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Biomedical subjects

Ryosuke Kuroda

Publications and source records attributed to Ryosuke Kuroda.

At least 19 recordsLinked to original sources
PubMed2007

In vitro multipotentiality and characterization of human unfractured traumatic hemarthrosis-derived progenitor cells: A potential cell source for tissue repair.

Mesenchymal progenitor cells (MPCs) are a very attractive tool in the context of repair and regeneration of musculoskeletal tissue damaged by trauma. The most common source of MPCs to date has been the bone marrow, but aspirating bone marrow from the patient is an invasive procedure. In an attempt to search for alternative sources of MPCs that could be obtained with minimal invasion, we looked into traumatic hemarthrosis of the knee. In this study, we determined whether a population of multipotent MPCs could be isolated from acute traumatic knee hemarthrosis in the absence of intra-articular fractures. Mononuclear cells were isolated from the aspirated hemarthrosis by density gradient separation, and cultured. We were able to obtain plastic adherent fibroblast-like cells from the mononuclear cell fractions. Flow cytometry analysis revealed that the adherent fibroblast-like cells were consistently positive for CD29, CD44, CD105, and CD166, and were negative for CD14, CD34, and CD45. These were similar to control bone marrow stromal cells. These cells could differentiate in vitro into osteogenic, adipogenic, and chondrogenic cells in the presence of lineage-specific induction factors. In conclusion, acute unfractured traumatic hemarthrosis of the knee contains MPCs with multipotentiality. Because knee hemarthrosis is easy to harvest with minimal pain and without unnecessary invasion, we regard hemarthrosis-derived cells as an additional progenitor cell source for future tissue engineering and cell-based therapy in knee injuries.

Adolescent↗
PubMed2007

Double-bundle ACL reconstruction can improve rotational stability.

Double-bundle anterior cruciate ligament (ACL) reconstruction reproduces anteromedial and posterolateral bundles, and thus has theoretical advantages over conventional single-bundle reconstruction in controlling rotational torque in vitro. However, its superiority in clinical practice has not been proven. We analyzed rotational stability with three reconstruction techniques in 60 consecutive patients who were randomly divided into three groups (double-bundle, anteromedial single-bundle, posterolateral single-bundle). In the reconstructive procedure, the hamstring tendon was harvested and used as a free tendon graft. Followup examinations were performed 1 year after surgery. Anteroposterior laxity of the knee was examined with a KT-1000 arthrometer, whereas rotatory instability, as elicited by the pivot shift test, was assessed using a new measurement system incorporating three-dimensional electromagnetic sensors. Routine clinical evaluations, including KT examination, demonstrated no differences among the three groups. However, using the new measurement system, patients with double-bundle ACL reconstruction showed better pivot shift control of complex instability than patients with anteromedial and posterolateral single-bundle reconstruction.

Adolescent↗
PubMed2006

The effect of graft tensioning in anatomic 2-bundle ACL reconstruction on knee joint kinematics.

Recently, double bundle ACL reconstruction, in which the two bundles thought to have different effects on knee kinematics are reconstructed separately, is widely believed to more favorably restore normal knee kinematics than conventional single bundle ACL reconstruction. However, rotational kinematics during physiological movement after double bundle reconstruction has rarely been tested. The purpose of this study was to measure the kinematics of the ACL deficient and reconstructed knees using two different tensioning conditions in double bundle reconstruction, and to examine the effects of each graft on knee kinematics. Six cadaveric knees were used. Six degrees-of-freedom of knee kinematics and the tension of each graft were monitored during simulated knee extension with the ACL intact, resected, and reconstructed under two different tensioning conditions: 50 N on anteromedial bundle and 0 N on posterolateral bundle (AM-favored condition); 0 N on anteromedial bundle and 50 N on posterolateral bundle (PL-favored condition). Tibial translation: After ACL reconstruction, the tibia overcorrected posteriorly in both conditions. Such an overcorrection in the AM-favored condition was larger than in the PL-favored condition. Tibial rotation: The tibia was significantly externally rotated after ACL reconstruction at a low flexion angle in both conditions. However, at a high flexion angle, tibial external rotation was shown only in the AM-favored condition. Graft tension: While total tensions were similar between the two conditions, the AM bundle shared more tension in the AM-favored condition than in the PL-favored condition. A total of 50 N of tension force was assumed to be excessive for normalizing knee kinematics at a low flexion angle even if double bundle reconstruction was used. Additionally, the AM-favored tensioning reconstruction made the tibia rotate externally and translate posteriorly even at a high flexion angle. Further research is needed to normalize knee kinematics after ACL reconstruction, however it is recommended that a moderate tensioning force is applied to the PL bundle and a minimal tensioning force to the AM bundle in double bundle reconstruction to obtain better knee kinematics.

