Meta-analysis of sonication prosthetic fluid PCR for diagnosing periprosthetic joint infection
Meta-analysis of sonication prosthetic fluid PCR for diagnosing periprosthetic joint infection
Kan Liu 1 2 3
Jun Fu 2 3
Baozhan Yu 2 3
Wei Sun 0 3
Jiying Chen 2 3
Libo Hao 2 3
0 Department of Intensive Care Unit, Nanyuan Hospital , Beijing , China
1 Department of Orthopedics, Beijing University of Chinese Medicine Third Affiliated Hospital , Beijing , China
2 Department of Orthopedics, General Hospital of Chinese People's Liberation Army , Beijing , China
3 Editor: Jaime Esteban, IIS-Fundacion Jimenez Diaz , SPAIN
Periprosthetic joint infection (PJI) is a catastrophic complication following total joint arthroplasty. Until now, the diagnosis of PJI is still confronted with difficulties, which is characterized by technical limitations. The question of whether sonication fluid PCR can provide high value in the diagnosis of PJI remains unanswered. This meta-analysis included 9 studies that evaluated PCR assays of sonication fluid for the diagnosis of PJI. The pooled sensitivity, specificity, Positive likelihood ratio (PLR), Negative likelihood ratio (NLR) and Diagnostic odds ratio (DOR) were 0.75 (95% confidence interval [CI], 0.71 to 0.81), 0.96 (CI, 0.94 to 0.97), 18.24 (CI, 6.07 to 54.78), 0.27 (CI, 0.20 to 0.36) and 86.97 (CI, 37.08 to 203.97), respectively. The AUC value of the SROC was 0.9244 (standard error, 0.0212). Subgroup analyses showed that use of multiplex PCR and may improve sensitivity and specificity. The results of this meta-analysis showed that PCR of fluid after sonication is reliable and of great value in PJI diagnosis.
Data Availability Statement: All relevant data are
within the paper and its Supporting Information
Funding: This work was funded by the National
Natural Science Foundation of China (NSFC)
(81672192). The funders had no role in study
design, data collection and analysis, decision to
publish, or preparation of the manuscript.
Competing interests: The authors have declared
that no competing interests exist.
The rise in the number of total joint arthroplasty performed worldwide could result in an
increasing number of complications, the most catastrophe of these include periprosthetic joint infection
(PJI), with an incidence of 1 to 12% [
]. PJI poses a significant burden on patients, surgeons, and
the healthcare economy. Early treatment requires early detection and identification of the
infectious agent. Unfortunately, diagnosis of infection is difficult and challenging in many cases .
Several studies have assessed the diagnostic value of PJI, including PCR techniques of
implant sonication samples [4±5]. However, the true diagnostic capabilities of these tests
remain controversial and inconsistent. Therefore, we performed a meta-analysis to evaluate
the detection validity of sonication fluid PCR in the diagnosis of PJI to provide further
evidence for its clinical use.
Material and methods
The methodological approach to evidence searching and synthesis described in this protocol
was conducted according to the Cochrane Collaboration's Diagnostic Test Accuracy methods
]. In our study, we performed a literature search, screened the studies identified, and
evaluated the studies that related to application of sonication fluid PCR in PJI diagnosis.
We searched electronic databases including PubMed, EMBASE, Cochrane Library, Web of
Science, Science Direct and OVID for articles that were published from the time of database inception
to June 2017, using the following medical subject headings (MeSH) or keywords: ªperiprosthetic
joint infection OR prosthesis-related infectionsº ªseptic looseningº, ªaseptic looseningº,
ªsonication OR sonicate OR ultrasoundº, ªPCR OR polymerase chain reactionº. We also manually
searched the reference lists of eligible studies and review articles. Animal-only studies and studies
that do not report data on the diagnostic performance of our target index were excluded.
Our reviewers independently evaluated the selected studies according to the following
inclusion criteria: (1) the study assessed the accuracy of sonication fluid PCR for the diagnosis of
PJI compared with the presence of a sinus tract communicating with the prosthesis, the visible
purulence of the synovial fluid or surgical site, simultaneously obtained microbiological
cultures from at least two periprosthetic tissue samples or acute inflammation in the
histopathological periprosthetic tissue sections; (2) sufficient data were reported to allow the calculation
of true-positive (TP), true-negative (TN), false-positive (FP), and false-negative (FN) values;
(3) the study reported at least 10 patients, from which data extraction using our standardized
data collection form. Discrepancies were resolved by discussion with other reviewers and
reanalysis of the original articles.
