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    Takahisa Sasho

    Biomechanical effects of laterally wedged insoles are assessed by reduction in the knee adduction moment. However, the degree of reduction may vary depending on the reference frame with which it is calculated. The purpose of this study... more
    Biomechanical effects of laterally wedged insoles are assessed by reduction in the knee adduction moment. However, the degree of reduction may vary depending on the reference frame with which it is calculated. The purpose of this study was to clarify the effect of reference frame on the reduction in the knee adduction moment by laterally wedged insoles. Twenty-nine healthy participants performed gait trials with a laterally wedged insole and with a flat insole as a control. The knee adduction moment, including the first and second peaks and the angular impulse, were calculated using four different reference frames: the femoral frame, tibial frame, laboratory frame and the Joint Coordinate System. There were significant effects of reference frame on the knee adduction moment first and second peaks (P < 0.001 for both variables), while the effect was not significant for the angular impulse (P = 0.84). No significant interaction between the gait condition and reference frame was found in either of the knee adduction moment variables (P = 0.99 for all variables), indicating that the effects of laterally wedged insole on the knee adduction moments were similar across the four reference frames. On the other hand, the average percent changes ranged from 9% to 16% for the first peak, from 16% to 18% for the second peak and from 17% to 21% for the angular impulse when using the different reference frames. The effects of laterally wedged insole on the reduction in the knee adduction moment were similar across the reference frames. On the other hand, Researchers need to recognize that when the percent change was used as the parameter of the efficacy of laterally wedged insole, the choice of reference frame may influence the interpretation of how laterally wedged insoles affect the knee adduction moment.
    Correction of pronation deformity and metatarsal primus varus is an important component of hallux valgus surgery, necessary to achieve a satisfactory correction and to prevent post-operative recurrence. Roundness of the lateral edge of... more
    Correction of pronation deformity and metatarsal primus varus is an important component of hallux valgus surgery, necessary to achieve a satisfactory correction and to prevent post-operative recurrence. Roundness of the lateral edge of the first metatarsal head (round sign) on the dorsoplantar radiograph of the foot has been empirically advocated as an indicator of first metatarsal pronation. The purpose of this study was to clarify the effect of rotation and inclination of the first metatarsal on the shape of the lateral edge of the first metatarsal head. Computed tomographic images of feet in 30 subjects, without pathology of the first metatarsophalangeal joint, were included. Digitally reconstructed radiographs of the first metatarsal were created using the computed tomographic data. Thirty-nine images were created of each first metatarsal at different degrees of rotation (-10° to 30° of pronation) and inclination (-10° to 20° of plantarflexion). Then, the shape of the lateral edge of the first metatarsal head was classified into three types: angular, intermediate, and round. Generalized estimation equations were used to test if the shapes of the first metatarsal head were significantly different across the range of pronation and plantarflexion angles. The positive round sign changed to negative as the first metatarsal supinated. In most feet, these changes occurred as the pronation angle decreased from 10° to 0°. The positive round sign also changed to negative as the first metatarsal head plantarflexed. Positive round sign of the first metatarsal head on the dorsoplantar radiograph of the foot was significantly associated with increased pronation as well as decreased inclination of the first metatarsal. Negative round sign may be used as an indicator of effective correction of first metatarsal pronation during hallux valgus surgery.
    Several MRI-based evaluation systems for osteoarthritis (OA) of the knee have been developed. Among them the whole-organ magnetic resonance imaging score (WORMS), which evaluates the status of the entire knee joint, appears to be... more
    Several MRI-based evaluation systems for osteoarthritis (OA) of the knee have been developed. Among them the whole-organ magnetic resonance imaging score (WORMS), which evaluates the status of the entire knee joint, appears to be representative. We developed an irregularity index system to measure irregularities of the contours of the femoral condyle on MRI. Only the contour of the condyle was assessed by the irregularity index, whereas several items comprising the knee joint were taken into account by WORMS. This study compared the irregularity index and WORMS in terms of their correlations with clinical scores. Thirty-one medial-type OA knees were studied. Kellgren-Lawrence grading was used for X-ray grading: 8 were grade II, 11 were grade III, and 12 were grade IV. Japanese Orthopaedic Association scores and Japanese knee osteoarthritis measure scores were used for clinical assessments. We determined the correlations between MRI-based assessment scores and clinical scores. Both t...
