Kan Sasaki

Increased Expression of Toll-like Receptors in Aseptic Loose Periprosthetic Tissues and Septic Synovial Membranes Around Total Hip Implants

Objective. Toll-like receptors (TLR) are transmembrane proteins found in various cells. They recognize infectious and endogenous threats, so-called danger signals, that evoke inflammation and assist adaptive immune reactions. It has been suggested that TLR play a role in periprosthetic tissues and arthritic synovium. Our objective was to elucidate tissue localization and functional roles of TLR in periprosthetic tissues in 2 different pathologic conditions, aseptic and septic implant loosening. Methods. For immunohistochemistry studies, aseptic synovial-like membranes of periprosthetic connective tissues (n = 15) and septic synovial capsular tissues (n = 5) were obtained at revision surgery and from salvage of infected totally replaced hips, respectively. Osteoarthritic synovial tissues were used for comparison (n = 5). Samples were processed for immunohistopathologic analyses for tissue colocalization of TLR with CD68 and/or CD15 using theAlexa fluorescent system. Total RNA was isolated from frozen tissues and converted into cDNA, TLR 2, 4, 5 and 9 sequences were amplified, and the products were quantified using real-time polymerase chain reaction. Results. Immunofluorescent staining showed colocalization of TLR 2, 4, 5, and 9 with CD68 in the focal monocyte/macrophage aggregates in aseptic synovial-like membranes from loose total hip replacements. TLR 2, 4, 5, and 9 were also found colocalized with CD15+ polymorphonuclear leukocytes and CD68+ mononuclear cells of the synovial membranes from septic total hip replacements. In osteoarthritic synovial tissues, expression of TLR was found only in vascular cells and mononuclear cells, and the reactivity was weak. mRNA levels of TLR 2, 4, 5, and 9 were increased in both aseptic and septic periprosthetic tissues. TLR 2 and 5 were significantly higher than TLR 4 and 9 in aseptic and septic samples. Conclusion. Peri-implant tissues were well equipped with TLR in both aseptic and septic conditions. TLR 2- and TLR 5-mediated responses seemed to dominate. In aseptic loosening, monocytes/ macrophages were the main TLR-equipped cells apparently responsible for alarmin-induced responses. This could lead to production of inflammatory cytokines and extracellular matrix-degrading proteinases after phagocytosis of wear debris derived from an implant, but in septic cases they eventually respond to microbial components. Thus, inflammatory cells in both aseptic and septic tissues were equipped with TLR, providing them with responsiveness to both endogenous and exogenous TLR ligands.

Toll-like receptors and their adaptors are regulated in macrophages after phagocytosis of lipopolysaccharide-coated titanium particles.

Macrophages phagocytose metallic wear particles and produce mediators, which can induce cellular host response and aseptic implant loosening. Lipopolysaccharide (LPS) on the wear debris can stimulate macrophages via Toll‐like receptor 4 (TLR4) and enhance the response. However, the precise functional role and interaction of TLRs and their adaptor molecules is still unclear. Rat bone marrow macrophages were stimulated with titanium particle (Ti) coated by LPS (Ti/LPS+) and LPS‐free Ti (Ti/LPS−). mRNA levels of cytokines, TLRs and their adaptor molecules were measured using real time PCR. mRNA levels of TNF‐α, IL‐1β, and IL‐6 increased in Ti/LPS+ than Ti/LPS−. In contrast, mRNA levels of TLR4, TLR5, and TLR9 decreased in Ti/LPS+ compared to Ti/LPS−. mRNA levels of MyD88, IRAK1, IRAK4 decreased gradually, and TRAF6 underwent an initial transient increase, followed by suppression in Ti/LPS+. However, mRNA levels of TLR2 and IRAK2 increased after phagocytosis of Ti/LPS+ than Ti/LPS−. The increased expressions of proinflammatory cytokines found in Ti/LPS+ indicated that their productions cytokines could be enhanced by phagocytosis of LPS‐coated particles. Subsequent down‐regulation of TLR4, TLR5, TLR9, MyD88, IRAK1, and IRAK4 suggests that self‐protective mechanisms to regulate excessive host responses are activated in macrophages. Increase of TLR2 and IRAK2 and a transient increase of TRAF6 in Ti/LPS+ suggest that another possible pathway to modulate TLR‐mediated cellular response to prolong inflammatory response in foreign body reaction of aseptic loosening. This down‐ and/or up‐regulation of the potential TLR‐mediated responses to LPS‐coated particles reflects the proactive behavior of effector cells.

