Reconstruction of mechanical leg axis using non-modular cemented hinged prosthesis in complex primary total knee arthroplasty.

PURPOSE: Modular cementless knee arthroplasty systems are capable of precise reconstruction of the mechanical axis. However, they are considered more susceptible to complications. In contrast, non-modular cemented systems are said to be more forgiving and show good long-term results. The aim of this study was to investigate the resulting leg axis after implantation of a non-modular cemented rotating hinged knee prosthesis. Furthermore, potential risk factors for the occurrence of malalignment and complications should be identified. METHODS: Between 2005 and 2015, 115 patients could be included in this monocentric retrospective cohort study. All patients underwent primary hinged non-modular cemented total knee arthroplasty. Preoperative and postoperative standardized long radiographs were analysed to determine resulting leg axis. Furthermore, epidemiological and intraoperative data as well as perioperative complications were surveyed. RESULTS: Average leg axis was 5.8° varus preoperatively and 0.6° valgus postoperatively. Considering an axis deviation of 3° as the target corridor, 27% of all cases examined were outside the desired range. 21% cases showed a femoral deviation from the target corridor and 15% showed a tibial deviation. There was a significant relationship between the preoperative mLDFA and the mechanical alignment of the femoral component (R = 0.396, p < 0.001) as well as between the preoperative mMPTA and the mechanical alignment of the tibial component (R = 0.187, p = 0.045). The mean operative duration was 96 min. No periprosthetic fractures were observed within the study cohort. CONCLUSION: The main result of the present work is that a non-modular cemented rotating hinged knee arthroplasty system can reconstruct the mechanical leg axis precisely and comparable to modular cementless and unconstrained total knee prostheses. Component malalignment is primarily dependent upon extraarticular deformity preoperatively. Periprosthetic fracture rates and duration of surgery were lower compared with current literature. LEVEL OF EVIDENCE: Level III: Retrospective cohort study.

Cones and sleeves present good survival and clinical outcome in revision total knee arthroplasty: a meta-analysis.

PURPOSE: The fixation of revision total knee arthroplasties (rTKA) tends to be difficult, leading to a reduction in implant survival. One option for achieving a more stable anchorage is to use metaphyseal cones and sleeves. The objective of the present paper is to provide a current comparative meta-analysis on survival and clinical results of cones vs. sleeves, with a differentiation between the short- and long-term outcome. METHODS: A search of the literature was conducted systematically to include original papers from 2010 to June 2021. The following parameters were taken into account: revision for aseptic loosening, revision for any reason, periprosthetic joint infections (PJI), KSS as well as KSFS. Studies with a mean follow-up of at least 60 months were defined to be long-term follow-up studies (LT). All other studies were included in the short-term (ST) study analysis. A pooled incidence was used as a summary statistic using a random intercept logistic regression model. RESULTS: The present meta-analysis included 43 publications with 3008 rTKA. Of these, 23 publications with 1911 cases were allocated to the sleeve group (SG) and 20 papers with 1097 cases to the cone group (CG). CG showed overall numerically higher complication rates in short- and long-term follow-up, compared with SG. Aseptic loosening occurred at a rate of 0.4% in SG (LT) and 4.1% in CG (LT) (p = 0.09). Periprosthetic joint infection (PJI) was more frequent in the cone group (7% in ST and 11.7% in LT) than in the sleeve group (3.4% in ST and 4.9% in LT, p = 0.02 both). The total revision rate was 5.5% in SG (LT) and 14.4% in CG (LT) (p = 0.12). The clinical scores were also comparable between the two groups. Hinged prothesis were used more frequent in the cone group (ST p < 0.001; LT p = 0.10), whereas CC type protheses were used more frequently in the sleeve group (ST p < 0.001; LT p < 0.11). CONCLUSIONS: This meta-analysis takes into account the longest follow-up periods covered to date. Both cones and sleeves represent a reliable fixation method in the case of severe bone loss in rTKA, although the higher rate of PJI after cone fixation remains a source of concern. A metaphyseal fixation of hinged implants should be taken into account. LEVEL OF EVIDENCE: II (meta-analysis).

Knee Arthrodesis Affects Gait Kinematics More in the Ankle Than in the Hip Joint.

