3D MRI evaluation of morphological characteristics of lateral ankle ligaments in injured patients and uninjured controls.

BACKGROUND: With ultrasonography or 2D magnetic resonance imaging (MRI) of the lateral ankle ligament, it is particularly difficult to show the entire calcaneofibular ligament (CFL). The purpose of this study was to evaluate the morphological characteristics of the lateral ankle ligaments in injured patients and uninjured controls using 3D MRI. METHODS: A total of 64 ankles of 59 healthy volunteers and lateral ligament injury patients (mean age of 32.4 years) were examined. The 64 ankles included a healthy group of 11 ankles, an acute injury group of 12 ankles that underwent MRI a month after injury, and a chronic injury group of 41 ankles that underwent MRI more than 3 months after injury. Using a 3.0-T MRI system, imaging was done with fast imaging employing steady-state acquisition cycled phases. Oblique sagittal images that most clearly depicted the entire anterior talofibular ligament (ATFL) and CFL were prepared manually and evaluated using a workstation. RESULTS: In the healthy group, both the ATFL and CFL were clearly and entirely visualized. The mean width in the central portion was 4.0 ± 1.0 mm in the ATFL and 4.8 ± 0.6 mm in the CFL. 3D MRI in the acute injury group showed findings of diffuse swelling with hyperintensity in the ATFL of all patients. The CFL in 7 of 12 ankles showed findings of diffuse swelling with hyperintensity. In the chronic injury group, morphological abnormalities of the ATFL were seen in 19 of 41 ankles. The ligament signal disappeared in 2 ankles, thinned in 4 ankles, and showed swelling in 13 ankles. Morphological abnormalities of the CFL were seen in 17 of 41 ankles. The ligament signal disappeared in 1 ankle, thinned in 2 ankles, and showed swelling in 14 ankles. CONCLUSION: 3D MRI may be a useful modality to visualize both the ATFL and the CFL.

Modified distal tibial oblique osteotomy for osteoarthritis of the ankle: Operative procedure and preliminary results.

BACKGROUND: Low tibial osteotomy is an effective joint-preserving surgery for ankle arthritis. However, poor postoperative wound healing, infection, and delayed or non-union of bones remain significant concerns. We describe a modified distal tibial oblique osteotomy procedure and report preliminary results for varus ankle arthritis. METHODS: The osteotomy path consisted of an oblique doglegged line from the lateral end of the distal tibia to a proximal point about one-third from the lateral edge and continuing along an arc defined by virtual coronal-plane rotation of the doglegged line to the medial edge. After osteotomy, the distal tibial fragment was rotated distally in the coronal plane for realignment while maintaining contact with the proximal tibia and the distal tibial fragment. The resulting wedge-shaped gap was filled with artificial bone blocks and tibial bone projecting medially from rotation. A locking plate was then applied for stabilization. We evaluated 7 ankles from 6 osteoarthritis patients both clinically and radiographically following this procedure. RESULTS: Bone union was achieved within 3 months for all patients. The Japanese Society for Surgery of the Foot ankle-hindfoot scale improved from a mean of 38.4 points preoperatively to 85.7 points at the latest follow-up. No wound healing problems, infections, or nerve disturbances were observed. Multiple radiographic parameters were also improved following the operation. CONCLUSIONS: This procedure maintains close bone contact for better postoperative union, obviates the need for iliac bone harvesting, and reduces tension on medial soft tissue. We believe these modifications are potential advantages for achieving stable results in patients with ankle osteoarthritis.

The distal margin of the lateral malleolus visible under ankle arthroscopy (articular tip) from the anteromedial portal, is separate from the ATFL attachment site of the fibula: A cadaver study.

