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.

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.

Effect of Initial Graft Tension During Anterior Talofibular Ligament Reconstruction on Ankle Kinematics, Laxity, and In Situ Forces of the Reconstructed Graft.

BACKGROUND: Although a variety of surgical procedures for anterior talofibular ligament (ATFL) reconstruction have been reported, the effect of initial graft tension during ATFL reconstruction remains unclear. PURPOSE/HYPOTHESIS: This study investigated the effects of initial graft tension on ATFL reconstruction. We hypothesized that a high degree of initial graft tension would cause abnormal kinematics and laxity. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve cadaveric ankles were tested with a robotic system with 6 degrees of freedom to apply passive plantarflexion and dorsiflexion motions and a multidirectional load. A repeated measures experiment was designed with the intact ATFL, transected ATFL, and reconstructed ATFL at initial tension conditions of 10, 30, 50, and 70 N. The 3-dimensional path and reconstructed graft tension were simultaneously recorded, and the in situ forces of the ATFL and reconstructed graft were calculated with the principle of superposition. RESULTS: Initial tension of 10 N was sufficient to imitate normal ankle kinematics and laxity, which were not significantly different when compared with those of the intact ankles. The in situ force on the reconstructed graft tended to increase as the initial tension increased. In situ force on the reconstructed graft >30 N was significantly greater than that of intact ankles. The in situ force on the ATFL was 19 N at 30° of plantarflexion. In situ forces of 21.9, 30.4, 38.2, and 46.8 N were observed at initial tensions of 10, 30, 50, and 70 N, respectively, at 30° of plantarflexion. CONCLUSION: Approximate ankle kinematic patterns and sufficient laxity, even with an initial tension of 10 N, could be obtained immediately after ATFL reconstruction. Moreover, excessive initial graft tension during ATFL reconstruction caused excessive in situ force on the reconstructed graft. CLINICAL RELEVANCE: This study revealed the effects of initial graft tension during ATFL reconstruction. These data suggest that excessive tension during ATFL reconstruction should be avoided to ensure restoration of normal ankle motion.

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.

Kinematics and Laxity of the Ankle Joint in Anatomic and Nonanatomic Anterior Talofibular Ligament Repair: A Biomechanical Cadaveric Study.

BACKGROUND: Although it is crucial to accurately identify the anterior talofibular ligament (ATFL) attachment site, it may not be feasible to fully observe the ATFL attachment site during arthroscopic surgery. As a result, the repair position might often be an unintentionally nonanatomic ATFL attachment site. HYPOTHESIS: Anatomic ATFL repair restores kinematics and laxity to the ankle joint, while nonanatomic ATFL repair does not. STUDY DESIGN: Controlled laboratory study. METHODS: Seven normal fresh-frozen human cadaveric ankles were used. The ankles were tested with a 6 degrees of freedom robotic system. The following ankle states were evaluated: intact, ATFL injured, ATFL anatomic repair, and ATFL nonanatomic repair. The ATFL nonanatomic repair position was set 8 mm proximal from the center of the ATFL attachment site of the fibula. For each state, a passive plantarflexion (PF)-dorsiflexion (DF) kinematics test and a multidirectional loading test (anterior forces, inversion moment, and internal rotation moment) were performed. RESULTS: The kinematics and laxity of the anatomic repair were not significantly different from those of the intact state. In nonanatomic repair, the inversion-eversion angle showed significant inversion (3.0°-3.4°) from 5° to 15° of DF, and the internal rotation-external rotation angle showed significant internal rotation (2.0°) at neutral PF-DF versus the intact state. In addition, internal rotation laxity was significantly increased (5.5°-5.8°) relative to the intact state in the nonanatomic repair at 30° and 15° of PF. There were no significant differences in anterior-posterior translation between the repairs. CONCLUSION: Although the anatomic ATFL repair state did not show significant differences in kinematics and laxity relative to the intact state, the nonanatomic ATFL repair state demonstrated significant inversion and internal rotation kinematics and internal rotation laxity when compared with the intact state. CLINICAL RELEVANCE: Nonanatomic repair alters kinematics and laxity from the intact condition.

