Understanding Periprosthetic Joint Infections After Hip Replacement

Total hip arthroplasty, often called hip replacement surgery, is a common procedure used to relieve pain and improve function in people with hip issues. Over the years, the number of these surgeries has been rising. For instance, in Canada alone, over $1.3 billion was spent on hip and knee replacement surgeries from 2020 to 2021. Looking ahead, it's projected that the costs will soar to over $5.3 billion in Australia by 2030. This increasing trend highlights the importance of understanding hip replacement surgeries.

While many patients experience good results, there is a risk of complications, one of which is periprosthetic joint infection (PJI). Studies show that PJI rates have been rising, resulting in more patients needing additional surgeries due to infections. This increase could be real, due to factors like older or sicker patients, or it could be an apparent increase from better detection and reporting methods. PJIs can be quite serious for patients, leading to emotional distress, loss of function, and in some cases, even death.

In this piece, we will look at how PJIs are treated after a hip replacement. We will explain different methods of revision surgery and the challenges in managing this type of infection.

#Types of Revision Surgery for PJI

When patients develop PJIs after hip replacement, there are different ways to treat them. The main approaches include:

1. Debridement, Antibiotics, and Implant Retention (DAIR): This method is used when the infection is caught early, and the surrounding tissue isn’t badly damaged. The aim is to clean the infection while keeping most of the original implant intact. It involves replacing only certain parts of the implant instead of the entire device.

2. One-stage revision: In this approach, all old components are taken out, and new ones are put in during the same surgery. This method is chosen when the infection is manageable.

3. Two-stage revision: This method involves a two-step process. First, all components are removed, and a temporary spacer is put in place. After a long course of antibiotics, the second surgery is conducted to replace the implant. Spacers can be made of various materials, including antibiotic-laden cement, to help fight infection.

While the two-stage method is generally favored for chronic infections, some studies suggest that one-stage revisions can also yield good results. One study found that 70% of DAIR procedures were successful.

#The Challenge of Diagnosing and Treating PJI

Diagnosing and treating PJIs involves many factors, making it a complex process. Over time, there have been discussions among experts to refine guidelines for PJI management. However, it’s uncertain whether these new guidelines are widely implemented in everyday medical practice.

Our goal is to track trends in how PJIs are treated after hip replacements. We will categorize the types of revision surgeries into DAIR, one-stage, and two-stage revisions. Additionally, we’ll look at the risk of needing a second surgery after each treatment type.

#Study Design and Data Collection

This study will use data from Denmark, where healthcare is accessible to all residents without cost. Most surgeries take place in public hospitals, although private facilities are becoming more common.

We will examine data from both public and private orthopedic departments from 1995 to 2022. We’ll track patients from the day of their first hip replacement until they either die or have their first revision surgery. Patients will be followed for up to 28 years, ensuring a thorough overview of their medical journeys.

#Who is Included in the Study?

We will include all adult patients (18 years and older) who had primary THA during the study period. Each patient can contribute data for each hip they had replaced. Exclusions will be made for those who had hemiarthroplasty or simultaneous surgeries on both hips.

#Data Sources

The data for this study will come from the Danish Hip Arthroplasty Register (DHR). This register contains records of all hip surgeries in Denmark, ensuring comprehensive data. Surgeons are required to report their surgeries, leading to high accuracy in the data collected. Additionally, the DHR data is verified against another national registry, further ensuring reliability.

#Types of Data We Will Analyze

We will track the total number of patients who underwent revision surgery, focusing on the reasons behind these revisions. Our primary interest will be in the yearly number of PJI-related revision surgeries, broken down into the three main surgical methods: DAIR, one-stage, and two-stage revisions.

We will also classify revision surgeries based on how soon they occurred after the initial surgery:

• Within 4 weeks
• Between 4 and 12 weeks
• More than 12 weeks

Finally, we will assess the risk of needing a second surgery after each type of revision.

#Methods of Analysis

To manage the data efficiently, we will organize patients based on which hip surgery they had (right or left). The analysis will be conducted using R statistical software. The risk of needing a second revision will be evaluated using a detailed statistical method, factoring in age and sex.

We plan to present our findings clearly. This will include diagrams showing how patients moved through the study and graphs illustrating the risk of a second revision based on the initial type of surgery.

#Strengths and Limitations of the Study

One major strength of this study is that it will provide insight into various methods of treating PJIs rather than focusing on just one approach. The data spans a long period, allowing for a better understanding of trends.

The DHR boasts high completeness rates for data, which boosts reliability. However, some private clinics may have issues with data accuracy, which could affect results. Additionally, since PJIs are reported by surgeons and not always verified by other tests, there might be cases where infections are misdiagnosed.

The results of this study should be viewed as descriptive. Since it relies on observational data from Denmark, the findings may not apply to other countries, especially those with different healthcare systems. However, because we have broad criteria for including patients, our findings are likely to reflect similar experiences in other developed nations.

#Conclusion

Total hip arthroplasty is an important procedure for many people, but it comes with risks such as periprosthetic joint infection. Understanding how to manage these infections is crucial for improving outcomes and reducing the need for additional surgeries. This study aims to shed light on current practices in revision surgeries for PJIs and assess the effectiveness of different treatment approaches. Through thorough data analysis, we hope to contribute valuable insight into the ongoing conversation about hip replacement surgery and its complications.