# Investigating the benefits of metagenomic next-generation sequencing for patients experiencing infections after total hip replacement surgery: a retrospective cohort study with a minimum of one year of follow-up

## TL;DR

This study shows that metagenomic next-generation sequencing (mNGS) is faster and more accurate than traditional bacterial culture for diagnosing hip replacement infections.

## Contribution

The study demonstrates mNGS's superior detection rate and speed in identifying pathogens in post-surgery joint infections.

## Key findings

- mNGS detected pathogens in 100% of cases, compared to 66.7% with bacterial culture.
- mNGS provided results in 1.67 days on average, significantly faster than bacterial culture's 3.07 days.
- 93.3% of patients had their infections controlled after treatment guided by mNGS.

## Abstract

To explore the clinical significance of metagenomic next-generation sequencing (mNGS) technology in diagnosing and treating periprosthetic joint infection (PJI) following total hip arthroplasty (THA).

From September 2018 to September 2024, 15 patients with periprosthetic infection after total hip arthroplasty were admitted. There were 11 males and 4 females; ages ranged from 28 to 87 years old, with an average of 63 years old. Infection occurred 6 to 42 months after total hip arthroplasty, with an average of 22.7 months. The infection lasted between 15 and 115 days, averaging 37.6 days. After being admitted to the hospital, joint fluid was collected for bacterial culture and mNGS. Following admission, joint fluid was collected for bacterial culture and mNGS, and antibiotics were adjusted based on the results, with surgery used to control the infection if needed.

Bacterial culture method was positive in 10 cases (66.7%), with a total of 12 pathogenic bacteria types detected. MNGS was positive in 15 cases (100.0%), with a total of 19 pathogenic bacteria types detected. There was a statistically significant difference in the positive rate between the two methods (P < 0.05). Out of the 10 patients, 5 who tested positive using both the bacterial culture method and mNGS test showed identical pathogenic bacterial types, resulting in a 50.0% compliance rate. The testing time (from sample delivery to results) was (3.07 ± 0.96) days for bacterial culture method and (1.67 ± 0.49) days for mNGS test, and the difference was statistically significant (t=5.03, P<0.001). The patients were followed up for 13 to 82 months, with a mean of 40.7 months. In one patient, the infection returned three months after undergoing one-stage revision surgery, while the other 14 patients showed no signs of infection, resulting in an infection control rate of 93.3%.

MNGS can detect the pathogenic bacteria of postoperative PJI after THA more quickly and accurately than the bacterial culture method, which is crucial for guiding antibiotic and surgical treatment combinations for patients with postoperative PJI after THA.