PURPOSE: The purpose of this study was to evaluate the relationship between the lateral malleolus view under ankle arthroscopy and the anterior talofibular ligament (ATFL) attachment site. METHODS: Seven normal ankles from Thiel-embalmed cadavers were investigated. Ankle arthroscopy was performed using a 2.7 mm-diameter, 30-degree, oblique-viewing endoscope. An antero-medial portal (AM), a medial midline portal (MML), and an antero-central portal (AC) were created in order, and the ankle arthroscope was inserted. The lateral malleolus was visualized as distally as possible, and the site that appeared to be the distal margin was marked with a 1.5 mm-diameter K-wire. Visualization with arthroscopy was carried out from all portals to mark the distal margin, and the ankle was subsequently exposed to directly measure the distance from the center of the ATFL attachment site at the fibula to each marking. RESULTS: The distances from the ATFL attachment site to the markings made under arthroscopy from the AM, MML, and AC portals were 10.4 ± 2.6 mm, 7.4 ± 1.9 mm, and 7.3 ± 1.9 mm, respectively. Compared to markings made from the MML or AC portal, the marking made from the AM portal was significantly further away from the ATFL attachment site. CONCLUSIONS: A typical ankle arthroscopy portal may not allow complete visualization of the tip of the lateral malleolus, indicating that it may not be feasible to thoroughly observe the ATFL attachment site. It is necessary to perform arthroscopic surgeries with the understanding that the distal margin of the lateral malleolus that appears under ankle arthroscopy is 7-10 mm proximal to the ATFL attachment site.

Suture-Button Fixation and Mini-Open Anterior Inferior Tibiofibular Ligament Augmentation Using Suture Tape for Tibiofibular Syndesmosis Injuries.

Tibiofibular fixation using suture-button implants is an optional method for the surgical treatment of syndesmosis injuries. Although good clinical outcomes have been reported, inadequate stability between the tibia and fibula has also been documented. Thus, suture-button fixation is not considered the reference standard. For surgical treatment of lateral ligament injuries of the ankle, good treatment outcomes have also been reported with ligament augmentation using nonabsorbable suture tape. Ligament augmentation tape with suture-button fixation could also be promising for improved treatment outcomes in syndesmosis injuries. We describe suture-button fixation together with mini-open anterior inferior tibiofibular ligament augmentation using suture tape for treatment of syndesmosis injuries.

Shrinkage temperature and anti-calcification property of triglycidylamine-crosslinked autologous tissue.

Since bioprosthetic valve dysfunction may arise due to histological calcification in the crosslinking process by glutaraldehyde (GA), non-GA crosslinking reagents have been investigated. We compared the efficacy of triglycidylamine (TGA), a newly synthesized epoxy compound, and GA as crosslinking reagents for the treatment of autologous tissues. We assessed the strength of crosslinked tissues using shrinkage temperature (Ts) measured by differential scanning calorimetry. We also conducted subdermal allografting of the crosslinked pericardium and thoracic aorta in rats, and verified the anti-calcification efficacy of TGA by histological evaluations with von Kossa stain, and immunological evaluations using tenascin-C (TN-C) or matrix metalloproteinase-9 (MMP-9). TGA treatment resulted in slower increases in Ts of the pericardium, and it required 9-12 h to reach Ts achieved by GA. In subdermal implantation of rat tissues, calcium content was lower in the TGA group than in the GA groups (p < 0.005). The expression site of TN-C and MMP-9 differed from the primary location of calcium deposition in the thoracic aorta treated with TGA suggesting a different underlying mechanism in calcification between GA and TGA crosslinking. In conclusion, TGA crosslinking in the allograft showed superior anti-calcification effect as compared to brief treatment by GA, although TGA crosslinking process was slow.

Early heparin administration attenuates tissue factor-mediated thrombin generation during simulated cardiopulmonary bypass.

