Publications by authors named "Kenji Kawamura"

128 Publications

Dynamic analysis of the ulnar nerve and cubital tunnel morphology using ultrasonography; A cadaveric study.

J Shoulder Elbow Surg 2022 Jul 8. Epub 2022 Jul 8.

Department of Orthopedic Surgery, Nara Medical University, Kashihara, Japan.

Background: The causes of ulnar neuropathy at the elbow are unclear. The authors hypothesized that the humeral trochlea protrudes into the cubital tunnel during elbow flexion and causes a dynamic morphologic change of the ulnar nerve in the cubital tunnel.

Methods: An ultrasonic probe was fixed to the ulnar shafts of 10 fresh cadavers with an external fixator, and dynamic morphology of the cubital tunnel and ulnar nerve was observed. The distance from the Osborne band to the trochlea (OTD), distance from ulnar nerve center to the trochlea (UTD), and short and long axis diameters of the nerve at 30°, 60°, 90°, 120° of elbow flexion were recorded. We compared the OTD, UTD, and the flattening of the ulnar nerve between angle of flexion using single factor analysis of variance. Correlation between the ulnar nerve flattering, OTD, and UTD was examined using Spearman's correlation coefficient. A p value less than 0.05 was used to denote statistical significance.

Results: Flattening of the ulnar nerve progressed with increasing elbow flexion and was significantly different between 0° and 60°, 90°, and 120° (p = 0.03 at 60º, p < 0.01 at 90º and 120º). OTD decreased with elbow flexion, and there was a significant difference among all elbow flexion angles (all p < 0.01). UTD decreased significantly from 0° flexion value to 90° flexion value (p = 0.03). Flattering of the nerve was significantly correlated with the OTD (r = 0.66, p < 0.01).

Conclusions: A positive correlation was found between the protrusion of the humeral trochlea into the cubital tunnel during elbow flexion and ulnar nerve flattening using cadaveric elbow and ultrasonography.
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http://dx.doi.org/10.1016/j.jse.2022.05.026DOI Listing
July 2022

Simultaneous Bilateral Chronic Volar Lunate Dislocation: A Case Report.

JBJS Case Connect 2022 04 15;12(2). Epub 2022 Jun 15.

Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Nara, Japan.

Case: A 24-year-old professional judo competitor suffered injuries to both the wrists when he fell on his back while lifting a 90-kg barbell in the bilateral dorsiflexed wrist position. Simultaneous bilateral volar lunate dislocation had been missed for a year. The degenerated lunates were simultaneously removed using a palmar approach. At 12 months postoperatively, the patient returned to judo competitions without pain. Radiography showed no progression of the intercarpal alignment abnormality.

Conclusion: Simultaneous bilateral chronic volar lunate dislocation is extremely rare. Long-term follow-up is necessary to check for carpal alignment.
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http://dx.doi.org/10.2106/JBJS.CC.22.00094DOI Listing
April 2022

Acromioclavicular joint instability on cross-body adduction view: the biomechanical effect of acromioclavicular and coracoclavicular ligaments sectioning.

BMC Musculoskelet Disord 2022 Mar 23;23(1):279. Epub 2022 Mar 23.

Department of Orthopedic Surgery, Nara Medical University, 840 Shijoutyou, Kashihara City, Nara, 634-5821, Japan.

Background: The acromioclavicular (AC) and coracoclavicular (CC) ligaments are important stabilizers of the AC joint. We hypothesized that AC and trapezoid ligament injuries induce AC joint instability and that the clavicle can override the acromion on cross-body adduction view even in the absence of conoid ligament injury. Accordingly, we investigated how sectioning the AC and CC ligaments contribute to AC joint instability in the cross-body adduction position.

Methods: Six fresh-frozen cadaveric shoulders were used in this study, comprising five male and one female specimen, with a mean age of 68.7 (range, 51-87) years. The left side of the trunk and upper limb, and the cervical and thoracic vertebrae and sternum were firmly fixed with an external fixator. The displacement of the distal end of the clavicle relative to the acromion was measured using an electromagnetic tracking device. We simulated AC joint dislocation by the sequential resection of the AC ligament, AC joint capsule, and CC ligaments in the following order of stages. Stage 0: Intact AC and CC ligaments and acromioclavicular joint capsule; stage 1: Completely sectioned AC ligament, capsule and joint disc; stage 2: Sectioned trapezoid ligament; and stage 3: Sectioned conoid ligament. The superior clavicle displacement related to the acromion was measured in the horizontal adduction position, and clavicle overriding on the acromion was assessed radiologically at each stage. Data were analyzed using a one-way analysis of variance and post-hoc tests.

Results: Superior displacement was 0.3 mm at stage 1, 6.5 mm at stage 2, and 10.7 mm at stage 3. On the cross-body adduction view, there was no distal clavicle overriding at stages 0 and 1, and distal clavicle overriding was observed in five cases (5/6: 83%) at stage 2 and in six cases (6/6: 100%) at stage 3.

Conclusion: We found that AC and trapezoid ligament sectioning induced AC joint instability and that the clavicle could override the acromion on cross-body adduction view regardless of conoid ligament sectioning. The traumatic sections of the AC and trapezoid ligament may lead to high grade AC joint instability, and the distal clavicle may subsequently override the acromion.
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http://dx.doi.org/10.1186/s12891-022-05245-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8943985PMC
March 2022

Gait cycle time variability in patients with knee osteoarthritis and its possible associating factors.

J Phys Ther Sci 2022 Feb 23;34(2):140-145. Epub 2022 Feb 23.

Graduate School of Health Science, Kyoto Tachibana University, Japan.