Background and Objectives: No gold standard exists for treating persistent periprosthetic knee infections. Knee arthrodesis represents one treatment concept for extensive bone defects and extensor system insufficiencies. It has already been shown that knee arthrodesis leads to a significant reduction in one's quality of life. The aim of this survey was to assess the influence of knee arthrodesis on the neighboring joints on the basis of gait analysis data. Our hypothesis is that the hip and ankle joints are negatively influenced by knee arthrodesis in the process of walking. Materials and methods: We performed six pedobarographic and four gait analytical measurements in six patients 2.4 ± 1.6 years after receiving knee arthrodesis at the operating ages of 69.1 ± 9.2 years. Gait analysis consisted of time-distance parameters/minute (number of steps, double support, cycle time, standing phase, step length, gait speed). A healthy group of test subjects (n = 52) was included as the control cohort. Gait analysis was conducted using a three-dimensional movement system and three force-measuring platforms to determine the ground reaction force. Foot pressure was measured using a pedography platform. Results: Five of six patients presented an incomplete rolling movement over the toes on the side that was operated on, presenting with a gait line ending in the forefoot area. All of the patients bore less weight on the side that was operated on. Three of six patients demonstrated a pathological gait line with a healthy opposite side ending in the forefoot area. All of the patients exhibited a reduction in gait speed and step length and a lower number of steps. All of the patients had a prolonged double support/cycle time. Conclusions: Isolated knee arthrodesis is associated with reduced forefoot repulsion, restricted movement on the side receiving the operation, and reduced movement in the ankle/knee joint. The hip showed norm deviations in the hip moment/angle. Knee arthrodesis causes reduced gait kinetics/kinematics. Our survey shows that the relative joint moments of the ankle joint and hip are often reduced. The ankle joint is more affected compared to the hip.

Cytotoxic effect of sodium hypochlorite (Lavanox 0.08%) and chlorhexidine gluconate (Irrisept 0.05%) on human osteoblasts.

PURPOSE: Soft tissue, bone and joint infections are severe complications in orthopedic and traumatological surgery. Lavanox (0.08% NaOCl) and Irrisept (0.05% chlorhexidine gluconate, CHG) are industrially produced antiseptic solutions commonly used in infection treatment. Regarding this clinical indication, the microbicidal effect is often investigated, but toxicity to osteoblasts has rarely been examined. This is important to decide whether these solutions should be used in septic situations in which bone healing must take place. The hypothesis of the present study is that NaOCl and CHG are cytotoxic to osteoblasts even after a short exposure time. METHODS: Human osteoblasts were isolated from donors with osteoarthritis during total knee and hip arthroplasty. Cells were cultivated and treated with both antiseptic solutions for 2, 5 and 10 min in different dilutions. Toxicity was quantified by counting cells, lactate dehydrogenase (LDH) expression, spectrophotometric quantification via XTT assay and FDA/PI fluorescence microscopy. RESULTS: Analyzing viable cells after treatment with both antiseptics showed a significant decrease in viable cells through LDH expression test, XTT assay, fluorescence microscopy and light microscopy, depending on concentration. The time dependence showed a trend to more cell death at longer exposure times, without significance. CONCLUSION: Toxic effects on osteoblasts were shown after treatment with 0.08% NaOCl and 0.05% CHG after an exposure time of 2 min which also was concentration dependent. There was no difference in cytotoxicity between both antiseptics. In conclusion, these antiseptic solutions may be used with caution in situations requiring bone healing. Trial registration number Local ethics committee registration number: 5176-07/16.

Robot-Assisted Gait Self-Training: Assessing the Level Achieved.

This paper presents the technological status of robot-assisted gait self-training under real clinical environment conditions. A successful rehabilitation after surgery in hip endoprosthetics comprises self-training of the lessons taught by physiotherapists. While doing this, immediate feedback to the patient about deviations from the expected physiological gait pattern during training is important. Hence, the Socially Assistive Robot (SAR) developed for this type of training employs task-specific, user-centered navigation and autonomous, real-time gait feature classification techniques to enrich the self-training through companionship and timely corrective feedback. The evaluation of the system took place during user tests in a hospital from the point of view of technical benchmarking, considering the therapists' and patients' point of view with regard to training motivation and from the point of view of initial findings on medical efficacy as a prerequisite from an economic perspective. In this paper, the following research questions were primarily considered: Does the level of technology achieved enable autonomous use in everyday clinical practice? Has the gait pattern of patients who used additional robot-assisted gait self-training for several days been changed or improved compared to patients without this training? How does the use of a SAR-based self-training robot affect the motivation of the patients?