BACKGROUND: We tested the hypothesis that heparin administration prior to the emergence of tissue factor (TF) would increase plasma TF pathway inhibitor (TFPI) and attenuate TF-mediated thrombin generation during simulated cardiopulmonary bypass (CPB). METHODS: Human blood was recirculated for 120 minutes using an oxygenator and roller pump. Four groups were examined: control group (heparin 3.75 U/mL, in donor blood, n = 7), rTF group (heparin + recombinant TF 1000 pg/mL, in donor blood, n = 7), TFPI boost group (heparin, in preheparinized donor blood, n = 8), and rTF + TFPI boost group (heparin + rTF, in preheparinized blood, n = 7). In the two TFPI boost groups, 50 U/kg of heparin was given to the donors intravenously five minutes before donation to boost plasma TFPI levels. Total plasma TFPI, thrombin-antithrombin complex, and prothrombin fragment F1+2 levels were measured before and during CPB. RESULTS: Preheparinization increased total plasma TFPI levels by a factor of 8.0. Administration of rTF significantly enhanced the generation of F1+2 (p = 0.0002). The heparin-induced TFPI elevation reduced both thrombin-antithrombin complex and F1+2 to control levels in rTF + TFPI boost group (p = 0.0158 for thrombin-antithrombin complex, p < 0.0001 for F1+2 ). F1+2 levels were at all times lower than control levels in TFPI boost group (p < 0.0001). CONCLUSIONS: Heparin-induced TFPI elevation attenuates TF-mediated thrombin generation. Early heparin administration prior to the emergence of plasma TF may represent a novel strategy for controlling thrombin generation by the extrinsic coagulation pathway during CPB.

A Novel Technique for Restricted Kinematic Alignment Total Knee Arthroplasty Without Computer-Assisted Devices.

Kinematic-alignment total knee arthroplasty (KA-TKA) aims to restore natural limb alignment and joint line obliquity, thereby improving patient satisfaction. Restricted KA-TKA (rKA-TKA) addresses abnormal knee anatomies and seeks to replicate natural anatomical structures within safe alignment boundaries. This study introduces a novel device and technique that enables rKA-TKA without computer-assisted surgery (CAS). The new device allows for precise cartilage thickness measurement and adjustment of osteotomy angles, facilitating accurate alignment. A heel-lift technique for tibial osteotomy is presented, offering a reproducible method for determining the osteotomy volume and angle. These innovations make KA and rKA-TKA feasible in any surgical setting, avoiding the high costs and limited availability associated with CAS.

Surgical Treatment for Non-union of the Great Toe Proximal Phalanx Stress Fracture in an Adolescent Jumping Athlete.

Stress fractures of the proximal phalanx of the great toe are primarily attributed to repetitive shear forces, with the vertical ground reaction forces exerting several times the body weight. In the initial stages of injury, conservative management anticipates bone healing within approximately five weeks, followed by a gradual return to sports activities over an additional five weeks. Athletes presenting with pain in this region warrant a thorough evaluation for stress fractures to initiate timely conservative care. In instances of delayed healing or non-union, surgical intervention is indicated. However, literature on the management and optimal timing of surgery, particularly in adolescent athletes, remains sparse. This case report, complemented by a literature review, offers insights into management based on the patient's clinical course.

Using synchrotron radiation angiography with a highly sensitive detector to identify impaired peripheral perfusion in rat pulmonary emphysema.

Owing to limitations in spatial resolution and sensitivity, it is difficult for conventional angiography to detect minute changes of perfusion in diffuse lung diseases, including pulmonary emphysema (PE). However, a high-gain avalanche rushing amorphous photoconductor (HARP) detector can give high sensitivity to synchrotron radiation (SR) angiography. SR angiography with a HARP detector provides high spatial resolution and sensitivity in addition to time resolution owing to its angiographic nature. The purpose of this study was to investigate whether this SR angiography with a HARP detector could evaluate altered microcirculation in PE. Two groups of rats were used: group PE and group C (control). Transvenous SR angiography with a HARP detector was performed and histopathological findings were compared. Peak density of contrast material in peripheral lung was lower in group PE than group C (p < 0.01). The slope of the linear regression line in scattering diagrams was also lower in group PE than C (p < 0.05). The correlation between the slope and extent of PE in histopathology showed significant negative correlation (p < 0.05, r = 0.61). SR angiography with a HARP detector made it possible to identify impaired microcirculation in PE by means of its high spatial resolution and sensitivity.

Nontraditional placement of an implantable cardioverter-defibrillator in a heterotaxy patient after the completion of total cavopulmonary connection.