[Purpose] Knee osteoarthritis can alter gait variability; however, few studies have investigated the associating factors with gait cycle time variability. The first objective was to compare gait cycle variability between female patients with knee osteoarthritis and healthy elderly females and to determine gait characteristics in patients with knee osteoarthritis. The second objective was to identify the associating factors with gait cycle time variability. [Participants and Methods] The participants included 24 female patients diagnosed with knee osteoarthritis and 12 healthy elderly females. Gait cycle variability (coefficient of variation of gait cycle time), knee extension range of motion, knee extension strength, 5-m walk test, Timed Up & Go Test, and Western Ontario and McMaster Universities Osteoarthritis Index were measured. All assessment results were compared between the knee osteoarthritis and healthy groups. [Results] Gait cycle time variability was significantly higher in the knee osteoarthritis group than in the healthy group. Further, it showed a significant positive correlation with the 5-m walk test and the Western Ontario and McMaster Universities Osteoarthritis Index. [Conclusion] Patients with knee osteoarthritis presented greater gait cycle variability than that of healthy individuals. Therefore, rehabilitation to improve gait variability might enhance the quality of life of patients with knee osteoarthritis.
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http://dx.doi.org/10.1589/jpts.34.140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8860692PMC
February 2022

A cross-sectional study to assess variability in knee frontal plane movement during single leg squat in patients with anterior cruciate ligament injury.

J Bodyw Mov Ther 2021 10 6;28:144-149. Epub 2021 Aug 6.

Center of Orthopaedic Surgery, The Taijukai foundation (social medical corporation) Kaisei General Hospital, 3-5-28 Muro-Machi, Sakaide-City, Kagawa, 762-0007, Japan. Electronic address:

Background: Single leg squat (SLS) tests help predict anterior cruciate ligament injuries. However, the variability in joint movement during this test has not been fully investigated. The aim of this study was to examine the knee frontal plane movement variability during SLS in patients with anterior cruciate ligament (ACL) injury.

Methods: In this cross-sectional study, we enrolled 56 patients with ACL injury (28 males; 28 females) and 46 healthy subjects (23 males; 23 females). All participants underwent SLS tests. All kinematic variables were joint angle of trunk, pelvis and lower limb, center of gravity (COG), center of pressure (COP). These data were obtained at the frontal plane and the coefficient of variation (CV) were calculated. Multiple comparisons were performed between healthy subjects and the injured leg and uninjured leg of patients with ACL injury. The correlation of the CV in knee varus/valgus range of motion (ROM) with the CV in other kinematic variables were investigated in patients with ACL injury.

Results: Compared with healthy subjects, patients with ACL injury exhibited significantly larger the CV in knee varus/valgus ROM. A positive correlation was observed between the CV in knee varus/valgus ROM and the CV in pelvic lateral inclination ROM in patients with ACL injury.

Conclusions: Knee frontal plane movement variability during SLS may help evaluate the risk of ACL injury/re-injury. In addition, pelvic lateral inclination variability during SLS may need to be evaluated in conjunction with knee frontal plane movement variability.
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http://dx.doi.org/10.1016/j.jbmt.2021.07.016DOI Listing
October 2021

Arthroscopic Lunate Excision Provides Excellent Outcomes for Low-Demand Patients with Advanced Kienböck's Disease.

Arthrosc Sports Med Rehabil 2021 Oct 28;3(5):e1387-e1394. Epub 2021 Aug 28.

Department of Orthopedic Surgery, Nara Medical University, Nara, Japan.

Purpose: To examine the clinical outcomes of arthroscopic lunate excisions for advanced Kienböck's disease.

Methods: Fifteen patients (six men and nine women; mean age: 65 years; range: 48-83 years) with advanced Kienböck's disease, who underwent arthroscopic lunate resection between April 2008 and March 2016, were reviewed clinically and radiographically after a follow-up of >2 years (mean: 29 months; range: 24-60 months). Clinical parameters, such as wrist range of motion, grip strength, Disabilities of the Arm, Shoulder, and Hand (DASH) score, and patient-rated wrist evaluation (PRWE) score were evaluated. Radiographic parameters included radioscaphoid angle, scaphocapitate angle, carpal height ratio, ulnar-triquetrum distance, and the scaphoid-triquetrum distance. Wilcoxon's signed-rank test was used to compare measurement results.

Results: During the final follow-up, patients exhibited significant improvements, such as 42.9° in wrist range of motion ( = .009), 24.5% of the contralateral side in grip strength ( = .001), 26.2 points in DASH score ( = .002), and 37.8 points in PRWE score ( .001), compared with the preoperative values. The radioscaphoid and scaphocapitate angles significantly increased by 4.8° ( = .0027) and 3.7° ( = .0012), respectively. The carpal height ratio, ulnar-triquetrum distance, and scaphoid-triquetrum distance significantly decreased by 0.05 ( .001), 2.6 mm ( .001), and 1.3 mm ( = .0012), respectively.

Conclusions: Our results suggest that arthroscopic lunate excisions provided excellent postoperative pain relief and functional recovery within 2 years of follow-up. Changes in carpal alignment and stress concentration on the radial side of the carpal bones could occur in the long term; however, arthroscopic lunate excision can be a good surgical option for treating low-demand patients with advanced Kienböck's disease.

Level Of Evidence: Level IV, therapeutic case series.
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http://dx.doi.org/10.1016/j.asmr.2021.06.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8527252PMC
October 2021

Minimally invasive 360-degree pelvic ring fixation using a combination of crab-shaped fixation and pelvic internal fixator for unstable pelvic ring fracture: A case report.

Trauma Case Rep 2021 Dec 1;36:100540. Epub 2021 Oct 1.

Department of Orthopedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara City, Nara 634-8522, Japan.

Surgery with both anterior and posterior fixation is recommended for unstable pelvic ring fractures; nonetheless, the surgical method remains controversial. Crab-shaped fixation is a minimally invasive and strong posterior fixation method using spinal instruments that can reduce vertical dislocations. The use of pelvic internal fixator as a minimally invasive anterior fixation method has been reported. It is recommended in cases where there is an open wound in the lower abdomen or damage to the pelvic organs. Conversely, to the best of our knowledge, there has been no report on the combined use of crab-shaped fixation and pelvic internal fixator to date. We performed a minimally invasive 360-degree fixation using a combination of crab-shaped fixation and pelvic internal fixator for an unstable pelvic ring fracture (AO-C2) and sacral fracture (Denis zone II) with 15-mm vertical dislocation. The sacral fracture was accompanied by a large bone fragment in the spinal canal, which was suspected to have caused neuropathy. Therefore, in addition to posterior fixation, we performed decompression and removed the bone fragment. Postoperative computed tomography revealed that the sacral vertical dislocation was reduced to 7.5 mm. The patient started getting out of bed on postoperative day 2. His neuropathy improved after surgery. Owing to abdominal discomfort, pelvic internal fixator was extracted at 3 months postoperatively. Bone fusion was completed, and posterior fixation was removed at 9 months postoperatively. Two years after, the patient walks independently and has returned to work. Minimally invasive 360-degree pelvic ring fixation is a treatment option for an unstable pelvic ring fracture (AO-C2).
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http://dx.doi.org/10.1016/j.tcr.2021.100540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8502949PMC
December 2021

Case Report: Transcatheter Arterial Embolization for the Initial Management of Intra-Abdominal Hemorrhage From a Hepatic Tumor in a Cat.