Snowboarder's wrist : Its severity compared with alpine skiing

BACKGROUND Although the upper extremity, especially the wrist, has been reported to be the most commonly injured site in snowboarding, the severity of these injuries is still unknown. The purpose of this study is to compare the severity of wrist injuries in snowboarding with those in alpine skiing for insight into the treatment of snowboarders wrist. MATERIALS AND METHODS The cases of 11,598 patients injured while snowboarding and skiing who presented to the Zao clinic during the past 7 seasons were reviewed and compared. Demographics were studied, focusing on fractures around the wrist joint. Roentgenographically precise assessment of the distal radial fracture was performed according to AO classification. RESULTS Snowboarders were more likely to injure the wrist than were skiers (18.7% vs. 2.5%, p<0.01). In these wrist injuries, distal radial fractures occurred at a rate of 0.28 per 1000 snowboarders and 0.008 per 1000 skiers. Comminuted and articular fractures classified as AO type A3, B and C, which required surgical treatment, were 49.4% of distal radial fractures in snowboarders and 23.8% in skiers. CONCLUSION Wrist injury sustained while snowboarding is characterized as a severe and complex injury. Thus, we call attention to its severity in the treatment of snowboarders wrist.

Antibiotics-impregnated cement spacers in the first step of two-stage revision for infected totally replaced hip joints: report of ten trial cases

BackgroundPeriprosthetic infection is one of the serious complications after total hip arthroplasty (THA). This study analyzed the perioperative and postoperative status of patients who underwent antibiotics-impregnated cement spacer technique in the first step of the two-stage revision.MethodsTen joints of the nine patients (mean age, 65 years; seven women, two men) received two-stage revision as a result of infection that appeared after primary THAs in seven joints, aseptic revision in one, and recurrent type in two. An antibiotics-impregnated cement spacer made by a mold system was applied in the femoral side of all joints. An acetabular spacer was made by hand using a cup gauge in eight joints with extensive tissue loss.ResultsThe change of leg length after the first stage was −2.2 mm, and range of hip flexion was 72° on average, respectively. Patients could walk with crutches after the first stage, except one patient with simultaneous infections of both hips and one with fracture of the cement spacer. One fracture of femoral cement spacer, and one dislocation of femoral spacer accompanied by fracture of acetabular cement spacer and curable recurrent infection, were found. In all cases of the second-stage procedure, the acetabular side was reconstructed with allogeneic bone graft with cross plate and that of the femur was by impaction bone grafting method. In the latest follow-up, reconstructed implants were stable. Seven patients could walk without any supportive devices and two could walk with the support of a T-cane.ConclusionsAn antibiotics-impregnated cement spacer in the first step of the two-stage revision was effective not only to compensate tissue loss after removal of the implants and to minimize discrepancy of leg length, but also to contribute to improvement of perioperative and postoperative daily activities of the patient’s life as well as treatment of the infection.

Lipoteichoic acid modulates inflammatory response in macrophages after phagocytosis of titanium particles through Toll-like receptor 2 cascade and inflammasomes

Toll-like receptor 2 (TLR2) and nucleotide-binding and oligomerization domain-like receptors with a pyrin domain 3 (NLRP3) inflammasomes have been presumed to participate in the pathogenesis of aseptic implant loosening. The aim of this study is to analyze the cellular localization of TLR2 and NLRP3 inflammasomes in the periprosthetic tissue from aseptically loose hip implants as well as the expression of these molecules in macrophages stimulated in vitro with titanium particles (Ti) coated with lipoteichoic acid (LTA). Using immunohistochemistry, immunoreactivity of TLR2 and NLRP3 inflammasomes was found in macrophages within the foreign body granulomatosis. Using RAW264.7 cells, stimulation with Ti increased the messenger RNA (mRNA) levels of TLR2 and TNF-α. Stimulation with LTA-coated Ti enhanced mRNA levels of NLRP3 and IL-1β, whereas reinforced secretion of IL-1β was not detected in spite of marked release of TNF-α. Finally, the same cells with silenced Irak2, an adaptor protein in the TLR2 cascade, suppressed this NLRP3 upregulation. This study suggests that TLR2 and NLRP3 inflammasomes are factors involved in cross-talk mediating the foreign body type response to wear particles. In addition, discrepant behavior in the release between TNF-α and IL-1β release may explain the variable pathomechanisms of aseptic implant loosening without acute inflammatory reactions.

