Effect of lag screw on stability of first metatarsophalangeal joint arthrodesis with medial plate.

Background: First metatarsophalangeal joint (MTP-1) arthrodesis is a commonly performed procedure in the treatment of disorders of the great toe. Since the incidence of revision after MTP-1 joint arthrodesis is not insignificant, a medial approach with a medially positioned locking plate has been proposed as a new technique. The aim of the study was to investigate the effect of the application of a lag screw on the stability and strength of first metatarsophalangeal joint arthrodesis with medial plate. Methods: The bending tests in a testing machine were performed for models of the first metatarsal bone and the proximal phalanx printed on a 3D printer from polylactide material. The bones were joined using the locking titanium plate and six locking screws. The specimens were divided into three groups of seven each: medial plate and no lag screw, medial plate with a lag screw, dorsal plate with a lag screw. The tests were carried out quasi-static until the samples failure. Results: The addition of the lag screw to the medial plate significantly increased flexural stiffness (41.45 N/mm vs 23.84 N/mm, p = 0.002), which was lower than that of the dorsal plate with a lag screw (81.29 N/mm, p < 0.001). The similar maximum force greater than 700 N (p > 0.50) and the relative bone displacements lower than 0.5 mm for a force of 50 N were obtained for all fixation techniques. Conclusions: The lag screw significantly increased the shear stiffness in particular and reduced relative transverse displacements to the level that should not delay the healing process for the full load of the MTP-1 joint arthrodesis with the medial plate. It is recommended to use the locking screws with a larger cross-sectional area of the head to minimize rotation of the medial plate relative to the metatarsal bone.

Development and validation of lumbar spine finite element model.

The functional biomechanics of the lumbar spine have been better understood by finite element method (FEM) simulations. However, there are still areas where the behavior of soft tissues can be better modeled or described in a different way. The purpose of this research is to develop and validate a lumbar spine section intended for biomechanical research. A FE model of the 50th percentile adult male (AM) Total Human Model for Safety (THUMS) v6.1 was used to implement the modifications. The main modifications were to apply orthotropic material properties and nonlinear stress-strain behavior for ligaments, hyperelastic material properties for annulus fibrosus and nucleus pulposus, and the specific content of collagenous fibers in the annulus fibrosus ground substance. Additionally, a separation of the nucleus pulposus from surrounding bones and tissues was implemented. The FE model was subjected to different loading modes, in which intervertebral rotations and disc pressures were calculated. Loading modes contained different forces and moments acting on the lumbar section: axial forces (compression and tension), shear forces, pure moments, and combined loading modes of axial forces and pure moments. The obtained ranges of motion from the modified numerical model agreed with experimental data for all loading modes. Moreover, intradiscal pressure validation for the modified model presented a good agreement with the data available from the literature. This study demonstrated the modifications of the THUMS v6.1 model and validated the obtained numerical results with existing literature in the sub-injurious range. By applying the proposed changes, it is possible to better model the behavior of the human lumbar section under various loads and moments.

Cytokines and chemokines multiplex analysis in patients with low disease activity rheumatoid arthritis.

Rheumatoid arthritis is a severe chronic autoimmune disorder that results from pathological activation of immune cells and altered cytokine/chemokine network. The aim of our study was to evaluate concentrations of chosen cytokines and chemokines in blood sera and synovial fluid samples isolated from low disease activity rheumatoid arthritis (RA) patients and osteoarthritis (OA) sufferers. Blood sera and synovial fluid samples have been obtained from 24 OA and 14 RA patients. Cytokines/chemokines levels have been determined using a Milliplex® Map 38-plex human cytokine/chemokine magnetic bead-based panel (Merck Millipore, Germany) and Luminex® MAGPIX® platform (Luminex USA). Low disease activity RA patients showed altered concentration of numerous cytokine/chemokine when compared to OA controls-they were characterized by, inter alia, increased: eotaxin/CCL11 (p = 0.037), GRO/CXCL1 (p = 0.037), IL-2 (p = 0.013), IL-4 (p = 0.017), IL-7 (p = 0.003), IL-8 (p = 0.0007) and GM-CSF (p = 0.037) serum levels, whilst MDC/CCL22 concentration was decreased in this group (p = 0.034). Eotaxin/CCL11 (p = 0.001), GRO/CXCL1 (p = 0.041), IL-10 (p = 0.003), GM-CSF (p = 0.01), IL-1RA (p = 0.0005) and VEGF (p = 0.01) concentrations in synovial fluid of RA females were also increased. Even with low disease activity score, RA patients exhibited increased concentrations of cytokines with pro- and anti-inflammatory activities, as well as numerous chemokines, growth factors and regulators of angiogenesis. Surprisingly, RA subjects also shown decreased concentration of CCL22 chemokine. The attempt to restore cytokine balance and tolerogenic environment is ineffective in RA sufferers even with good disease management. Distinguished factors could serve as possible indicators of disease progression even in low disease activity patients.