Front Vet Sci 2021 2;8:707120. Epub 2021 Aug 2.

Kawamura Animal Hospital, Niigata, Japan.

An 8-year-old Ragdoll cat was admitted to our hospital after its owner noticed sudden lethargy. Abdominal ultrasonography showed a large amount of blood in the abdominal cavity, and the cat was diagnosed as having hemorrhagic shock caused by the rupture of an intra-abdominal mass. Blood transfusion was performed on the 1st day of hospitalization. On the 2nd day, contrast-enhanced computed tomography (CT) was performed, and hemorrhage from a mass originating in the caudate lobe of the liver was noted. Transcatheter arterial embolization (TAE) was performed to stop the bleeding from the mass using Gelpart to embolize the feeding artery. The following day, fever and elevation of liver enzyme levels were observed, but these subsided within a few days. At discharge 5 days after TAE, no fluid was found in the peritoneal cavity, and no further intra-abdominal bleeding occurred. Sixty-six days after TAE, we were able to perform resection surgery with the cat in good condition. A partial response was observed on CT performed before surgery. Histopathology revealed cholangiocellular adenoma. The cat was doing well as of postoperative day 549. This case indicates that TAE may be effective for initial hemostasis and stabilization of conditions in animals with tumor-induced hemorrhage.
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http://dx.doi.org/10.3389/fvets.2021.707120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8366023PMC
August 2021

Treatment of painful median nerve neuroma using pedicled vascularized lateral antebrachial cutaneous nerve with adipofascial flap: a cadaveric study and exploration of clinical application.

J Plast Surg Hand Surg 2022 Apr 9;56(2):74-78. Epub 2021 Jun 9.

Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Japan.

The most common procedure for the treatment of painful median nerve neuroma is coverage with vascularized soft tissue following external neurolysis. However, the ideal treatment should include reconnecting the proximal and distal stumps of the damaged nerve to allow the growth of regenerating axons to their proper targets for a functional recovery. We developed a useful technique employing radial artery perforator adipofascial flap including the lateral antebrachial cutaneous nerve (LABCN) to repair the median nerve by vascularized nerve grafting and to achieve coverage of the nerve with vascularized soft tissue. In an anatomical study of 10 fresh-frozen cadaver upper extremities, LABCN was constantly bifurcated into two branches at the proximal forearm (mean: 8.2 cm distal to the elbow) and two branches that run in a parallel manner toward the wrist. The mean length of the LABCN branches between the bifurcating point and the wrist was 18.2 cm, which enabled inclusion of adequate length of the LABCN branches into the radial artery perforator adipofascial flap. The diameters of the LABCN branches (mean: 1.7 mm) were considered suitable to bridge the funiculus of the median nerve defect after microsurgical internal neurolysis. In all cadaver upper extremities, the 3-cm median nerve defect at the wrist level could be repaired using the LABCN branches and covered with the radial artery perforator adipofascial flap. On the basis of this anatomical study, the median nerve neuroma was successfully treated with radial artery perforator adipofascial flap including vascularized LABCN branches.
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http://dx.doi.org/10.1080/2000656X.2021.1933994DOI Listing
April 2022

Antarctic surface temperature and elevation during the Last Glacial Maximum.

Science 2021 06;372(6546):1097-1101

Department of Chemistry "Ugo Schiff," University of Florence, Florence, Italy.

Water-stable isotopes in polar ice cores are a widely used temperature proxy in paleoclimate reconstruction, yet calibration remains challenging in East Antarctica. Here, we reconstruct the magnitude and spatial pattern of Last Glacial Maximum surface cooling in Antarctica using borehole thermometry and firn properties in seven ice cores. West Antarctic sites cooled ~10°C relative to the preindustrial period. East Antarctic sites show a range from ~4° to ~7°C cooling, which is consistent with the results of global climate models when the effects of topographic changes indicated with ice core air-content data are included, but less than those indicated with the use of water-stable isotopes calibrated against modern spatial gradients. An altered Antarctic temperature inversion during the glacial reconciles our estimates with water-isotope observations.
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http://dx.doi.org/10.1126/science.abd2897DOI Listing
June 2021

Intercostal artery rupture associated with thoracic spinal hyperextension injury caused by a minor trauma: A case report.

Trauma Case Rep 2021 Jun 21;33:100487. Epub 2021 Apr 21.

Department of Orthopedic Surgery, Nara Medical University, 840 Shijotyo, Kashihara City, 654-8522, Nara, Japan.

Diffuse idiopathic skeletal hyperostosis is associated with hyperextension injury of the spine caused by a minor trauma and may often be diagnosed late, thus preventing effective treatment. To date, there have been no reported cases of segmental arterial injury associated with a hyperextension injury caused by a minor trauma in super-elderly patients with diffuse idiopathic skeletal hyperostosis. Herein, we present the findings and treatment provided for a 92-year-old woman with a right massive hemothorax and 12th thoracic vertebral fracture. The patient was diagnosed with diffuse idiopathic skeletal hyperostosis. Bleeding stopped naturally, and we successfully treated the patient using posterior fixation with percutaneous pedicle screws. At 6 months post-surgery, there was no complication, instrumentation failure, or correction loss, and she could walk independently using a cane. To our knowledge, this is the first report of intercostal artery rupture and massive hemothorax associated with diffuse idiopathic skeletal hyperostosis fracture caused by a minor trauma. It is notable that diffuse idiopathic skeletal hyperostosis following a minor trauma in such elderly patients may cause segmental arterial rupture associated with spinal burst fracture and hyperextension injury.
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http://dx.doi.org/10.1016/j.tcr.2021.100487DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8102801PMC
June 2021

Partial Trapeziotrapezoid Resection and Thumb Range of Movement After Trapeziometacarpal Joint Fusion-A Biomechanical Study.