Edoxaban for prevention of venous thromboembolism after major orthopedic surgery

Correspondence: Hiroyuki Kawaji Department of Orthopaedic Surgery, Saiseikai Yamagata Saisei Hospital, 79-1 Okimachi, Yamagata, Japan Tel +812 3682 1111 Fax +812 3682 0122 Email hiroyuki.kawaji@ameria.org Abstract: Fatal pulmonary thromboembolism is the most serious complication following surgery. Patients undergoing major orthopedic surgeries, including total hip replacement, total knee replacement, and hip fracture surgery, represent a group at particularly high risk of venous thromboembolism. Therefore, prophylaxis for thromboembolic events has been of great concern to surgeons. Edoxaban is a novel, orally available, and highly specific and direct factor Xa inhibitor. This new agent was approved for the prevention of venous thromboembolism in patients undergoing major orthopedic surgery, including total hip replacement, total knee replacement, and hip fracture surgery, by the Japanese Ministry of Health, Labor, and Welfare in 2011. Preclinical and Phase I clinical trials demonstrated several promising properties. Its rapid absorption and short life-time in blood are known. Edoxaban inhibits factor Xa activity directly and selectively. It also has a strong antithrombotic effect without any influence of food intake. Coagulation monitoring is not required. Edoxaban has predictable linear pharmacokinetic and pharmacodynamic profiles. Phase II and III clinical trials have been completed to examine its efficacy and safety in patients undergoing major orthopedic surgery. In these clinical trials, oral administration of edoxaban showed efficacy superior to that of oral placebo or subcutaneously administered dalteparin or enoxaparin. Edoxaban can be regarded as a first choice to prevent venous thromboembolism after major orthopedic surgery.

Fracture and dislocation of snowboarder's elbow.

BACKGROUND This study focuses on the analysis of snowboarding versus skiing injuries, especially fracture, dislocation, or both, of the elbow, based on 7 years of medical records and roentgenograms of patients injured at a ski-snowboard area, Mt. Zao National Park, and demonstrates the precise characteristics of snowboard injury in the elbow region. METHODS A retrospective study of 1,445 injured snowboarders and 10,152 injured skiers was undertaken to assess both snowboarding and skiing injuries. Sixty-four cases of snowboarding injuries and 152 cases of skiing injuries were available for precise analysis of fracture, dislocation, or both, in the elbow region. RESULTS Fractures, dislocations, or both, in the elbow were more frequently observed for snowboarders (30 of 64 cases, 46.9%) when compared with that for skiers (26 of 152 cases, 17.1%) (p < 0.001). The rate of dislocation with or without fracture of the elbow was also significantly higher for snowboarders (17 of 64 cases, 26.6%) than for skiers (8 of 152 cases, 5.3%, p < 0.001). Seventeen cases of elbow dislocation in snowboarding were all of the posterior type, which accompanied two coronoid process fractures and two radial neck fractures. Fractures of the coronoid process (five cases), radial head (one case), radial neck (five cases), olecranon (one case), proximal ulnar shaft (one case), and extension-type fracture of distal humerus (four cases) were the fracture types observed in the analysis. CONCLUSION Posterior dislocation; fractures of coronoid process, radial neck, and radial head; and extension-type fracture of the distal humerus characterize the particular and frequent injury mechanism responsible for snowboarding trauma in the elbow region. Thus, snowboarding injury of the elbow is recognized as a severe injury and is characterized by a frequent risk of posterior dislocation, fracture, or both. The severity of elbow injuries in snowboarding mainly seems to be due to direct mechanical force on the elbow, receiving the full impact of falling down, combined with an outstretched hand and elbow extension, or with an outstretched hand and longitudinal thrust force, to the proximal radius and ulna and distal humerus.

Inflammatory immune cell responses and Toll-like receptor expression in synovial tissues in rheumatoid arthritis patients treated with biologics or DMARDs

Biologic antirheumatic drugs (BIO) have been reported to be potent therapeutic agents in the prevention of inflammatory joint destruction in rheumatoid arthritis (RA). The aim of this study was to investigate the immune-inflammatory cells, including Toll-like receptor (TLR)-equipped cells, in synovial tissue samples from RA patients on BIO compared to patients, who are only on conventional disease-modifying antirheumatic drug (DMARD). We analyzed immune-inflammatory cells in RA synovitis in patients of BIO group (n = 20) or DMARD group (n = 20). The grading scores of synovitis was 1.7 and 1.8 in each BIO and DMARD group and correlated best with the CD3+ T (r = 0.71/0.70, p < 0.05) and CD20+ B (r = 0.80/0.84, p < 0.05) cells in the both groups, but less well with the CD68+ macrophages and S-100+ dendritic cells (DCs). Interestingly, both T (116 vs. 242, p < 0.05) and B (80 vs. 142, p < 0.05) cell counts were lower in the BIO than in the DMARD group, whereas macrophage and DC counts did not differ. In contrast, the C-reactive protein (CRP) and disease activity score DAS28-CRP did not show clear-cut correlations with the inflammatory grade of the synovitis (r range, 0–0.35). Similar numbers of cells immunoreactive for TLR-1 to TLR-6 and TLR-9 were found in synovitis in both groups. Patients clinically responding to biologics might still have the potential of moderate/severe local joint inflammation, composed in particular of and possibly driven by the autoinflammatory TLR+ cells.