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.

Early surgical management of traumatic dislocation of the tibialis posterior tendon: a case report and review of the literature.

BACKGROUND: Traumatic dislocation of the tibialis posterior tendon at the ankle is a rare injury. Some of these cases are misdiagnosed as ankle sprains and are not treated properly. In addition, because the conservative treatment is not as effective as the surgical treatment, it is essential that patients be diagnosed early so that proper surgical treatment can be performed. We report the early surgical management of traumatic dislocation of the tibialis posterior tendon. CASE PRESENTATION: A 44-year-old Japanese man, who was a karate coach, was injured while acting as an umpire in a karate competition. On the same day of his injury, he came to our hospital. He complained of swelling and pain in the medial malleolus. Anterior dislocation of the tibialis posterior tendon was detected upon palpation. Magnetic resonance imaging showed the presence of anterior dislocation of the tibialis posterior tendon with retinaculum injury. Four days after the injury, we performed the Das De procedure as the surgical treatment. Three months after the surgery, the patient was able to participate in karate again. CONCLUSIONS: Dislocation of the tibialis posterior tendon is likely to be misdiagnosed, thus delaying the start of proper treatment. It is essential to diagnose the patient accurately by carefully assessing the physical symptoms manifested. Moreover, magnetic resonance imaging can also be used for better diagnosis, thereby leading to an early and proper surgical treatment.

Suture-button fixation and anterior inferior tibiofibular ligament augmentation with suture-tape for syndesmosis injury: A biomechanical cadaveric study.

BACKGROUND: Suture-button (SB) fixation has been widely performed for syndesmosis injuries, but it has been reported unstable in some biomechanical studies. The purpose of this study was to evaluate the stability of the syndesmosis using SB fixation with anterior inferior tibiofibular ligament augmentation using suture-tape (ST). METHODS: Eight normal fresh-frozen cadaveric legs were used. After initial tests of intact and injured models, SB fixation, SB fixation with ST augmentation, ST augmentation alone, and screw fixation were performed sequentially for each specimen. Loading tests stimulating dorsiflexion, inversion, and external rotation of the ankle joint were performed for each model. The tibiofibular diastasis (TFD) and the fibular rotational angle related to the tibia (FRA) were measured using a magnetic tracking system. FINDINGS: In the injured model, both TFD and FRA increased significantly compared with the intact model in all directions (P < .05). In the SB fixation model, TFD and FRA generally showed significant increases (P < .05, except for TFD in external rotation). In the SB fixation with ST augmentation model and ST augmentation alone, TFD and FRA were not significantly different compared with the intact model (P > .05). In the screw fixation model, FRA with inversion force at the ankle was significantly decreased compared with the intact model (P = .027). INTERPRETATION: SB fixation alone did not provide stability of the syndesmosis, and screw fixation became too rigid compared with the intact model. Using ST augmentation achieved dynamic stability similar to the intact model for syndesmotic injuries.

ACL Function in Bicruciate-Retaining Total Knee Arthroplasty.