J Hand Surg Am 2021 12 2;46(12):1126.e1-1126.e7. Epub 2021 May 2.

Department of Orthopedic Surgery, Nara Medical University, Nara, Japan.

Purpose: Trapeziometacarpal (TMC) joint arthrodesis is an effective treatment for stage III osteoarthritis. Although this procedure alleviates thumb pain and restores grip power and pinch strength, persistent limitation of thumb movement is inevitable. This biomechanical study aimed to investigate the altered kinematics of thumb circumduction motion after TMC joint arthrodesis and subsequent excision of the trapeziotrapezoid (TT) and trapezio-second metacarpal (T-2MC) joint spaces.

Methods: Eight cadaver upper extremities were mounted on a custom testing apparatus. The hand and carpal bones were fixed to the apparatus, except for the first metacarpal bone, trapezium, and trapezoid. A 50-g load was applied at the tip of the first metacarpal head to generate passive thumb circumduction. An electromagnetic tracking system measured the angular and rotational displacement of the first metacarpal. All specimens were tested in 4 conditions: intact, after simulated TMC joint fusion, after subsequent excision of 3 mm of bone at the TT joint space, and after additional 3 mm resection at the T-2MC joint space.

Results: After simulated TMC arthrodesis, the range of angular motion of thumb circumduction decreased to 25% that of the intact thumb. Subsequent resections at the TT and T-2MC joint spaces increased circumduction ranges to 49% (TT joint) and 73% (TT plus T-2MC joints) that of the intact thumb. The range of thumb rotational motion showed a similar trend.

Conclusions: Trapeziometacarpal arthrodesis decreased the range of both angular and rotational motion during thumb circumduction. Subsequent resections at the paratrapezial space increased the range of thumb motion, suggesting that hypermobility of the paratrapezial joints increases thumb mobility after TMC joint fusion.

Clinical Relevance: Patients with hypermobile paratrapezial joints may have larger thumb movement after TMC joint fusion. Additional resections of the TT and T-2MC joint spaces may further mobilize the thumb in patients who complain of stiffness after TMC fusion.
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http://dx.doi.org/10.1016/j.jhsa.2021.03.016DOI Listing
December 2021

Biomechanical comparison of arthroscopic and open lunate excisions in the cadaveric wrist.

Clin Biomech (Bristol, Avon) 2021 04 26;84:105343. Epub 2021 Mar 26.

Department of Orthopaedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, Japan.

Background: In advanced Kienböck disease, unreconstructible lunate should be excised as a salvage procedure. There is a lack of information about the biomechanical approaches evaluating the carpal kinematics after lunate excision. We hypothesized that arthroscopic lunate excision would not break the ring structure of the proximal carpal row, preventing carpal instability. We aimed to investigate changes in carpal kinematics following arthroscopic and open lunate excisions.

Methods: We used upper extremities from five fresh cadavers and simulated arthroscopic and open lunate excisions. Arthroscopic lunate excision was performed to preserve the attachment sites of intrinsic and extrinsic carpal ligaments to the lunate. Open lunate excision was conducted with sectioning of the intrinsic and extrinsic carpal ligaments. Using a three-dimensional space electromagnetic tracking device, rotation angles of the scaphoid and triquetrum and the change of scaphotriquetrum distance were measured under axial loading. We compared the rotation angles and the change of scaphotriquetrum distance among intact wrists, open, and arthroscopic lunate excisions.

Findings: No Significant differences in the rotation angle of the scaphoid and triquetrum or the change of scaphotriquetrum distance were found between intact wrist and arthroscopic lunate excision. The triquetrum significantly dorsiflexed and supinated in wrists with open lunate excisions compared with intact wrists. Significant differences in the change of scaphotriquetrum distance were found between intact and openly excised wrists and between arthroscopic and open excisions.

Interpretation: Arthroscopic lunate excision potentially prevented kinematic change of the proximal carpal row under axial loading by maintaining the integrity of attachment sites of carpal ligaments.
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http://dx.doi.org/10.1016/j.clinbiomech.2021.105343DOI Listing
April 2021

Impacted intraarticular fragments of distal radius fractures: A radiographic characterization and analysis of reliability and diagnostic accuracy.

J Orthop Sci 2022 Mar 9;27(2):384-388. Epub 2021 Mar 9.

Department of Orthopedic Surgery, Nara Medical University, Kashihara, Nara, 634-8522, Japan.

Background: Reduction using ligamentotaxis may not be effective enough to treat impacted intraarticular fragments of distal radius fractures. Articular incongruence resulting from the loss of reduction is a risk factor for postoperative osteoarthritis and worse clinical outcome. This study aimed to analyze the radiographic characterization of the impacted intraarticular fragments of distal radius fractures using two/three-dimensional computed tomography (CT). Further, we assessed the reliability and diagnostic accuracy in detecting the fragments using plain radiographs.

Methods: We analyzed 167 three-dimensional CT images of the intraarticular distal radius fractures and selected 12 fractures with impacted intraarticular fragments. We recorded the location, size, and displacement of the fragment using CT images. In addition, six examiners evaluated 25 fractures including those 12 fractures having the fragments using plain radiographs for detecting the fragments and their displacements. Further, we evaluated the reliability and diagnostic accuracy of the plain radiographs in the detection of the fragment.

Results: Fifteen impacted intraarticular fragments were found in 12 wrists. The displacement of the scaphoid facet fragment was significantly larger than that of the lunate facet fragment in CT measurement (7.0 mm and 3.6 mm). Inter and intraobserver reliability of the diagnosis for the fragment in plain radiographs were poor and fair (κ: 0.14 and κ:0.27). Diagnostic accuracy in detecting the fragment in plain radiographs generated mean sensitivity: 0.4, mean specificity: 0.73, and mean accuracy: 0.58. The mean sensitivity in detecting a lunate facet fragment was lower than that of a scaphoid facet fragment in plain radiographs (0.24 and 0.44).