Two reviewers independently screened the retrieved clinical studies for inclusion, extracted
data from all included studies and conducted the quality assessment. The methodological
quality of the selected studies was evaluated by using the quality assessment of diagnostic accuracy
studies tool (QUADAS-2) , which was specifically developed for systematic reviews focusing
on diagnostic accuracy. When confronted with disagreements, a third reviewer adjudicated.
Data were extracted independently by two reviewers with all outcomes and then verified by
the other reviewers. The following information were abstracted: (1) study characteristics
including author, year of publication, country, sample size, study design, sample site and
diagnostic criteria; (2) intervention characteristics including ultrasonic conditions, sample
conditions, type of PCR and target gene; (3) diagnostic outcomes including sensitivity and
specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR).
For the analysis of diagnostic value of sonication fluid PCR, all statistical analyses were
conducted using Meta-Disc software (version 1.4, Unit of Clinical Biostatistics team, Madrid,
Spain). The specificity, sensitivity, PLR, NLR, diagnostic odds ratio (DOR), and area under the
curve (AUC) of summary receiver operating characteristic (SROC) were estimated.
Metaregression and subgroup analyses were performed to assess potential heterogeneity. The
percentage of the total variation across studies was described by the I2 statistic, which indicated
the existence of significant heterogeneity when the value exceeded 50%. The value of I2 ranges
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from 0 to 100%, with 0 implying no observed heterogeneity, and larger values indicating
increasing heterogeneity [
]. Analysis of heterogeneity between studies was conducted using
the χ2 test. If there was no significant heterogeneity between studies (P>0.1, I2 50%), the
analysis was performed using a fixed-effects model; otherwise, the random effects model (P 0.1,
I2>50%) was used [
Of the yielded 287 primary articles, 162 of which were excluded with the reasons of duplicates.
Among the left 125 articles, 114 were excluded after reviewing the title, abstract and full text of
the articles. After reading the whole 11 articles included, 2 were unqualified due to insufficient
data. Finally, a total of 9 studies were considered suitable for the diagnostic meta-analysis [5,
10±17], the flow diagram is shown in Fig 1. Graphical summary of the methodological
assessment based on QUADAS-2 quality assessment for the recruited studies of meta-analysis is
illustrated in Fig 2. All of which were of moderate to high quality. Detailed characteristics of
individual study are summarized in Table 1.
Significant Heterogeneity was found in sensitivity (I2 = 68.2%), specificity (I2 = 87.4%), PLR
(I2 = 90.2%), NLR (I2 = 55.6%) and DOR (I2 = 58.9%), respectively; thus, the random-effects
model was used. No threshold effect existed (Spearman correlation coefficient: 0.243, P =
0.529) in the pooled data. The pooled sensitivity, specificity, PLR, NLR, DOR estimates for the
detection of PJI using sonication fluid PCR were 0.75 (95% confidence interval [CI], 0.71 to
0.79), 0.96 (CI, 0.94 to 0.97), 18.24 (CI, 6.07 to 54.78), 0.27 (CI, 0.20 to 0.36), and 86.97(CI,
37.08 to 203.97), respectively (Figs 3, 4, 5, 6 and 7). The SROC plot showed the summary
sensitivity and specificity and the 95% confidence and prediction regions, with an AUC of 0.9244
(standard error 0.0212) (Fig 8).
Fig 1. Flow diagram of the selection process for eligible studies.
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We used the likelihood ratios to simulate low, moderate, and high clinical scenarios using
25%, 50%, and 75% pre-test probabilities of PJI and further calculated and plotted post-test
probability on Fagan nomograms (Fig 9). A positive sonication fluid PCR resulted in post-test
probabilities of 88%, 96%, and 99%, respectively, and a negative PCR resulted in post-test
probabilities of 7%, 18%, and 40%, respectively.
In subgroup analyses, the test performances varied by study design, vortexing,
centrifugation, sample conditions, type of PCR, geographical location, and sample size (Table 2, Fig 10).
Compared with non-multiplex PCR, multiplex PCR had a higher specificity of 0.98 (CI, 0.96 to
0.99) (P<0.05). Compared to the article of USA, the article of Europe and Asia had a higher
sensitivity of 0.83 (CI, 0.75 to 0.90) (P<0.05). The sensitivity and specificity of the fresh
samples were 0.82 (CI, 0.76 to 0.87) and 0.95 (CI, 0.93 to 0.97), and those of the frozen samples
were 0.70 (CI, 0.64 to 0.76) and 0.96 (CI, 0.94 to 0.98), respectively.
