34(8), 1593-1597.