IL-33/ST2 induces neutrophil-dependent reactive oxygen species production and mediates gout pain.

Objective: Gout, induced by monosodium urate (MSU) crystal deposition in joint tissues, provokes severe pain and impacts life quality of patients. However, the mechanisms underlying gout pain are still incompletely understood. Methods: We established a mouse gout model by intra-articularly injection of MSU crystals into the ankle joint of wild type and genetic knockout mice. RNA-Sequencing, in vivo molecular imaging, Ca2+ imaging, reactive oxygen species (ROS) generation, neutrophil influx and nocifensive behavioral assays, etc. were used. Results: We found interleukin-33 (IL-33) was among the top up-regulated cytokines in the inflamed ankle. Neutralizing or genetic deletion of IL-33 or its receptor ST2 (suppression of tumorigenicity) significantly ameliorated pain hypersensitivities and inflammation. Mechanistically, IL-33 was largely released from infiltrated macrophages in inflamed ankle upon MSU stimulation. IL-33 promoted neutrophil influx and triggered neutrophil-dependent ROS production via ST2 during gout, which in turn, activated transient receptor potential ankyrin 1 (TRPA1) channel in dorsal root ganglion (DRG) neurons and produced nociception. Further, TRPA1 channel activity was significantly enhanced in DRG neurons that innervate the inflamed ankle via ST2 dependent mechanism, which results in exaggerated nociceptive response to endogenous ROS products during gout. Conclusions: We demonstrated a previous unidentified role of IL-33/ST2 in mediating pain hypersensitivity and inflammation in a mouse gout model through promoting neutrophil-dependent ROS production and TRPA1 channel activation. Targeting IL-33/ST2 may represent a novel therapeutic approach to ameliorate gout pain and inflammation.

Gait and electromyographic alterations due to early onset of injury and eventual rupture of the cranial cruciate ligament in dogs: A pilot study.

OBJECTIVE: Identify relevant electromyography (EMG), kinematic, and kinetic changes resulting from monopolar radiofrequency energy (MRFE)-induced cranial cruciate ligament (CCL) injury and eventual rupture in dogs. STUDY DESIGN: Experimental, repeated measures. ANIMALS: Five purpose-bred female dogs free of orthopedic and neurologic disease. METHODS: Surface EMG, joint kinematics, and ground reaction forces were assessed at a trot in the pelvic limbs at baseline, at 2 and 4 weeks after unilateral MRFE-induced CCL injury, and at 4, 8, and 16 weeks after CCL rupture (CCLR). RESULTS: After MRFE-induced injury, average hip joint range of motion (ROM) during stance decreased within the untreated pelvic limb. After CCLR, stifle flexion angles decreased within the treated limb at 8 weeks and within the untreated pelvic limb at all time points, whereas average tarsal joint ROM decreased in the treated limb and increased in the untreated limb. Peak vertical ground reaction force and impulse decreased within the treated limb. Qualitative alterations of many EMG values were noted after MRFE-induced injury and CCLR, although significant differences between limbs or from baseline values were not detected. CONCLUSION: Monopolar radiofrequency energy-induced injury altered contralateral hip kinematics, suggesting early regional compensatory gait alterations. After CCLR, additional compensatory gait patterns occurred in both pelvic limbs. CLINICAL IMPACT: The qualitative analysis of trial-averaged EMG data in this small population supports a relationship between neuromuscular function and induced CCL injury leading to rupture.

UP1306: A Composition Containing Standardized Extracts of Acacia catechu and Morus alba for Arthritis Management.

Osteoarthritis (OA) is characterized by progressive articular cartilage degradation. Although there have been significant advances in OA management, to date, there are no effective treatment options to modify progression of the disease. We believe these unmet needs could be bridged by nutrients from natural products. Collagen induced arthritis in rats was developed and utilized to evaluate anti-inflammatory and cartilage protection activity of orally administered botanical composition, UP1306 (50 mg/kg) and Methotrexate (75 µg/kg) daily for three weeks. Objective arthritis severity markers, urine, synovial lavage, and serum were collected. At necropsy, the hock joint from each rat was collected for histopathology analysis. Urinary cartilage degradation marker (CTX-II), pro-inflammatory cytokines (tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß), and IL-6), and proteases (Matrix Metallopeptidase 3 (MMP3) and 13) were measured. Rats treated with UP1306 showed statistically significant improvements in arthritis severity markers, including uCTX-II (91.4% vs. collagen-induced arthritis (CIA)), serum IL-1ß, TNF-α, and IL-6 levels as well as synovial MMP-13. The histopathology data were also well aligned with the severity score of arthritis for both UP1306 and Methotrexate. UP1306, a botanical composition that contains a standardized blend of extracts from the heartwood of Acacia catechu and the root bark of Morus alba, could potentially be considered as a dietary supplement product for the management of arthritis.