PJI is currently one of the most catastrophic complications associated with TJA. Since PJI
diagnosis remains a challenge, many preoperative and intraoperative tests have been employed [1±
Fig 2. Methodological quality assessment of included studies.
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RT S- and
RT BR-PCR 16S rRNA
IOF, H, M
IOF, H, M
RT, real time; BR, broad-range; qPCR, quantitative PCR; S, Staphylococcus; H, histological examination; IOF, intraoperative finding; M, microbiological or laboratory
examination; MSIS: Musculoskeletal Infection Society; IDSA, Infectious Diseases Society of America; NA, not available.
4, 18]. Unfortunately, the current diagnostic methods are not highly accurate. Historically,
intraoperative tissue culture has been used as the gold standard in most hospitals, although the
results of culture lack optimal sensitivity (range, 0.70 to 0.90) or specificity (range, 0.67 to 0.91)
and are sometimes difficult to interpret, especially when few samples are analyzed [3, 19±23].
In fact, the true diagnostic ability of cultures depends on the accurate recovery of bacteria
from samples. Dislodging bacteria from the prosthetic surface by sonication may be an
appropriate option . In addition, Zhai et al. found that sonication fluid cultures (SFC) had a high
sensitivity and a very high specificity for diagnosing PJI . Further, various factors may
influence the diagnostic accuracy of sonication prosthetic fluid samples. Most studies
considered false-positive results to be caused by specimen contamination and false-negative results to
Fig 3. Forest plots of sensitivity of sonication fluid PCR for PJI diagnosis.
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Fig 4. Forest plots of specificity of sonication fluid PCR for PJI diagnosis.
Fig 5. Forest plots of positive likelihood ratio of sonication fluid PCR for PJI diagnosis.
Fig 6. Forest plots of negative likelihood ratio of sonication fluid PCR for PJI diagnosis.
Fig 7. Forest plots of diagnostic odds ratio of sonication fluid PCR for PJI diagnosis.
PLOS ONE | https://doi.org/10.1371/journal.pone.0196418
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Fig 8. Summary of SROC of sonication fluid PCR for PJI diagnosis.
be caused by prior antibiotic treatment, which may have induced an underestimated sensitivity
PCR techniques have demonstrated beneficial diagnostic value for diagnosing PJI in recent
years. Compared to intraoperative tissue culture, PCR theoretically has higher sensitivity, a
faster turnaround time, and is not as affected by antibiotic treatments . However,
differences in sample types analyzed by PCR may influence the diagnostic ability of PJI. Sonication
prosthetic fluid samples may offer additional insight for improving the diagnostic accuracy of
Fig 9. Pre-test probabilities and likelihood ratios (LR) for sonication fluid PCR.
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Sen, Sensitivity; Spe, Specificity; PLR, Positive likelihood ratio; NLR, Negative likelihood ratio; DOR, Diagnostic odds ratio; SROC, Summarized receiver-operating
curve; CI, Confidence interval; SE, Standard error; NA, Not available.
PCRs for diagnosing PJI [5, 12±14]. Guidelines for PJI by the American Academy of
Orthopaedic Surgeons and the Infectious Diseases Society of America recommend further ªhigh
evidenceº-based studies to evaluate the diagnostic value of PCR .
Our results showed that PCR is another diagnostic method that has an equivalent or better
diagnostic value to that of intraoperative tissue culture and may add important insight into the
diagnosis of PJI. However, the main problems in the diagnosis of PJI are recovery and
identification of bacteria from the samples. Whether relying on intraoperative tissue culture or PCR,
the bacterial recovery from the samples is always one of the most important aspects in the
diagnosis of PJI. In this meta-analysis, sonication prosthetic fluid samples for PCR had an adequate
diagnostic value for the detection of PJI. It was estimated that, in current practice, the
sensitivity and specificity of PCR are approximately 75% and 96%, respectively. Our subgroup
analyses showed that compared with non-multiplex PCR, use of multiplex PCR had a higher
specificity (0.98 versus 0.94, P<0.05). However, this type of PCR cannot satisfy both increased
sensitivity and increased specificity concurrently.