    Purpose To determine if magnetic resonance (MR) imaging T2 mapping can be used to quantify histologic tendon healing by using a rabbit Achilles tendon transection model treated with platelet-rich plasma (PRP). Materials and Methods... more
    Purpose To determine if magnetic resonance (MR) imaging T2 mapping can be used to quantify histologic tendon healing by using a rabbit Achilles tendon transection model treated with platelet-rich plasma (PRP). Materials and Methods Experiments were approved by the Institutional Animal Care and Use Committee. The Achilles tendons of 24 New Zealand white rabbits (48 limbs) were surgically transected, and PRP (in the test group) or saline (in the control group) was injected into the transection site. The rabbits were sacrificed 2, 4, 8, and 12 weeks after surgery. Thereafter, T2 mapping and histologic evaluations were performed by using the Bonar scale. A mixed-model multivariate analysis of variance was used to test the effects of time and PRP treatment on the T2 value and Bonar grade, respectively. The correlation between the T2 value and Bonar grade was also assessed by using the Spearman correlation coefficient. Results The Bonar scale values decreased in both groups during tendon ...
    Intratendinous ganglion cysts are rare lesions of unknown etiology that originate within a tendon. We report the case of a 34-year-old female with an intratendinous ganglion in the plantar portion of the flexor hallucis longus tendon. The... more
    Intratendinous ganglion cysts are rare lesions of unknown etiology that originate within a tendon. We report the case of a 34-year-old female with an intratendinous ganglion in the plantar portion of the flexor hallucis longus tendon. The intratendinous ganglion recurred after ultrasound-guided needle aspiration. Tendoscopic excision of the intratendinous ganglion cyst achieved a satisfactorily result without recurrence.
    Small peptides including the Arg-Gly-Asp (RGD) motif have been used in studies on cell-extracellular matrix (ECM) attachment due to their ability to disturb integrin-mediated attachment on the cell surface. As another biological action of... more
    Small peptides including the Arg-Gly-Asp (RGD) motif have been used in studies on cell-extracellular matrix (ECM) attachment due to their ability to disturb integrin-mediated attachment on the cell surface. As another biological action of RGD peptides, several reports have shown that RGD peptides are incorporated into cytoplasm and induce apoptosis by direct activation of caspase-3. This study evaluated the effect of RGD peptides on chondrocytes and synovial cells and studied the involvement of caspases. Chondrocytes and synovial cells were isolated and cultured from the knee joints of New Zealand White rabbits. Cells were incubated in serum-free medium with peptides (RGD, RGDS, GRGDSP, GRGDNP, RGES), and the survival rates were evaluated. The rate of apoptotic cells was measured by flow cytometry in cells treated with RGDS, GRGDSP, and RGES. Caspase-3, -8 and -9 activity was measured in cells treated with RGDS and GRGDSP. Osteochondral explants harvested from rabbits were also incu...
    The aim of this study was to investigate the biochemical properties, histological and immunohistochemical appearance, and magnetic resonance (MR) imaging findings of reparative cartilage after autologous chondrocyte implantation (ACI) for... more
    The aim of this study was to investigate the biochemical properties, histological and immunohistochemical appearance, and magnetic resonance (MR) imaging findings of reparative cartilage after autologous chondrocyte implantation (ACI) for osteochondritis dissecans (OCD). Six patients (mean age 20.2 +/- 8.8 years; 13-35 years) who underwent ACI for full-thickness cartilage defects of the femoral condyle were studied. One year after the procedure, a second-look arthroscopic operation was performed with biopsy of reparative tissue. The International Cartilage Repair Society (ICRS) visual histological assessment scale was used for histological assessment. Biopsied tissue was immunohistochemically analyzed with the use of monoclonal antihuman collagen type I and monoclonal antihuman collagen type II primary antibodies. Glycosaminoglycan (GAG) concentrations in biopsied reparative cartilage samples were measured by high performance liquid chromatography (HPLC). MR imaging was performed wi...
