Incidence of hip replacement among national health insurance enrollees in Taiwan

Abstract

Background: There is no national joint replacement registry in the country of Asia and reports of national outcomes of joint replacement in Asia as yet. Therefore, this study was then to report a national data of the number of hip replacements, incidence rate, demographic characteristics of hip replacement patients, and short-time survival rate after hip replacement of Han Chinese in Taiwan.

Methods: We analyzed 105,688 cases of hip replacements (including primary partial hip replacement, primary total hip replacement and revision of hip replacement) from National Health Insurance research database between 1996 and 2004. The survival rate of primary hip replacement was estimated for each disease by the Kaplan-Meier method.

Results: Average annual number of primary partial hip replacement and primary total hip replacement were 4,257 and 6,206 cases, respectively. The most two common diagnosis of primary partial hip replacement were femoral neck fractures (73.6%, 34% men, mean age 76 years) and avascular necrosis (18.0%, 84% men, mean age 48 years). In primary total hip replacements, the most two common diagnosis were avascular necrosis (46.9%, 79% men, mean age 50 years) and osteoarthrosis (41.6%, 43% men, mean age 60 years). Both the number of primary partial hip replacements and primary total hip replacements increased steadily between 1996 and 2004. The cumulative survival of primary partial hip replacements and primary total hip replacements in all patients were 93.97% and 79.47% in 9 years follow-up, respectively.

Conclusion: Avascular necrosis is the main disease in total hip replacement in Taiwan. The epidemiology of hip diseases was different between Han Chinese (in Taiwan) and Caucasian and the number of hip replacements increased substantially in Taiwan between 1996 and 2004.

Figure 1

Number of hip replacements recorded in the NHI research database 1996–2004.

Figure 2

Distribution of diagnosis by age, there were 94,182 observations in 1996–2004.

Figure 3

Distribution of age and gender in Taiwan who undertaken (a) primary PHR and (b) primary THR in 1996–2004.

Figure 4

Annual proportion of patients who aged 65 years old (retired on merit) and received (a) primary PHR or (b) primary THR.

Figure 5

Cumulative survival of (a) primary PHR and THR in all patients, (b) primary PHR in elder and young patients, (c) primary PHR in FNF, AVN and OA patients, (d) primary THR in elder and young patients, and (e) primary THR in FNF, AVN and OA patients.