Lifetime medical costs of knee osteoarthritis management in the United States: impact of extending indications for total knee arthroplasty.

OBJECTIVE: The impact of increasing utilization of total knee arthroplasty (TKA) on lifetime costs in persons with knee osteoarthritis (OA) is understudied. METHODS: We used the Osteoarthritis Policy Model to estimate total lifetime costs and TKA utilization under a range of TKA eligibility criteria among US persons with symptomatic knee OA. Current TKA utilization was estimated from the Multicenter Osteoarthritis Study and calibrated to Health Care Cost and Utilization Project data. OA treatment efficacy and toxicity were drawn from published literature. Costs in 2013 dollars were derived from Medicare reimbursement schedules and Red Book Online. Time costs were derived from published literature and the US Bureau of Labor Statistics. RESULTS: Estimated average discounted (3% per year) lifetime costs for persons diagnosed with knee OA were $140,300. Direct medical costs were $129,600, with $12,400 (10%) attributable to knee OA over 28 years. OA patients spent a mean ± SD of 13 ± 10 years waiting for TKA after failing nonsurgical regimens. Under current TKA eligibility criteria, 54% of knee OA patients underwent TKA over their lifetimes. Estimated OA-related discounted lifetime direct medical costs ranged from $12,400 (54% TKA uptake) when TKA eligibility was limited to Kellgren/Lawrence grades 3 or 4 to $16,000 (70% TKA uptake) when eligibility was expanded to include symptomatic OA with a lesser degree of structural damage. CONCLUSION: Because of low efficacy of nonsurgical regimens, knee OA treatment-attributable costs are low, representing a small portion of all costs for OA patients. Expanding TKA eligibility increases OA-related costs substantially for the population, underscoring the need for more effective nonoperative therapies.

Estimating the burden of total knee replacement in the United States.

BACKGROUND: In the last decade, the number of total knee replacements performed annually in the United States has doubled, with disproportionate increases among younger adults. While total knee replacement is a highly effective treatment for end-stage knee osteoarthritis, total knee replacement recipients can experience persistent pain and severe complications. We are aware of no current estimates of the prevalence of total knee replacement among adults in the U.S. METHODS: We used the Osteoarthritis Policy Model, a validated computer simulation model of knee osteoarthritis, and data on annual total knee replacement utilization to estimate the prevalence of primary and revision total knee replacement among adults fifty years of age or older in the U.S. We combined these prevalence estimates with U.S. Census data to estimate the number of adults in the U.S. currently living with total knee replacement. The annual incidence of total knee replacement was derived from two longitudinal knee osteoarthritis cohorts and ranged from 1.6% to 11.9% in males and from 2.0% to 10.9% in females. RESULTS: We estimated that 4.0 million (95% confidence interval [CI]: 3.6 million to 4.4 million) adults in the U.S. currently live with a total knee replacement, representing 4.2% (95% CI: 3.7% to 4.6%) of the population fifty years of age or older. The prevalence was higher among females (4.8%) than among males (3.4%) and increased with age. The lifetime risk of primary total knee replacement from the age of twenty-five years was 7.0% (95% CI: 6.1% to 7.8%) for males and 9.5% (95% CI: 8.5% to 10.5%) for females. Over half of adults in the U.S. diagnosed with knee osteoarthritis will undergo a total knee replacement. CONCLUSIONS: Among older adults in the U.S., total knee replacement is considerably more prevalent than rheumatoid arthritis and nearly as prevalent as congestive heart failure. Nearly 1.5 million of those with a primary total knee replacement are fifty to sixty-nine years old, indicating that a large population is at risk for costly revision surgery as well as possible long-term complications of total knee replacement.

Lifetime risk and age at diagnosis of symptomatic knee osteoarthritis in the US.

OBJECTIVE: To estimate the incidence and lifetime risk of diagnosed symptomatic knee osteoarthritis (OA) and the age at diagnosis of knee OA based on self-reports in the US population. METHODS: We estimated the incidence of diagnosed symptomatic knee OA in the US by combining data on age-, sex-, and obesity-specific prevalence from the 2007-2008 National Health Interview Survey, with disease duration estimates derived from the Osteoarthritis Policy (OAPol) Model, a validated computer simulation model of knee OA. We used the OAPol Model to estimate the mean and median ages at diagnosis and lifetime risk. RESULTS: The estimated incidence of diagnosed symptomatic knee OA was highest among adults ages 55-64 years, ranging from 0.37% per year for nonobese men to 1.02% per year for obese women. The estimated median age at knee OA diagnosis was 55 years. The estimated lifetime risk was 13.83%, ranging from 9.60% for nonobese men to 23.87% in obese women. Approximately 9.29% of the US population is diagnosed with symptomatic knee OA by age 60 years. CONCLUSION: The diagnosis of symptomatic knee OA occurs relatively early in life, suggesting that prevention programs should be offered relatively early in the life course. Further research is needed to understand the future burden of health care utilization resulting from earlier diagnosis of knee OA.