Conclusion: Impacted intraarticular fragments were found in 7% of intraarticular distal radius fractures. We observed low reliability and sensitivity in detecting the fragment using plain radiographs. Preoperative recognition of the fragments using plain radiograph were difficult, even though the magnitude of step-off of the scaphoid facet fragment was large.
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http://dx.doi.org/10.1016/j.jos.2020.12.029DOI Listing
March 2022

The Role of the Acromioclavicular Ligament in Acromioclavicular Joint Stability: A Cadaveric Biomechanical Study.

Orthop J Sports Med 2021 Feb 10;9(2):2325967120982947. Epub 2021 Feb 10.

Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Nara, Japan.

Background: Acromioclavicular (AC) joint dislocation is evaluated using the radiologically based Rockwood classification. The relationship between ligamentous injury and radiological assessment is still controversial.

Purpose/hypothesis: To investigate how the AC ligament and trapezoid ligament biomechanically contribute to the stability of the AC joint using cadaveric specimens. The hypothesis was that isolated sectioning of the AC ligament would result in increased instability in the superior direction and that displacement >50% of the AC joint would occur.

Study Design: Controlled laboratory study.

Methods: Six shoulders from 6 fresh-frozen cadavers were used in this study. Both the scapula and sternum were solidly fixed on a customized wooden jig with an external fixator. We simulated distal clavicular dislocation with sequential sectioning of the AC and coracoclavicular (CC) ligaments. Sectioning stages were defined as follows: stage 0, the AC ligament, CC ligament, and AC joint capsule were left intact; stage 1, the anteroinferior bundle of the AC ligament, joint capsule, and disk were sectioned; stage 2, the superoposterior bundle of the AC ligament was sectioned; and stage 3, the trapezoid ligament was sectioned. The distal clavicle was loaded with 70 N in the superior and posterior directions, and the magnitudes of displacement were measured.

Results: The amounts of superior displacement averaged 3.7 mm (stage 0), 3.8 mm (stage 1), 8.3 mm (stage 2), and 9.5 mm (stage 3). Superior displacement >50% of the AC joint was observed in stage 2 (4/6; 67%) and stage 3 (6/6; 100%). The magnitudes of posterior displacement were 3.7 mm (stage 0), 3.7 mm (stage 1), 5.6 mm (stage 2), and 9.8 mm (stage 3). Posterior displacement >50% of the AC joint was observed in stage 3 (1/6; 17%).

Conclusion: We found that the AC ligaments contribute significantly to AC joint stability, and superior displacement >50% of the AC joint can occur with AC ligament tears alone.

Clinical Relevance: The AC ligament plays an important role not only in horizontal stability but also in vertical stability of the AC joint.
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http://dx.doi.org/10.1177/2325967120982947DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7878954PMC
February 2021

Joint movement variability during landing in patients with anterior cruciate ligament reconstruction.

J Sports Med Phys Fitness 2021 Dec 8;61(12):1629-1635. Epub 2021 Feb 8.

Center of Orthopedic Surgery, The Taijukai Foundation (Social Medical Corporation) Kaisei General Hospital, Sakaide, Japan.

Background: Rapid knee valgus and knee internal rotation motions in the initial phase of landing are the known mechanisms for anterior cruciate ligament injury, and many studies have been investigated on knee joint peak angle during landing. However, the variability in joint movement during landing has not been fully investigated. This study aimed to compare the coefficient of variation of lower extremity range of motion in patients with anterior cruciate ligament reconstruction and healthy subjects during landing.

Methods: In this cross-sectional study, 54 patients with anterior cruciate ligament reconstruction and 44 healthy subjects were enrolled. All participants underwent six trials of single-leg hop landing for maximum safe horizontal distance. The kinematic variables were the coefficient of variation during two discrete (0.05 after initial contact and maximum knee flexion) time points for selected three-dimensional hip and knee joint range of motion. Comparisons were performed between the two groups.

Results: Compared with healthy subjects, patients with anterior cruciate ligament reconstruction had greater the coefficient of variation in hip internal/external rotation range of motion (patients with anterior cruciate ligament reconstruction had 41.9%, healthy subjects had 25.5%; P=0.0018; effect size: 0.32) and knee internal/external rotation range of motion (patients with anterior cruciate ligament reconstruction had 68.4%; healthy subjects had 48.1%; P=0.0014; effect size: 0.32) for periods that spanned 0.05 s from the initial contact.

Conclusions: Patients with anterior cruciate ligament reconstruction could be disadvantageous in ability to control and adapt hip and knee joint rotations when controlling landings.
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http://dx.doi.org/10.23736/S0022-4707.21.11911-5DOI Listing
December 2021

Periprosthetic tibial fracture after total knee arthroplasty with popliteal artery injury-A case report.

Trauma Case Rep 2020 Dec 8;30:100359. Epub 2020 Oct 8.

Department of Orthopedic Surgery, Nara Medical University, 840 Shijotyo, Kashihara City, Nara 654-8522, Japan.

We present the case of a 79-year-old woman who presented at our center with a periprosthetic tibial fracture with a popliteal artery injury after total knee arthroplasty. Anastomosis of the popliteal artery was performed on the day of injury, and was later treated by open reduction and internal fixation. The patient was able to walk 3 months after injury. The present case was difficult to treat because of the arterial injury associated with periprosthetic fracture. Although revision of the implant was considered, open reduction and internal fixation was selected because of the severity of soft-tissue damage. The mechanism of injury is not uncommon, and it is expected that similar fractures will become more prevalent in the future as the number of knee replacement surgeries increases.
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http://dx.doi.org/10.1016/j.tcr.2020.100359DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7578748PMC
December 2020

Vascularized pedicled bone graft from the distal radius supplied by the anterior interosseous artery for treatment of ulnar shaft nonunion: An anatomical study of cadavers and a case report.

Microsurgery 2020 May 12;40(4):479-485. Epub 2020 Feb 12.

Department of Orthopedic Surgery, Nara Medical University, Kashihara, Japan.