Evaluation of the Area of the Lisfranc Ligament Damaged by Screw Fixation.

BACKGROUND: A cannulated screw is currently the standard fixation method to reduce and stabilize diastasis at the lisfranc joint following injury. Currently, there is no literature examining the area of the lisfranc ligament damaged by screw placement. The objective of this investigation is to define the area of the ligament damaged by fixation with a 3.5-mm cannulated screw. MATERIALS AND METHODS: Twelve cadaveric feet were dissected to identify the Lisfranc ligament metatarsal insertion site and origin on the medial cuneiform. A 3.5-mm cannulated screw was then passed over the course of the ligament and removed. The Lisfranc joint was then dissected to measure the dimensions of the ligament and damage from screw passage at the origin and insertion using imaging software. RESULTS: Mean injury area on the metatarsal was 3.49 mm2 and the area of injury for the cuneiform was 3.33 mm2. The mean percent of the area damaged was calculated to be 1.75% and 2.43% at the cuneiform and metatarsal, respectively. CONCLUSION: A proportionally small area of the Lisfranc ligament is disrupted following screw fixation, but the implications of this on ligament healing and outcomes remain to be elucidated. LEVELS OF EVIDENCE: Level V: Cadaveric study.

Remodeling of the Calcaneocuboid Joint in the Acquired Flatfoot.

There has been debate recently as to whether the lateral column is actually short in the acquired flatfoot. Doubters argue that it is not possible for the lateral column to change in length and actually shorten, especially in the acquired type. In this series of 21 consecutive patients operated on for an acquired flatfoot, the calcaneocuboid joint (CC) had remodeled in all, resulting in the calcaneal side being short, facing laterally and dorsally. These findings give evidence to the rationale for performing a lateral column lengthening (LCL) proximal to the CC joint to treat the acquired flatfoot. When performing a LCL, one should attempt to restore length to the calcaneal side of the joint and to redirect it medially and plantarward. (Journal of Surgical Orthopaedic Advances 27(3):237-245, 2018).

Incidence and characteristics of juvenile tarsocrural osteochondrosis in purebred Angus bulls.

Osteochondrosis (OC) of the bovine tarsus has been suggested to contribute to osteoarthritis. The objective of this prospective cohort study was to provide data specific to the Angus breed. Clinical and radiographic exams evaluating OC lesions, effusion and osteoarthritis were performed in 50 purebred bull calves at three time points between 5.8 and 21 months of age. The likelihood of OC was lower at a median age of 12.4 months (P<0.001), primarily due to resolution of distal talus changes (P<0.01). Significant associations were observed between medial malleolus lesions and effusion at median age of 7.4 months (P<0.001). This study suggests that clinical and radiographic screening performed at approximately one year of age may be beneficial in detecting tarsal OC lesions in Angus breeding herds.

Anatomy of the Tarsal Canal and Sinus in Relation to the Subtalar Joint Capsule.

BACKGROUND: Anatomical knowledge of the tarsal canal and sinus is still unclear owing to the complexity of the ligamentous structures within them, particularly the relationship with the capsules of the subtalar joints. The aim of this study was to examine the anatomical relationship between the fibrous tissues of the tarsal canal and sinus and the articular capsules of the subtalar joint. METHODS: We conducted a descriptive anatomical study of 21 embalmed cadaveric ankles. For a macroscopic overview of the subtalar joint, we removed the talus in 18 ankles and separated the fibrous tissues from the surrounding connective tissues to analyze the layered relationship between the inferior extensor retinaculum (IER) and the subtalar joint capsule. Additionally, we histologically analyzed the tarsal canal and the medial and lateral sides of the tarsal sinus using Masson's trichrome staining in 3 ankles. RESULTS: The medial and intermediate roots of the IER and interosseous talocalcaneal ligament (ITCL) were located in the same layer and were connected to each other, between the capsules of the posterior talocalcaneal and talocalcaneonavicular joints. The intermediate root of the IER and the cervical ligament (CL) had adjacent attachments on the tarsal sinus, and synovial tissues originating from the joint capsules filled the remaining area in the tarsal canal and sinus. CONCLUSION: We determined that the tarsal canal and sinus tarsi contained 3 layered structures: the anterior capsule of the posterior talocalcaneal joint, including the anterior capsule ligament; the layer of ITCL and IER; and the posterior capsule of the talocalcaneonavicular joint, including the CL. CLINICAL RELEVANCE: The results of this study may help with the understanding of the pathomechanism of subtalar instability and sinus tarsi syndrome, resulting in better treatment.