A 15-year-old boy with heterotaxy syndrome developed a prolonged QT interval and intractable torsade de pointes after the administration of sodium channel blockers for atrial tachyarrhythmia. Although this situation called for the placement of an implantable cardioverter-defibrillator, a conventional transvenous approach was not available since the patient had previously undergone a nonfenestrated extracardiac total cavopulmonary connection. We were urged to carry out the surgical placement of an epicardial lead for an implantable cardioverter-defibrillator using a single coil transvenous shock lead through re-do midline sternotomy. Here we describe the details of this nontraditional surgical procedure for the placement of a lead for an implantable cardioverter-defibrillator in a case without venous access into the heart.

Significant correlation between endothelial nitric oxide synthase (eNOS) expression and alveolar repair in elastase-induced rat pulmonary emphysema.

BACKGROUND AND PURPOSE: Angiogenic factors, such as endothelial nitric oxide synthase (eNOS), are thought to play an important role in the repair of pulmonary emphysema (PE); yet, the correlation of the factors involved has not been investigated. We conducted this study to clarify the positive correlation between eNOS expression and alveolar repair in PE recovery. METHODS: We used elastase to induce PE in rats, which were divided into Groups A (Control), B (G-CSF), C (PE) and D (PE + G-CSF). G-CSF was injected for 12 days, 4 weeks after which the alveolar walls, arterioles, and angiogenic factors including eNOS were examined histopathologically and by western blotting. RESULTS: In comparing Groups A, B, C, and D, the alveolar density was 2.4 ± 0.2, 2.4 ± 0.1, 1.8 ± 0.1, 2.5 ± 0.1 per 100 µm(2), respectively (C vs. others; p < 0.00001) and the number of arterioles was 4.5 ± 1.0, 5.6 ± 0.6, 3.2 ± 0.5, 5.5 ± 0.7/mm(2), respectively (C vs. others; p < 0.05). Immunohistochemical staining (IHC) revealed different eNOS expression in Group D versus Group C (p < 0.0001) and western blotting revealed different eNOS, VEGF, and FLT-1 expression in Group D versus Group C (p < 0.01, p < 0.05, p < 0.001), reflecting the contribution of angiogenesis to PE repair. eNOS showed a significantly positive correlation to alveolar density and arteriole repair. CONCLUSION: Alveolar repair was correlated positively with eNOS expression by vascular regeneration in elastase-induced rat PE.

Prospective intraindividual comparison of unenhanced magnetic resonance imaging vs contrast-enhanced computed tomography for the planning of endovascular abdominal aortic aneurysm repair.

OBJECTIVE: This study clarified whether unenhanced magnetic resonance imaging (MRI) is an alternative to contrast-enhanced computed tomography (CT) for aortoiliac arterial measurement before endovascular abdominal aortic aneurysm repair (EVAR). METHODS: The institutional review board approved this prospective study. Twenty patients being considered for EVAR underwent MRI using a steady-state free-precession sequence in a 1.5-T system and contrast-enhanced CT within 4 weeks of each other. Two independent observers reviewed MRI and CT in random order using vessel analysis software and measured seven diameters, four lengths, and the angle of the aortoiliac arteries. The intermodality, interobserver, and intraobserver agreements were assessed for each measurement by intraclass correlation coefficients (ICCs) and the Altman-Bland method. Additionally, the observers independently recorded the number of bilateral renal arteries, decided EVAR suitability, and selected the main endograft on each modality. RESULTS: Intermodality ICCs for observers A and B showed ranges of 0.83 to 0.99 and 0.70 to 0.98; interobserver ICCs for MRI and CT showed ranges of 0.73 to 0.99 and 0.65 to 0.99; and intraobserver ICCs for MRI and CT showed ranges of 0.59 to 0.99 and 0.59 to 0.99. In intermodality, interobserver, and intraobserver comparisons, mean differences in diameters were included within the range -1 to +1 mm, excluding three of seven diameters on CT in interobserver comparison and one of seven on CT in intraobserver comparison. Mean differences in lengths were included within the range -5 to +5 mm, excluding one of four lengths in observer B in intermodality comparison and one of four on MRI and CT in interobserver comparison. All mean differences in angles were included within the range -5° to +5°. Both observers detected all 40 bilateral main renal arteries on MRI and CT. Of the 13 accessory renal arteries, observers A and B detected four (31%) and nine (69%), respectively, on MRI; in contrast, both observers detected 11 (85%) on CT. The observers independently determined that the same seven patients were suitable for EVAR on MRI and CT. Of the seven selected main endografts, seven and six diameters and five and six lengths agreed exactly between MRI and CT for observers A and B, respectively. CONCLUSIONS: Although contrast-enhanced CT remains the gold standard for preoperative EVAR planning, unenhanced MRI with steady-state free-precession sequence can be an alternative modality for patients with contraindications for CT, such as renal impairment, because the intermodality agreement for preoperative measurements is as good as interobserver and intraobserver agreement.

