The epidemiology of bearing surface usage in total hip arthroplasty in the United States.
BACKGROUND
Hard-on-hard bearings offer the potential to improve the survivorship of total hip arthroplasty implants. However, the specific indications for the use of these advanced technologies remain controversial. The purpose of this study was to characterize the epidemiology of bearing surface utilization in total hip arthroplasty in the United States with respect to patient, hospital, geographic, and payer characteristics.


METHODS
The Nationwide Inpatient Sample database was used to analyze bearing type and demographic characteristics associated with 112,095 primary total hip arthroplasties performed in the United States between October 1, 2005, and December 31, 2006. The prevalence of each type of total hip arthroplasty bearing was calculated for population subgroups as a function of age, sex, census region, payer class, and hospital type.


RESULTS
The most commonly reported bearing was metal-on-polyethylene (51%) followed by metal-on-metal (35%) and ceramic-on-ceramic (14%). Metal-on-polyethylene bearings were most commonly reported in female Medicare patients who were sixty-five to seventy-four years old, while metal-on-metal and ceramic-on-ceramic bearings were most commonly reported in privately insured male patients who were less than sixty-five years old. Thirty-three percent of patients over sixty-five years old had a hard-on-hard bearing reported. There was substantial regional variation in bearing usage; the highest prevalence of metal-on-polyethylene bearings was reported in the Northeast and at nonteaching hospitals, and the highest prevalence of metal-on-metal bearings was reported in the South and at teaching hospitals.


CONCLUSIONS
The usage of total hip arthroplasty bearings varies considerably by patient characteristics, hospital type, and geographic location throughout the United States. Despite uncertain advantages in older patients, hard-on-hard bearings are commonly used in patients over the age of sixty-five years. Further study is necessary to define the appropriate indications for these advanced technologies in total hip arthroplasty.
Bozic
Kevin J
KJ
Department of Orthopaedic Surgery and Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco, 500 Parnassus Avenue, MU 320W, San Francisco, CA 94143-0728. bozick@orthosurg.ucsf.edu.
Kurtz
Steven
S
Lau
Edmund
E
Ong
Kevin
K
Chiu
Vanessa
V
Vail
Thomas P
TP
Rubash
Harry E
HE
Berry
Daniel J
DJ
D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D002516:Ceramics; D003625:Data Collection; D005260:Female; D006622:Hip Prosthesis / Q000706:statistics & numerical data*; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D014481:United States
D008670:Metals; D020959:Polyethylene