Tarsometatarsal joint communication during fluoroscopy-guided therapeutic joint injections and relationship with patient age and degree of osteoarthritis.

OBJECTIVE: Although the tarsometatarsal joints are separated into three distinct synovial compartments, communications between adjacent compartments are often noted during image-guided injections. This study aims to determine whether abnormal inter-compartment tarsometatarsal joint communication is associated with patient age or degree of tarsometatarsal osteoarthritis. MATERIALS AND METHODS: One hundred forty tarsometatarsal injections were retrospectively reviewed by two radiologists. Extent of inter-compartment communication and degree of osteoarthritis were independently scored. Univariate and multivariable analyses were performed to assess whether the presence of and number of abnormal joint communications were related to age and degree of osteoarthritis. RESULTS: Forty out of 140 tarsometatarsal joints showed abnormal communication with a separate synovial compartment, and 3 of the 40 showed abnormal communication with two separate compartments. On univariate analysis, higher grade osteoarthritis (p < 0.001) and older age (p = 0.014) were associated with an increased likelihood of abnormal inter-compartment tarsometatarsal communication and a greater number of these abnormal communications. On multivariate analysis, the degree of osteoarthritis remained a significant predictor of the presence of (p < 0.001) and number of (p < 0.001) abnormal communications, while the association of age was not statistically significant. There was significant correlation between age and degree of osteoarthritis (p < 0.001). CONCLUSION: Higher grade osteoarthritis increases the likelihood of abnormal inter-compartment tarsometatarsal joint communication and is associated with a greater number of abnormal communications. Diagnostic injection to localize a symptomatic tarsometatarsal joint may be less reliable in the setting of advanced osteoarthritis.

Normative size of the osseous part of calcaneal bursa and its comparison with other calcaneal articular areas.

The retro-calcaneal bursa presents a synovial and a non-synovial osseous part of variable dimensions. Studies objectively measuring the variability of the size of this osseous bursal surface cannot be found in literature. The objective of this study was to investigate (i) the dimension variability of the bony part of the bursa and (ii) the relationship of this surface to other articulating areas of the calcaneus. A digital planimeter was used to measure the bursae (n=86) and other articular surface areas of the calcaneus and statistically compared with ANOVA and correlation estimations. The osseous area measured 1.12 (±0.55) cm2, with only the superior articulating area demonstrating a weak correlation to this osseous surface. The osseous area presents a weak correlation with the axial articulating area of the calcaneus. Information on the size of the bony bursa may help safe excision of retrocalcaneal exostoses and in Achille's tendon repair around the posterior tuberosity.

Therapeutic antibody targeting of indoleamine-2,3-dioxygenase (IDO2) inhibits autoimmune arthritis.

Rheumatoid arthritis (RA) is a debilitating inflammatory autoimmune disease with no known cure. Recently, we identified the immunomodulatory enzyme indoleamine-2,3-dioxygenase 2 (IDO2) as an essential mediator of autoreactive B and T cell responses driving RA. However, therapeutically targeting IDO2 has been challenging given the lack of small molecules that specifically inhibit IDO2 without also affecting the closely related IDO1. In this study, we develop a novel monoclonal antibody (mAb)-based approach to therapeutically target IDO2. Treatment with IDO2-specific mAb alleviated arthritis in two independent preclinical arthritis models, reducing autoreactive T and B cell activation and recapitulating the strong anti-arthritic effect of genetic IDO2 deficiency. Mechanistic investigations identified FcγRIIb as necessary for mAb internalization, allowing targeting of an intracellular antigen traditionally considered inaccessible to mAb therapy. Taken together, our results offer preclinical proof of concept for antibody-mediated targeting of IDO2 as a new therapeutic strategy to treat RA and other autoantibody-mediated diseases.