Background: A vascularized distal radius graft can be a reliable solution for the treatment of refractory ulnar nonunion. The aim of this study is to establish the anatomical basis of a vascularized bone graft pedicled by the anterior interosseous artery and report its clinical application, using cadaveric studies and a case report.

Methods: Fourteen fresh frozen cadaveric upper limbs were used. The branches of the anterior interosseous artery (the 2, 3 intercompartmental supraretinacular artery and the fourth extensor compartment artery) were measured at the bifurcation site. The anatomical relationship between the anterior interosseous artery and motor branches of the posterior interosseous nerve was investigated. An anterior interosseous artery pedicled bone flap was used in a 48-year-old woman with refractory ulnar nonunion.

Results: There were two variations depending on whether the 2,3 intercompartmental supraretinacular artery branched off distally or proximally from the terminal motor branch of the posterior interosseous nerve. The proximal border of the graft was located at an average of 10.5 cm (range, 6.5-12.5 cm) from the distal end of the ulnar head in the distal type (57%) and 17.5 cm (range, 9.5-21.5 cm) in the proximal type (43%). In the clinical application, successfully consolidation was achieved 4 months post-surgery. The patient had not developed any postoperative complications until the 2-year postoperative follow-up.

Conclusions: The anterior interosseous artery-pedicled, vascularized distal radius bone graft would be a reliable alternative solution for the treatment of an ulnar nonunion located within the distal one-third of the ulna.
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http://dx.doi.org/10.1002/micr.30566DOI Listing
May 2020

Early Last Interglacial ocean warming drove substantial ice mass loss from Antarctica.

Proc Natl Acad Sci U S A 2020 02 11;117(8):3996-4006. Epub 2020 Feb 11.

Department of Earth Sciences, Royal Holloway University of London, Surrey TW20 OEX, United Kingdom.

The future response of the Antarctic ice sheet to rising temperatures remains highly uncertain. A useful period for assessing the sensitivity of Antarctica to warming is the Last Interglacial (LIG) (129 to 116 ky), which experienced warmer polar temperatures and higher global mean sea level (GMSL) (+6 to 9 m) relative to present day. LIG sea level cannot be fully explained by Greenland Ice Sheet melt (∼2 m), ocean thermal expansion, and melting mountain glaciers (∼1 m), suggesting substantial Antarctic mass loss was initiated by warming of Southern Ocean waters, resulting from a weakening Atlantic meridional overturning circulation in response to North Atlantic surface freshening. Here, we report a blue-ice record of ice sheet and environmental change from the Weddell Sea Embayment at the periphery of the marine-based West Antarctic Ice Sheet (WAIS), which is underlain by major methane hydrate reserves. Constrained by a widespread volcanic horizon and supported by ancient microbial DNA analyses, we provide evidence for substantial mass loss across the Weddell Sea Embayment during the LIG, most likely driven by ocean warming and associated with destabilization of subglacial hydrates. Ice sheet modeling supports this interpretation and suggests that millennial-scale warming of the Southern Ocean could have triggered a multimeter rise in global sea levels. Our data indicate that Antarctica is highly vulnerable to projected increases in ocean temperatures and may drive ice-climate feedbacks that further amplify warming.
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http://dx.doi.org/10.1073/pnas.1902469117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7049167PMC
February 2020

Vascularized medial femoral condyle graft for nonunion after failed radiolunate arthrodesis.

Case Reports Plast Surg Hand Surg 2019 22;6(1):7-10. Epub 2019 Jan 22.

Department of Orthopedic Surgery, Nara Medical University, Kashihara city, Japan.

Since the medial femoral condyle flap was originally described in 1989, the indications for use of this versatile flap as a graft have broadened. We used this procedure in a patient with nonunion after failed arthrodesis of the radiolunate joint. Early bone union was achieved, with marked postoperative improvement in VAS and DASH scores.
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http://dx.doi.org/10.1080/23320885.2018.1544848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6968543PMC
January 2019

Dorsal Intercarpal Ligament Preserving Arthrotomy and Capsulodesis for Scapholunate Dissociation.

Tech Hand Up Extrem Surg 2020 Mar;24(1):43-46

Orthopedic Surgery, Nara Medical University, Kashihara.

Carpal instability secondary to scapholunate (SL) ligament tears can lead to a significant disability of the wrist. Different surgical procedures have been proposed to treat SL instability. A variety of dorsal capsulodesis techniques tethering the scaphoid have been used in patients with SL dissociation. We report a novel technique of modified dorsal intercarpal ligament (DICL) capsulodesis for the treatment of SL dissociation. The surgical indication for this procedure is complete SL ligament tear with a reducible carpal malalignment and no secondary osteoarthritis. This procedure is indicated when the remnant of torn ligament in the dorsal SL interosseous space is available for repair. First, carpal malalignment is corrected and the scaphoid and the lunate are temporarily fixed with a transosseous screw or Kirschner wires. Using a dorsal approach, the DICL is then exposed, which originates from the triquetrum and attaches to the scaphoid, trapezium, and trapezoid. The distal and proximal borders of the ligament are identified and elevated without detaching the attachment sites. The DICL is transferred proximally to reinforce the dorsal SL interosseous ligament. The wrist joint is immobilized for 3 weeks postoperatively, and dart-throwing motion is permitted until temporary SL fixation is removed at 2 to 3 months after surgery. A wrist brace is recommended until 3 to 6 months after the first surgery depending on the patient's occupation and sports activity.
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http://dx.doi.org/10.1097/BTH.0000000000000273DOI Listing
March 2020

Effect of soft tissue injury and ulnar angulation on radial head instability in a Bado type I Monteggia fracture model.

Medicine (Baltimore) 2019 Nov;98(44):e17728

Department of Orthopedic Surgery.