Vancomycin is toxic to human chondrocytes in vitro.

INTRODUCTION: Vancomycin powder (VP) is a well-established topical antibiotic used in spinal surgery to prevent surgical site infections. More recently its extension to hip and knee arthroplasty was introduced. The aim of this study was to examine toxic effects of VP on the viability of human chondrocytes. Our hypothesis was that VP damages human chondrocytes in vitro with increasing concentration and length of exposure. MATERIAL AND METHODS: Primary human chondrocytes were isolated and cultured from donated human knee joints. VP was added to these cultures with increasing concentrations (0-50 mg/ml) and length of exposure (0-336 h). Toxicity and viability were analyzed using LDH und XTT Elisa assays. Cell structure and determination of vital versus dead cells were visualized using light microscopy and fluorescence microscopy. RESULTS: Light microscopy and fluorescence microscopy visualized defect cell structures and cell death proportional to increasing dose and length of exposure to VP. The analysis of LDH activity data showed toxic effects on chondrocytes as early as 2,5 min after exposure to VP. XTT activity data revealed a significant toxic threshold of a VP concentration above 12.5 mg/ml. CONCLUSIONS: These results show that exposure to high VP concentrations yields to a damage of human chondrocytes in vitro. Chondrotoxicity is an immediate effect that is proportional to VP concentration. Therefore, the intraarticular use of high concentrations of vancomycin powder in the presence of native cartilage tissue must be considered critically.

[Bone defect management in revision knee arthroplasty]. / Knochendefektmanagement in der Revisionsknieendoprothetik.

BACKGROUND: In 2019, 124,677 primary total knee arthroplasties and 14,462 revision TKA were performed in Germany. This corresponds to a percentage of 11.6%. According to the EPRD, the probability of further revision surgery after the first exchange operation is around 15%. REASONS: The most common reason for revision surgery is still aseptic loosening with 23.9%. One possible cause could be the difficult fixation of revision total knee arthroplasty. If the bone quality is insufficient, cement-free or cemented diaphyseal anchoring of the prosthesis is often not sufficient to ensure adequate fixation. As a rule, defect management and fixation of the implant are based on the defect situation and the quality of the bone. Therefore, revision total knee arthroplasties based on the fixation principle of Jones et al. should be sufficiently fixed in at least 2 zones. TECHNIQUES: There are various techniques for stable anchoring of revision implants. In addition to cemented or cementless stem anchoring, bone allografts, wedges and blocks and, in recent years, cones and sleeves have become increasingly popular. In the present work, the various options for a stable anchoring of revision implants are presented and evaluated. In addition, the clinical and radiological outcome of cones vs. sleeves in bone defect management in revision knee arthroplasty will be compared.

[Knee realignment osteotomy in adults]. / Kniegelenksnahe Umstellungsosteotomien des Erwachsenen.

BACKGROUND: Nowadays, osteotomy near the knee joint for axial deformities has become an indispensable surgical procedure for joint preservation in the orthopaedic-surgical spectrum. The exact localization and analysis of the deformity are crucial to restoring physiological loading conditions of the entire leg by means of a suitable osteotomy. PROCEDURES: Thus, above all, the medial "open-wedge" osteotomy has established itself as a standard procedure for the treatment of gonarthrosis caused by varus malalignment. Furthermore, the varus closed-wedge osteotomy of the distal femur also shows very good long-term results. Basically, osteotomies close to the knee are causal corrections in which biological and mechanical aspects must be taken into account. Thus, the correct indication, attention to risk factors, and surgical technique determine the long-term success of the procedure. The doctrine of femoral valgus deformity and the resulting lateral arthrosis, on the other hand, must be reconsidered according to the latest knowledge.

Cone beam-navigated core decompression of bone marrow edema syndrome.

