Publications by authors named "Riku Hayashi"

The profunda artery perforator (PAP) flap, commonly used for small- to medium-sized breast reconstructions, offers easy harvest and inconspicuous donor-site scars. However, its shorter vascular pedicle compared with the deep inferior epigastric perforator flap limits its reach to lateral recipient vessels. This often requires strategic placement of perforators at the flap's edge to extend reach, potentially causing congestion in the distal part of the flap.

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The Ras homology (Rho) family of GTPases serves various functions, including promotion of cell migration, adhesion, and transcription, through activation of effector molecule targets. One such pair of effectors, the Rho-associated coiled-coil kinases (ROCK1 and ROCK2), induce reorganization of actin cytoskeleton and focal adhesion through substrate phosphorylation. Studies on ROCK knockout mice have confirmed that ROCK proteins are essential for embryonic development, but their physiological functions in adult mice remain unknown.

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Background: As food allergy potentially can induce life-threatening anaphylaxis, measures for food allergy are required at nurseries caring for food allergy children, but a large-scale factual investigation has not been carried out.

Objective: We evaluated measures for food allergy emergency in nurseries.

Methods: A questionnaire survey regarding emergency measures in all authorized nurseries (411 facilities including 20,586 children) was conducted in Kawasaki city, Japan.

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Background: Infection after shoulder arthroplasty can present a diagnostic challenge. The purpose of this study was to evaluate the utility of serum interleukin-6 (IL-6) levels in diagnosis of periprosthetic infection in patients undergoing revision shoulder arthroplasty.

Methods: We prospectively enrolled 69 patients who underwent revision shoulder arthroplasty at one institution.

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Most patients who undergo total joint arthroplasty experience dramatic relief of pain and improved ambulation for many years, but some eventually develop pain, often accompanied by radiographic evidence of bone resorption around their implants. The most frequent cause of device failure is osteolysis, but infection is another important cause of pain and arthroplasty failure. The distinction between infection and aseptic loosening is important because the 2 conditions are treated very differently.

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  • A new sheep model for ACL reconstruction using the semitendinosus tendon has been established to investigate healing and structural outcomes.
  • The study found that the tendon graft was largely acellular (necrotized) for up to 12 weeks post-surgery, with gradual improvement at later time points, but never fully matched the normal ACL strength.
  • Even after a year, the reconstructed knee showed significant instability compared to the control knee, indicating that the structural properties of the graft did not return to normal levels.
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Background: Although previous studies suggested that female patients are predisposed to increase graft laxity compared with male patients after single-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons, there have been no studies specifically examining gender-based differences in outcome after anatomic double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.

Hypotheses: (1) Female patients have significantly smaller hamstring graft diameters than do men for anatomic double-bundle anterior cruciate ligament reconstruction surgery; (2) female patients will have increased graft laxity compared with male patients after anatomic double-bundle anterior cruciate ligament reconstruction using autogenous hamstring tendons.

Study Design: Cohort study; Level of evidence, 2.

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Extramedullary hematopoiesis (EMH) occurs as a compensatory reaction to an underlying hematologic abnormality. EMH is most commonly seen in the liver and spleen but rarely has been reported in other locations, as well. On rare occasions, EMH may mimic a neoplasm in hematologically noncompromised patients.

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Background: The structural properties of a tendon autograft deteriorate during the remodeling phase after anterior cruciate ligament (ACL) reconstruction.

Hypothesis: A local application of autologous synovium-derived cells cultured in medium supplemented with transforming growth factor β (TGFβ) may inhibit the deterioration of structural properties of the tendon graft after ACL reconstruction.

Study Design: Controlled laboratory study.

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  • A study analyzed knee joint changes in 39 patients (median age 64) who underwent an opening wedge high tibial osteotomy (OWHTO) due to osteoarthritis or osteonecrosis.
  • Before and after surgery, various knee angles and alignment were measured using radiographs, revealing a significant decrease in lateral patellar tilt (LPT).
  • The findings suggest OWHTO may negatively impact the patellofemoral joint's alignment, advising that corrections should not exceed 15 degrees to avoid further issues.
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This is the first report of an anatomic double-bundle ACL and PCL reconstruction procedure with the autogenous hamstring tendons. We prepare two pairs of the doubled tendon grafts, to which a polyester tape and an Endobutton-CL are attached using our original technique at the tibial and femoral ends, respectively. Under arthroscopic and fluoroscopic observations, two tibial tunnels for PCL reconstruction are created so that they pass through the posteromedial and anterolateral bundle attachments, respectively.

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  • Achieving proper limb alignment post-surgery is crucial for the success of an opening-wedge high tibial osteotomy (OWHTO) in patients with knee issues like osteoarthritis or osteonecrosis.
  • A study of 42 knees showed significant changes in various angles related to limb alignment after the procedure, while the weight bearing line angle remained unchanged.
  • The research revealed that the degree of limb correction post-surgery is negatively correlated with the preoperative tibial axis angle, indicating that knowing the pre-surgery alignment may help predict potential alignment problems after the operation.
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We evaluated the clinical outcomes, in terms of early weight bearing, of using opening wedge high tibial osteotomy (OWHTO) to treat spontaneous osteonecrosis of the medial femoral condyle of the knee (SONK) using TomoFix and artificial bone substitute. Damaged cartilage tissue was removed and drilling of the necrotic area followed by OWHTO was performed in 30 knees from 30 patients with an average age of 71 years (range 58-82) at the time of operation. Patients were allowed to undertake partial weight-bearing exercises 1 week after the osteotomy procedure, with all patients performing full weight-bearing exercise at 2 weeks post-surgery.

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The purpose of this study was to evaluate the clinical results of simultaneous arthroscopically assisted reconstruction of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) using autogenous tendon grafts in chronic knee injuries. Nineteen patients (17 men and 2 women) with chronic multi-ligamentous injuries underwent one-stage ACL and PCL reconstruction. ACL, PCL and medial collateral ligament were reconstructed in seven knees, and ACL, PCL and posterolateral structure were reconstructed in two knees.

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