Minocycline-induced periarticular black bones in inflamed joints which underwent arthroplastic reconstruction.

Background Minocycline-induced pigmentation of bone (black bone) is well described in tooth-bearing intra-oral bone, but is less known in periarticular bone in patients who have undergone total joint arthroplasty. On a retrospective basis, we investigated the short-term clinico-radiological results of total joint arthroplasties in which the patient developed minocycline-induced periarticular black bone. Methods We found 5 cases (0.08%), in 4 patients, of periarticular bone pigmentation revealed during total joint arthroplasties (2 hips, 2 knees, and 1 ankle) in our series of total joint surgeries (6,548 cases) over a 10-year time period in our 3 institutes. Their mean age was 56 years at surgery. All patients had received long-term minocycline treatment. Mean dosage and duration of minocycline was 160 mg/day and 2.2 years, respectively. Minocycline had been prescribed for reactive arthritis (one), rheumatoid arthritis (two) and late infection after total joint arthroplasty (two patients). Mean follow-up period was 3.4 years after the surgeries. Results All cases had black or brown pigmentation in the periarticular bones during the surgery. There was no pigmentation in the cartilage or soft tissues of the joints. The mean Japanese Orthopaedic Association (JOA) score or Japanese Society for Surgery of the Foot (JSSF) scale for rheumatoid arthritis foot and ankle joints at latest follow-up (case 1, 66; case 2, 87; case 3, 77; case 4, 77; case 5, 80) improved compared to those of pre-surgery (case 1, 47; case 2, 45; case 3, 55; case 4, 34; case 5, 55). No implant loosening was noted on radiographic examination during the follow-up period. No abnormal bone formation, bone necrosis, hemosiderin deposition, malignancy or metallic debris was found on histological examination. Conclusions No clinico-radiological symptoms of total joint arthroplasties showed in the patients with minocycline-induced periariticular black bone in the short-term. Systemic minocycline treatment has the potential to induce significant black pigmentation of many tissues. In particular, minocycline-induced pigmentation of periarticular bone may be accelerated by inflammation due to rheumatic or pyogenic arthritis. Surgeons should recognize the risk of bone pigmentation in inflamed joints due to the systemic treatment of minocycline and explore its influence on periarticular bone and total joint arthroplasty in the long-term.

Initial Evaluation on Subsidence of Cemented Collarless Polished Tapered Stem Applied to the Patients with Narrow Femoral Medullar Canal

Purpose: The geometry of the proximal femur is one of the important factors for choosing the suitable stem. We have been applied cemented collarless polished tapered (CPT) stem to the patients with small femur. Radiographic evaluation was performed to access the clinical feature of the stem in early stage of the follow-up. Methods: One hundred total hip arthroplasties with CPT system were performed between October 2004 to February 2006. This study focused on the 53 cases to whom size 1 or smaller sized stem were implanted, and its post-operative period was 41 months (30-46 months). Morphologic classification of preoperative proximal femur, stem alignment, thickness of the cement mantle, cementing technique, subsidence of the stem, improvement in the bone-cement interface, and stress shielding were assessed. Results: The size of the inserted stem was X-SMALL in one case, SMALL in two cases, SIZE 0 in 12 cases, and SIZE 1 in 38 cases. Canal shape of proximal femur was stovepipe type in five cases, normal type in 43 cases, and champagne-flute type in five cases. There was no subsidence in eight cases. 44 stems subsided within 1 mm, one stem subsided 1 to 2 mm, and no stem subsided over 2 mm. In 39 of 45 cases, subsidence was appeared within six months after operation. Marked progressive and excessive subsidence was not seen after the two years of follow-up. Conclusions: Short term radiographic results of THA with CPT stem to small femur were satisfactory with less unfavorable radiographic findings, which imply contribution to longer survivorship of the stem.