Biomechanics of the medial meniscus in the osteoarthritic knee joint.

BACKGROUND: Increased mechanical loading and pathological response of joint tissue to the abnormal mechanical stress can cause degradation of cartilage characteristic of knee osteoarthritis (OA). Despite osteoarthritis is risk factor for the development of meniscal lesions the mechanism of degenerative meniscal lesions is still unclear. Therefore, the aim of the study is to investigate the influence of medial compartment knee OA on the stress state and deformation of the medial meniscus. METHODS: The finite element method was used to simulate the stance phase of the gait cycle. An intact knee model was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. Degenerative changes in the medial knee OA model were simulated by nonuniform reduction in articular cartilage thickness in specific areas and by a decrease in the material parameters of cartilage and menisci. Two additional models were created to separately evaluate the effect of alterations in articular cartilage geometry and material parameters of the soft tissues on the results. A nonlinear dynamic analysis was performed for standardized knee loads applied to the tibia bone. RESULTS: The maximum von Mises stress of 26.8 MPa was observed in the posterior part of the medial meniscus body in the OA model. The maximal hoop stress for the first peak of total force was 83% greater in the posterior horn and only 11% greater in the anterior horn of the medial meniscus in the OA model than in the intact model. The reduction in cartilage thickness caused an increase of 57% in medial translation of the medial meniscus body. A decrease in the compressive modulus of menisci resulted in a 2.5-fold greater reduction in the meniscal body width compared to the intact model. CONCLUSIONS: Higher hoop stress levels on the inner edge of the posterior part of the medial meniscus in the OA model than in the intact model are associated with a greater medial translation of the meniscus body and a greater reduction in its width. The considerable increase in hoop stresses shows that medial knee OA may contribute to the initiation of meniscal radial tears.

Medially positioned plate in first metatarsophalangeal joint arthrodesis.

OBJECTIVE: The purpose of this study was to biomechanically compare the stability of first metatarsophalangeal (MTP1) joint arthrodesis with dorsally and medially positioned plates. METHODS: A physical model of the MTP1 joint consists of printed synthetic bones, a titanium locking plate and screws. In the experiments, samples with dorsally and medially positioned plates were subjected to loading of ground load character in a universal testing machine. Force-displacement relations and relative displacements of bones were recorded. The obtained results were used to validate the corresponding finite element models of the MTP1 joint. Nonlinear finite element simulations of the toe-off phase of gait were performed to determine the deformation and stress state in the MTP1 joint for two positions of the plate. RESULTS: In numerical simulations, the maximum displacement in the dorsal direction was noticed at the tip of the distal phalanx and was equal to 19.6 mm for the dorsal plate and 9.63 mm for the medial plate for a resultant force of 150 N. Lower relative bone displacements and smaller plastic deformation in the plate were observed in the model with the medial plate. Stress values were also smaller in the medially positioned plate and locking screws compared to fixation with the dorsal plate. CONCLUSIONS: A medially positioned locking plate provides better stability of the MTP1 joint than a dorsally positioned plate due to greater vertical bending stiffness of the medial plate. Smaller relative bone displacements observed in fixation with the medial plate may be beneficial for the bone healing process. Moreover, lower stress values may decrease the risk of complications associated with hardware failure.

Safety and Efficacy of Medial Plate in First Metatarsophalangeal Joint Arthrodesis.