BACKGROUND: Bicruciate-retaining total knee arthroplasty (BCR-TKA) is attracting attention because of the functional and satisfaction outcomes associated with keeping the anterior cruciate ligament (ACL) intact. However, knowledge of the functional importance of the ACL after BCR-TKA is limited. We performed a biomechanical investigation of ACL function following BCR-TKA compared with that in the intact knee. METHODS: We investigated 8 fresh-frozen human cadaveric knees using a 6-degrees-of-freedom robotic system that allowed natural joint motion. Three knee states-intact knee, BCR-TKA, and BCR-TKA with ACL transection (BCR-TKA + ACLT)-were evaluated. For each knee state, the kinematics during passive flexion-extension motion (from 0° to 120°) and anteroposterior laxity at 0°, 15°, 30°, 60°, and 90° of flexion in response to a 100-N load were investigated. The recorded knee motions of the intact and BCR-TKA knees during each test were repeated after ACLT to calculate the ACL in situ force. RESULTS: The femur in the BCR-TKA group translated posteriorly and rotated externally during passive knee flexion and was in an anterior position compared with the femur in the intact-knee state. After ACLT, the femur translated posteriorly, compared with the BCR-TKA group, at 0° and 10° (p < 0.05). The anteroposterior laxities of the BCR-TKA and intact knees were comparable at all flexion angles and increased 2-fold or more after ACLT (p < 0.01). The ACL in situ force in the BCR-TKA knees was 2-fold to 6-fold higher than that in the intact knees at 0°, 15°, 90°, and 120° during a passive path (p < 0.05) and equivalent to that in the intact knees under anterior loading. CONCLUSIONS: The preserved ACL in the BCR-TKA knees was functional, like the ACL in the intact knees, under anterior tibial loading and contributed to good anteroposterior stability. However, the kinematics and ACL in situ force differed between the intact and BCR-TKA knees during passive flexion-extension movements. CLINICAL RELEVANCE: Surgeons may not be able to prevent overtensioning of the ACL during a standardized BCR-TKA procedure, which could potentially limit range of motion.

Effect of Initial Graft Tension During Calcaneofibular Ligament Reconstruction on Ankle Kinematics and Laxity.

BACKGROUND: Although a variety of surgical procedures for lateral ankle ligament reconstruction have frequently been reported, little is known about the effects of initial graft tension. Purpose/Hypothesis: The purpose was to investigate the effects of initial graft tension in calcaneofibular ligament (CFL) reconstruction. It was hypothesized that a high degree of initial graft tension would cause abnormal kinematics, laxity, and excessive graft tension. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve cadaveric ankles were tested with a 6 degrees of freedom robotic system to apply passive plantarflexion-dorsiflexion motion and multidirectional loads. A repeated-measures experiment was designed with the CFL intact, CFL transected, and CFL reconstructed with 4 initial tension conditions (10, 30, 50, and 70 N). The 3-dimensional path and reconstructed graft tension were simultaneously recorded. RESULTS: The calcaneus in CFL reconstruction with an initial tension of 70 N had the most eversion relative to the intact condition (mean eversion translations of 1.2, 3.0, 5.0, and 6.2 mm were observed at initial tensions of 10, 30, 50, and 70 N, respectively). The calcaneus also moved more posteriorly with external rotation as the initial tension increased. The reconstructed graft tension tended to increase as the initial tension increased. CONCLUSION: Ankle kinematic patterns and laxity after CFL reconstruction tended to become more abnormal as the initial graft tension increased at the time of surgery. Moreover, excessive initial graft tension caused excessive tension on the reconstructed graft. CLINICAL RELEVANCE: This study indicated the importance of initial graft tension during CFL reconstruction. Overtensioning during CFL reconstruction should be avoided to imitate a normal ankle.

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.

Tibiotalocalcaneal Arthrodesis Using a Soft Tissue-Preserved Fibular Graft for Treatment of Large Bone Defects in the Ankle.

BACKGROUND: Pathogenesis of ankle disorders with a large bone defect is varied and treatment for those problems is challenging for orthopaedic surgeons. The aims of this study were to present an operative technique of arthrodesis for the reconstruction of the ankle and hindfoot with a large bone defect using a soft tissue-preserved fibular strut graft and to report outcomes of consecutively treated patients. METHODS: Twelve feet from 11 patients, including feet with aseptic necrosis of the talus and total ankle implant loosening, were treated. Bone defects were filled using iliac bone and/or resected fibula and tibiotalocalcaneal arthrodesis was performed using a retrograde intramedullary nail. A modified transfibular approach was used to expose the affected joint while preserving the lateral to posterior skin and soft tissues on the fibula. The periods of bony fusion and outcomes were radiographically and clinically evaluated. The mean follow-up period was 33.4 months. RESULTS: Bony fusion was achieved within 3 months in all cases. Coronal and sagittal alignments were acceptable, and the mean American Orthopaedic Foot & Ankle Score improved from 53.8 to 75.5 at the final follow-up. All patients graded their results of treatment as "satisfied." CONCLUSION: This procedure did not require special techniques and it should be applicable to complicated cases with large bone defects. High fusion rates that we believe are due to preserving blood supply to the fibular graft can be expected with preservation of the hindfoot height. LEVEL OF EVIDENCE: Level IV, case series.