INTRODUCTION: The aim of the study was to compare decompression of bone-marrow edema or osteonecrosis of the proximal femur by means of a cone beam-based imaging and navigation system (cone beam-navigated decompression, CBND) with decompression by the conventional technique of drilling using fluoroscopy (FD). MATERIALS AND METHODS: The data of patients with bone-marrow edema syndrome treated between 2016 and 2018 by drilling of the proximal femur in CBND or FD technique were compared retrospectively. RESULTS: Each treatment group included 20 patients. The mean operating time for CBND was 16.4 ± 5.8 min, compared with 29.1 ± 20.8 min for FD (p = 0.018). The lesion was definitely reached by CBND in 19/20 patients. Eighteen of the 20 patients in the CBND group reported that their pain decreased after the treatment, compared with 12/20 patients in the FD group (p = 0.065). The radiation dosage was significantly higher (p < 0.001) for CBND than for FD. CONCLUSION: Decompression by CBND can be carried out safely and without complications. The advantages of CBND over FD are the minimally invasive access and the ability to address the affected area precisely with only one drilling maneuver. The high radiation dose of CBND can be reduced using low-dose protocols.

Good clinical and radiological results of total knee arthroplasty using varus valgus constrained or rotating hinge implants in ligamentous laxity.

PURPOSE: The optimal degree of constraint of a total knee arthroplasty for treatment of knee osteoarthritis with ligamentous laxity is under debate. While varus valgus constrained knees require a minimum level of ligamentous stability, rotating hinge knees can even be implanted if the collateral ligaments have been lost completely. It seems plausible that joint kinematics are determined by implant design in rotating hinge knees, whereas varus valgus constrained knees may be influenced by remaining stabilizers. This may result in more predictable clinical results of hinge knees. The hypothesis of the present study, therefore, was that stability and clinical outcome are better after total knee arthroplasty using rotating hinge knees than after using varus valgus constrained knees. METHODS: All patients who were treated using a mobile-bearing varus valgus constrained knee or a rotating hinge knee for treatment of end-stage osteoarthritis and ligamentous laxity were included. At follow-up, clinical scores were determined (WOMAC, VAS, KSS, FJS, Lysholm). Furthermore, body mass index, operating time, and postoperative complications were documented. Whole leg radiographs as well as patella axial radiographs were analyzed for implant alignment and patella tracking. RESULTS: Eighty-five patients were included in this retrospective study. Both groups showed an average range of motion of 113°. No significant difference between the two groups was observed for any of the scores recorded. In the rotating hinge knee group, a more precise tibia positioning in relation to the mechanical axis but also a significant lateralisation and tilting of the patella were seen, compared with the varus valgus constrained knee group. CONCLUSIONS: Rotating hinge knees did not perform better than mobile-bearing varus valgus constrained knees clinically. Both prosthesis types showed equally good clinical outcomes with regard to stability, mobility, satisfaction, pain and operating time. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

CTLA-4 Mediates Inhibitory Function of Mesenchymal Stem/Stromal Cells.

Mesenchymal stem/stromal cells (MSCs) are stem cells of the connective tissue, possess a plastic phenotype, and are able to differentiate into various tissues. Besides their role in tissue regeneration, MSCs perform additional functions as a modulator or inhibitor of immune responses. Due to their pleiotropic function, MSCs have also gained therapeutic importance for the treatment of autoimmune diseases and for improving fracture healing and cartilage regeneration. However, the therapeutic/immunomodulatory mode of action of MSCs is largely unknown. Here, we describe that MSCs express the inhibitory receptor CTLA-4 (cytotoxic T lymphocyte antigen 4). We show that depending on the environmental conditions, MSCs express different isoforms of CTLA-4 with the secreted isoform (sCTLA-4) being the most abundant under hypoxic conditions. Furthermore, we demonstrate that the immunosuppressive function of MSCs is mediated mainly by the secretion of CTLA-4. These findings open new ways for treatment when tissue regeneration/fracture healing is difficult.

Long-term effects of intravenous iloprost therapy in patients with bone marrow oedema of the hip.

