Stefan Sesselmann

Chemokine and cytokine levels in osteoarthritis and rheumatoid arthritis synovial fluid.

To develop a method of the assay of chemokine and cytokine signaling in synovial fluid from patients suffering from osteoarthritis (OA) or rheumatoid arthritis (RA) and evaluate the effect of heterophilic antibodies on the reliability of the data. 21 synovial fluid samples from OA and 16 synovial fluid samples from RA patients were analyzed using a unique 2 step dot sandwich ELISA based micro-well protein array designed to detect heterophilic antibody signaling in the presence or absence of an effective heterophilic blocking reagent with assays carried out for Eotaxin, hGROa, interleukin (IL)-8, IP10, MCP-1, MCP-2, MIG, RANTES, TARC and IL-6. Array analysis reveals that the selective presence of heterophilic antibodies interferes with the accurate assay of synovial fluid samples from a minority of RA patients but not OA synovia. Using a commercial blocking diluent OA and RA synovial fluids reveal significant differences in chemokine content (IL-6, Eotaxin, hGROa, MCP-2, MIG, TARC, IL-8, RANTES). Using a two-step assay protocol it is possible to readily detect inappropriate antibody signaling due to heterophilic antibodies and devise a protocol designed to eliminate this problem thereby more accurately quantify cytokines and chemokines specific to both RA and OA fluids.

Radiostereometric migration analysis of the Lubinus SP II hip stem: 59 hips followed for 2 years.

Abstract The aim of this prospective study was to analyze the migration pattern of the Lubinus SP II hip stem and to evaluate the clinical results. Fifty-nine patients were followed for 2 years. Translational and rotational micromotion of the implant was measured by radiostereometric analysis (RSA) and the Harris hip score (HHS), and the Charnley classification was used to assess the clinical outcome. Although there was a very small, but statistically significant, distal migration of 0.04±0.83 mm, the prosthesis was found stable at 2 years of follow-up. The main migration in this direction took place between 6 months and 1 year. Maximum total point motion (MTPM) showed a mean of 0.99±0.69 mm. Good clinical outcome with HHS results of 42±11 before and 79±16 at 2 years after surgery was observed. The Charnley classification showed increasing additional impairments in the 2-year interval, which is likely to influence the HHS results of future follow-ups. The migration values measured in the present study are far below the thresholds considered clinically relevant in literature. Thus, the conclusion can be drawn that the implant is not at risk for early aseptic loosening. Long-term RSA is required to assess possible late migration.

Migration measurement of the cemented Lubinus SP II hip stem - a 10-year follow-up using radiostereometric analysis.

Abstract In a previous radiostereometric analysis (RSA) of the Lubinus SP II (Link, Hamburg, Germany), which is one of the most often used cemented hip stems worldwide, our research group detected a very small but statistically significant distal migration of -0.03±0.17 mm 2 years after surgery compared to the postoperative radiograph. Maximum subsidence occurred between 6 and 12 months. The implant appeared to have stabilized after 2 years. The mean value of maximum total point motion (MTPM) was 0.99±0.69 mm, which was detected 2 years after surgery. The purpose of this study was to analyze the migration pattern and to verify the predictive value of short-term RSA of the Lubinus SP II stem after 10 years. After a follow-up of 5 and 10 years, 38 and 27 out of 100 patients remained available for further assessment, respectively. No statistically significant implant translation or rotation was found along or about the axes of the global coordinate system 5 and 10 years after surgery with respect to the postoperative radiograph. Furthermore, the MTPM was stable in both follow-up periods. The results suggest that the Lubinus SP II hip stem is still stable 10 years after surgery, supporting that determining prognosis by short-term RSA follow-up of 2 years could be an appropriate tool for appraisal of implant behavior 10 years after surgery.

Radiostereometric migration analysis of the Cerafit femoral stem: 28 patients followed for 2 years.

