Mycoplasma as a possible trigger for the development of idiopathic avascular necrosis of the femoral head

BACKGROUND: The death of bone tissue cells with impaired blood supply, followed by the development of secondary arthrosis/arthritis of the adjacent joint, is most characteristic of osteonecrosis of the femoral head. This condition is common in young patients mainly in men of working age. Hip arthroplasty at a young age has a high risk of loosening of the endoprosthesis components, which can lead to many repeated surgical interventions. In recent years, hypotheses about the possible role of infectious agents in articular pathology have been discussed, as evidenced by the detection of specific antibodies and antigens of pathogens in the joint fluid and periarticular tissues. Mycoplasmas can trigger the development of osteonecrosis because the bone marrow is the main depot and source of endogenous reinfection (when immunity is weakened). 
АIM: This study aimed to identify signs of the presence of mycoplasmas in the soft tissues of the hip joint and bone marrow of the femur during hip arthroplasty in patients with idiopathic avascular necrosis of the femoral head. 
MATERIALS AND METHODS: Clinical and laboratory data of 36 patients with idiopathic aseptic necrosis of the femoral head who underwent total hip arthroplasty were analyzed, and 11.1% of the patients had a history of sexually transmitted diseases. The tissues of the synovium and bone marrow were examined by polymerase chain reaction for the presence of DNA to sexually transmitted infections. 
RESULTS: The average age of the patients was 42.7 years, and the average period from disease onset to the time of surgery was 46.2 months. Bilateral joint damage was found in 78% of cases, and 91.7% of the patients had stage 4 femoral head disease (ARCO). The preoperative Harris score was 33.7 points on average. In history, 4 (11.1%) patients had sexually transmitted diseases. During the study, when analyzing tissue samples of the synovial membrane and bone marrow, DNA fragments of Chlamydia trachomatis, Mycoplasma genitalium, Ureaplasma spp., and M. hominis were not isolated in any case, including in patients with previous mycoplasma and chlamydial infection. 
CONCLUSION: The absence of mycoplasma suggests that a history of sexually transmitted diseases does not significantly affect the outcomes of hip arthroplasty in aseptic necrosis of the femoral head.