Inhibition of protein kinase C ß ameliorates impaired angiogenesis in type I diabetic mice complicating myocardial infarction.

BACKGROUND: In recent studies, the inhibition of protein kinase C (PKC) ß has been shown to improve diabetic vascular complications. However, the effect on angiogenesis in myocardial ischemia with diabetes mellitus (DM) is still unknown. METHODS AND RESULTS: Mice were divided into 3 groups: control, DM and DM+PKC-I groups (n=8, respectively). In the DM and DM+PKC-I groups, diabetes was induced by streptozotocin (STZ) (1.5mg/body i.p.) for 5 days. Next, left anterior descending artery (LAD) ligation was performed in all groups. In the DM+PKC-I group, PKC ß inhibitor (Cat. No. 539654; 10 nmol/L) was administered from days 1 to 10. After 4 weeks of LAD ligation, the animals were killed. Microvascular density was significantly improved by PKC ß inhibitor (control: 87.9±5.2/high-power field (HPF); DM: 51.4±6.9/HPF; PKC-I: 80.3±4.9/HPF; P<0.05). Expression of both vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS), which was decreased in the DM group, were significantly improved by inhibition of PKC ß [VEGF (DM: 0.36±0.11-fold and DM+PKC-I: 0.77±0.07-fold vs. control), eNOS (DM: 0.35±0.06-fold and DM+PKC-I: 0.73±0.08-fold vs. control); both P<0.05)]. CONCLUSIONS: Inhibition of PKC ß ameliorated impaired angiogenesis by hyperglycemia in STZ-induced DM mice complicated by myocardial infarction. These results suggest a new possible indication of PKC ß inhibitor for myocardial ischemia with DM.

Concealed infective endocarditis associated with subaortic left ventricular aneurysm.

We describe a case of subaortic left ventricular aneurysm with concealed infective endocarditis. The patient, who was diagnosed with aortic regurgitation and a subaortic left ventricular aneurysm, did not exhibit any evidence of infective endocarditis preoperatively. However, histopathological examination after an aortic valve replacement revealed neutrophil infiltration in the resected aneurysm. One year postoperatively, the infection recurred and an aortic root replacement was performed.

Surgical removal of infected pacemaker leads without cardiopulmonary bypass after failed extraction using the Excimer Laser Sheath Extraction System.

With the growing number of cardiac pacemakers and internal cardioverter defibrillator implantations, problems with endocardial lead infection have been increasing. The newly developed Excimer Laser Sheath Lead Extraction System has been recognized as being highly useful for removing chronic infected leads. However, serious bleeding complications are a concern when this system is used. Here we report our experience with a 67-year-old man who was diagnosed with pacemaker endocarditis. Initially, lead removal was attempted using the Excimer Laser Sheath Extraction System, though this was abandoned because of severe adhesion of the leads and the junction of the supra vena cava (SVC) with the right atrium. Surgical removal of the leads was performed without using cardiopulmonary bypass and the leads were removed without any complications. During surgery, we found there was a silent perforation of the innominate vein brought about by the Excimer Laser Sheath System. Also, the junction of the SVC with the right atrium was thought to be an area potentially at high risk of perforation, because of a lack of surrounding tissue. It is our opinion that those who carry out procedures with the Excimer Laser Sheath System should understand the potential risk of perforation based on cardiac anatomy and should be prepared for lethal bleeding complications. Also, for emergent situations, we believe that close backup by a cardiovascular surgical team should be considered essential for performing the Excimer Laser Sheath Lead Extraction safely.