Abstract Radiostereometric analysis (RSA) is the gold standard evaluating micromovements after total hip arthroplasty. The aim of this study was to investigate the migratory pattern of an uncemented femoral stem during the first 2 years after surgery. We followed 28 patients with a mean age of 57 (SD 13) years for the first two postoperative years. Radiostereometric analysis was used to measure the translation and rotation of the femoral component. The Harris hip score (HHS) was determined to evaluate the clinical outcome. No stem had to be revised. The mean HHS advanced from 35 (SD 11) preoperative to 89 (SD 10) 1 year after surgery. At the end of the observation period, mean subsidence of the stem was 0.26 mm (SD 0.82). Maximum total point motion (MTPM) was 1.23 mm (SD 1.22). The main distal migration took place up to 6 weeks after surgery with nearly no further subsidence up to 2 years postoperatively. All the measured migrations of the hip stem were very small. Results of the HHS demonstrate good clinical outcome. Long-term RSA is necessary to assess possible late migration of the Cerafit standard femoral stem.

CD3+ lymphocytosis in the peri-implant membrane of 222 loosened joint endoprostheses depends on the tribological pairing

Background and purpose — The most frequent cause of arthroplasty failure is aseptic loosening—often induced by particles. Abrasion material triggers inflammatory reactions with lymphocytic infiltration and the formation of synovial-like interface membranes (SLIM) in the bone–implant interface. We analyzed CD3 quantities in SLIM depending on articulating materials and possible influences of proven material allergies on CD3 quantities. Patients and methods — 222 SLIM probes were obtained from revision surgeries of loosened hip and knee arthroplasties. SLIM cases were categorized according to the SLIM-consensus classification and to the particle algorithm. The CD3 quantities were analyzed immunohistochemically, quantified, and correlated to the particle types. Results — Metal–metal pairings showed the highest CD3 quantities (mean 1,367 counted cells). CD3 quantities of metal–polyethylene (mean 243), ceramic–polyethylene (mean 182), and ceramic–ceramic pairings (mean 124) were significantly smaller. Patients with contact allergy to implant materials had high but not statistically significantly higher CD3 quantities than patients without allergies. For objective assessment of the CD3 response as result of a pronounced inflammatory reaction with high lymphocytosis (adverse reaction), a defined CD3 quantity per high power field was established, the “CD3 focus score” (447 cells/0.3 mm2, sensitivity 0.92; specificity 0.90; positive predictive value 0.71; negative predictive value 0.98). Interpretation — The high CD3 quantities for metal–metal pairings may be interpreted as substrate for previously described adverse reactions that cause severe peri-implant tissue destruction and SLIM formation. It remains unclear whether the low CD3 quantities with only slight differences in the various non-metal–metal pairings and documented contact allergies to implant materials have a direct pathogenetic relevance.

Classification of Polyethylene Particles and the Local CD3+ Lymphocytosis in Histological Slices

In 2014, about 400.000 endoprosthetic operations were performed in Germany [1]. Unfortunately, the lifespan is limited and already after 10 years 5 percent of the patients have primary complaints [2]. All the more important it is to clarify the causes for this failure. One main cause is an immune response to abrasion particles of the implant, an effect which is assumed to be correlated with occurrence and count of CD3+ immune/inflammatory cells [3]. For the further analysis of this effect, computer-aided classification and image analysis methods provide a high value for the medical research. Aim of this work was the development of an threshold-based algorithm for the segmentation of polyethylene abrasion particles and the CD3+ immune/inflammatory response of histological slice images.

Radiostereometric migration measurement of an uncemented Cerafit® femoral stem: 26 patients followed for 10 years

Abstract Radiostereometric analysis (RSA) is the gold standard for evaluating micromotions of orthopaedic implants. The method is applied for identifying novel design weaknesses in endoprostheses. Current research frequently assesses relatively short time periods. Short-term RSA studies have been widely used for predicting the long-term stability of many hip prosthetic designs, but only a few studies have focused on uncemented hip implants, especially for extended periods. The purpose of this study was to analyse the migration pattern of the Cerafit® femoral stem within 10 years and to verify the predictive value of short-term RSA after 2 years for this uncemented femoral hip stem. Twenty-six patients were followed for 10 years. Ten years after implantation, a mean subsidence of 0.22 mm±0.56 mm, a mean internal rotation of 0.59°±1.67° and a mean maximum total point motion (MTPM) of 1.28 mm±0.54 mm were detected. The main migration took place in the first 6 weeks after surgery (subsidence of 0.36 mm±0.73 mm; internal rotation of 0.62°±1.49°, MTPM of 1.05 mm±0.68 mm). All the migration values measured were small. No late-onset migration was observed. This study suggests that the Cerafit® implants are stable after 10 years. Thus, RSA could be the best tool to assess long-term implant behaviour.