Introduction: Arthroplasty plays a growing role in our society today. Due to scientific and medical progress there are an increasing number of viable candidates and the improvement of quality of life thereafter speaks for itself.

Even though the operations are largely successful, complications after joint replacement surgery occur frequently. Approximately 10% of lower limb arthroplasties need surgical revision, of which 70% are due to loosening. The purpose of this study was to assess the feasibility of 18-fluorodeoxyglucose positron emission tomography (18FFDG–PET) in detecting septic and aseptic endoprosthetic loosening of hip and knee endoprostheses.

Materials and Methods: Thirty-three patients (age range: 45–90y) with lower limb arthroplasty complaints (74 prostheses) were studied preoperatively with 18F-FDG-PET. All patients underwent surgery at a later stage with microbiological culturing to differentiate aseptic and septic loosening and to confirm the final diagnosis. Prostheses were tested intraoperatively for stability and microbiology.

Results: The sensitivity/specificity of 18F-FDG-PET towards implant loosening in the hip was 80%/87%, in the knee 56%/82%.

The sensitivity/specificity for infectious loosening in hip replacement arthroplasties was 67%/83%, in the knee 14%/89%.

Discussion: 18F-FDG-PET seems an excellent method for detecting hip endoprosthetic loosening and a moderate tool to diagnose hip implant infection. It should not be seen as the method of choice to diagnose knee endoprosthetic loosening and infection.

Introduction: Arthroplasty plays a growing role in our society today. Due to scientific and medical progress there are an increasing number of viable candidates and the improvement of quality of life thereafter speaks for itself.

Even though the operations are largely successful, complications after joint replacement surgery occur frequently. Approximately 10% of lower limb arthroplasties need surgical revision, of which 70% are due to loosening. The purpose of this study was to assess the feasibility of 18-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) in detecting septic and aseptic endoprosthetic loosening of hip and knee endoprostheses.

Materials and Methods: Thirty-three patients (age range: 45 – 90y) with lower limb arthroplasty complaints (74 prostheses) were studied preoperatively with 18F-FDG-PET. All patients underwent surgery at a later stage with microbiological culturing to differentiate aseptic and septic loosening and to confirm the final diagnosis. Prostheses were tested intraoperatively for stability and microbiology.

Results: The sensitivity/specificity of 18F-FDG-PET towards implant loosening in the hip was 80%/87%, in the knee 56%/82%.

The sensitivity/specificity for infectious loosening in hip replacement arthroplasties was 67%/83%, in the knee 14%/89%.

Discussion: 18F-FDG-PET seems an excellent method for detecting hip endoprosthetic loosening and a moderate tool to diagnose hip implant infection. It should not be seen as the method of choice to diagnose knee endoprosthetic loosening and infection.

Goal Is Positron Emission Tomography (PET) with [18F] fluordesoxyglucose (FDG) a suitable procedure in diagnostic of osteitis?

Method In a prospective clinical study from 02/2000 until 05/2004 we observed 120 patients with osteitis. The average age was 46 years, the relationship between female and male 1: 3 (31 female, 89 male). The PET was performed under the question of a posttraumatic osteitis. In cases of operative revision procedures bacteriological examinations were carried out

Results In 73 cases (61%) the PET showed positive findings. Surgical revision was carried out in 57 of these 73 patients (78%). The bacteriological findings in this cases were positive in 59% (n=34). Most of the proved germs were St. aureus in 53%, followed by St. epidermidis in 17%.

In the group of patients with negative findings in the PET (n=47) in 17 cases (36%) an operative procedure was carried out. The bacteriological findings were negative in 12 cases (70%). St. epidermidis was found in 4 cases with positive bacteriological findings.

Conclusion In our opinion the PET seems to be a valuable complement in the spectrum of diagnostically possibilities in connection with osteitis. Despite the low level of specifity in this study one of the great advantages is the visualization of the hot spot in a third plane. So the planning and carrying out of the surgical revision procedure can be improved. To increase the specifity of the PET in connection with the treatment of osteitis further research is required.