    The purpose of this study is to compare the anatomy of rheumatoid hallux valgus with that of idiopathic hallux valgus from the standpoint of joint-preserving surgery. One hundred forty-eight feet of 81 rheumatoid patients were included.... more
    The purpose of this study is to compare the anatomy of rheumatoid hallux valgus with that of idiopathic hallux valgus from the standpoint of joint-preserving surgery. One hundred forty-eight feet of 81 rheumatoid patients were included. Feet with idiopathic hallux valgus and normal feet were compared as controls. Weight-bearing dorsoplantar radiographs of the feet were taken of each patient. A two-dimensional coordinate system was defined on the radiographic image, and 19 anatomic points of the forefoot were measured. In rheumatoid hallux valgus, the first metatarsal head shifted medially as hallux valgus angle increased, which was similar to the deformity of idiopathic hallux valgus. Proximal deviation of the tips of the lesser toes, caused by clawing and dislocations of the metatarsophalangeal joints, occurred in rheumatoid hallux valgus. Specifically the tips of the second toes in rheumatoid hallux valgus were located more proximally than those in idiopathic hallux valgus irrespective of the severity of hallux valgus. Corrective osteotomy of the first metatarsal is a reasonable procedure for rheumatoid hallux valgus. Additionally, correction of the second toe deformity to make a stable lateral support on the hallux may be another important factor for successful joint-preserving surgery.
    Many studies have reported successful outcomes less than 10 years after anterior cruciate ligament (ACL) reconstruction. However, longer-term outcomes have not been analyzed. We assessd outcomes 24 years after anterior cruciate ligament... more
    Many studies have reported successful outcomes less than 10 years after anterior cruciate ligament (ACL) reconstruction. However, longer-term outcomes have not been analyzed. We assessd outcomes 24 years after anterior cruciate ligament reconstruction with iliotibial tract and compared them with shorter-term results in the same patients. Between 1979 and 1981, 45 patients underwent combined intra- and extra-articular ACL reconstruction with iliotibial tract. Follow-up evaluations of these patients were performed at 6, 13, and 24 years after surgery, which included manual and instrumental laxity testing, functional assessments, and radiography. Twenty-six (60%) patients of the original ACL reconstruction cohort participated in all three follow-up assessments. Three patients had undergone meniscectomy prior to ACL reconstruction and 18 underwent meniscectomy together with ACL reconstruction. Eleven patients underwent subsequent meniscectomy. The mean Lysholm score was 96.2, 93.8, and 87.8 at 6-, 13-, and 24-year follow-up, respectively. A significant decrease in mean Lysholm score was found between 13- and 24-year follow-up. The mean KT-1000 side-to-side difference was 3.5 mm at 24-year follow-up. Overall knee laxity did not change significantly during the follow-up period. At 24-year follow-up, 17 (71%) patients had moderate or severe degenerative changes on radiographs although about 50% of the patients participated in regular sports activities and no patient required regular clinical intervention.
    Synovial haemangioma of the knee joint is a relatively rare benign condition with around 200 reported cases. We have recently encountered two cases of synovial haemangioma of the knee joint which preoperative MRI had assessed as highly... more
    Synovial haemangioma of the knee joint is a relatively rare benign condition with around 200 reported cases. We have recently encountered two cases of synovial haemangioma of the knee joint which preoperative MRI had assessed as highly suspect and which arthroscopic resection and subsequent histological examinations confirmed as synovial hemangiomas. Published studies have identified the following as characteristic MRI features of synovial haemangioma: homogenous low intensity to iso-intensity on T1 sequence; and heterogeneous high intensity with low-intensity septa or spots within the lesion on T2 sequence. However, several other intra-knee disorders mimic these characteristics. In our two cases, we found that gadolinium (Gd)-enhanced images, which have been relatively rarely discussed in the literature, were useful for making the diagnosis and for determining the extent of this condition. These images also were very helpful during arthroscopic excision of the lesion. Nonetheless, even after Gd enhancement, differentiating between malignant conditions such as synovial sarcoma and haemangioma solely from MRI findings is still difficult.
