Diagnostik der infizierten Hüftendoprothese

Diagnostic and prognostic relevance of plain radiographs for periprosthetic joint infections of the hip: a literature review

Conventional radiography is regularly used to evaluate complications after total hip arthroplasty. In various recent consensus meetings, however, plain radiographs of a potentially infected hip joint have been judged as being only relevant to exclude diagnoses other than infection. Solid data on radiographic presentations of periprosthetic joint infection (PJI) are scarce. As a result, the prognostic value of radiological features in low-grade PJI remains uncertain. The present review article aims to present an overview of the available literature and to develop ideas on future perspectives to define the diagnostic possibilities of radiography in PJIs of the hip. The primary outcome of interest of this systematic review was the radiologic presentation of periprosthetic joint infections of the hip. As secondary outcome of interest served the sensitivity and specificity of the radiologic presentation of periprosthetic joint infections. Of the included articles, 26 were reviews, essays, or case reports and only 18 were clinical studies. Typical radiologic abnormalities of PJI were a periosteal reaction, a wide band of radiolucency at the cement-bone or metal-bone interface, patchy osteolysis, implant loosening, bone resorption around the implant, and transcortical sinus tracts. The frequency of their occurrence is still inadequately defined. A deeper understanding of the underlying causes and the relation between microorganisms to radiologic abnormalities can probably help clinicians in the future to diagnose a PJI. This is why further research shall focus on the radiographic features of PJI.

Ultrasonic Interferometric Procedure for Quantifying the Bone-Implant Interface

The loosening of an artificial joint is a frequent and critical complication in orthopedics and trauma surgery. Due to a lack of accuracy, conventional diagnostic methods such as projection radiography cannot reliably diagnose loosening in its early stages or detect whether it is associated with the formation of a biofilm at the bone-implant interface. In this work, we present a non-invasive ultrasound-based interferometric measurement procedure for quantifying the thickness of the layer between bone and prosthesis as a correlate to loosening. In principle, it also allows for the material characterization of the interface. A well-known analytical model for the superposition of sound waves reflected in a three-layer system was combined with a new method in data processing to be suitable for medical application at the bone-implant interface. By non-linear fitting of the theoretical prediction of the model to the actual shape of the reflected sound waves in the frequency domain, the thickness of the interlayer can be determined and predictions about its physical properties are possible. With respect to determining the layer's thickness, the presented approach was successfully applied to idealized test systems and a bone-implant system in the range of approx. 200 µm to 2 mm. After further optimization and adaptation, as well as further experimental tests, the procedure offers great potential to significantly improve the diagnosis of prosthesis loosening at an early stage and may also be applicable to detecting the formation of a biofilm.

Periprosthetic joint infection: Comparison of automated multiplex-PCR Unyvero i60 ITI cartridge system with bacterial culture and real-time PCR

