Low frequency of local findings in periprosthetic hip infection caused by low-virulent bacteria compared to periprosthetic knee infection

Takashi Imagama,Yuta Matsuki,Takashi Sakai,Kazushige Seki,Kazuhiro Yamazaki,Toshihiro Seki

doi:10.1038/s41598-021-91139-w

Takashi Imagama, Yuta Matsuki + Show 4 more

Open Access

https://doi.org/10.1038/s41598-021-91139-w

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Journal: Scientific Reports	Publication Date: Jun 3, 2021
Citations: 2	License type: open-access

Affiliation: Yamaguchi University

Abstract

Periprosthetic joint infection (PJI) is suspected when local findings such as pain, swelling, hyperthermia, and sinus tract are present. However, the frequency of these findings and the difference between hip and knee are unclear. This study compared the positive rates of local findings in periprosthetic hip infection (PHI) with periprosthetic knee infection (PKI), and aimed to identify potential risk factors associated with the frequency. One hundred one PJI (46 hips and 55 knees) fulfilled the 2018 Musculoskeletal infection society criteria were analysed retrospectively to assess the positive rates of each local finding. Patients were categorized into two groups based on the presence or absence of each local finding, and the influence of two potential risk factors [body mass index (BMI) and C-reactive protein (CRP)] was investigated. Causative bacterial species were divided into high and low-virulent groups, and then culture negative cases were included in low-virulent group. PHI had significantly lower rates of pain, swelling and hyperthermia compared to PKI. Overall, up to one-third of PHI had pain as only symptom. High BMI and low-virulent bacteria were associated with lower frequency of swelling and hyperthermia in PHI. CRP had no impact on positive rates of local findings. PHI was oligosymptomatic in a significant percentage of cases. This is particularly important in obese patients and infection by low-virulent bacteria.

Highlights

Periprosthetic joint infection (PJI) is suspected when local findings such as pain, swelling, hyperthermia, and sinus tract are present
low-virulent bacteria (LVB) accounted for 45.7% (21/46) of periprosthetic hip infection (PHI) and 40.0% (22/55) of periprosthetic knee infection (PKI)
Pain, swelling, and hyperthermia were significantly less frequent, and sinus tract was contrarily more frequent in PHI compared with PKI

Summary

Introduction

Periprosthetic joint infection (PJI) is suspected when local findings such as pain, swelling, hyperthermia, and sinus tract are present. As the other tests for diagnosis of PJI, synovial fluid leucocyte c ount[8], neutrophil p ercentage[8], and C-reactive p rotein[9] have high sensitivity and specificity (89.5%/91.3%, 89.7%/86.6%, and 85%/95%, respectively) These tests have been included in the 2018 Musculoskeletal Infection Society (MSIS) minor c riteria[10], and their results are very helpful for definitive diagnosis of PJI. Joint infections are generally suspected with local findings such as pain, swelling, hyperthermia, and occasionally sinus tract at the initial examination[11,12], the sensitivity of swelling and hyperthermia was reported to be relatively low (61.5% and 46.2% respectively) in overall PJI13. Knowing the frequency of local findings in each joint helps to improve diagnostic accuracy and definite early diagnosis

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