Projections of Primary TKA and THA in Germany From 2016 Through 2040

Abstract

Background: Future projections for both TKA and THA in the United States and other countries forecast a further increase of already high numbers of joint replacements. The consensus is that in industrialized countries, this increase is driven by demographic changes with more elderly people being less willing to accept activity limitations. Unlike the United States, Germany and many other countries face a population decline driven by low fertility rates, longer life expectancy, and immigration rates that cannot compensate for population aging. Many developing countries are likely to follow that example in the short or medium term amid global aging. Due to growing healthcare expenditures in a declining and aging population with a smaller available work force, reliable predictions of procedure volume by age groups are requisite for health and fiscal policy makers to maintain high standards in arthroplasty for the future population.Questions/purposes (1) By how much is the usage of primary TKA and THA in Germany expected to increase from 2016 through 2040? (2) How is arthroplasty usage in Germany expected to vary as a function of patient age during this time span?

Methods: The annual number of primary TKAs and THAs were calculated based on population projections and estimates of future healthcare expenditures as a percent of the gross domestic product (GDP) in Germany. For this purpose, a Poisson regression analysis using age, gender, state, healthcare expenditure, and calendar year as covariates was performed. The dependent variable was the historical number of primary TKAs and THAs performed as compiled by the German federal office of statistics for the years 2005 through 2016.

Results: Through 2040, the incidence rate for both TKA and THA will continue to increase annually. For TKA, the incidence rate is expected to increase from 245 TKAs per 100,000 inhabitants to 379 (297-484) (55%, 95% CI 21 to 98). The incidence rate of THAs is anticipated to increase from 338 to 437 (357-535) per 100,000 inhabitants (29% [95% CI 6 to 58]) between 2016 and 2040. The total number of TKAs is expected to increase by 45% (95% CI 14 to 8), from 168,772 procedures in 2016 to 244,714 (95% CI 191,920 to 312,551) in 2040. During the same period, the number of primary THAs is expected to increase by 23% (95% CI 0 to 50), from 229,726 to 282,034 (95% CI 230,473 to 345,228). Through 2040, the greatest increase in TKAs is predicted to occur in patients aged 40 to 69 years (40- to 49-year-old patients: 269% (95% CI 179 to 390); 50- to 59-year-old patients: 94% (95% CI 48 to 141); 60- to 69-year-old patients: 43% (95% CI 13 to 82). The largest increase in THAs is expected in the elderly (80- to 89-year-old patients (71% [95% CI 40 to 110]).

Conclusions: Although the total number of TKAs and THAs is projected to increase in Germany between now and 2040, the increase will be smaller than that previously forecast for the United States, due in large part to the German population decreasing over that time, while the American population increases. Much of the projected increase in Germany will be from the use of TKA in younger patients and from the use of THA in elderly patients. Knowledge of these trends may help planning by surgeons, hospitals, stakeholders, and policy makers in countries similar to Germany, where high incidence rates of arthroplasty, aging populations, and overall decreasing populations are present.

Level of evidence: Level III, economic and decision analysis.

Fig. 1

Germany's population since 2005 (solid blue line) and projected population through 2040 (dotted blue line), and Germany's historic and projected GDP (green line) are shown.

Fig. 2

The numbers of TKAs in Germany are shown. For both genders (blue = women [W]; red = men [M]), numbers from 2005 to 2016 and projected numbers (dashed lines) until 2040 are shown. The spread resulting from the statistical calculation increased with time for both genders.

Fig. 3

This figure shows the annual number of THAs in Germany. In addition to the current trend from 2005 to 2016, the projection of prosthetic implants until 2040 is shown for both genders (blue = women [W]; red = men [M]) (dashed line). The spread resulting from the statistical calculation increased with time for both genders.

Fig. 4

This figure shows the past and future numbers of TKAs by age group in 10-year increments. Especially in patients aged 40 to 60 years, an exponential increase in primary TKAs is expected by 2040. For people aged 60 to 69 years, we expect an initially steep increase in the number of procedures through 2034 followed by an annual decline.

Fig. 5

This figure shows the past and future numbers of primary THAs by age group in 10-year increments, beginning at the age of 20 years. Particularly in patients aged 70 to 90 years, an increase in the number of procedures can be expected in the next two decades.

Fig. 6

Germany's population projection broken down by age group in 10-year increments is shown.