Revision total hip arthoplasty: factors associated with re-revision surgery.
BACKGROUND
The survivorship of implants after revision total hip arthroplasty and risk factors associated with re-revision are not well defined. We evaluated the re-revision rate with use of the institutional total joint replacement registry. The purpose of this study was to determine patient, implant, and surgeon factors associated with re-revision total hip arthroplasty.


METHODS
A retrospective cohort study was conducted. The total joint replacement registry was used to identify patients who had undergone revision total hip arthroplasty for aseptic reasons from April 1, 2001, to December 31, 2010. The end point of interest was re-revision total hip arthroplasty. Risk factors evaluated for re-revision total hip arthroplasty included: patient risk factors (age, sex, body mass index, race, and general health status), implant risk factors (fixation type, bearing surface, femoral head size, and component replacement), and surgeon risk factors (volume and experience). A multivariable Cox proportional hazards model was used.


RESULTS
Six hundred and twenty-nine revision total hip arthroplasties with sixty-three (10%) re-revisions were evaluated. The mean cohort age (and standard deviation) was 57.0 ± 12.4 years, the mean body mass index (and standard deviation) was 29.5 ± 6.1 kg/m(2), and most of the patients were women (64.5%) and white (81.9%) and had an American Society of Anesthesiologists score of <3 (52.9%). The five-year implant survival after revision total hip arthroplasty was 86.8% (95% confidence interval, 83.57% to 90.25%). In adjusted models, age, total number of revision surgical procedures performed by the surgeon, fixation, and bearing surface were associated with the risk of re-revision. For every ten-year increase in patient age, the hazard ratio for re-revision decreases by a factor of 0.72 (95% confidence interval, 0.58 to 0.90). For every five revision surgical procedures performed by a surgeon, the risk of revision decreases by a factor of 0.93 (95% confidence interval, 0.86 to 0.99). At the time of revision, a new or retained cemented femoral implant or all-cemented hip implant increases the risk of revision by a factor of 3.19 (95% confidence interval, 1.22 to 8.38) relative to a retained or new uncemented hip implant. A ceramic on a highly cross-linked polyethylene bearing articulation decreases the hazard relative to metal on highly cross-linked polyethylene by a factor of 0.32 (95% confidence interval, 0.11 to 0.95). Metal on constrained bearing increases the hazard relative to metal on highly cross-linked polyethylene by a factor of 3.32 (95% confidence interval, 1.16 to 9.48).


CONCLUSIONS
When evaluating patient, implant, and surgical factors at the time of revision total hip arthroplasty, age, surgeon experience, implant fixation, and bearing surfaces had significant impacts on the risk of re-revision.
Department of Orthopaedic Surgery, Southern California Permanente Medical Group, 6041 Cadillac Avenue, Los Angeles, CA 90034. E-mail address for M. Khatod: Monti.X.Khatod@kp.org.
Monti
M
Khatod
Surgical Outcomes and Analysis, Kaiser Permanente, 8954 Rio San Diego Drive, Suite 406, San Diego, CA 92108.
Guy
G
Cafri
Surgical Outcomes and Analysis, Kaiser Permanente, 8954 Rio San Diego Drive, Suite 406, San Diego, CA 92108.
Maria C S
MC
Inacio
Surgical Outcomes and Analysis, Kaiser Permanente, 8954 Rio San Diego Drive, Suite 406, San Diego, CA 92108.
Alan L
AL
Schepps
Surgical Outcomes and Analysis, Kaiser Permanente, 8954 Rio San Diego Drive, Suite 406, San Diego, CA 92108.
Elizabeth W
EW
Paxton
Department of Orthopaedic Surgery, The Permanente Medical Group, 280 MacArthur Boulevard, Oakland, CA 94611.
Stefano A
SA
Bini
D019644:Arthroplasty, Replacement, Hip / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005260:Female; D006622:Hip Prosthesis / Q000145:classification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012042:Registries; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States