    The purpose of this study was to test if radial shock waves could enhance the introduction of nuclear factor-kappa B (NF-kappaB) decoy oligodeoxynucleotides, which is reported to markedly inhibit NF-kappaB activation and suppress... more
    The purpose of this study was to test if radial shock waves could enhance the introduction of nuclear factor-kappa B (NF-kappaB) decoy oligodeoxynucleotides, which is reported to markedly inhibit NF-kappaB activation and suppress pro-inflammatory cytokine gene expression, using rat Achilles tendon cells. In the presence of NF-kappaB decoy labeled with or without fluorescein isothiocyanate (FITC) in culture media, radial shock waves were applied to the tendon cells in variable conditions and cultivated for 24 h. The transfection rate was assessed by counting FITC-positive cells, and IL-1-induced NF-kappaB activation in the cells was assessed. Radial shock waves significantly enhanced introduction of NF-kappaB decoy-FITC into the tendon cells. IL-1-induced NF-kappaB activation was significantly inhibited by pretreatment of the cells with NF-kappaB decoy combined with radial shock wave exposure. The present study demonstrated the effectiveness of radial shock waves on introduction of NF-kappaB decoy into tendon cells. Radial shock wave treatment combined with local NF-kappaB decoy administration could be a novel therapeutic strategy for chronic tendinopathy.
    Understanding the effect of weightbearing on subtalar and ankle joint kinematics is critical for the diagnosis and treatment of foot disorders. However, dynamic in vivo kinematics of these joints are not well studied. The purpose of this... more
    Understanding the effect of weightbearing on subtalar and ankle joint kinematics is critical for the diagnosis and treatment of foot disorders. However, dynamic in vivo kinematics of these joints are not well studied. The purpose of this study was to compare in vivo kinematics during nonweightbearing and weightbearing activities in healthy subjects. Seven healthy subjects with a mean age of 32 (range, 23 to 42) years were enrolled. Oblique lateral fluoroscopic images of nonweightbearing and weightbearing dorsiflexion-plantarflexion activities were recorded. Three dimensional subtalar, ankle, and ankle-subtalar joint complex kinematics were determined using 3D-2D model registration techniques with 3D bone models and single-plane fluoroscopy. During the weightbearing activity from 20 degrees dorsiflexion to 15 degrees plantarflexion, the subtalar joint was significantly more everted, dorsiflexed, and abducted, and the calcaneus showed a significantly more posterior position, than during the nonweightbearing activity. The ankle joint was significantly more plantarflexed and adducted during the weightbearing activity than the nonweightbearing activity. The ankle-subtalar joint complex was significantly more everted, and the calcaneus showed significantly greater posterior position than the nonweightbearing activity. These observations provide basic quantitative descriptions of weightbearing and nonweightbearing kinematics for healthy joints. These data can serve as the basis for comparison with pathologic feet for both diagnostic and therapeutic purposes.
    Knee pain is predominant among osteoarthritis (OA) patients, but the mechanism is poorly understood. We investigated subchondral bone as a source of OA knee pain using immunohistochemistry. Fifteen medial-type OA knees with minimum... more
    Knee pain is predominant among osteoarthritis (OA) patients, but the mechanism is poorly understood. We investigated subchondral bone as a source of OA knee pain using immunohistochemistry. Fifteen medial-type OA knees with minimum involvement of the lateral compartment determined by X-ray as well as magnetic resonance imaging that received total knee arthroplasty (TKA) were involved. Each pair of the medial femoral condyle (MFC) and lateral femoral condyle (LFC) was compared obtained at the time of TKA. Osteocartilaginous MFC and LFC specimens were histologically examined and stained with antibodies against cyclooxygenase 1 (Cox-1), cyclooxygenase 2 (Cox-2), substance P, tumor necrosis factor-alpha (TNF-alpha), and neuron-specific class III beta-tubulin (TUJ1), a pan-neuronal marker. Formation of cystic lesions was more frequently seen in the MFC. The lesions were composed of vascular endothelial cells, osteoclasts, and mononuclear cells and were present in similar proportions between the MFC and the LFC. Four out of 15 MFC specimens were positive for Cox-1, 15 for Cox-2, and 13 for TNF-alpha. No LFC specimens were positive for any antibodies. Substance P-positive and TUJ1-positive fibers were found in the subchondral area of the MFC, but not in the LFC. Pathological changes in the subchondral bone can be a source of knee pain, which was detectable by the positive immunoreactivity of substance P, Cox-2, TNF-alpha, and TUJ1, in the subchondral bone of affected compartments. The relatively immediate reduction in pain obtained by TKA might account for the involvement of the subchondral bone in knee pain because most of the affected subchondral plate is excised in TKA (debridement effect of TKA).
