[Diagnostic algorithm "FAI and sports hernia" : Results of the consensus meeting for groin pain in athletes]. / Diagnostik-Algorithmus Grenzbereich "FAI und Sportlerleiste" : Ergebnisse des Konsensustreffens Leistenschmerz beim Sportler.

As a result of the complexity and diversity of diseases in the region of the groin, differentiation of the various soft-tissue and bone pathologies remains a challenge for differential diagnosis in routine clinical practice. In the case of athletes with pain localized in the area of the groin, femoroacetabular impingement (FAI) and athlete's groin must be considered as important causes of the groin pain, whereby the common occurrence of double pathologies further complicates diagnosis. Despite the importance of groin pain and its differential diagnoses in everyday clinical practice, there has been a lack of recognized recommendations for diagnostic procedure to date. To this end, a consensus meeting was held in February 2017, in which a group composed equally of groin and hip surgeons took part. With the formulation of recommendations and the establishment of a practicable diagnostic path, colleagues that are involved in treating such patients should be sensitized to this issue and the quality of the diagnosis of groin pain improved in routine clinical practice.

The 'Hip Vacuum Sign'-a new radiographic phenomenon in femoro-acetabular impingement.

Femoro-acetabular impingement (FAI) is a frequent cause for groin pain in young and active patients. We discovered a so far undescribed radiographic phenomenon only visible in frog-leg lateral radiographs. The aim of this study was to describe this new radiological sign, to determine its prevalence in a symptomatic population and to investigate the correlation to a potential underlying pathology. We retrospectively reviewed all patients, who had been sent to our clinic between 2010 and 2012 for hip complaints. We excluded patients older than 50 years and patients with advanced osteoarthritis. Two independent investigators blinded to clinical data independently examined all images for the presence, location and dimension of a vacuum phenomenon and a potential underlying hip pathology. We included 242 patients. 137 of them showed clinical and radiological signs of FAI. A hip vacuum phenomenon was identified in 20 of 242 patients (8%). Interestingly, all these patients showed distinct signs of femoro-acetabular impingement. In reference to this, the prevalence of the "Hip Vacuum Sign" was 15% (20/137) in symptomatic patients with FAI. There was no correlation with age or gender. We identified a new radiological sign, the "Hip Vacuum Sign", in 15% of symptomatic patients with FAI. It was only visible in frog-leg lateral radiographs. We suggest that it represents a subluxation of the femoral head due to a lever mechanism between the femoral neck and the acetabular rim and is, therefore, a hint for a relevant femoro-acetabular impingement mechanism.

Expression of CD9, CD11b, CD18, CD52 and PDGFR-beta in the interface membrane of loose endoprostheses.

The number of endoprosthesis revision operations is increasing. In a previous analysis using cDNA microarrays, differentially expressed genes were detected in the wear-particle-induced membrane and in the infectious periprosthetic membrane. This study aims at validation of these gene expression profiles in order to find genes that are potentially relevant for the pathogenesis, diagnosis, or therapy of endoprosthesis loosening. Tissue samples from 16 wear-particle-induced and 20 infectious periprosthetic membranes were analyzed by reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization, and immunohistochemistry with regard to the expression of CD9, CD11b, CD18, CD52, and platelet-derived growth factor (PDGFR)-beta. RT-PCR demonstrated cd9, cd11b, cd18, cd52, and pdgfr-beta RNA in all samples. Macrophages and multinuclear giant cells in the wear-particle-induced membranes showed intense immunohistochemical staining for CD9, CD11b, and CD52. The staining of PDGFR-beta was stronger in the infectious membranes, whereas there were no differences for CD18. Using RT-PCR and immunohistochemical analysis, the cDNA-microarray data of cd9, cd11b, cd52, and pdgfr-beta could be validated, whereas the differential expression of cd18 was not confirmed. The potential relevance of these genes for prosthesis loosening is discussed.