Primary synovial chondromatosis of the talonavicular joint: A case report.

Synovial chondromatosis developes by metaplasia of the synovial cells in the synovium of joints, and is a benign synovial tumor with multiple cartilaginous nodules. It is most commonly found in single and large joints, such as the knee, hip, and shoulder. Occurrence in the foot and ankle is uncommon, although there have been previous reports in the orthopedic and radiological literature of primary synovial chondromatosis in the subtalr, calcaneocuboid, naviculocuneiform, and metatarsaophalangeal joints. To our knowledge, occurrence in the talonavicular joint is even rarer, with only one report in the literature to date. Here, we report a case of synovial chondromatosis of the talonavicular joint, alongside a review of the literature.

Arthroscopy of the Dorsal and Plantar Pouches of the Tarsocrural Joint for the Treatment of Osteochondritis Dissecans in the Horse: Clinical Features and Follow-Up.

OBJECTIVE: To describe the clinical details and pathology within the dorsal and plantar pouches of the tarsocrural joint of a population of horses that underwent arthroscopic surgery for tarsocrural osteochondritis dissecans (OCD). STUDY DESIGN: Retrospective cohort study. ANIMALS: Horses referred for arthroscopic treatment of tarsocrural OCD between 2005 and 2013 (102 horses; 144 joints). METHODS: Case records of all horses that had tarsocrural arthroscopy for OCD at Rossdales Equine Hospital, Newmarket, United Kingdom were included. Cases from 3 ECVS Diplomates were included, 1 of whom routinely examined 70 plantar pouches concurrently with routine dorsal pouch investigation. A structured questionnaire was used to obtain follow-up data alongside examination of racing records where appropriate. Descriptive data and 95% CI were calculated. RESULTS: Of the 70 joints that had both dorsal and plantar pouches examined, there was cartilage erosion/degeneration in 22 dorsal pouches (31.4%), cartilage wear lines in 32 plantar pouches (45.7%), and fragments were removed at the time of surgery from 7 plantar pouches (10.0%). Of the plantar pouches with wear lines, 18 (25.7%) had no evidence of cartilage abnormalities (separate from the OCD lesion) within the dorsal pouch. From the 102 horses with available follow-up, 34 horses (66.7%) achieved their intended use postsurgery. CONCLUSION: Routine plantar pouch investigation is warranted in cases of tarsocrural OCD to provide further information on the health of the joint and allows for removal of fragments from the plantar pouch that may not have been identified by routine diagnostic radiography.

An international multi-centre prospective study on the efficacy of an intraarticular polyacrylamide hydrogel in horses with osteoarthritis: a 24 months follow-up.

BACKGROUND: Polyacrylamide hydrogel (PAAG) was evaluated recently to treat osteoarthritis (OA) in horses with highly encouraging results; however no long term field-study was done to explore its clinical efficacy and lasting effect. The objective of this study was to evaluate the efficacy of PAAG in improving clinical signs of OA in horses. We hypothesized that lameness grade would significantly improve and the effect would last at least 2 years in osteoarthritic joints treated with PAAG. Forty three horses older than 2 years with OA in only one joint based on clinical evaluation, intra-articular anaesthesia and imaging (radiography) were included in this study. Horses were injected with 2 ml of PAAG into the affected joint and were followed up at 1, 3, 6, 12 and 24 months. Efficacy of PAAG was evaluated by blinded clinical assessment of lameness. Adverse reactions to joint injection were assessed. Data relating to case details, type of activity, joint and limb involved, lameness duration, lameness grading, previous joint treatment, joint effusion grading, radiographic grading, and owner assessment were recorded. Factors associated with the outcome measure "lameness grading" were analyzed using generalized linear mixed model for logistic regression. RESULTS: At 1, 3, 6, 12 and 24 months follow-up, 59%, 69%, 79%, 81/% and 82.5% of horses were non-lame respectively. Reduction of joint effusion was observed over time. No side effect was observed in the treated joints. There was a significant decrease in lameness grade from baseline to 1, 3, 6, 12 and 24 months (P < 0.0001) and a significant positive association with joint effusion (P < 0.0001). Estimates for odds ratio (OR) showed that the effect of treatment increased over time (OR for lower lameness from month 1 to month 24 relative to baseline increased from 20 to 58). CONCLUSIONS: PAAG significantly alleviated lameness and joint effusion in osteoarthritic joints. PAAG is a safe and lasting (at least 24 months) OA treatment in horses. PAAG is a promising new treatment for OA in horses.