BACKGROUND: Arthrodesis of the first metatarsophalangeal joint (MTP-1) is a recognized and effective procedure in advanced osteoarthritis of this joint. Fixation with a dorsal plate and a compression screw has been described as the most stable. Nevertheless, the frequency of revision procedures after MTP-1 arthrodesis has been reported to exceed 10% in some reports. The need for revision surgery is mostly related to the fixation material used and concern both its destabilization and a conflict between the implants and soft tissues. Therefore, there is still scope for developing new stabilization methods for the MTP-1 joint. MATERIALS AND METHODS: With the approval of the relevant Bioethics Committee, we conducted a pilot clinical trial to assess the safety and efficacy of the use of the medial plate in MTP-1 fusion. Twenty patients qualified for treatment due to osteoarthritis of the metatarsophalangeal joint were evaluated. The clinical results of the surgical treatment were assessed at least one year after the surgery. RESULTS: The mean AOFAS MTP-IP score increased from 35.29±18.76 to 75.59±12.15. The mean EFAS score in-creased from 9.24±5.73 to 18.35±5.66. Pain level as per a VAS decreased from 6.24±1.48 to 1.59±2.58. A total of 18 patients were satisfied with the procedure, with the remaining 2 patients reporting the result as unsatisfactory. Two revision procedures were performed, both due to migration of the fixation material. CONCLUSIONS: 1. The clinical results of MTP-1 arthrodesis with the medial plate are comparable to the results in the litera-ture. 2. It can be concluded that the use of the medial plate in arthrodesis of the MTP-1 joint is safe and effective, and is a va--luable alternative to existing methods.

Influence of the femoral offset on the muscles passive resistance in total hip arthroplasty.

BACKGROUND: Soft tissue tension is treated as a crucial factor influencing the post-THA dislocation. The femoral offset is regarded as one of the major parameters responsible for the stabilization of the prosthesis. It is unclear which soft tissue is mostly affected by the offset changes. METHODS: A finite element model of the hip was created. The model comprised muscles, bones, a stem, the acetabular component and a liner. The muscles were modelled as a Hill-type musculo-tendon nonlinear springs. Nonlinear analyses of the hip flexion and internal rotation were performed for the two values of the femoral stem offset. RESULTS: We observed that the quadratus femoris and gluteus medius produce the largest resisting moment opposing the external load excreted by the surgeon during the intraoperative hip dislocation test. CONCLUSIONS: An increased femoral offset increases the stretching of the quadratus femoris muscle significantly and provides the growth of its initial passive force. This muscle serves as a stiff band, providing stabilisation of the hip prosthesis, measured during the simulated intraoperative test.

Mid-term Functional Results and Failure Analysis after First Metatarsophalangeal Joint Arthrodesis.

BACKGROUND: First metatarsophalangeal joint arthrodesis is the gold standard in the treatment of arthritis of the first MTP joint as well as an effective salvage procedure after unsuccessful primary forefoot procedures. The paper aims to present an evaluation of mid-term functional results and specify the causes of low postoperative satisfaction among patients. MATERIAL AND METHODS: 44 patients who underwent operative treatment in the years 2012-2018 were assessed with the AOFAS-MTP, EFAS and VAS scores and a radiological evaluation after at least half a year of follow-up. Multiple factors were analysed with regard to their influence on functional results and overall patient satisfaction. Our results were then compared to those of the most recent meta-analysis. RESULTS: The mean follow-up time was 27.4 months (from 6 to 82 months). The mean AOFAS-MTP score increased from 30.5 (SD 15.6) to 67.16 (SD 18.68), the mean EFAS score increased from 8.2 (SD 5.2) to 17.2 (SD 6.7), and the mean VAS score decreased from 7.6 (SD 1.6) to 3.2 (SD 2.5). Additionally, 35 patients (79.5%) were satisfied or very satisfied with the surgery, 9 patients (20.5%) reported their satisfaction as low or very low, while 6 patients (13.6%) required a revision procedure. CONCLUSIONS: Despite using methods of treatment comparable to those found in the literature and achieving similarly comparable functional and radiological results, the finding that a significant proportion of patients were not satisfied with the surgery shows the need for further investigation and optimization of operative techniques.

Chemical variability of Rhododendron tomentosum (Ledum palustre) essential oils and their pro-apoptotic effect on lymphocytes and rheumatoid arthritis synoviocytes.

