Abstract
The comprehensive care for joint replacement model from the Center for Medicare and
Medicaid Services and similar programs from other payers make hospitals and health
care systems more responsible for better clinical and economic outcomes of total hip
arthroplasty (THA) patients. The objective of the study was to evaluate hospital-related
clinical and economic outcomes of using the cementless R3 cup and Polarstem with an
oxidized zirconium bearing compared with other cementless hip systems using a ceramic
bearing in THA patients. We retrospectively reviewed primary THA patients from the
premier perspective database between 2014 and 2018Q3. Patients with R3 cup and Polarstem
with an oxidized zirconium bearing were identified using appropriate keywords from
billing records and compared against cementless and ceramic-on-polyethylene (CoP)
THA patients who did not meet the keywords' criteria. Patients were excluded if they
were < 21 years of age; outpatient hospital discharges; evidence of revision THA;
bilateral THA in same discharge or different discharges. 1:3 propensity score matching
was used to control patients' demographic, clinical, and hospital characteristics.
Generalized estimating equation model with appropriate distribution and link function
was used to estimate hospital-related cost while logistic regression models were used
to estimate discharged status, transfusion, and 30-days readmission. The study matched
818 R3/Polarstem with oxidized zirconium bearing patients with 2,454 CoP cementless
THA patients. Length of stay for the R3/Polarstem patients (mean = 1.61 days; confidence
interval [CI] = 1.41–1.80) was significantly lower (p-value ≤ 0.0001) than CoP THA patients (mean = 2.06 days; CI = 1.95–2.17). R3/Polarstem
hip patients were 36% (odds ratio [OR] = 1.36; CI = 1.07–1.72; p-value = 0.0112) more likely to be discharged to home/home health care, 18% (OR = 0.82;
CI = 0.63–1.06; p-value = 0.1235) less likely to be discharged to a skilled nursing facility (SNF),
84% less likely to have transfusion (OR = 0.16; CI = 0.09–0.29; p-value ≤ 0.0001), and 44% (OR = 0.56; CI = 0.32–0.98; p-value = 0.0412) less likely to readmitted within 30 days than CoP THA patients. Mean
total hospital costs was marginally higher for R3/Polarstem patients (mean = $15,611;
vs. $15,002; p-value = 0.0041) than CoP THA patients. While the total hospital costs for the R3/Polarstem
was higher than CoP, the reduced length of stay, reduced discharge to SNF, and lower
readmission rates can help to save money in the bundled payment and make the use of
certain cementless hip systems a potential cost saving solution.
Keywords
oxidized zirconium hip implant - length of stay - discharge status - total hospital
cost