Effects of immobilization and remobilization on the ankle joint in Wistar rats

A sprained ankle is a common musculoskeletal sports injury and it is often treated by immobilization of the joint. Despite the beneficial effects of this therapeutic measure, the high prevalence of residual symptoms affects the quality of life, and remobilization of the joint can reverse this situation. The aim of this study was to analyze the effects of immobilization and remobilization on the ankle joint of Wistar rats. Eighteen male rats had their right hindlimb immobilized for 15 days, and were divided into the following groups: G1, immobilized; G2, remobilized freely for 14 days; and G3, remobilized by swimming and jumping in water for 14 days, performed on alternate days, with progression of time and a series of exercises. The contralateral limb was the control. After the experimental period, the ankle joints were processed for microscopic analysis. Histomorphometry did not show any significant differences between the control and immobilized/remobilized groups and members, in terms of number of chondrocytes and thickness of the articular cartilage of the tibia and talus. Morphological analysis of animals from G1 showed significant degenerative lesions in the talus, such as exposure of the subchondral bone, flocculation, and cracks between the anterior and mid-regions of the articular cartilage and the synovial membrane. Remobilization by therapeutic exercise in water led to recovery in the articular cartilage and synovial membrane of the ankle joint when compared with free remobilization, and it was shown to be an effective therapeutic measure in the recovery of the ankle joint.

Effect of nonanimal high- and low-molecular-mass chondroitin sulfates produced by a biotechnological process in an animal model of polyarthritis.

BACKGROUND/AIMS: We planned to report on the effect of two nonanimal chondroitin sulfates (CSs) with different molecular masses produced using an innovative biotechnological process in an adjuvant arthritis animal model. METHODS: The experiments included healthy animals, untreated arthritic animals and arthritic animals having been administered 900 mg/kg of either of the two CS samples daily. Arthritic score, γ-glutamyltransferase (GGT) activity in hind paw joint tissue homogenates, plasmatic C-reactive protein (CRP) and pro-inflammatory cytokines IL-1ß and IL-6 were assayed. RESULTS AND CONCLUSIONS: Low-molecular-mass (LMM) CS significantly reduced the arthritic score by up to about 30% from 14 to 28 days. In contrast, no significant differences were observed for high-molecular-mass (HMM) CS, even if a trend in its capacity to decrease the arthritic score by up to about 11% was observed. Additionally, LMM CS was able to significantly decrease GGT activity by approximately 31% and plasmatic CRP levels by about 9%. Both nonanimal CS samples were effective in reducing plasmatic levels of proinflammatory cytokines. A greater efficacy was also observed for LMM CS compared with a pharmaceutical-grade CS of extractive origin, while the efficacy of the HMM CS sample was found to be rather similar. The greater effect of LMM CS in reducing arthritic parameters may be related to its lower molecular mass with respect to HMM CS and natural CS.

Effects of immobilization and remobilization on the ankle joint in Wistar rats.

A sprained ankle is a common musculoskeletal sports injury and it is often treated by immobilization of the joint. Despite the beneficial effects of this therapeutic measure, the high prevalence of residual symptoms affects the quality of life, and remobilization of the joint can reverse this situation. The aim of this study was to analyze the effects of immobilization and remobilization on the ankle joint of Wistar rats. Eighteen male rats had their right hindlimb immobilized for 15 days, and were divided into the following groups: G1, immobilized; G2, remobilized freely for 14 days; and G3, remobilized by swimming and jumping in water for 14 days, performed on alternate days, with progression of time and a series of exercises. The contralateral limb was the control. After the experimental period, the ankle joints were processed for microscopic analysis. Histomorphometry did not show any significant differences between the control and immobilized/remobilized groups and members, in terms of number of chondrocytes and thickness of the articular cartilage of the tibia and talus. Morphological analysis of animals from G1 showed significant degenerative lesions in the talus, such as exposure of the subchondral bone, flocculation, and cracks between the anterior and mid-regions of the articular cartilage and the synovial membrane. Remobilization by therapeutic exercise in water led to recovery in the articular cartilage and synovial membrane of the ankle joint when compared with free remobilization, and it was shown to be an effective therapeutic measure in the recovery of the ankle joint.