Aged↗
PubMed2006

Rapid chondrolysis after arthroscopic partial lateral meniscectomy in athletes: a case report.

We present a patient with a severe chondrolysis after arthroscopic partial lateral meniscectomy in a 17-year-old high school basketball player. This is a rare but severe complication after arthroscopic partial lateral meniscectomy. At 7 months after the first operation, a second-look arthroscopy showed numerous cartilaginous debris floating in the knee and a high-grade cartilage damage on the lateral compartment of the tibia. This unexpected complication and a consideration of its etiology are shown.

Adolescent↗
PubMed2006

Cartilage repair using bone morphogenetic protein 4 and muscle-derived stem cells.

OBJECTIVE: Muscle-derived stem cells (MDSCs) isolated from mouse skeletal muscle exhibit long-time proliferation, high self-renewal, and multipotent differentiation. This study was undertaken to investigate the ability of MDSCs that were retrovirally transduced to express bone morphogenetic protein 4 (BMP-4) to differentiate into chondrocytes in vitro and in vivo and enhance articular cartilage repair. METHODS: Using monolayer and micromass pellet culture systems, we evaluated the in vitro chondrogenic differentiation of LacZ- and BMP-4-transduced MDSCs with or without transforming growth factor beta1 (TGFbeta1) stimulation. We used a nude rat model of a full-thickness articular cartilage defect to assess the duration of LacZ transgene expression and evaluate the ability of transplanted cells to acquire a chondrocytic phenotype. We evaluated cartilage repair macroscopically and histologically 4, 8, 12, and 24 weeks after surgery, and performed histologic grading of the repaired tissues. RESULTS: BMP-4-expressing MDSCs acquired a chondrocytic phenotype in vitro more effectively than did MDSCs expressing only LacZ; the addition of TGFbeta1 did not alter chondrogenic differentiation of the BMP-4-transduced MDSCs. LacZ expression within the repaired tissue continued for up to 12 weeks. Four weeks after surgery, we detected donor cells that coexpressed beta-galactosidase and type II collagen. Histologic scoring of the defect sites 24 weeks after transplantation revealed significantly better cartilage repair in animals that received BMP-4-transduced MDSCs than in those that received MDSCs expressing only LacZ. CONCLUSION: Local delivery of BMP-4 by genetically engineered MDSCs enhanced chondrogenesis and significantly improved articular cartilage repair in rats.

Animals↗
PubMed2006

The structural properties of an osteochondral cylinder graft-recipient construct on autologous osteochondral transplantation.

PURPOSE: The purpose of this study was to investigate the changes in structural properties of an osteochondral cylinder graft-recipient construct after autologous osteochondral transplantation. METHODS: A full-thickness cylindrical osteochondral defect (5 mm in diameter and 3 mm in depth) was made on the femoral condyle of a mature female Japanese white rabbit using the Osteochondral Autograft Transfer System (OATS; Arthrex, Naples, FL). The defect was repaired with an osteochondral plug (6 mm in diameter and 3 mm in depth) taken from the contralateral femoral condyle using the OATS. The implanted osteochondral grafts were evaluated immediately after surgery and at postoperative weeks 1, 3, 8, and 12. The stiffness of articular cartilage was analyzed using a tactile sensor system (AXIOM, Fukushima, Japan), which measures stiffness based on changes in resonance frequency when a vibrating tactile sensor touches articular cartilage. The specimens were stained with hematoxylin and eosin and serial sections were examined microscopically. RESULTS: The cartilage stiffness of the graft immediately after surgery was 107,695.1 N/m, which was not statistically different from the normal cartilage stiffness (100,027.5 N/m). The stiffness at postoperative weeks 1, 3, 8, and 12 was 95,386.8, 92,899.3, 95,969.8, and 104,683.7 N/m, respectively. The stiffness at postoperative weeks 1, 3, and 8 was significantly lower than the normal cartilage stiffness and the stiffness at postoperative week 12 was the same as normal cartilage. A new bone formation with an increase of bone trabeculae between the osteochondral cylinder graft and the recipient was observed at postoperative weeks 1, 3, and 8. Thereafter, at postoperative week 12, bone trabeculae decreased to the same level as observed in a normal model due to the progress of bone remodeling. CONCLUSIONS: The stiffness of articular cartilage of the osteochondral graft was normal at the time the graft was initially placed and at postoperative week 12. However, the stiffness at postoperative weeks 1, 3, and 8 was lower than the normal cartilage stiffness. CLINICAL RELEVANCE: Care should be taken when planning the rehabilitation program at an early phase after osteochondral transplantation.