Rhododendron tomentosum (Ledum palustre) is an aromatic plant traditionally used for alleviating rheumatic complaints which makes it a potential candidate for a natural drug in rheumatoid arthritis (RA) treatment. However, the effects of plants' volatiles on apoptosis of synovial fibroblasts and infiltrating leucocytes of RA synovia, have not been reported. Volatile fraction of R. tomentosum is chemically variable and chemotypes of the plants need to be defined if the oil is to be used for therapeutic purposes. In the presented work, cluster analysis of literature data enabled to define 10 chemotypes of the plant. The volatile fractions of known composition were then tested for bioactivity using a RA-specific in vitro models. Essential oils of two wild types (γ-terpineol and palustrol/ledol type) and one in vitro chemotype (ledene oxide type) were obtained by hydrodistillation and their bioactivity was tested in two in vitro models: I - peripheral blood lymphocytes of healthy volunteers and II - synoviocytes and immune cells isolated from synovia of RA patients. The influence of oils on blood lymphocytes' proliferation and apoptosis rates of synovia-derived cells was determined by flow cytometry. Dose-dependent inhibitory effect of the serial dilutions of R. tomentosum oils on proliferation rates of blood lymphocytes was found. At 1:400 dilutions, all the tested oils increased the number of necrotic cells in synovial fibroblasts from RA synovia. Additionally, increased proportions of late apoptotic cells were observed in leucocyte populations subjected to oils at 1:400 dilution.

The "Optimum Volume" of Acrylic Cement Filling for Treating Vertebral Compression Fractures: A Morphometric Study of Thoracolumbar Vertebrae.

Percutaneous vertebroplasty is a treatment option in vertebral compression fractures (VCF). The aim of the study was to propose the mathematical calculation of the "optimum volume" of acrylic cement filling of the vertebral body, depending on the severity of a fracture. Two hundred computed tomography (CT) scans of vertebral columns in healthy adult Caucasians were analyzed. Vertebral body width (VBW), vertebral body depth (VBD), vertebral body height (VBH), and vertebral body volume (VBV) were measured. The "optimum volume" of cement injections in mild (25% collapse) and moderate (40% collapse) VCF were calculated. We found that moving caudally from Th11 to L2, the mean values of the examined parameters increased: VBH from 22.6 to 26.0 mm, VBW from 34.0 to 39.5 mm, VBD from 28.1 to 30.9 mm, and VBV from 17.1 to 24.8 cm3. The calculated hypothetical "optimum volume" of cement injection increased from 7.4 to 10.0 cm3 in mild VCF and from 5.9 to 7.8 cm3 in moderate VCF, with some variability depending on the vertebral level and gender. These values are akin to those present in other past studies. We conclude that morphometric measurements, based on CT images, are a reliable source of practical anatomical savvy, which may be of help in spine surgery.

Morphometric Analysis of the Lumbar Vertebrae Concerning the Optimal Screw Selection for Transpedicular Stabilization.

Transpedicular stabilization is a frequently used spinal surgery for fractures, degenerative changes, or neoplastic processes. Improper screw fixation may cause substantial vascular or neurological complications. This study seeks to define detailed morphometric measurements of the pedicle (height, width, and surface area) in the aspects of screw length and girth selection and the trajectory of its implantation, i.e., sagittal and transverse angle of placement. The study was based on CT examinations of 100 Caucasian patients (51 women and 49 men) aged 27-75 with no anatomical, degenerative, or post-traumatic spine changes. The results were stratified by gender and body side, and they were counter compared with the available literature database. Pedicle height decreased from L1 to L4, ranging from 15.9 to 13.3 mm. Pedicle width increased from L1 to L5, extending from 6.1 to 13.2 mm. Pedicle surface area increased from L1 to L5, ranging from 63 to 140 mm2. Distance from the point of entry into the pedicle to the anterior surface of the vertebral body, defining the maximum length of a transpedicular screw, varied from 54.0 to 50.2 mm. Variations concerning body sides were inappreciable. A transverse angle of screw trajectory extended from 20° to 32°, shifting caudally from L1 to L5, with statistical differences in the L3-L5 segments. A sagittal angle varied from 10° to 12°, without such definite relations. We conclude that the L1 and L2 segments display the most distinct morphometric similarities, while the greatest differences, in both genders, are noted for L3, L4, and L5. The findings enable the recommendation of the following screw diameters: 4 mm for L1-L2, 5 mm for L3, 6 mm for L4-L5, and the length of 50 mm. We believe the study has extended clinical knowledge on lumbar spine morphometry, essential in the training physicians engaged in transpedicular stabilization.