BACKGROUND: In the past, various efforts have been made to investigate diagnostic tools for periprosthetic-joint-infection (PJI). It is little-known about the diagnostic utility of polymerase-chain-reaction (PCR) in this context, especially concerning the role of multiplex-PCR assays comparing with conventional tissue culture. OBJECTIVE: Evaluation of an automated-multiplex-PCR cartridge system for patients with suspicion of PJI in comparison with conventional microbiological culture and 16S-rDNA-PCR. METHODS: On suspicion of PJI synovial fluid specimen were taken preoperatively or periprosthetic tissue was collected intraoperatively. Microbiological analysis included conventional culture, 16S-rDNA-PCR and automated-multiplex-PCR (Unyvero-i60-ITI®). The European-Bone-and-Joint-Infection-Society (EBJIS) criteria were used for PJI diagnosis. Positive and negative percent agreement was calculated. Total percentage agreement and Cohen’s kappa coefficient were calculated. Sensitivity, specificity and positive predictive value of conventional culture, 16S-rDNA-PCR and multiplex-PCR were calculated. Ten specimens of proved PJI were used as control group. RESULTS: Fifty specimen were suitable for culture. 14 (28%) were classified as PJI, 36 (72%) were aseptic. Coagulase-negative staphylococci was the most frequent detected pathogen. Concordance-rate between mPCR and culture results was 75.6% with a Cohen’s kappa of 0.28. Concordance-rate between mPCR and 16S-rDNA was 82.9%, Cohen’s kappa was 0.13. Concordance analysis between culture results and 16S-rDNA lead to a concordance-rate of 88.9%. Cohen’s kappa was calculated with 0.6. With regard to the microbiological culture as reference, sensitivity of the mPCR was 0.33 and specificity was 0.91. Sensitivity and specificity of the 16S-rDNA-PCR was 0.55 and 0.97. The positive predictive value was 0.57 for the mPCR and 0.83 for the 16S-rDNA-PCR. CONCLUSIONS: Due to fair agreement between mPCR and conventional microbiological culture, the tested multiplex-PCR could be an additional instrument for the detection of PJI but is not superior over the conventional culture.

Evaluation of the use of sonication of retrieved implants for the diagnosis of prosthetic joint infection in a routine setting

In order to evaluate the usefulness of sonication of retrieved implants for the diagnosis of prosthetic joint infection (PJI) in a large group of patients in a routine setting, we designed a 3-year retrospective study. Patients were classified into two groups: those meeting the clinical criteria of PJI and those that did not (control group). Two hundred patients and 276 samples were included. The types of infection were early (n = 44), delayed (n = 53), positive intraoperative cultures (n = 13) and late-acute (n = 8). The culture sensitivities of sonicate fluid, periprosthetic tissue, synovial fluid and combination of periprosthetic tissue and/or synovial fluid were 69.5, 52.8, 54.8 and 60.2%, respectively. The specificities were 97.6, 90.3, 93.0 and 89.9%, respectively. Sonicate fluid culture of implants was more sensitive than peri-implant tissue, synovial fluid and combination of periprosthetic tissue and/or synovial fluid for all infection types, though it was especially useful in delayed infection: 91.3% vs. 60.0% (p = 0.0015), 63.2% (p = 0.0005) and 66.7% (p = 0.0001), respectively. When sonicate fluid culture of implants was performed in addition to conventional cultures, the sensitivity increased significantly in total (from 60.2 to 77.1%) and delayed PJI (from 45.1 to 71.7%). On the other hand, for early PJI, sonicate fluid culture of prosthesis was not superior to conventional diagnostic methods.

[Joint infections of the hand]

Joint infections of the hand may lead to irreversible lesions and impairment of hand function due to early cartilage damage. Furthermore, persistent infections which are not treated immediately can cause osteitis and/or spread systemically. Finger joints are prone to infection due to bite wounds or crush and sharp injuries. Whereas the wrist is often affected in patients with immunosuppression or chronic diseases, such as diabetes mellitus. If diagnosis and therapy are delayed, joint damage may be inevitable. Therefore, urgent treatment of the infected joint is imperative to preserve the function of the hand. This article reviews the current diagnostics and treatment of joint infections of the hand.

Spontaneous radioscapholunate fusion after septic arthritis of the wrist: a case report

Bacterial septic arthritis rarely occurs in the upper extremities. Yet, early diagnosis and treatment is important, as a delay in diagnosis results in pain, impaired hand function, and degenerative joint disease. Radioscapholunate (RSL) arthrodesis is a well-established procedure for treating inflammatory arthritis and osteoarthritis (primary or posttraumatic), primarily to achieve pain relief. The wrist deformity correction offers an alternative option to total wrist arthrodesis. Indications for a RSL arthrodesis are osteoarthritis of the radiolunate and radioscaphoid joint with a concomitant intact midcarpal joint. We present a case study of spontaneous RSL fusion post wrist infection caused by a dog bite.