The effects of soft tissue damage and ulnar angulation deformity on radial head instability in Monteggia fractures are unclear. We tested the hypothesis that radial head instability correlates with the magnitude of ulnar angular deformity and the degree of proximal forearm soft tissue injury in Bado type I Monteggia fractures.We performed a biomechanical study in 6 fresh-frozen cadaveric upper extremities. Monteggia fractures were simulated by anterior ulnar angulation osteotomy and sequential sectioning of ligamentous structures. We measured radial head displacement during passive mobility testing in pronation, supination, and neutral rotation using an electromagnetic tracking device. Measurements at various ligament sectioning stages and ulnar angulation substages were statistically compared with those in the intact elbow.Radial head displacement increased with sequential ligament sectioning and increased proportionally with the degree of anterior ulnar angulation. Annular ligament sectioning resulted in a significant increase in displacement only in pronation (P < .05). When the anterior ulnar deformity was reproduced, the radial head displaced least in supination. The addition of proximal interosseous membrane sectioning significantly increased the radial head displacement in supination (P < .05), regardless of the degree of anterior ulnar angulation.Our Monteggia fracture model showed that radial head instability is influenced by the degree of soft tissue damage and ulnar angulation. Annular ligament injury combined with a minimal (5°) ulnar deformity may cause elbow instability, especially in pronation. The proximal interosseous membrane contributes to radial head stability in supination, regardless of ulnar angulation, and proximal interosseous membrane injury led to significant radial head instability in supination.
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http://dx.doi.org/10.1097/MD.0000000000017728DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946299PMC
November 2019

Contrast bath-induced neurite outgrowth in PC12m3 cells via the p38 mitogen-activated protein kinase pathway.

Heliyon 2019 Oct 15;5(10):e02656. Epub 2019 Oct 15.

Graduate School of Health Science, Kibi International University, 8-Iga-machi, Takahashi, Okayama, 716-8508, Japan.

We investigated the differentiation and activation of p38 MAPK induced by contrast bath in drug-hypersensitive PC12m3 mutant cells. The rate of neurite outgrowth in PC12m3 cells induced by contrast bath was much higher than that induced by warming or cooling alone or that induced by two warmings with an interval of room temperature, indicating that contrast bath has a synergistic effect. The results of an experiment using a p38 MAPK inhibitor, SB203580, showed that neurite outgrowth of PC12m3 cells induced by contrast bath is p38 MAPK-dependent. Moreover, p38 MAPK activity induced by contrast bath was greater than that induced by warming or cooling alone, indicating that the synergistic effect of a contrast bath on neurite outgrowth depends on the activity of p38 MAPK. Since calcium ions are involved in the activations of P38 MAPK, we investigated the effect of the TRP ion channel inhibitor (Capsazepine) that inhibits calcium influx in the cells. Neurite outgrowth induced by contrast bath treatment was greatly suppressed by the addition of Capsazepine. These findings suggest that calcium dependent activation of the p38 MAPK pathway induced by contrast bath is responsible for the neurite outgrowth of PC12m3 cells.
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http://dx.doi.org/10.1016/j.heliyon.2019.e02656DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6812228PMC
October 2019

C-SH2 point mutation converts p85β regulatory subunit of phosphoinositide 3-kinase to an anti-aging gene.

Sci Rep 2019 09 3;9(1):12683. Epub 2019 Sep 3.

Graduate School of Health Science, Kibi International University, 8-Iga-machi, Takahashi, Okayama, 716-8508, Japan.

Insulin interacts with the insulin receptor, and the activated receptor promotes activity of the phosphoinositide-3 kinase (PI3K) enzyme. A decrease in insulin or insulin-like growth factor 1 (IGF-1) signaling increases the lifespan in mammalian species. We found that a point mutation in the C-SH2 domain of the p85β regulatory subunit of PI3K results in a prolonged lifespan. In p85β mutant cells, nerve growth factor (NGF) activates the longevity protein FOXO, and the mutant p85β gene produces strong resistance to oxidative stress, which contributes to aging. The p85β gene mutation causes increased serum insulin and low blood glucose in p85β mutant transgenic mice. Our results indicate that the p85β mutant allele alters the activity of downstream targets of PI3K by NGF and platelet-derived growth factor (PDGF) but not by insulin. We report that a point mutation in the C-SH2 domain of p85β transforms p85β into a novel anti-aging gene by abnormally regulating PI3K.
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http://dx.doi.org/10.1038/s41598-019-48157-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6722097PMC
September 2019

Tamai Zone 1 Fingertip Amputation: Reconstruction Using a Digital Artery Flap Compared With Microsurgical Replantation.

J Hand Surg Am 2019 Aug 10;44(8):655-661. Epub 2019 May 10.

Department of Orthopaedic Surgery, Nara Medical University, Nara, Japan.

Purpose: The surgical treatment of fingertip amputations is controversial. This study was designed to compare the clinical results of 2 surgical procedures for fingertip amputation: reconstruction with a digital artery flap and microsurgical replantation.

Methods: Between 2003 and 2015, 37 patients with Tamai zone 1 fingertip amputation of the index or middle finger were treated by reconstruction with a digital artery flap (n = 23) or microsurgical replantation (n = 14). Data for these patients were evaluated retrospectively. Nerve suture was not conducted in microsurgical replantation because spontaneous sensory recovery is expected in zone 1 replantation. Primary outcomes included hand dexterity (Purdue Pegboard Test), and disability of the upper extremity (Disabilities of the Arm, Shoulder, and Hand score). Secondary outcomes included strength (key pinch), digital sensitivity (Semmes-Weinstein test), and finger mobility (% total active motion).

Results: The average follow-up period was 34 months. There was no significant difference in the primary outcomes between the 2 groups. The reconstruction group showed significantly better results for the secondary outcomes.

Conclusions: This study suggests that the 2 procedures were comparable regarding postoperative activities of daily living and hand performance, but reconstruction using a digital artery flap gave better objective functional outcomes than microsurgical replantation.

Type Of Study/level Of Evidence: Therapeutic IV.
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http://dx.doi.org/10.1016/j.jhsa.2019.03.016DOI Listing
August 2019

Minimally invasive spinopelvic "crab-shaped fixation" for unstable pelvic ring fractures: technical note and 16 case series.

J Orthop Surg Res 2019 Feb 15;14(1):51. Epub 2019 Feb 15.

Department of Orthopedic Surgery, Nara Medical University, Kashihara, Nara, Japan.

Background: Unstable sacral fractures are high-energy injuries and comprise polytrauma. Internal fixation to enable withstanding vertical loads is required to get up early from the bed after an unstable sacral fracture. We developed a new minimally invasive surgical (MIS) procedure for unstable pelvic ring fractures and reported it in Japanese in 2010. We presented our minimally invasive surgical technique of crab-shaped fixation for the treatment of unstable pelvic ring fractures and report on its short-term outcomes.