Analysis of selected pro- and anti-inflammatory cytokines in patients with multiple injuries in the early period after trauma.

INTRODUCTION: Severe trauma causes damage to the protective barriers of the organism, and thus activates immunological reaction. Among substances secreted during this process pro-inflammatory cytokines are of high importance. THE AIM OF THE STUDY: Severe trauma causing multiple injuries is more likely to lead to particularly intensive inflammatory reaction, which can sometimes lead to serious complications, even life-threatening. The aim of the study is to determine those parameters which may serve as predictors of infectious complications and to enable estimation of the patient's immunological status before the decision to introduce elective procedures. MATERIAL AND METHODS: The study population included patients with multiple trauma treated in the Department of Trauma Surgery of the Medical University of Gdansk. The severity of injuries was evaluated with commonly used numerical scales (Revised Trauma Score - RTS, Injury Severity Score - ISS, Glasgow Coma Scale - GCS). Blood samples were collected on the first, second, and fifth day after injury. Evaluated parameters: C-reactive protein (CRP), the level of cytokines: IL-8, IL-1ß, IL-6, TNF, IL-12p70, and IL-10. Control population: individuals without injury. RESULTS: Evaluation of IL-6, IL-8, and CRP levels in patients with multiple trauma in the early period after injury (2-3 days) could be considered as a predictor of delayed infection (5-10 days). CRP level, being cheap and commonly accessible, can be used in clinical practice enabling identification of patients at higher risk of infectious complications and introduction of appropriate treatment and prevention. The analysis of the mentioned parameters may contribute to choosing an appropriate management strategy, including "timing" depending on the patient's biological status.

The influence of a change in the meniscus cross-sectional shape on the medio-lateral translation of the knee joint and meniscal extrusion.

OBJECTIVE: The purpose of this study was to evaluate the influence of a change in the meniscus cross sectional shape on its position and on the biomechanics of a knee joint. METHODS: One main finite element model of a left knee joint was created on the basis of MRI images. The model consisted of bones, articular cartilages, menisci and ligaments. Eight variants of this model with an increased or decreased meniscus height were then prepared. Nonlinear static analyses with a fixed flexion/extension movement for a compressive load of 1000 N were performed. The additional analyses for those models with a constrained medio-lateral relative bone translation allowed for an evaluation of the influence of this translation on a meniscus external shift. RESULTS: It was observed that a decrease in the meniscus height caused a decrease in the contact area, together with a decrease in the contact force between the flattened meniscus and the cartilage. For the models with an increased meniscus height, a maximal value of force acting on the meniscus in a medio-lateral direction was obtained. The results have shown that the meniscus external shift was approximately proportional to the meniscus slope angle, but that relationship was modified by a medio-lateral relative bone translation. It was found that the translation of the femur relative to the tibia may be dependent on the geometry of the menisci. CONCLUSIONS: The results have suggested that a change in the meniscus geometry in the cross sectional plane can considerably affect not only the meniscal external shift, but also the medio-lateral translation of the knee joint as well as the congruency of the knee joint.

Naturally occurring xanthone and benzophenone derivatives exert significant anti-proliferative and proapoptotic effects in vitro on synovial fibroblasts and macrophages from rheumatoid arthritis patients.

