Biofilm Investigation on Bearing Components of Explanted Hip Joint Prosthesis

Study Overview
=================
Brief Summary
-----------------
In this study the investigators sonicate the bearing components of the explanted hip prosthesis which allows highly sensitive detection of in vivo biofilms (qualitatively and quantitatively). The hip prosthesis bearing components are composed from different material. The purpose of this study is to analyse the resistance against biofilm adhesion of ceramic, metal and polyethylene prosthesis components through microbiologic analysis of sonicates.

Detailed Description
-----------------
The main reasons for hip prosthesis failure are aseptic loosening and periprosthetic joint infection (PJI). The real frequency of PJI is probably largely underestimated because of non-standardized definition criteria, diagnostic procedure, treatment algorithm and other confounders. Therefore, data from joint registries are not reflecting the frequency of PJI and can be misleading; particularly low-grade PJI can be frequently misdiagnosed as aseptic failure. Microbiological analysis of sonicate has in comparison with joint aspirate significantly higher sensitivity and specificity, which allows better detection of low grade infection. With aspiration only free-floating, high metabolically active, planktonic form of bacteria could be collected. Contrarily, the less metabolically active bacteria are hidden under the biofilm can remain undetected. Sonication of prosthetic material mechanically dislodge the biofilm from surface and expose the sessile bacteria for the microbiological analysis. All foreign materials provoke biofilm formation however, different materials showed different resistance for biofilm adhesion. In this study patients with PJI are undergoing standard one- or two- stage revision procedure of the hip. The removed bearing components will be sonicated and sent in microbiological analysis. The ceramic, metal and polyethylene prosthesis components will undergo qualitative and quantitative microbiological analysis. The materials will be compared regarding to the presence of biofilm formation.

Official Title
-----------------
Biofilm Investigation on Ceramic, Metal and Polyethylene Bearing Components From Explanted Hip Joint Prosthesis

Conditions
-----------------
Sonication, Total Hip Replacement, Biofilm

Intervention / Treatment
-----------------
* Other: Sonication
* Other: Microbiological analysis


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Subject must be aged 18 or more. Subject must be scheduled to undergo an explanation of the hip endoprosthesis during the 1- or 2- stage revision procedure because of the septic or mechanical indication. Subject must personally sign and date the informed consent document indicating that the subject has been informed of all pertinent aspects of the study. Exclusion Criteria: Patient not scheduled for the index Operation procedure with removal of hip endoprosthesis

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Sonication|Ultrasound bath (40 kHz, 1 W/cm2, 1 min) of bearing components of the prosthesis in sterile conditions.|
|Other: Microbiological analysis|Plating the sonicates on agar plates.|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Qualitative analysis of sonication fluid after sonication of explanted bearing components of the hip endoprosthesis during a revision surgery | Qualitative Analysis, i.e. frequency of positive sonication fluid cultures (No. positive/No. all cultures) deriving from 3 different biomaterials (namely: Ceramic, Cobalt-chrome-metal, and Polyethylene), the number of variables which will be evaluated following: bearing component and its material (Ceramic, Cobalt-chrome-metal, and Polyethylene). All three material types will be compared between each other regard to microbiology analysis of sonication fluid of bearing components. | Prospective: patient recruitment up to 2 years | 
| Quantitative Analysis e.g. No. of microorganisms in sonication fluid (CFU/ml) deriving from 3 different biomaterials (namely: Ceramic, Cobalt-chrome-metal, and Polyethylene). |  | Prospective: patient recruitment up to 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Amount of patients with septic loosening of hip joint |  | Prospective: patient recruitment up to 2 years | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
biofilm, periprosthetic joint infection, hip, endoprothesis, ceramic, bearing components, sonication, low grade infection, joint aspiration