Epidemiological samplings for long-term HBM-studies during a pandemic situation - Experiences and lessons-learned, the German Environmental Specimen Bank during the COVID-19 pandemic.

For the investigation of diseases and other harmful environmental influences (e.g., chemicals) epidemiological studies rely on high quality human samples, among others. Collecting samples and data in the field can pose an enormous challenge to the study team with regard to health protection and occupational safety, especially in the context of a pandemic where there was great uncertainty about the biological risks associated with SARS-CoV-2. The German Environmental Specimen Bank (German ESB) is a key element of environmental and human biomonitoring in Germany with the aim to document and assess trends of human and environmental exposure to chemicals over time and to provide scientific data for policy decision makers. Starting with a pilot study in 1978 human samples are now collected at four sampling locations annually, while sampling is carried out with a highly standardized mobile laboratory since 2013. Due to the corona pandemic 3 of 4 ESB sampling campaigns had to be cancelled in 2020. However, a continuous sampling is crucial to generate current policy relevant data on chemical exposure. Hence, a protection and hygiene concept has been developed including COVID-19 testing with the goal to protect the health of participants and employees during sampling and to meet legal requirements, while sustaining the standardized procedures of sampling and sample preparation. The concept is based on a flexible approach to allow adjustments to changing government regulations and recommendations in the course of the pandemic. By implementing this concept, all samplings were successfully carried out in 2021 & 2022, with the pandemic still ongoing. This paper provides an example of good practice and valuable insights in how to collect human samples during a pandemic.

Wear patterns of taper connections in retrieved large diameter metal-on-metal bearings.

Wear of the modular taper between head and shaft has been related to clinical failure resulting from adverse reactions to metallic debris. The problem has become pronounced in large metal-on-metal bearings, but the mechanism has not yet been fully understood. We analyzed retrieved components from five patients revised with various diagnoses. Two distinct wear patterns were observed for the head tapers. Three samples demonstrated "asymmetric" wear towards the inner end of the head taper. The other two showed "axisymmetric" radial wear (up to 65 µm) presenting the largest wear volumes (up to 20 mm(3)). Stem tapers demonstrated relatively little wear, and the fine thread on the stem taper surface was observed to be imprinted on the taper inside of the head. Our findings demonstrate that the cobalt-chrome head wears preferentially to the titanium stem taper. "asymmetric" wear suggests toggling due to the offset of the joint force vector from the taper. In contrast, samples with "axisymmetric" radial wear and a threaded imprint suggested that corrosion led to head subsidence onto the stem taper with gradual rotation.

MicroHip: a minimally invasive procedure for total hip replacement surgery using a modified Smith-Peterson approach.

This article presents an anterior, minimally invasive surgical approach to the hip joint, aligned along an inter-nervous plane. Positioning in lateral decubitus position on a regular operation table obviates the need for a special orthopedic or fracture table. Traction is not applied. Most of the instruments used for this procedure are standard instruments for reaming of the acetabulum and positioning of the cup; specific, angulated instruments are recommended at least for obese patients. Using an incision of < 6-8 cm, this MI approach provides a perfect view of the acetabulum and proximal femur,including natural landmarks for proper implant positioning. The approach follows the gap between the tensor muscle and the gluteus medius muscle, using part of the anterior ilo-femoral Smith-Peterson approach. No tendons or muscles are cut or detached. The joint capsule is split and left in place. The hip joint is not dislocated; we perform the osteotomy of the femoral neck in situ. To date we have performed several hundred MicroHip operations, with no nerve lesions or trochanter fractures. Definitive results are not yet available, but our experience to date shows that this method can be used with virtually any patient, while such factors as hospitalization time, pain, blood loss and work incapacity can be cut almost in half. The MicroHip technique, used by an increasing number of clinics around the world, can be successfully applied by good surgeons after suitable training.