Animals↗
PubMed2006

Joint gap kinematics in posterior-stabilized total knee arthroplasty measured by a new tensor with the navigation system.

BACKGROUND: The management of soft tissue balance during surgery is essential for the success of total knee arthroplasty (TKA) but remains difficult, leaving it much to the surgeon's feel. Previous assessments for soft tissue balance have been performed under unphysiological joint conditions, with patellar eversion and without the prosthesis only at extension and 90 deg of flexion. We therefore developed a new tensor for TKA procedures, enabling soft tissue balance assessment throughout the range of motion while reproducing postoperative joint alignment with the patellofemoral (PF) joint reduced and the tibiofemoral joint aligned. Our purpose in the present study was to clarify joint gap kinematics using the tensor with the CT-free computer assisted navigation system. METHOD OF APPROACH: Joint gap kinematics, defined as joint gap change during knee motion, was evaluated during 30 consecutive, primary posterior-stabilized (PS) TKA with the navigation system in 30 osteoarthritic patients. Measurements were performed using a newly developed tensor, which enabled the measurement of the joint gap throughout the range of motion, including the joint conditions relevant after TKA with PF joint reduced and trial femoral component in place. Joint gap was assessed by the tensor at full extension, 5 deg, 10 deg, 15 deg, 30 deg, 45 deg, 60 deg, 90 deg, and 135 deg of flexion with the patella both everted and reduced. The navigation system was used to obtain the accuracy of implantations and to measure an accurate flexion angle of the knee during the intraoperative joint gap measurement. RESULTS: Results showed that the joint gap varied depending on the knee flexion angle. Joint gap showed an accelerated decrease during full knee extension. With the PF joint everted, the joint gap increased throughout knee flexion. In contrast, the joint gap with the PF joint reduced increased with knee flexion but decreased after 60 deg of flexion. CONCLUSIONS: We clarified the characteristics of joint gap kinematics in PS TKA under physiological and reproducible joint conditions. Our findings can provide useful information for prosthetic design and selection and allow evaluation of surgical technique throughout the range of knee motion that may lead to consistent clinical outcomes after TKA.

Aged↗
PubMed2006

Therapeutic potential of vasculogenesis and osteogenesis promoted by peripheral blood CD34-positive cells for functional bone healing.

Failures in fracture healing are mainly caused by a lack of vascularization. Adult human circulating CD34+ cells, an endothelial/hematopoietic progenitor-enriched cell population, have been reported to differentiate into osteoblasts in vitro; however, the therapeutic potential of CD34+ cells for fracture healing is still unclear. Therefore, we performed a series of experiments to test our hypothesis that functional fracture healing is supported by vasculogenesis and osteogenesis via regenerative plasticity of CD34+ cells. Peripheral blood CD34+ cells, isolated from total mononuclear cells of adult human volunteers, showed gene expression of osteocalcin in 4 of 20 freshly isolated cells by single cell reverse transcriptase-polymerase chain reaction analysis. Phosphate-buffered saline, mononuclear cells, or CD34+ cells were intravenously transplanted after producing nonhealing femoral fractures in nude rats. Reverse transcriptase-polymerase chain reaction and immunohistochemical staining at the peri-fracture site demonstrated molecular and histological expression of human-specific markers for endothelial cells and osteoblasts at week 2. Functional bone healing assessed by biomechanical as well as radiological and histological examinations was significantly enhanced by CD34+ cell transplantation compared with the other groups. Our data suggest circulating human CD34+ cells have therapeutic potential to promote an environment conducive to neovascularization and osteogenesis in damaged skeletal tissue, allowing the complete healing of fractures.

Angiogenesis Inhibitors↗
PubMed2006

Clinical values in computer-assisted total knee arthroplasty.

Thirty posterior stabilized total knee prostheses implanted using a computed tomography-free navigation system were compared to a control group of 30 matched total knee prostheses of the same type implanted via a classical, surgeon-controlled technique. The accuracy of the implantations in relation to the mechanical axis in the navigation group was superior to that of the manual group. Early two-year clinical results including range of motion and Knee Society Clinical Rating Score were equally good compared to the manual group. However, potential long-term outcome and functional improvement require further investigation.

Aged↗
PubMed2005

A comparison of bone-patellar tendon-bone and bone-hamstring tendon-bone autografts for anterior cruciate ligament reconstruction.