Bone marrow oedema (BMO) is a multifactorial condition. Various conservative treatment options include analgesic therapy, immobilisation of the affected joint and/or systemic intravenous iloprost or bisphosphonate therapy. Many studies confirm the positive effect of iloprost therapy in larger joints, e.g. the hip and knee joint, after short-term follow up. The objective of this study was to investigate that treatment with iloprost leads to positive long-term functional and radiological outcomes for BMO of the hip joint. Nineteen patients with BMO of the hip joint, ARCO stage 1-2, were included in this study. The Harris Hip Score, the SF-36, the WOMAC score and a visual analogue pain scale (VAS) were evaluated before and 29 ± 11 months after Ilomedin therapy. All patients underwent MRI for radiological follow-up monitoring three months after treatment. Significant improvements were found in the WOMAC Index and the VAS. In 79% of patients, follow-up MRI after three months showed complete regression of the oedema. Based on the positive results of our study, we support treatment with iloprost for BMO of the hip joint at ARCO stage 1-2.

Effects on proprioception by Kinesio taping of the knee after anterior cruciate ligament rupture.

INTRODUCTION: The use of Kinesio tape (KT) to improve proprioception is a matter of considerable debate. In comparison, the rupture of the anterior cruciate ligament is a sufficiently well-investigated injury with a proven compromise of proprioception. The objective of the present study was to assess a supportive effect on proprioception after KT application, taking the anterior cruciate ligament (ACL) rupture as an example. MATERIALS AND METHODS: Forty-eight patients who had suffered an ACL rupture, confirmed clinically and by magnetic resonance imaging, and who were treated conservatively or were awaiting surgery were included in this study. In all patients, a gait analysis was performed on the affected leg before and after KT application. In addition, the IKDC score, the Lysholm score, stability using the Rolimeter, and the angle reproduction test were determined. RESULTS: Thirty-nine men and nine women who had had an ACL rupture for at least 3 weeks were included in the study. Significant improvements were achieved on the affected knee joint for the gait analysis parameters touchdown and unrolling, cadence, stability and stance phase as well as an extension of the hip joint. The Lysholm score improved from 79.3 to 85.8 (p < 0.001) and the IKDC score from 60.2 to 71.3 points (p < 0.001). Significant improvements were achieved in the Rolimeter and angle reproduction test. CONCLUSIONS: The use of KT has a positive effect on proprioception in patients with an anterior cruciate ligament rupture. Therefore, the application may improve gait pattern as well as the subjective function of the affected knee joint.

Effects of Kinesio taping compared to arterio-venous Impulse System™ on limb swelling and skin temperature after total knee arthroplasty.

PURPOSE: It is an established fact that post-operative (p.o.) soft-tissue swelling and lymphoedema after total knee arthroplasty (TKA) have a major influence on the p.o. early functional outcome. Kinesio taping has a proven clinical effect in increasing lymph drainage. Despite the decades of experience gained and the assumed positive effects, hardly any investigations have been conducted to date on the influence of Kinesio taping on the p.o. healing process after TKA. The objective of the present study was to test the hypothesis that Kinesio taping used as a lymph application leads to a reduction of p.o. soft-tissue swelling. As a secondary objective, it was to be tested whether there is an effect on skin temperature as a surrogate parameter for dermal micro-circulation. METHODS: In this prospective study with a historical control (A-V Impulse System™ group), 42 subjects were included and treated with Kinesio taping after implantation of a TKA. The patients of the study group were treated immediately p.o. with Kinesio® Tex Gold™ fan cut tape as a lymph application with a common base. A thermographic temperature determination of the knee joint operated on was performed on each patient in the supine position every day from the first to the seventh p.o. day. The leg circumference was documented daily at eight specified measuring points on both lower limbs. As a statistical analytical approach, the so-called principal component analysis was used. An analysis of variance was performed. The significance level was set at p < 0.001. RESULTS: The course of soft-tissue swelling of the study group did not differ from that of the control group at any point in time. For the temperature course of the medial wound aspect, no difference was seen between the Kinesio taping study group and the A-V Impulse System™ group. In contrast, the temperature course of the lateral wound aspect showed a reproducibly higher temperature in the Kinesio tape group than in the control group (0.6 °C (0.5-0.8), p < 0.001). CONCLUSION: The hypothesis of the study that Kinesio taping as a lymph application induces a reduction of soft-tissue swelling after TKA must be rejected on the basis of the present data. Solely the temperature of the lateral wound aspect was higher in the Kinesio taping group than in the control group, so that an increased blood circulation can be assumed here. Considering that the actively working A-V Impulse System™ used in the control group also increases local blood circulation, the effect of the passive Kinesio tape is surprising. However, this was not reflected in a quicker wound healing, as the day of last wound secretion was the same in both groups. Kinesio taping as a lymph application represents an equivalent alternative to the A-V Impulse System™ for therapy after total knee arthroplasty with regard to soft-tissue swelling and wound healing.

