Post-cam clunk syndrome after posterior stabilized total knee arthroplasty as a sign of early femoral component loosening.

Soft tissue impingements are well-known complications of total knee arthroplasty. The impingements usually occur between the medial or lateral femoral component and tibial insert, and between the patella and femoral components. We report a rare case of impingement of the soft tissue between the femoral intercondylar fossa and post of the polyethylene insert, which caused pain and walking disability. After the surgery for the arthroscopic removal of the soft tissue, the symptoms disappeared. However, prosthetic loosening of the femur occurred several months after the arthroscopic surgery, requiring revision surgery. We would propose to call this symptom as post-cam clunk syndrome.

Retrospective comparison of three thromboprophylaxis agents, edoxaban, fondaparinux, and enoxaparin, for preventing venous thromboembolism in total knee arthroplasty.

PURPOSE: Patients undergoing total knee arthroplasty (TKA) are at high risk of venous thromboembolism, manifesting as deep vein thrombosis (DVT) or pulmonary embolism. The purpose of this study is to evaluate the efficacy and safety of edoxaban 15 mg once daily (o.d.) for preventing DVT in patients undergoing TKA. METHODS: Three hundred patients undergoing primary TKA under general anaesthesia for osteoarthritis were enrolled in this study: 100 treated with enoxaparin 2,000 IU twice daily (b.i.d.), 100 treated with fondaparinux 1.5 mg o.d. and 100 treated with edoxaban 15 mg o.d.. All treatments were scheduled to continue for 14 days. RESULTS: The incidence of DVT in patients treated with edoxaban 15 mg o.d. was lower than in patients with enoxaparin 2,000 IU b.i.d. and fondaparinux 1.5 mg o.d.. D-dimer levels were significantly lower in patients with edoxaban than in patients with enoxaparin and fondaparinux 1.5 mg o.d. on the first postoperative day; ΔHb levels were lower in patients with edoxaban than in patients with enoxaparin and fondaparinux on postoperative days, However, the difference was not statistically significant. Finally, the incidence of hepatic dysfunction was lower in patients with edoxaban than in patients with enoxaparin and fondaparinux. CONCLUSIONS: Edoxaban 15 mg o.d. was more efficient than enoxaparin 2,000 IU b.i.d. and fondaparinux 1.5 mg o.d.. Furthermore, edoxaban was safe compared with enoxaparin and fondaparinux. Edoxaban, an orally administered direct factor Xa (FXa) inhibitor, may offer a new option for preventing DVT, with a level of evidence III.

Endogenous interleukin-6, but not tumor necrosis factor alpha, contributes to the development of toll-like receptor 4/myeloid differentiation factor 88-mediated acute arthritis in mice.

OBJECTIVE: To generate a mouse model of reactive arthritis (ReA), an aseptic synovitis that develops in joints distant from the primary bacterial infection site, to examine roles for Toll-like receptors (TLRs) that recognize bacterial components involved in the development of this arthritis, and to identify the cytokine(s) relevant to this arthritis. METHODS: Mice were treated with cell wall extract from Escherichia coli (ECW) gram-negative bacterium by injection into the footpads. Seven days later, the mice were challenged with lipopolysaccharide (LPS), a TLR-4 ligand, which was injected into the knee joint cavity. To investigate the cytokine(s) involved in this arthritis, mice deficient in various arthritogenic cytokines, such as interleukin-6 (IL-6), IL-12, IL-18, interferon-gamma, and tumor necrosis factor alpha (TNFalpha), were sequentially treated with ECW and LPS. RESULTS: ECW-primed mice manifested acute severe arthritis after intraarticular challenge with ECW or LPS, while unprimed mice exhibited modest changes after these challenges. Mutant mice lacking functional TLR-4 or myeloid differentiation factor 88 (MyD88), an adaptor molecule of TLR-4 signaling, were resistant to this arthritis. Although both TNFalpha and IL-6 were equally expressed in the joint after LPS challenge, Il6(-/-) mice, but not Tnf(-/-) mice, were resistant to ECW/LPS-induced arthritis. CONCLUSION: Our present results clearly indicate the importance of priming with ECW and the requirement of TLR-4/MyD88-mediated IL-6, but not TNFalpha, for the development of ECW/LPS-induced arthritis. LPS-induced IL-6, in the absence of TNFalpha, mediates LPS-induced arthritis. These results suggest that IL-6 is a rational target for therapeutic regimens for inflammatory arthritis, including ReA and rheumatoid arthritis.