There is a need for novel, safer and cheaper drugs for the therapy of rheumatoid arthritis (RA), better targeted against the cellular processes involved in the disease pathogenesis. Using advanced analysis of microscopic images and flow cytometry, we demonstrate that naturally occurring xanthone and benzophenone derivatives exert strong, dose- and O2 concentration-dependent anti-proliferative and pro-apoptotic effects on RA patients' fibroblast-like synoviocytes (FLS) and macrophages. Suspensions containing fibroblasts, macrophages and other infiltrating cells were obtained from inflamed synovial tissue collected from female RA patients. Cells were grown in the presence of xanthone (mangiferin, isomangiferin, neomangiferin, norathyriol) or benzophenone (iriflophenone 3-C-glucoside, maclurin) derivatives for 48h or 7days, at 5% or 21% O2. Proportions of macrophages, FLS and infiltrating T cells undergoing apoptosis (annexin- or annexin and 7-AAD-positive) were determined by flow cytometry. The extent of late apoptosis (DNA degradation) was assessed by fluorescent microscopy and image analysis in cultures where DNA was stained with Hoechst 33342. Majority of tested compounds exert anti-proliferative and pro-apoptotic, O2-dependent effects on T cells, FLS and macrophages. The results indicate that xanthone- and benzophenone-rich plant products provide a basis for the development of dietary strategy for rheumatoid arthritis management.

The Influence of Articular Cartilage Thickness Reduction on Meniscus Biomechanics.

OBJECTIVE: Evaluation of the biomechanical interaction between meniscus and cartilage in medial compartment knee osteoarthritis. METHODS: The finite element method was used to simulate knee joint contact mechanics. Three knee models were created on the basis of knee geometry from the Open Knee project. We reduced the thickness of medial cartilages in the intact knee model by approximately 50% to obtain a medial knee osteoarthritis (OA) model. Two variants of medial knee OA model with congruent and incongruent contact surfaces were analysed to investigate the influence of congruency. A nonlinear static analysis for one compressive load case was performed. The focus of the study was the influence of cartilage degeneration on meniscal extrusion and the values of the contact forces and contact areas. RESULTS: In the model with incongruent contact surfaces, we observed maximal compressive stress on the tibial plateau. In this model, the value of medial meniscus external shift was 95.3% greater, while the contact area between the tibial cartilage and medial meniscus was 50% lower than in the congruent contact surfaces model. After the non-uniform reduction of cartilage thickness, the medial meniscus carried only 48.4% of load in the medial compartment in comparison to 71.2% in the healthy knee model. CONCLUSIONS: We have shown that the change in articular cartilage geometry may significantly reduce the role of meniscus in load transmission and the contact area between the meniscus and cartilage. Additionally, medial knee OA may increase the risk of meniscal extrusion in the medial compartment of the knee joint.

Assessment of the Relationship between the Shape of the Lateral Meniscus and the Risk of Extrusion Based on MRI Examination of the Knee Joint.

BACKGROUND: Meniscus extrusion is a serious and relatively frequent clinical problem. For this reason the role of different risk factors for this pathology is still the subject of debate. The goal of this study was to verify the results of previous theoretical work, based on the mathematical models, regarding a relationship between the cross-section shape of the meniscus and the risk of its extrusion. MATERIALS AND METHODS: Knee MRI examination was performed in 77 subjects (43 men and 34 women), mean age 34.99 years (range: 18-49 years), complaining of knee pain. Patients with osteoarthritic changes (grade 3 and 4 to Kellgren classification), varus or valgus deformity and past injuries of the knee were excluded from the study. A 3-Tesla MR device was used to study the relationship between the shape of the lateral meniscus (using slope angle, meniscus-cartilage height and meniscus-bone angle) and the risk of extrusion. RESULTS: Analysis revealed that with values of slope angle and meniscus-bone angle increasing by one degree, the risk of meniscus extrusion raises by 1.157 and 1.078 respectively. Also, an increase in meniscus-cartilage height by 1 mm significantly elevates the risk of extrusion. At the same time it was demonstrated that for meniscus-bone angle values over 42 degrees and slope angle over 37 degrees the risk of extrusion increases significantly. CONCLUSIONS: This was the first study to demonstrate a tight correlation between slope angle, meniscus-bone angle and meniscus-cartilage height values in the assessment of the risk of lateral meniscus extrusion. Insertion of the above parameters to the radiological assessment of the knee joint allows identification of patients characterized by an elevated risk of development of this pathology.

Influence of meniscus shape in the cross sectional plane on the knee contact mechanics.

