Summary

There are increasing rates of uncemented total knee arthroplasty, and younger patients, male patients, patients operated on more recently, patients with private insurance, and patients from certain regions in the United States are more likely to be implanted with an uncemented total knee arthroplasty.

Abstract

Introduction

Uncemented total knee arthroplasty (TKA) has become a viable option in recent years. While institutions may monitor their implant usage, the evolution of the use of uncemented technology has not been well describe on a national level in the United States. Therefore, we sought to characterize the use of cemented and uncemented TKA across the United States.

Methods

We searched IBM MarketScan database for patients who underwent primary TKA using a cemented or uncemented implant based on the International Classification of Diseases, Tenth Revision Procedure Coding System between 2018 and 2020. Records were reviewed for age, sex, date of TKA, laterality, region, length of stay, type of insurance, discharge, and net payments to hospitals and physicians. Chi-square and independent-samples t-test were used to compare groups. Multiple logistic regression was performed to establish risk factors for cemented or uncemented TKA. Significance was set at p<0.05.

Results

We identified a total of 62981 cemented and 5460 uncemented TKAs. The rate of uncemented TKAs increased from 6.46 percent (%) in 2018 to 10.78% in 2020 (p<0.001). Females were more likely to be implanted with a cemented TKA (59.6% vs 40.4%, p<0.001), and younger patients were more likely to receive an uncemented TKA (59.73 vs 61.45 years, p<0.001). There was no difference in the laterality between groups (p=0.448). Patients were more likely to receive an uncemented TKA if they were from the northeast (9.2%) or the south (9.1%) than if they were from the north central region (6.6%) or the west (5.8%, p<0.001). Patients implanted with an uncemented TKA had a shorter average length of stay (1.89 vs 2.02 days, p<0.001), and were more likely to be discharged home (49.7%) or home with services (44.3%, p=0.001).
Patients with private insurance were more likely to receive an uncemented TKA (83.9%) than patients who had Medicare supplemental insurance (16.1%, p<0.001). Net total payment did not differ between cemented and uncemented TKA ($29779.65 vs $29397.64, p=0.127), nor did the net hospital collection rate ($26352.25 vs $25920.79, p=0.127). However, physicians were reimbursed more for uncemented TKA than for cemented TKA ($2084.39 vs $1986.16, p=0.004).
Multiple logistic regression demonstrated that patients having surgery more recently (p<0.001), younger patients (p<0.001), male patients (p<0.001), privately insured patients (p<0.001), and the region that the patient was located all strongly predicted a higher chance of being implanted with an uncemented TKA.

Discussion

Although 92.0% of TKAs are still cemented, there is a trend towards increasing use of uncemented TKA from 2018 to 2020. Younger patients, males, patients with private insurance, patients who underwent TKA more recently, and patients in the northeast or south were more likely to be implanted with an uncemented TKA. Uncemented TKA was associated with a shorter length of stay and patients were more likely to be discharged home with or without services. While there was no difference between total or hospital reimbursement between cemented and uncemented TKA, physicians were reimbursed more for uncemented TKA. It is important for surgeons to understand the trends with evolving technology.