Therapeutic effect of irradiation of magnetic infrared laser on osteoarthritis rat model.

Osteoarthritis (OA) is a degenerative joint disease caused by articular cartilage loss. Many complementary and alternative medicines for OA have been reported so far, but the effectiveness is controversial. Previously, we have shown anti-inflammatory effects of low level laser therapy with static magnetic field, magnetic infrared laser (MIL), in various animal models. Therefore, the beneficial effects were examined in OA rat model. Rats were divided by six groups; no treatment controls of sham and OA model, three MIL treatment groups of OA model at 6.65, 2.66 and 1.33 J cm(-2), and Diclofenac group of OA model with 2 mg kg(-1) diclofenac sodium. The OA control exhibited typical symptoms of OA, but 4-week MIL treatment improved the functional movement of knee joint with reduced edematous changes. In addition, cartilage GAGs were detected more in all MIL treatment groups than OA control. It suggests that 4-week MIL irradiation has dose-dependent anti-inflammatory and chondroprotective effects on OA. Histopathological analyses revealed that MIL treatment inhibits the cartilage degradation and enhances chondrocyte proliferation. The fact that MIL has an additional potential for the cartilage formation and no adverse effects can be regarded as great advantages for OA treatment. These suggest that MIL can be useful for OA treatment.

Accessory talar facet impingement in pathologic conditions of the peritalar region in adults.

INTRODUCTION: Associations between accessory anterolateral talar facet (AALTF) and sinus tarsi pain in adults have not been reported. This study aimed to investigate the clinical and imaging characteristics of pathologic conditions of the peritalar region in adults with painful accessory talar facet impingement (ATFI). METHODS: We included 31 patients (aged 19-75 years) with persistent sinus tarsi pain who underwent surgery and had pathologic conditions of the peritalar region, including adult acquired flatfoot deformity (AAFD; 18 patients), ankle osteoarthritis (8 patients), and ankle instability (5 patients). Continuity between the articular surface of the posterior facet of the talus and AALTF was identified on preoperative computed tomography and magnetic resonance imaging (MRI) of the cartilage. In addition, focal abutting bone marrow edema (FABME) of the talus and calcaneal neck around the AALTF on short TI inversion recovery sequence MRI was confirmed. Subtalar arthroscopy was used to evaluate the AALTF surface characteristics. Pre- and postoperative objective scores were compared. Eight pre- and postoperative radiographic parameters were compared to confirm the effect of foot alignment changes after reconstructions on sinus tarsi pain with ATFI. Pre- and postoperative changes in FABME were compared with 17.1 (7-60) months of follow-up. RESULTS: Subjects underwent accessory facet resection with balancing reconstruction. Arthroscopically, 66% of patients showed a focal defect on the AALTF cartilage surface, and 83% showed attenuation of the posterior capsular ligament. All x-ray parameters in AAFD patients showed significant improvement postoperatively (P < .001). Mean objective scores improved from 54.0 preoperatively to 91.0 postoperatively (P < .001). Sinus tarsi pain and FABME were absent in all cases at the final follow-up. CONCLUSION: AALTF represents a new etiology of subsequent painful intra-articular talocalcaneal impingement. When addressing sinus tarsi pain, it is important to detect the signs of AALTF on MRI of the cartilage and accompanying FABME. LEVEL OF EVIDENCE: Level IV, retrospective case series.

[Amyloidosis in turkeys (Meleagris gallopavo f. domestica)--a case report]. / Amyloidose beim Truthuhn (Meleagris gallopavo f. domestica)--ein Fallbericht.

High prevalence of leg disorders in fattening meat turkey farm was observed. Four birds as well as tracheal and joint swabs were submitted to the Bavarian Health and Food Safety Authority in Oberschleissheim and to the Institute of Poultry Diseases, Faculty of Veterinary Medicine, Free University of Berlin. At the post-mortem, all birds showed an inflammation of the hock joints (intertarsal joint). The histopatholical investigations revealed a chronic inflammation of the joint and amyloid deposits in the joints in two cases as well as in different tissues (liver, spleen and kidneys) in another two cases. Using polymerase chain reaction, Ornithobacterium rhinotracheale-DNA could be detected in the examined tracheal and joint swabs. On the other hand, Mycoplasma gallisepticum- and Mycoplasma synoviae-DNA could not be detected. A causal correlation between the detected infectious agent and amyloidosis in relation to the leg disorders were discussed.