1wMoreover, the number of samples taken for PCR may impact the diagnostic sensitivity
and specificity of PCR. Marin et al.  showed that when only considering the number of
positive samples, a PCR-positive result in one sample had good specificity and a positive
predictive value for PJI (specificity, 0.96; positive predictive value, 0.92). The best combination of
results for PCR was observed when 5 samples were studied and the same microorganism was
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Fig 10. Forest plots of subgroup analyses of sensitivity and specificity.
detected in 2 of them (sensitivity, 0.94; specificity, 1.00). In addition, in our meta-analysis,
there were 112 false-negative results from 9 studies. Most of the included studies explained
that the false-negative resulted from the patient receiving antibiotics previous to sampling [5,
This study had some limitations. First, there was no established gold standard for
diagnosing PJI, which is a universal drawback to all studies assessing PCR procedures for diagnostic
accuracy in the detection of PJI. In this meta-analysis, individual studies cited different
reference standards. Misclassification bias, which results from the use of an imperfect reference
standard, may affect the estimates of diagnostic accuracy of a tested method and lead to
underestimated diagnostic accuracy. Second, not all studies explicitly stated whether they were
performed prospectively, which may reduce the strength of our study conclusions. We performed
subgroup analysis and examined study design as possible sources of heterogeneity. Third,
despite the summary results of this meta-analysis had high statistical heterogeneity, which may
have led to an overestimation of the true diagnostic performance, a number of the significant
differences in the subgroup analyses are based on only two sources including type of PCR and
In summary, PCR for sonication prosthetic fluid was found to have adequate and clinically
acceptable diagnostic values for detecting PJI, with a sensitivity of 75% and specificity of 96%.
Future cost-effectiveness of this test studies should be performed.
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S1 PRISMA Checklist. PRISMA checklist.
Conceptualization: Jiying Chen, Libo Hao.
Data curation: Jun Fu, Wei Sun.
Formal analysis: Kan Liu, Jun Fu.
Funding acquisition: Jiying Chen.
Investigation: Jun Fu, Baozhan Yu.
Methodology: Kan Liu, Wei Sun.
Project administration: Libo Hao.
Resources: Jiying Chen, Libo Hao.
Software: Kan Liu, Wei Sun.
Supervision: Jiying Chen, Libo Hao.
Validation: Kan Liu, Jun Fu.
Visualization: Baozhan Yu, Wei Sun.
Writing ± original draft: Kan Liu, Jun Fu.
Writing ± review & editing: Libo Hao.
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1. Del Pozo JL , Patel R. Clinical practice. Infection associated with prosthetic joints . N Engl J Med . 2009 ; 361 ( 8 ): 787 ± 794 . https://doi.org/10.1056/NEJMcp0905029 PMID: 19692690
2. Parvizi J , Ghanem E , Menashe S , Barrack RL , Bauer TW . Periprosthetic infection: what are the diagnostic challenges ? J Bone Joint Surg Am . 2006 ; 88 ( Suppl 4 ): 138 ± 147 .
3. Parvizi J , Adeli B , Zmistowski B , Restrepo C , Greenwald A. Management of periprosthetic joint infection: the current knowledge: AAOS exhibit selection . J Bone Joint Surg Am . 2012 ; 94 ( 14 ): e104. https:// doi.org/10.2106/JBJS.K.01417 PMID: 22810411
4. Trampuz A , Piper KE , Jacobson MJ , Hanssen AD , Unni KK , Osmon DR , et al. Sonication of removed hip and knee prostheses for diagnosis of infection . N Engl J Med . 2007 ; 357 ( 357 ): 654 ± 663 .
5. Esteban J , Alonso-Rodriguez N , del-Prado G , Ortiz-Perez A , Molina- Manso D , Cordero-Ampuero J , et al. PCR-hybridization after sonication improves diagnosis of implant-related infection . Acta Orthop . 2012 ; 83 ( 3 ): 299 ± 304 . https://doi.org/10.3109/17453674. 2012 .693019 PMID: 22616742
6. Leeflang MM , Deeks JJ , Takwoingi Y , Macaskill P. Cochrane diagnostic test accuracy reviews . Syst Rev . 2013 ; 2 : 82 . https://doi.org/10.1186/2046-4053-2-82 PMID: 24099098 7.
