Diagnostic Accuracy of Probe to Bone to Detect Osteomyelitis in the Diabetic Foot: A Systematic Review
Kenrick Lam 1, Suzanne A V van Asten 2, Tea Nguyen 1, Javier La Fontaine 1, Lawrence A Lavery 1
The probe-to-bone (PTB) test is a commonly used clinical tool for diagnosing osteomyelitis (OM), particularly in diabetic foot infections (DFI). However, its utility has been questioned in clinical settings. Diabetic foot infections can occur in up to 60% of patients with diabetic foot ulcers, making it crucial for clinicians to differentiate between soft tissue infections and osteomyelitis.
While bone culture is the standard for diagnosing OM, the PTB test offers a simpler and quicker alternative that requires fewer resources. This test involves inserting a sterile, metal surgical probe into the ulcer and identifying a positive result if a hard, gritty surface is felt inside.
A systematic review was conducted to evaluate the accuracy of the PTB test in diagnosing diabetic foot osteomyelitis. Seven studies met the inclusion criteria, and the recommendation is to utilize the PTB test to diagnose OM in high-risk patients with DFI and to rule out OM in those with a low risk of DFI.
The findings from this meta-analysis demonstrate that the PTB test is an effective tool in diagnosing diabetic foot OM. The pooled sensitivity, specificity, and diagnostic odds ratio were 0.87, 0.83, and 32 (range, 1.95–630), respectively, for the PTB test, which is similar to reported values for MRI (0.90, 0.83, and 42) and the erythrocyte sedimentation rate (0.81 and 0.90).
However, it’s important to note that the reliability of the PTB test may vary with clinician experience and ulcer location. Nonetheless, the PTB test offers a valuable diagnostic tool for clinicians managing diabetic foot infections, allowing for timely and accurate identification of osteomyelitis.
Reference:
Lam, K., van Asten, S. A., Nguyen, T., La Fontaine, J., & Lavery, L. A. (2016). Diagnostic Accuracy of Probe to Bone to Detect Osteomyelitis in the Diabetic Foot: A Systematic Review. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America, 63(7), 944–948. https://doi.org/10.1093/cid/ciw445
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