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Current Concepts Review:
Thomas W. Bauer, Javad Parvizi, Naomi Kobayashi, and Viktor Krebs
Diagnosis of Periprosthetic Infection
J Bone Joint Surg Am 2006; 88: 869-882 [Abstract] [Full text] [PDF]
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[Read Letter to the Editor] Dr. Bauer and colleagues respond to Dr. Pignatti
Thomas W. Bauer, MD, PhD, Javad Parvizi, MD, Naomi Kobayashi, MD, PhD, Viktor Krebs, MD   (1 October 2009)
[Read Letter to the Editor] Letter to the Editor
Giovanni Pignatti, MD   (1 October 2009)

Dr. Bauer and colleagues respond to Dr. Pignatti 1 October 2009
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Thomas W. Bauer, MD, PhD,
Physician
The Cleveland Clinic, Cleveland, Ohio,
Javad Parvizi, MD, Naomi Kobayashi, MD, PhD, Viktor Krebs, MD

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Re: Dr. Bauer and colleagues respond to Dr. Pignatti

osteoclast{at}aol.com Thomas W. Bauer, MD, PhD, et al.

Dr. Pignatti correctly notes that, when we quoted (1) Spangehl’s 1999 study (2), we accidentally reversed the percents for the CRP and ESR predictive values, and transcribed the sensitivity of CRP as 86% instead of 96%. We appreciate Dr. Pignatti bringing those details to our attention. Our interpretation that Dr. Spangehl's findings indicated the CRP level to be an overall better indication of infection than the ESR is correct. Additional studies have also shown that both analytes are nonspecific markers of inflammation, that there may be differences in the magnitude of elevation and the time course of normalization based on the type of operation (for example, total hip versus total knee arthroplasty) (3), and that the CRP returns to normal more rapidly than the ESR (3-5). We agree with Dr. Spangehl's comment that, when used in the appropriate clinical context, "these investigations become useful as a safe and economical screening tool with which to exclude infection" (2).

References

1. Bauer TW, Parvizi J, Kobayashi N, Krebs V. Diagnosis of periprosthetic infection. J Bone Joint Surg Am. 2006;88:869-82.

2. Spangehl MJ, Masri BA, O'Connell JX, Duncan CP. Prospective analysis of preoperative and intraoperative investigations for the diagnosis of infection at the sites of two hundred and two revision total hip arthoplasties. J Bone Joint Surg Am. 1999;81:672-83.

3. Bilgen O, Atici T, Durak K, Karaeminoǧullari, Bilgen MS. C-reactive protein values and erythrocyte sedimentation rates after total hip and total knee arthroplasty. J Int Med Res. 2001;29:7-12.

4. Moreschini O, Greggi G, Giordano MC, Nocente M, Margheritini F. Postoperative physiopathological analysis of inflammatory parameters in patients undergoing hip or knee arthroplasty. Int J Tissue React. 2001;23:151-4.

5. Shih LY, Wu JJ, Yang DJ. Erythrocyte sedimentation rate and C-reactive protein values in patients with total hip arthroplasty. Clin Orthop. 1987;225:238-46.
Letter to the Editor 1 October 2009
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Giovanni Pignatti, MD,
Orthopaedic Surgeon
Istituto Ortopedico Rizzoli, Bologna, Italy

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Re: Letter to the Editor

giovanni.pignatti{at}ior.it Giovanni Pignatti, MD

To the Editor:

I was reading the paper by Bauer et al. (1). On page 873, it is reported that, "Spangehl et al. (2) prospectively evaluated several different diagnostic tests that had been performed in a series of 202 revision hip arthroplasties. If inflammatory arthropathies were excluded, the erythrocyte sedimentation rate was found to have a sensitivity of 82% and a specificity of 85%. The predictive value of a negative test was only 58%, while the predictive value of a positive result was 95%. The C- reactive protein level was found to be a better indicator of infection than the erythrocyte sedimentation rate, with the C-reactive protein level having a sensitivity of 86%, a specificity of 92%, and predictive values for negative and positive tests of 74% and 99%, respectively".

In the original paper of Spangehl et al. (2), it is reported that erythrocyte sedimentation rate, "showed a sensitivity of 0.82 (0.65 to 0.93), a specificity of 0.85 (0.78 to 0.91), a positive predictive value of 0.58 (0.43 to 0.72), and a negative predictive value of 0.95 (0.89 to 0.98)". Moreover, C-reactive protein, "showed a sensitivity of 0.96 (0.78 to 1.00), a specificity of 0.92 (0.85 to 0.96), a positive predictive value of 0.74 (0.55 to 0.87), and a negative predictive value of 0.99 (0.94 to 1.00)". In my opinion, there is something wrong with the figures reported by Bauer et al.

The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the author, or a member of his immediate family, is affiliated or associated.

References

1. Bauer TW, Parvizi J, Kobayashi N, Krebs V. Diagnosis of periprosthetic infection. J Bone Joint Surg Am. 2006;88:869-82.

2. Spengehl MJ, Masri BA, O'Connell JX, Duncan CP. Prospective analysis of preoperative and intraoperative investigations for the diagnosis of infection at the sites of two hundred and two revision total hip arthroplasties. J Bone Joint Surg Am. 1999;81:672-83.