BACKGROUND: Most of the previous comparative studies between patellar tendon and hamstring tendon anterior cruciate ligament grafts compared grafts of different constructs fixed with different methods. PURPOSE: To compare patellar tendon and hamstring tendon grafts with the same fixation method used to reconstruct the anterior cruciate ligament. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: During the reconstructive procedure, the hamstring tendon graft was prepared as a bone-hamstring-bone graft; both bone-patellar tendon-bone and bone-hamstring-bone grafts were fixed with interference screws. Eighty consecutive patients who underwent anterior cruciate ligament reconstruction were randomly assigned to either bone-patellar tendon-bone or bone-hamstring-bone groups. Follow-up examinations were performed for at least 5 years postoperatively. Seventy-two of the 80 patients (37 patients in the bone-patellar tendon-bone group and 35 in the bone-hamstring-bone group) were evaluated, with a mean follow-up period of 87.0 and 80.8 months, respectively. Follow-up examinations were performed using the International Knee Documentation Committee knee ligament standard and subjective knee forms. RESULTS: The mean KT-1000 arthrometer evaluation results showed no significant difference between the bone-patellar tendon-bone and bone-hamstring-bone groups (1.2 +/- 2.1 mm and 1.7 +/- 1.4 mm, respectively; P = .24). However, symptoms related to graft harvest (anterior kneeling pain) were more frequently observed in the bone-patellar tendon-bone group, and unsatisfactory results were correlated with severe kneeling pain in 3 patients from this group (P = .0056). Significant hamstring muscle weakness without complaint of functional deficit was found in the bone-hamstring-bone group (P = .0045). CONCLUSION: Bone-hamstring-bone grafts were shown to reduce the risk of problems at the graft harvest site compared to bone-patellar tendon-bone grafts, with comparable results in the remaining clinical parameters tested.

Adolescent↗
PubMed2005

Human hemarthrosis-derived progenitor cells can differentiate into osteoblast-like cells in vitro.

We hypothesized that intraarticular osteochondral fracture-induced hemarthrosis could be a useful cell source for bone regeneration, as it is thought to contain osteoprogenitor cells derived from bone marrow. Therefore, we investigated whether human hemarthrosis-derived cells have the potential to differentiate into osteoblast-like cells in vitro. We aspirated hemarthrosis from patients suffering from osteochondral fractures of knee joints, and cultured hemarthrosis-derived cells in a medium supplemented with dexamethasone, beta-glycerophosphate, and ascorbic acid, or without them as control. The morphology of the treated cells appeared to be cuboidal shape, differing from spindle-like shape observed in the control. Matrix mineralization was observed only in the treated culture. Alkaline phosphatase activity and gene expression of alkaline phosphatase, parathyroid hormone receptor, osteopontin, and osteocalcin were up-regulated compared with the control. These studies demonstrate that human hemarthrosis-derived cells can differentiate into osteoblast-like cells, i.e., they contain osteoprogenitor cells and are a useful cell source for bone regeneration.

Adolescent↗
PubMed2005

Bilateral painful snapping elbows triggered by daily dumbbell exercises: a case report.

We treated a 64-year-old female with bilateral painful snapping elbows due to synovial folds. Resection of the bilateral synovial folds resulted in relief from pain and snapping, and resulted in patient satisfaction. Daily dumbbell exercises of the bilateral elbows starting at an elderly age may have led to the bilateral snapping. Painful snapping elbow is a relatively rare condition, which usually occurs in a unilateral elbow of a younger patient. To our knowledge, bilateral painful snapping elbows triggered by daily dumbbell exercises in older patients have not been previously reported.

Arthralgia↗
PubMed2005

Mechanical evaluation of a soft tissue interference screw with a small diameter: significance of graft/bone tunnel cross-sectional area ratio.

The purpose of this study is to evaluate the mechanical properties of a graft fixation using a small diameter soft tissue interference screw and analyze the factors affecting the fixation strength. Forty porcine knees were used. A bone tunnel, either 4.5 mm (n=40) or 5.0 mm (n=40) in diameter, was created in the bone block obtained from the proximal tibia or the distal femur. A patella-patellar tendon specimen with varied width was harvested, and the distal end of the patellar tendon was fixed within the bone tunnel using a small diameter soft tissue interference screw (4 x 15 mm). Then, the patella-patellar tendon-bone block complex was loaded until failure occurred and the maximum load was measured. As potential influential factors on the fixation strength, the insertion torque, bone mineral density of the bone block, and graft/tunnel cross-sectional area ratio (GTR) of each specimen were calculated. A significant correlation between the maximum failure load and the insertion torque was demonstrated. The quadratic regression analysis showed a statistically significant correlation between the failure load and the GTR. Optimal GTR for achieving high fixation strength was approximately 80%. When used in appropriate conditions, the mean failure load was 177 N for the 4.5 mm screw and 180 N for the 5 mm screw. The use of a small diameter interference screw for the fixation of a tendon graft to a bone is clinically feasible. Our research showed that the selection of appropriate fitting conditions is an important factor for optimizing the properties of the fixation.