Methods: Sixteen patients with unstable pelvic ring fractures (AO types C1, 2, and 3) were treated using crab-shaped fixation. All procedures were performed with the patient in the prone position through 5-cm skin incisions created bilaterally at the level of the posterior superior iliac spine. Four iliac screws were inserted and connected with two rods under the fascia. Percutaneous pedicle screws were inserted at L5 or L4 and connected to the iliac rod using offset connectors. Fracture reduction was then performed.

Results: The average surgical time was 158 min (range, 117-230 min), with an intraoperative bleeding volume of 299 ml (range, 80-480 ml). Thirty-three pedicle screws and 64 iliac screws were implanted with no instance of malpositioning or perforation. A surgical site infection developed in 2 of the 16 cases. Both were deep methicillin-resistant Staphylococcus aureus infections, with the removal of the distal implants required in only one of these cases. Bony union was achieved in all patients, and all vertical displacements reduced by 7.0 mm, on average (range, 5.4-9.0 mm), to < 10 cm. Correction was retained in all cases.

Conclusions: Crab-shaped fixation provides a feasible MIS approach for spinopelvic fixation, which allows good reduction of the vertical displacement of unstable pelvic ring fractures and bony union.
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http://dx.doi.org/10.1186/s13018-019-1093-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376779PMC
February 2019

MEP50/PRMT5-mediated methylation activates GLI1 in Hedgehog signalling through inhibition of ubiquitination by the ITCH/NUMB complex.

Commun Biol 2019 18;2:23. Epub 2019 Jan 18.

Department of Molecular Oncology, Institute for Advanced Medical Sciences, Nippon Medical School, Kosugi-cho 1-396, Nakahara-ku, Kawasaki, Kanagawa 211-8533 Japan.

Transcription factor GLI1 is an effecter of Hedgehog (HH) signalling and activated in a broad spectrum of cancers. However, the role of the HH-GLI1 pathway in cancer and the activation mechanism of GLI1 in HH signalling after dissociation from its inhibitor, SUFU, are not fully understood. Here, we found that GLI1 associated with the methylosome protein 50 (MEP50)/protein arginine methyltransferase 5 (PRMT5) complex and was methylated. Association of MEP50/PRMT5 with GLI1 was enhanced and expression of MEP50 and PRMT5 was activated by HH signals, suggesting their role in positive feedback regulation. Methylated GLI1 lost its ability to bind ubiquitin ligase ITCH/NUMB, resulting in nuclear accumulation and activation of GLI1. Moreover, protein expression of GLI1 was enhanced by MEP50/PRMT5 and expression of MEP50, PRMT5, and GLI1 target genes was upregulated in HH-expressing cancers. These results suggest that MEP50/PRMT5 is important for HH signal-induced GLI1 activation, especially in cancers.
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http://dx.doi.org/10.1038/s42003-018-0275-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6338668PMC
April 2020

Reverse vascularized bone graft of the lateral distal humerus for non-union of the radial neck fracture: anatomical study and case report.

J Plast Surg Hand Surg 2019 Feb 12;53(1):20-24. Epub 2019 Jan 12.

a Department of Orthopaedic Surgery , Nara Medical University , Kashihara , Japan.

A few treatment options for radial neck non-union have been reported, including radial head excision, radial head replacement, and internal fixation with a bone graft. We describe a new treatment for radial neck non-union using a reverse vascularized bone graft of the lateral distal humerus. In the anatomical study, the posterior radial collateral artery (PRCA) was dissected in eight fresh-frozen cadaver arms. The number of branches from the PRCA to the humerus was determined, and the distances from these branches to the lateral epicondyle of the humerus were measured. We then used this information to create a reverse vascularizedhumeral bone graft, which was used to treat non-union of a radial neck fracture in a 73-year-old female. There were two to four PRCA branches (mean: 3.3) entering the bone. The distance from the branches to the lateral epicondyle of the humerus ranged from 2.5 to 10.8 cm. The mean distances from the most proximal and distal PRCA branches to the lateral epicondyle of the humerus were 7.6 cm and 3.4 cm, respectively. The case of non-union of a radial neck fracture was successfully treated with a reverse vascularized humeral bone graft. There were no major complications, and radiographs showed bony union at 8 weeks postoperatively. This procedure may become a new option for the treatment of non-union of fractures of the radial head and neck, as it enables preservation of the radial head, which is an important structure in the elbow and proximal radioulnar joints.
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http://dx.doi.org/10.1080/2000656X.2018.1520122DOI Listing
February 2019

Electrical stimulation induces neurite outgrowth in PC12m3 cells via the p38 mitogen-activated protein kinase pathway.

Neurosci Lett 2019 04 8;698:81-84. Epub 2019 Jan 8.

Graduate School of Health Science, Kibi International University, 8 Iga-machi, Takahashi City, Okayama, 716-8508, Japan.

We investigated the role of the p38 mitogen-activated protein kinase (MAPK) pathway in electrical stimulation-induced neurite outgrowth of PC12 mutant cells in which nerve growth factor (NGF)-induced neurite outgrowth is impaired. When cultures of the PC12 mutant (PC12m3) cells were exposed to electrical stimulation at 100 mA for 30 min, activity of p38 MAPK increased and neurite outgrowth was greatly enhanced. The frequency of neurite outgrowth induced by electrical stimulation was approximately 10-fold greater than that of neurite outgrowth induced by NGF alone. The neurite outgrowth induced by electrical stimulation was inhibited by a specific p38 MAPK inhibitor, SB203580. The activation of p38 MAPK induces activation of the transcription factor CREB. The activation of CREB induced by electrical stimulation was inhibited by SB203580. Longer electrical stimulation of PC12m3 cells provoked cell death, which was enhanced by SB203580. These findings suggest that electrical stimulation-induced activation of the p38 MAPK/CREB pathway is responsible for the neurite outgrowth and survival of PC12m3 cells.
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http://dx.doi.org/10.1016/j.neulet.2019.01.015DOI Listing
April 2019
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