Surgical repair for rupture of a chronic traumatic thoracic aneurysm 14 years after injury: report of a case.

Traumatic thoracic aortic injury is a lethal condition. Because its mortality rate is extremely high in the acute phase, these patients rarely survive long enough for a chronic aneurysm to develop. We herein report a case of surgical repair for a ruptured chronic traumatic thoracic aneurysm. A 32-year-old man, who had been involved in a traffic accident 14 years earlier, was diagnosed with a rupture of a chronic traumatic thoracic aneurysm. Preoperative computed tomography showed that the ruptured aneurysm arose from the aortic isthmus and was accompanied by multiple daughter lesions. He underwent an aorta graft replacement with reconstruction of the left subclavian artery using both a median sternotomy and a left thoracotomy. The surgery was successful and the postoperative course was uneventful. Chronic traumatic thoracic aneurysm is usually a single lesion, and cases with daughter aneurysms have rarely been reported. We include a review of the previous literature and also discuss the etiology of this condition.

[Cooperation between the Department of Cardiovascular Surgery in University of Tsukuba and Cho-Ray Hospital, Ho-Chi-Minh City, Vietnam--for an attractive collaboration in international medical education].

The Department of Cardiac Surgery in Cho-Ray Hospital, Ho-Chi-Minh city stands for a representative high volume center in the south of Vietnam. In the department about 1,200 cases of open-heart surgery are performed in a year. In next era, they wish to improve their surgical quality, focusing on complex and low-weight congenital cases, mitral repair, maze operation and off-pump CABG. Since 2008, University of Tsukuba has started to collaborate with many departments in Cho-Ray Hospital as a project of international medical educations in Global 30, and has been establishing meaningful activities in the Department of Cardiac Surgery as well. We keep providing opportunities for education, research and training for young Vietnamese doctors and investigators as much as possible both in Cho-Ray Hospital and University of Tsukuba with some financial support. We believe that our steady collaboration with Cho-Ray Hospital will bring certain developments not only for Vietnamese but for ourselves.

The Lateral Drawer Test: A New Clinical Test to Assess Mortise Instability in Weber B Fibula Fractures.

Background: Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. Although instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the isolated Weber B fibula fracture often requires further investigation. Prior authors have demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis, and swelling with instability. The goal of this study is to test the validity of a new clinical examination maneuver, the lateral drawer test, against the gravity stress view (GSV) in a cohort of patients with Weber B fibula fractures. Secondary goals included assessing pain tolerability of the lateral drawer test, as well as testing interobserver reliability. Methods: Sixty-two patients presenting with isolated fibula fractures were prospectively identified by an orthopaedic nurse practitioner or resident. Three nonweightbearing radiographic views of the ankle as well as a GSV were obtained. Radiographs were not visualized before conducting the lateral drawer test. Two foot and ankle fellowship-trained orthopaedic surgeons performed and graded the lateral drawer test. Radiographs were then examined and medial clear space (MCS) was measured. Visual analog scale (VAS) pain scores were obtained before and after testing. The results of the lateral drawer test were compared with radiographic measurements of MCS on GSV. A cadaveric experiment was devised to assess interobserver reliability of the lateral drawer test. Results: Thirty (48%) of 62 consecutively enrolled patients demonstrated radiographic instability with widening of the MCS ≥5 mm on GSV. When correlated with MCS measurement, the lateral drawer test demonstrated a sensitivity of 83%, specificity of 97%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 86%. There was a strong correlation between the lateral drawer test grade and amount of MCS widening (Spearman correlation ρ = 0.82, P < .005). Patients tolerated the maneuver well with an average increase of 0.7 on the VAS pain scale. Testing of 2 observers utilizing the cadaveric model demonstrated a Cohen's Kappa coefficient of 0.7 indicating moderate interobserver agreement. Conclusion: The lateral drawer test demonstrates high sensitivity, specificity, PPV, and NPV with moderate interobserver reliability compared with the MCS on GSV in patients presenting with Weber B fibula fractures. Although further external validation is required, the lateral drawer test may offer an adjunct tool via physical examination to help determine mortise stability. Level of Evidence: Level II, Prospective Cohort Study.