Anatomy, Cross-Sectional↗
PubMed2005

Medial collateral ligament reconstruction using autogenous hamstring tendons: technique and results in initial cases.

BACKGROUND: Although various surgical procedures that attempt to restore the function of the medial collateral ligament have been reported, none have achieved consistently satisfactory results. HYPOTHESIS: Our reconstructive procedure using autogenous semitendinosus and gracilis tendons yields improved results compared with conventional procedures. STUDY DESIGN: Case series. Level of evidence, 4. METHOD: In our surgical procedure, autogenous semitendinosus and gracilis tendons were used to anatomically reconstruct the anterior longitudinal component of the superficial medial collateral ligament. From April 1995 through December 2000, 27 patients with symptomatic medial instability underwent this surgical procedure. The majority of the subjects were diagnosed with combined cruciate ligament injuries, necessitating concomitant cruciate ligament reconstructions. Of these 27 patients, 24 were evaluated after a minimum period of 2 years, with a mean follow-up period of 27 months (range, 24-48 months). RESULTS: At follow-up, medial stability, as well as postoperative range of motion in all patients, was graded as normal or nearly normal according to the International Knee Documentation Committee evaluation system. No significant postoperative complications were encountered. CONCLUSION: Although this is a short-term follow-up study involving a small number of cases, we considered our procedure to be an effective method of surgically restoring the function of the medial collateral ligament.

Adolescent↗
PubMed2004

The load of an implanted graft during and after fixation in anterior cruciate ligament reconstruction.

Although the importance of initial graft load has been discussed in the literature, it has not been confirmed whether a surgeon can provide the desired load to an implanted graft in anterior cruciate ligament reconstruction. The purpose of this study was to compare the set force (initial load given to the graft before fixation) and residual load in the implanted graft using three different fixation techniques. A total of ninety porcine knees were tested using bone-patellar tendon-bone autograft. Each bone-tendon-bone autograft was fixed to the tibia with either the interference-fit screw, fixation post, or button technique. Graft load was monitored during fixation procedures, and for 10 min after fixation. Residual graft load with each fixation technique exhibited unique features. Highest graft load was obtained by the interference-screw fixation technique; however, the graft was usually over-loaded beyond the intended set force with this technique. In the fixation-post technique, the load of the graft increased while the screw was retightened. The graft load in the button-fixation technique was low, probably due to slight slippage of the button. When the graft was fixed under maximum manual tension, the graft loads at completion of fixation for the interference fit screw, fixation post, and button techniques were 116.3, 54.2, and 25.9 N respectively.

Animals↗
PubMed2004

Prosthetic alignment and sizing in computer-assisted total knee arthroplasty.

We implanted 60 posterior stabilized total knee prostheses (P.F.C. Sigma, DePuy, Warsaw, USA). In 30 cases, we used a CT-free navigation system (Vector Vision, Brain LAB, Heimstetten, Germany), and in 30 matched-paired controls, we used a conventional manual implantation. We compared postoperative long-leg radiographs in the two groups. The results revealed a significant difference in favor of navigation. In addition, we compared the preoperative anteroposterior dimension of the femoral condyle with the postoperative value. While there were no significant differences in the preoperative anteroposterior dimension of the femoral condyle between the two groups, the postoperative value in the navigation group was significantly larger than that of the preoperative value. Therefore, surgeons using navigation systems should guard against the possibility of oversizing when determining the size of the femoral component.

Aged↗
PubMed2004

Functional comparison of posterior cruciate-retaining versus posterior stabilized total knee arthroplasty.

A prospective, randomized comparison of posterior cruciate-retaining (PCR) and posterior stabilized (PS) total knee arthroplasties (TKAs) was conducted in 20 patients who underwent bilateral TKAs for osteoarthritis. All procedures were performed by a single surgeon. One knee was implanted with a PCR TKA, and a contralateral knee with a PS TKA. Both prosthetic designs were of the same TKA series, with comparable surface geometries. Patients had a clinical and radiographic evaluation at a mean of 31.7 months for PCR TKAs and 30.6 months for PS TKAs postoperatively. There were no significant differences between the PCR and PS TKAs in postoperative knee scores. However, postoperative improvement in range of motion was significantly superior in the PS group.

Aged↗