We present a three dimensional finite element analysis of stress distribution and menisci deformation in the human knee joint. The study is based on the Open Knee model with the geometry of the lateral meniscus which shows some degenerative disorders. The nonlinear analysis of the knee joint under compressive axial load is performed. We present results for intact knee, knee with complete radial posterior meniscus root tear and knee with total meniscectomy of medial or lateral meniscus. We investigate how the meniscus shape in the cross sectional plane influences knee-joint mechanics by comparing the results for flat (degenerated) lateral and normal medial meniscus. Specifically, the deformation of the menisci in the coronal plane and the corresponding stress values in cartilages are studied. By analysing contact resultant force acting on the menisci in axial plane we have shown that restricted extrusion of the torn lateral meniscus can be attributed to small slope of its cross section in the coronal plane. Additionally, the change of the contact area and the resultant force acting on the menisci as the function of compressive load are investigated.

Isolation of xanthone and benzophenone derivatives from Cyclopia genistoides (L.) Vent. (honeybush) and their pro-apoptotic activity on synoviocytes from patients with rheumatoid arthritis.

A fast and efficient method for the isolation of the C-glucosidated xanthones mangiferin and isomangiferin from the South-African plant Cyclopia genistoides was developed for the first time. The procedure involved extraction, liquid-liquid partitioning with ethyl acetate and subsequent precipitation of mangiferin and isomangiferin from methanol and acetonitrile-water fractions, respectively. Additionally, two benzophenone derivatives: 3-C-ß-glucosides of maclurin and iriflophenone, were isolated from C. genistoides extracts using semi-preparative HPLC. Apart from the above, the isolation procedure also yielded hesperidin and small amounts of luteolin. The structures of the compounds were determined by 1D and 2D NMR experiments and/or LC-DAD-ESI-MS. The selected Cyclopia constituents were screened for pro-apoptotic activity on TNF-α-stimulated synovial cells isolated from rheumatoid arthritis patients. The strongest effect, measured as percent of apoptotic cells, was recorded for isomangiferin (75%), followed by iriflophenone 3-C-ß-glucoside (71%), hesperidin (67%) and mangiferin (65%). The results are encouraging for further studies on the use of the above compounds in the treatment of rheumatoid arthritis.

Possible causes of failure in treatment of forearm bone shaft fractures - own experience.

BACKGROUND: Non-surgical treatment of forearm shaft fractures in adults is associated with a high incidence of non-union. Operator errors during surgery also often result in bone union complications. We attempted to identify the errors made during the treatment or other factors that might influence the development of forearm shaft union complications. MATERIALS AND METHODS: We have analysed the causes of 67 cases of non-union in 53 patients (17 women and 36 men), aged 18 to 85 years. Thirty-five patients were treated by open repositioning and fixation with plates and screws, 11 patients were treated by closed or open reposition and stabilization with Kirschner wires, and 4 patients had closed reposition and immobilization in a plaster cast. Other methods were used in 3 patients. RESULTS: In the group treated by open reposition and plate fixation, we found the following complications that might impede bone union: plate fracture, technical errors, screw loosening, bone inflammation, and other complications. In the group treated by closed or open repositioning and stabilization with Kirschner wires, we found the following factors that might impede bone union: open fractures, inaccurate fracture repositioning and inappropriately inserted Kirschner wires. CONCLUSIONS: Using rigid fixation, for example with a plate and screws, and avoidance of technical errors seem to be the most appropriate measures helping to decrease the risk of non-union during treatment of a fracture of both forearm shafts.

[The height of intervertebral foramen in operative treatment of isthmic spondylolisthesis]. / Wysokosc otworu miedzykregowego w operacyjnym leczeniu kregozmyku ciesniowego.

49 patients with spondylolisthesis isthmica were treated in the years 1991-2006. The age of patients varied between 21 and 65 years, 43.7 year on average. Two stages operative protocol consisted of reduction of the slip by pedicular implant and anterior interbody fusion with the cages was used. The evaluation was based on x-rays height of the lumbar intervertebral foramen and posterior disc height in the 2 distal lumbar vertebrae pre and post operatively. This results showed clearly a decrease of both these values on the level of the slip, demonstrating the lumbar intervertebral stenosis. Te operative procedure decomprssed the lumbar intervertebral foramen and increased both values evaluated Postoperatively in the neighbor vertebrae a height lumbar intervertebral foramen was increased but posterior disc height a unchanged.