Experimental study of neural repair of the transected spinal cord using peripheral nerve graft.

It has been reported that transected spinal cord shows signs of axonal regeneration after peripheral nerve (PN) graft. We studied the membrane excitability and ion distribution in axons from transected rat spinal cord 3 weeks after PN graft using the spinal cord evoked potential, electron probe X-ray microanalysis, and the patch-clamp technique. Axonal structures were also observed using conventional electron microscopy. At the Th11 level, laminectomy was performed (=control) and the left thoracic segments of the spinal cord 2 mm in length were excised (=nongrafted group). PN sections from 8-week-old male Wistar rats were grafted into the spinal cord gap (=PN-grafted group). The spinal cord evoked potential in the PN-grafted group partly recovered in contrast to that in the nongrafted group, which showed no recovery. Higher Na, Cl, and Ca peaks and lower K peaks in the PN-grafted group were demonstrated compared with those in the nongrafted group. In the PN-grafted group, a higher current signal appeared in the axonal membrane of the spinal cord, suggesting a greater membrane activity compared with that in the nongrafted group. Unlike the nongrafted group, in which no myelinated axons were found, demyelinated axons that were myelinated by Schwann cells from the grafted peripheral nerve were observed in the PN-grafted group. These findings suggested that Schwann cells from the transplanted PN contributed to the repair of the transected spinal cord.

Relation between interleukin-18 and PGE2 in synovial fluid of osteoarthritis: a potential therapeutic target of cartilage degradation.

Osteoarthritis (OA) is characterized by articular cartilage degradation and hypertrophic joint changes. Interleukin (IL)-18 is a potent inducer of prostaglandin (PG) E2 in vitro. We determined the relation between IL-18 and PGE2 in synovial fluid (SF) of human OA, and discussed the role of IL-18 in the pathogenesis of OA and also its therapeutic consequences. SF was collected from 30 patients with knee OA. The concentrations of IL-18 and other cytokines including IL-1beta, tumor necrosis factor (TNF)-alpha, IL-6, and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA). The concentration of PGE2 was also assessed by inhibitory ELISA. The average value of IL-18 was 248 +/- 310 pg/mL. The average value of PGE2 was 93 +/- 103 pg/mL. There was a relatively strong correlation between IL-18 and PGE2 (r = 0.78, p = 0.0001). In contrast, IL-1beta was undetectable (cutoff point of 20 pg/mL), except for one case. TNF-alpha was also undetectable (cutoff point of 20 pg/mL), except for two cases. The average value of IL-6 was 1,310 +/- 2,623 pg/mL (n = 17), whereas IL-8 was 5,208 +/- 6,031 pg/mL (n = 5). Furthermore, IL-6 and IL-8 correlated with IL-18 (r = 0.69, p = 0.0024 and r = 0.87, p = 0.0527, respectively). Our results suggest that IL-18 could play a major role in vivo in inducing the production of PGE2, which in turn can cause cartilage degradation in OA pathogenesis. Thus, targeting this cytokine appears to be an important therapeutic approach in OA.

Successful limb salvage of pathological fracture of the distal tibia caused by cancer metastasis.

Pathological fractures of the distal tibia as a result of cancer metastases are rare. In particular, the management of intraarticular fractures of the distal tibia has not been established. In this article, we present a case of pathological intraarticular fracture with an extensive bone defect of the distal tibia that was successfully treated by limb salvage with a locked intramedullary nail and pirarubicin-impregnated methylmethacrylate. A 52-year-old patient with duodenal cancer presented with a painful swelling in the left crus. The condition was diagnosed as an impending pathological fracture of the tibia because of cancer metastasis. During radiation therapy, an actual pathological fracture of the distal tibia occurred due to an accident. Limb-salvage surgery was performed by removing the metastatic lesion, followed by using a locked intramedullary nail. Three distal and seven proximal locking screws were inserted into the tarsal bones and the remaining tibia. About 10 cm of bone defect was reconstructed by pirarubicin-impregnated methylmethacrylate. Consequently, good stability was achieved. One month later the patient could walk without any aid. Postoperative functional score was 77% according to the Musculoskeletal Tumor Society criteria. There was no recurrence; however, the patient died of lung metastases 4 months after the limb-salvage surgery.