Effects of the Ankle Flexion Angle During Anterior Talofibular Ligament Reconstruction on Ankle Kinematics, Laxity, and In Situ Forces of the Reconstructed Graft.

BACKGROUND: This study aimed to evaluate the effects of the ankle flexion angle during anterior talofibular ligament (ATFL) reconstruction on ankle kinematics, laxity, and in situ force of a graft. METHODS: Twelve cadaveric ankles were evaluated using a 6-degrees of freedom robotic system to apply passive plantar flexion and dorsiflexion motions and multidirectional loads. A repeated measures experiment was designed using the intact ATFL, transected ATFL, and reconstructed ATFL. During ATFL reconstruction (ATFLR), the graft was fixed at a neutral position (ATFLR 0 degrees), 15 degrees of plantar flexion (ATFLR PF15 degrees), and 30 degrees of plantar flexion (ATFLR PF30 degrees) with a constant initial tension of 10 N. The 3-dimensional path and reconstructed graft tension were simultaneously recorded, and the in situ force of the ATFL and reconstructed grafts were calculated using the principle of superposition. RESULTS: The in situ forces of the reconstructed grafts in ATFLR 0 degrees and ATFLR PF 15 degrees were significantly higher than those of intact ankles. The ankle kinematics and laxity produced by ATFLR PF 30 degrees were not significantly different from those of intact ankles. The in situ force on the ATFL was 19.0 N at 30 degrees of plantar flexion. In situ forces of 41.0, 33.7, and 21.9 N were observed at 30 degrees of plantar flexion in ATFLR 0, 15, and 30 degrees, respectively. CONCLUSION: ATFL reconstruction with the peroneus longus (PL) tendon was performed with the graft at 30 degrees of plantar flexion resulted in ankle kinematics, laxity, and in situ forces similar to those of intact ankles. ATFL reconstructions performed with the graft fixed at 0 and 15 degrees of the plantar flexion resulted in higher in situ forces on the reconstructed graft. CLINICAL RELEVANCE: Fixing the ATFL tendon graft at 30 degrees of plantar flexion results in an in situ force closest to that of an intact ankle and avoids the excessive tension on the reconstructed graft.

Identification of human placenta-derived mesenchymal stem cells involved in re-endothelialization.

Human placenta is an attractive source of mesenchymal stem cells (MSC) for regenerative medicine. The cell surface markers expressed on MSC have been proposed as useful tools for the isolation of MSC from other cell populations. However, the correlation between the expression of MSC markers and the ability to support tissue regeneration in vivo has not been well examined. Here, we established several MSC lines from human placenta and examined the expression of their cell surface markers and their ability to differentiate toward mesenchymal cell lineages. We found that the expression of CD349/frizzled-9, a receptor for Wnt ligands, was positive in placenta-derived MSC. So, we isolated CD349-negative and -positive fractions from an MSC line and examined how successfully cell engraftment repaired fractured bone and recovered blood flow in ischemic regions using mouse models. CD349-negative and -positive cells displayed a similar expression pattern of cell surface markers and facilitated the repair of fractured bone in transplantation experiments in mice. Interestingly, CD349-negative, but not CD349-positive cells, showed significant effects on recovering blood flow following vascular occlusion. We found that induction of PDGFß and bFGF mRNAs by hypoxia was greater in CD349-negative cells than in CD349-positive cells while the expression of VEGF was not significantly different in CD349-negative and CD349-positive cells. These findings suggest the possibility that CD349 could be utilized as a specialized marker for MSC isolation for re-endothelialization.