Evaluation of 68Ga-Citrate PET/CT for Diagnosing Chronic Prosthetic Joint Infection in Hip and Knee Arthroplasty Patients

The primary objective of this study is the **estimation of diagnostic accuracy** of 68Ga citrate PET/CT in diagnosing chronic hip or knee joint prosthesis infection. This is clinically relevant as accurate diagnosis is crucial for the effective management and treatment of **prosthetic joint infection**, which can significantly impact patient outcomes and quality of life.

Secondary objectives include:

• Estimation of the inter-observer reproducibility of the PET/CT reading at 68Ga citrate.
• Estimation of the diagnostic accuracy of multinuclear scintigraphy in diagnosing chronic hip or knee joint prosthesis infection.
• Estimation of the diagnostic accuracy of PET/CT with citrate 68Ga and scintigraphy with polymorphonuclear in two patient subpopulations: knee or hip infection.
• Comparison of the diagnostic accuracy of PET/CT with 68Ga citrate to that of scintigraphy using polymorphonuclear drugs in diagnosing chronic hip or knee joint prosthesis infection.

The clinical trial focuses on individuals diagnosed with **prosthetic joint infection**, specifically targeting those with suspected chronic hip or knee joint prosthesis infection. The study population includes both male and female participants aged over 18 years, with no vulnerable populations being selected. Participants are required to be patients who are being addressed for the first time to a reference center for joint prosthesis infection, with a suspicion of artificial joint infection that began at least one month prior to evaluation. The trial does not specify the total number of participants, as this information was not provided by the sponsor. Participants must have a positive bone scintigraphy and be undergoing routine diagnostic procedures, including both bone scintigraphy and polynuclear scintigraphy. Additionally, participants are required to be affiliated with a health insurance system and must have signed an informed consent form prior to any examination required by the research. The trial does not emphasize any specific lifestyle considerations such as diet or physical activity.

The clinical trial is designed to evaluate the **diagnostic accuracy** of **68Ga citrate PET/CT** in diagnosing chronic infections of hip or knee joint prostheses. This trial is a **randomized, double-blind, controlled** study, conducted over a period from February 2, 2022, to February 2, 2025. Participants will be involved in the study for a maximum of one year, with the primary endpoint being the assessment of diagnostic accuracy, including sensitivity, specificity, and predictive values. Secondary endpoints include the reproducibility of PET/CT interpretation and comparison with marked polynuclear scintigraphy.

The study begins with an inclusion visit, where participants are screened based on criteria such as age over 18, suspicion of prosthetic joint infection, and positive bone scintigraphy. Following the inclusion visit, participants will undergo routine diagnostic procedures, including both bone and polynuclear scintigraphy. Subsequent follow-up visits will be scheduled to monitor the participants' response to the diagnostic procedures and to collect data on the primary and secondary endpoints. The end-of-study visit will conclude the trial, where final assessments and data collection will occur.

Participants are expected to remain in the study for its entire duration unless specific conditions necessitate early termination. These conditions include withdrawal of consent, adverse events, or any situation that compromises the participant's safety or the integrity of the study. The trial is conducted under strict adherence to ethical guidelines, ensuring that all participants provide informed consent before any study-related procedures are performed.

The clinical trial involves the use of **68 Gallium citrate**, a radiopharmaceutical agent, as the experimental medication. The active substance, **Gallium citrate Ga-68**, is administered in the form of a **solution for injection**. The pharmaceutical form is specifically designed for **intravenous use**. The maximum daily dose is set at 150 MBq (megabecquerels), with the same limit applied to the total dose amount. The treatment period is restricted to a single day. The chemical origin of the active substance ensures its suitability for the intended diagnostic application. The administration of the drug is conducted under controlled conditions to ensure participant safety and compliance with the study protocol.

In this clinical trial, no non-experimental treatments such as standard-of-care therapy, placebo, or comparator treatments are utilized. The focus remains solely on evaluating the diagnostic accuracy of **68 Gallium citrate** in the context of chronic hip or knee joint prosthesis infection. Participant compliance is monitored through adherence to the dosing schedule and administration route, ensuring the integrity of the trial data. The trial is authorized and conducted by the Centre Hospitalier Universitaire de Bordeaux, with all procedures adhering to regulatory standards.

The clinical trial aims to assess the efficacy of **68Ga citrate PET/CT** in diagnosing chronic infections of artificial hip or knee joints. The primary endpoint for evaluating efficacy is the diagnostic accuracy of **68Ga citrate PET/CT**, which includes parameters such as sensitivity, specificity, and predictive values (both positive and negative). These parameters will be measured to determine the effectiveness of the imaging technique in identifying infections.

Secondary endpoints include the reproducibility of **68Ga citrate PET/CT** interpretation among different observers, the diagnostic accuracy of marked polynuclear scintigraphy, and a comparative analysis of the diagnostic accuracy between **68Ga citrate PET/CT** and marked polynuclear scintigraphy. The study will also explore discrepancies between these two diagnostic methods. The trial is designed to provide a comprehensive evaluation of the imaging techniques' performance in detecting infections in patients with artificial hip or knee joints.