A Pronounced Inflammatory Activity Characterizes the Early Fracture Healing Phase in Immunologically Restricted Patients.

Immunologically restricted patients such as those with autoimmune diseases or malignancies often suffer from delayed or insufficient fracture healing. In human fracture hematomas and the surrounding bone marrow obtained from immunologically restricted patients, we analyzed the initial inflammatory phase on cellular and humoral level via flow cytometry and multiplex suspension array. Compared with controls, we demonstrated higher numbers of immune cells like monocytes/macrophages, natural killer T (NKT) cells, and activated T helper cells within the fracture hematomas and/or the surrounding bone marrow. Also, several pro-inflammatory cytokines such as Interleukin (IL)-6 and Tumor necrosis factor α (TNFα), chemokines (e.g., Eotaxin and RANTES), pro-angiogenic factors (e.g., IL-8 and Macrophage migration inhibitory factor: MIF), and regulatory cytokines (e.g., IL-10) were found at higher levels within the fracture hematomas and/or the surrounding bone marrow of immunologically restricted patients when compared to controls. We conclude here that the inflammatory activity on cellular and humoral levels at fracture sites of immunologically restricted patients considerably exceeds that of control patients. The initial inflammatory phase profoundly differs between these patient groups and is probably one of the reasons for prolonged or insufficient fracture healing often occurring within immunologically restricted patients.

Temporary arthrodesis using fixator rods in two-stage revision of septic knee prothesis with severe bone and tissue defects.

PURPOSE: The present study describes a new temporary arthrodesis procedure, which aims for septic knee prosthesis replacement, in particular for larger bone and soft tissue defects. Our technique offers high stability and full weight-bearing capacity of the knee joint. METHODS: The study included 16 patients with major bone defects (AORI type IIb or greater) after receiving a radical debridement and a septic two-stage revision total knee arthroplasty. After removing the infected prosthesis and debridement, two AO fixator rods were positioned into the intramedullary space of the femur and tibia. Subsequently, both rods were joined tube-to-tube and adjusted in the center of the knee joint. Finally, the whole cavity of the knee joint was filled with PMMA. The number of previous surgeries, bacterial spectrum, risk factors for further infection and reinfection rates was recorded. Immediately after the temporary arthrodesis, radiographs of the knee with the enclosed spacers were taken in order to compare to previous radiographs and avoiding to miss possible spacer loosening. RESULTS: Nine of sixteen patients underwent more than two revision surgeries before receiving our new arthrodesis technique. No cases of spacer loosening were observed in all 16 patients; further, there were no peri-implant fractures, and four persistent infections were noted. CONCLUSIONS: Temporary arthrodesis using AO fixator rods offers a high stability without loosening. Its potential to replace conventional augmentation techniques should be taken into account, particularly in the case of larger bone and tissue defects. In clinical practice, the cemented spacer using AO fixator rods could be an alternative technique for temporary knee arthrodesis after septic debridement. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

Human osteoblast damage after antiseptic treatment.

PURPOSE: Antiseptics are powerful medical agents used for wound treatment and decontamination and have a high potential for defeating joint infections in septic surgery. Both chlorhexidine and polyhexanide are frequently used in clinical practice and have a broad antimicrobial range, but their effect on human osteoblasts has not been sufficiently studied. Our objective was to investigate the toxic effects of polyhexanide and chlorhexidine on human osteoblasts in vitro to evaluate their clinical applicability in septic surgery. METHODS: We isolated and cultivated human osteoblasts in vitro and assayed the toxic effects of chlorhexidine 0.1% and polyhexanide 0.04%, concentrations commonly applied in clinical practice. Toxicity analysis was performed by visualisation of cell structure, lactate dehydrogenase (LDH) activity and evaluation of vital cells. Toxicity was evaluated by microscopic inspection of cell morphology, trypan blue staining and determination of LDH release. RESULTS: Damaged cell structure could be shown by microscopy. Both antiseptics promoted LDH activity after incubation with osteoblasts. The evaluation of vital osteoblasts showed a significant decrease of vital cells. CONCLUSIONS: Both antiseptics induced significant cell death of osteoblasts at optimum exposure. We therefore recommend cautious use of polyhexanide and chlorhexidine in septic surgery to avoid severe osteoblast toxicity.