Life-threatening acute heart failure due to primary cardiac undifferentiated pleomorphic sarcoma.

A 41-year-old man was admitted with acute heart failure and shock status. An echocardiogram showed a mobile tumor obstructing blood flow through the mitral valve with a stalk on the posterior left atrium (LA) wall. Emergent open-heart surgery was performed to resect the tumor (77×36×30 mm). Histological examination confirmed that it was an undifferentiated pleomorphic sarcoma. Unfortunately, positron emission tomography performed five months after surgery demonstrated a local recurrence around the right pulmonary vein and LA. We performed proton beam radiotherapy to treat the local recurrence, and it was effective. The patient has survived more than one year since the first life-threatening heart failure episode.

Focusing on delayed clearance for identifying small-sized metastatic lung tumors using synchrotron radiation angiography with a highly sensitive receiver.

OBJECTIVES: To detect metastatic lung tumors of less than 1 mm in size by focusing on the clearance of contrast material using synchrotron radiation (SR) angiography characterized by high spatial resolution and high-sensitivity receiver. METHODS: C6 cells, derived from rat glioma cells, were injected to the rat tail vein. Two weeks after injection, the rats underwent SR angiography using a high-gain avalanche rushing amorphous photoconductor (HARP) receiver of extra-high sensitivity with high contrast resolution. The 256-grayscale value was employed in the analysis of images. RESULTS: 19 nodules were identified in images. The tumors were confirmed histopathologically. The average tumor size was 621±193 µm. The clearance curve of the densities was expressed as a logarithm function. Tumors showed delayed clearance of contrast material, taking up to 28 s, compared with arteries, which cleared rapidly at 8 s. In 256 grayscale, the distance was 50. This gap in density clearance made it possible to identify tumors. CONCLUSIONS: SR angiography with a HARP receiver provides high sensitivity and spatial resolution and makes it possible to diagnose metastatic lung tumors of less than 1 mm in size by focusing on differences in the clearance times of contrast material.

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.

Cardiopulmonary bypass induces recruitment of bone marrow-derived leukocytes to the lungs in monkeys.

BACKGROUND: A bone marrow (BM) response induced by cardiopulmonary bypass (CPB) as a systemic inflammatory reaction has previously been postulated but not clarified. Newly released polymorphonuclear leukocytes (PMNs) and monocytes from the BM are known to be immature, indicating their greater potential to damage tissue. The present study aimed to examine the kinetics of BM-derived leukocytes associated with CPB in a nonhuman primate model. METHODS: Normothermic CPB was performed in cynomolgus monkeys for 2 hours through a median sternotomy. Leukocyte precursors were labeled in the BM of the monkeys in vivo by an intravenous injection of 5-bromo-2'-deoxyuridine (BrdU), and their release into the circulation and recruitment to the lungs after operation with or without CPB (control group) were monitored over time by flow cytometry. RESULTS: In normal-state monkeys, the calculated transit time of BrdU-labeled PMNs (PMNBrdU) through the BM was 143.6±4.5 hours and that of monocytes was 100.9±7.6 hours. CPB caused a rapid release of PMNs and monocytes from the BM, shortened their transit through the BM to 92.0±4.1 and 60.3±2.9 hours, respectively, and further induced their increased appearance in the alveolar spaces, with a significant increase in both interleukin (IL)-6 and IL-8 levels in the bronchoalveolar lavage fluid (BALF) 24 hours after CPB. CONCLUSIONS: CPB accelerated the release of PMNs and monocytes from the BM and their recruitment to the lungs in our monkey model, indicating that this model is relevant for monitoring the kinetics of BM-derived leukocytes in humans.