When and how do prosthetic hips fail after total hip arthroplasties?-A retrospective study.
OBJECTIVE
Understanding failure modes, time to revision, and vulnerable components in revision hips could help reduce the risk of revision surgeries. Our aim was to investigate the association between the index diagnosis and the failure mode in patients undergoing revision surgeries.


METHODS
A total of 402 patients who underwent a first revision surgery in a single hospital between 2000 and 2012 were recruited in a retrospective study. Multiple logistic regression analysis was used to evaluate the association of the index diagnosis of the primary total hip arthroplasty and short-term failure, as well as specific failure mode that occurred early, while controlling for sex, age, and the type of prosthesis.


RESULTS
The mean time to revision due to all failure modes was 9.48 (standard deviation = 6.08) years. Defining short-term failure as a time to revision <5 years after total hip arthroplasty, the primary failure mode was infection (32.4%), followed by loosening (25.7%) and instability (17.1%). In multivariate analysis, as compared to osteonecrosis, patients with index diagnosis as infection was significantly associated with revision due to infection (odds ratio = 9.69, p = 0.013). In addition, osteoarthritis increased the odds of loosening (odds ratio = 4.18, p = 0.012). In contrast to studies in the United States and Europe, acetabular component revisions were the most common type found in our study.


CONCLUSIONS
This study demonstrates that, compared with patients with osteonecrosis, patients with infection and osteoarthritis had higher odds of revision due to infection and loosening, respectively. Further studies are needed to examine the cause-effect relationship between index diagnosis and mode of failure.
Department of Orthopedics, Buddhist Tzu Chi General Hospital, Hualien, Taiwan; Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.
Kuan-Lin
KL
Liu
Department of Orthopedics, Buddhist Tzu Chi General Hospital, Hualien, Taiwan; School of Medicine, Tzu Chi University, Hualien, Taiwan.
Wen-Tien
WT
Wu
Department of Medical Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.
Jen-Hung
JH
Wang
Department of Orthopedics, Buddhist Tzu Chi General Hospital, Hualien, Taiwan; School of Medicine, Tzu Chi University, Hualien, Taiwan.
Tzai-Chiu
TC
Yu
Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan; Department of Public Health, College of Medicine, Tzu Chi University, Hualien, Taiwan. Electronic address: shwen@mail.tcu.edu.tw.
Shu-Hui
SH
Wen
Department of Orthopedics, Buddhist Tzu Chi General Hospital, Hualien, Taiwan; School of Medicine, Tzu Chi University, Hualien, Taiwan. Electronic address: ing.ho@msa.hinet.net.
Ing-Ho
IH
Chen
D000077:Acetabulum / Q000601:surgery; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015207:Osteoarthritis, Hip / Q000601:surgery*; D010020:Osteonecrosis / Q000601:surgery*; D011475:Prosthesis Failure; D012086:Reoperation / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D013624:Taiwan; D013997:Time Factors
failure modes; infection; osteonecrosis; time to revision; total hip arthroplasty