Whiting PF , Rutjes AWS , Westwood ME , Mallett S , Deeks JJ , Reitsma JB , et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies . Ann Intern Med . 2011 ; 155 ( 8 ): 529 ± 536 .
https://doi.org/10.7326/ 0003 -4819-155-8- 201110180 -00009 PMID: 22007046
8. Reitsma JB , Glas AS , Rutjes AW , Scholten RJ , Bossuyt PM , Zwinderman AH . Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews . J Clin Epidemiol . 2005 ; 58 ( 10 ): 982 ± 990 . https://doi.org/10.1016/j.jclinepi. 2005 . 02 .022 PMID: 16168343
9. Liu H , Zhang Y , Li L , Zou HC . The application of sonication in diagnosis of periprosthetic joint infection . Eur J Clin Microbiol Infect Dis . 2017 ; 36 ( 1):1±9 . https://doi.org/10.1007/s10096-016 -2778-6 PMID: 27649698
10. Kobayashi N , Procop GW , Krebs V , Kobayashi H , Bauer TW . Molecular identification of bacteria from aseptically loose implants . Clin Orthop Relat Res . 2008 ; 466 ( 7 ): 1716 ± 1725 . https://doi.org/10.1007/ s11999-008-0263-y PMID: 18438724 Piper KE , Jacobson MJ , Cofield RH , Sperling JW , Sanchez-Sotelo J , Osmon DR , et al. Microbiologic Diagnosis of Prosthetic Shoulder Infection by Use of Implant Sonication . J Clin Microbiol . 2009 ; 47 ( 6 ): 1878 ± 1884 . https://doi.org/10.1128/JCM.01686-08 PMID: 19261785 Portillo ME , Salvad oÂ M , Sorli L , Alier A , MartÂõnez S , Trampuz A , et al. Multiplex PCR of sonication fluid accurately differentiates between prosthetic joint infection and aseptic failure . J Infect . 2012 ; 65 ( 6 ): 541 ± 548 . https://doi.org/10.1016/j.jinf. 2012 . 08 .018 PMID: 22960370 Gomez E , Cazanave C , Cunningham SA , Greenwood-Quaintance KE , Steckelberg JM , Uhl JR , et al.
Prosthetic joint infection diagnosis using broad-range PCR of biofilms dislodged from knee and hip arthroplasty surfaces using sonication . J Clin Microbiol . 2012 ; 50 ( 11 ): 3501 ± 3508 . https://doi.org/10.
1128/JCM.00834-12 PMID: 22895042 Cazanave C , Greenwood-Quaintance KE , Hanssen AD , Karau MJ , Schmidt SM , Gomez Urena EO , et al. Rapid molecular microbiologic diagnosis of prosthetic joint infection . J Clin Microbiol . 2013 ; 51 ( 7 ): 2280 ± 2287 . https://doi.org/10.1128/JCM.00335-13 PMID: 23658273 Ryu SY , Greenwood-Quaintance KE , Hanssen AD , Mandrekar JN , Patel R . Low sensitivity of periprosthetic tissue PCR for prosthetic knee infection diagnosis . Diagn Microbiol Infect Dis . 2014 ; 79 ( 4 ): 448 ± 453 . https://doi.org/10.1016/j.diagmicrobio. 2014 . 03 .021 PMID: 24972853 Rak M , KavčIč M , TrebsÏe R , CőR A . Detection of bacteria with molecular methods in prosthetic joint infection: sonication fluid better than periprosthetic tissue . Acta Orthop . 2016 ; 87 ( 4 ): 339 ± 345 . https:// doi.org/10.3109/17453674. 2016 .1165558 PMID: 27123818 Prieto-Borja L , Rodriguez-Sevilla G , Auñon A , PeÂrez-Jorge C , Sandoval E , Garcia-Cañete J , et al. Evaluation of a commercial multiplex PCR (Unyvero i60®) designed for the diagnosis of bone and joint infections using prosthetic-joint sonication . Enferm Infecc Microbiol Clin . 2017 ; 35 ( 4 ): 236 ± 242 . https://doi.
https://doi.org/10.2106/JBJS.G.01255 PMID: 18762646 24 . Janz V , Wassilew GI , Hasart O , Matziolis G , Tohtz S , Perka C . Evaluation of sonicate fluid cultures in comparison to histological analysis of the periprosthetic membrane for the detection of periprosthetic joint infection . Int Orthop . 2013 ; 37 ( 5 ): 931 ± 936 . https://doi.org/10.1007/s00264-013 -1853-1 PMID: 23525549 25.
Zhai Z , Li H , Qin A , Liu G , Liu X , Wu C , et al. Meta-analysis of sonication fluid samples from prosthetic components for diagnosis of infection after total joint arthroplasty . J Clin Microbiol . 2014 ; 52 ( 5 ): 1730 ± 1736 . https://doi.org/10.1128/JCM.03138-13 PMID: 24574298