Chronic Pain, Inflammation and Infection After Joint Replacement
Condition: Infection and Inflammatory Reaction; Joint Prosthesis
MeSH terms: Infections; Communicable Diseases; Inflammation; Chronic Pain
Study type: Observational

Summary: 
      Revision surgery after total hip or knee arthroplasty is an ongoing issue due to an
      increasing number of primary surgeries. Patients seek physicians due to pain. The cause is
      divided between loosening, infection or chronic pain. Some are operated on the suspicion of a
      chronic infection. However, postoperative microbiological testing does not always correlate
      with the suspicion and the operation may have been superfluous.

      The objective is to employ a highly advanced diagnostic algorithm based on state of the art
      diagnostic techniques in order to improve the basis of preoperative diagnosis. Through this
      approach treatment can be given according to the causal problem.
    

Detailed description: 
      The aim of the project is to improve the preoperative diagnosis of infections and persistent
      pain in patients with prosthesis-related problems. Prosthesis infection is of chronic nature.
      Recent research has shown that one important explanation of this is the formation of
      encapsulated 'bacterial communities' on the surface of the prosthesis, where bacteria are
      well protected against antibiotic treatment. Surgery is therefore necessary for this patient
      group. But it is important to make diagnosis more accurate than it currently is today. In
      contrast, patients with persistent pain, but no indication of infection or prosthetic
      loosening, are best served by avoiding surgery, and instead receiving a treatment that is
      directed against the chronic pain condition. Based on the pain research carried out at
      Aalborg University, an understanding of chronic pain and treatment principles that would be
      beneficial for this patient group have been developed.

      The investigators want to:

        1. describe the postoperative course of specific serologic markers for primary and
           secondary total hip arthroplasty (THA) and total knee arthroplasty (TKA).

        2. describe the bacteriologic diversity through revision of THA and TKA using cultivation
           techniques and molecular biological analysis comprehensive fluorescence in-situ
           hybridization (FISH), cloning and phylogeny, quantitative polymerase chain reaction
           (qPCR) and gene expression profiling.

        3. describe pain and sensitization with new diagnostic technology in patients with stem
           loosening, suffering from infection and pain.

        4. apply to a new diagnostic algorithm for the diagnosis of infection and pain following
           THA and TKA, which includes pain assessment, diagnostic X-ray, bone scintigraphy, PET
           scan, percutaneous biopsy, specific serologic parameters and molecular biological
           analysis.

        5. describe the effect of the diagnostic algorithm, compared with a descriptive
           retrospective cohort of patients who have undergone revision of THA or TKA.
    

Intervention name(s): Blood samples
Intervention type(s): Biological
Intervention description(s): 4 x 10 ml blood samples.
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        Primary care clinic.
      
Biospecimen description: 
      4 x 10 ml blood samples for each patient.
    
Keywords: Pain; Infection; Inflammation; Prosthesis