Effects of intravenous iloprost therapy in patients with bone marrow oedema of the foot and ankle.

OBJECTIVE: Bone marrow oedema (BMO) is a multifactorial condition. The conservative treatment options include immobilisation of the affected region and systemic intravenous iloprost therapy. Whereas many studies confirm the positive effect of iloprost therapy in larger joints, e.g. knee and hip, there have been few studies of BMO in smaller areas such as the ankle joint or midfoot. The purpose of this study is to show that treatment with iloprost leads to positive long-term outcomes for BMO of the foot and ankle. METHODS: Twenty-three patients with BMO of the ankle joint or midfoot, Association Research Circulation Osseous (ARCO) stages 1-2, were included in this study. A questionnaire was used to record the Ankle-hindfoot, Kaikkonen, SF-36 and VAS scores before and after iloprost therapy. In addition, all patients underwent MRI for radiological follow-up monitoring 3 months after treatment. RESULTS: A significant improvement in function based on the ankle-hindfoot and Kaikkonen scale was demonstrated after iloprost therapy. In 22 patients, follow-up MRI after 3 months showed complete regression of the oedema. CONCLUSION: Based on the positive results of our study, we recommend treatment with iloprost for BMO of the upper ankle joint and foot at ARCO stages 1-2.

Incidence of Secondary Osteoarthritis after Primary Shoulder and Knee Empyema and Its Risk Factors.

Empyema of the joint is an orthopedic emergency that is associated with a prolonged healing process despite adequate surgical and medical therapy. The risk of developing postinfectious osteoarthritis (OA) after successfully treated joint empyema is unknown. Both incidence and risk factors are important for prognostication and would therefore be clinically relevant for the selection of an adequate infectious therapy as well as for the individual follow-up of patients. The aim of this retrospective clinical study was to describe the risk of secondary OA after empyema based on knee and shoulder joint infections after successful primary infection treatment and its risk factors. Thirty-two patients were examined clinically and radiographically after completion of treatment for primary empyema of the knee or shoulder joint. Patients with previous surgery or injections in the affected joint were excluded from the study. The cumulative incidence of new-onset radiographic OA was 28.6%, representing a 5.5-fold increased risk of developing OA compared to the normal population. A figure of 25% of patients underwent total knee arthroplasty after knee empyema. Identified risk factors for primary empyema were obesity, hyperuricemia, and rheumatoid arthritis. Only about 60% of the patients tested positive for bacteria. Staphylococcus aureus, the most common pathogen causing joint empyema, was present in approximately 40% of cases. Secondary osteoarthritis, as a possible secondary disease after joint empyema, could be demonstrated and several risk factors for the primary empyema were identified.

Osteoarthritis synovial fluid activates pro-inflammatory cytokines in primary human chondrocytes.

PURPOSE: Two of the most common joint diseases are rheumatoid arthritis (RA) and osteoarthritis (OA). Cartilage degradation and erosions are important pathogenetic mechanisms in both joint diseases and have presently gained increasing interest. The aim of the present study was to investigate the effects of the synovial fluid environment of OA patients in comparison with synovial fluids of RA patients on human chondrocytes in vitro. METHODS: Primary human chondrocytes were incubated in synovial fluids gained from patients with OA or RA. The detection of vital cell numbers was determined by histology and by using the Casy Cell Counter System. Cytokine and chemokine secretion was determined by a multiplex suspension array. RESULTS: Microscopic analysis showed altered cell morphology and cell shrinkage following incubation with synovial fluid of RA patients. Detection of vital cells showed a highly significant decrease of vital chondrocyte when treated with RA synovial fluids in comparison with OA synovial fluids. An active secretion of cytokines such as vascular endothelial growth factor (VEGF) of chondrocytes treated with OA synovial fluids was observed. CONCLUSIONS: Significantly increased levels of various cytokines in synovial fluids of RA, and surprisingly of OA, patients were shown. Activation of pro-inflammatory cytokines of human chondrocytes by synovial fluids of OA patient supports a pro-inflammatory process in the pathogenesis of OA.