    Forearm rotation is an indispensable activity of daily living and comprises complex motions with rotational and translational components. It is thought that changes in these motions with injury or disease may affect diagnostic indices.... more
    Forearm rotation is an indispensable activity of daily living and comprises complex motions with rotational and translational components. It is thought that changes in these motions with injury or disease may affect diagnostic indices. Several studies have assessed in vivo forearm kinematics with static conditions, but dynamic forearm kinematics have not yet been reported. The purpose of this study was to analyze forearm kinematics during dynamic rotation using radiographic 3D-2D registration methods. Ten forearms of five healthy males with the mean age of 37 years old were enrolled. Lateral fluoroscopic images were taken during forearm rotation from maximum supination to maximum pronation with their elbows flexed to approximately 45°. Geometric bone models were created from CT scans of the humerus, the radius and the ulna. Three-dimensional kinematics were determined using 3D-2D model registration techniques with the images and models, and the arc of axial rotation of the radius, volar/dorsal translation of the ulna at the distal radioulnar joint and rotation axis of forearm were computed. The radial rotation arc was 157°. The ulna translated 3.9 mm (SD 1.5mm) dorsally during activity. The rotation axis of the forearm passed through the center of the radial head and the ulnar head at the 1.9 mm (SD 0.7 mm) posterior from its geometric centroid. The posteriorly deviated rotation axis at the ulnar head may result in the ulnar head translating dorsally during pronation. These data provide a basis for objective assessment of pathological forearm function.
    The aim of this study was to evaluate the qualitative change in reparative cartilage after autologous chondrocyte implantation (ACI). Ten knees of 10 patients were studied. The signal intensities of reparative and normal cartilage were... more
    The aim of this study was to evaluate the qualitative change in reparative cartilage after autologous chondrocyte implantation (ACI). Ten knees of 10 patients were studied. The signal intensities of reparative and normal cartilage were evaluated by fat-suppressed three-dimensional spoiled-gradient recalled (FS 3D-SPGR) MR imaging. The signal intensity (SI) index (signal intensity of reparative cartilage divided by that of normal cartilage) was defined and the change in SI index was investigated. Histological and biochemical evaluation was done at the second look arthroscopy. The SI index was at its lowest level immediately after ACI and increased with time to 9 months thereafter. After 9-12 months, the SI index settled to almost level and was maintained at that value for at least 2-3 years postoperatively. The average of the SI indexes after 12 months to the last examination was 74.2 +/- 4.6 (range 64.2-82.8), which means signal intensity of reparative cartilage was maintained at a value lower than that of normal cartilage. The total ICRS score was 11.6 +/- 2.3 points (mean +/- SD). The GAG concentration was 107.9 +/- 17.0 microg/mg (mean +/- SD) in normal cartilage and 65.9 +/- 9.4 microg/mg in reparative cartilage. The quality of reparative cartilage as hyaline cartilage was inferior to that of normal cartilage. In the present study, the time course change in the SI index indicates that the major maturation process of implanted chondrocytes neared completion in 9-12 months. Minor changes, such as matrix remodeling with reorganization of the collagen fibers in reparative cartilage, may continue, but an almost identical condition seemed to be maintained during the first 2-3 years of follow-up. SI index does not always reflect all properties of reparative cartilage but may be a useful parameter for noninvasive evaluation.
    To elucidate the etiology of and find a preferable surgical treatment for spontaneous recurrent hemarthrosis in osteoarthritic knee joints arthroscopically. Nineteen patients referred to our institution from affiliate hospitals between... more
    To elucidate the etiology of and find a preferable surgical treatment for spontaneous recurrent hemarthrosis in osteoarthritic knee joints arthroscopically. Nineteen patients referred to our institution from affiliate hospitals between April 1998 and October 2006 were involved in this study. Their demographics, preoperative radiographic findings, preoperative magnetic resonance imaging (MRI) findings, arthroscopic findings and procedures performed, the patient's medical history, and the postoperative clinical course were retrospectively reviewed. There were 9 male and 10 female patients with average age of 61.9 years (range, 41 to 83 yrs). The average number of joint aspirations before surgery was 5.4. The average time from onset to arthroscopy was 10 months. Radiographs showed 2 knees with isolated lateral compartment osteoarthritis (OA), one with isolated patellofemoral (PF) OA, 14 with medial and lateral compartment OA, and 2 with tricompartmental OA. Classifying them according to the dominant compartment, 6 knees were medial-dominant OA, 11 lateral-dominant OA, and 2 PF-dominant OA. The MRI scans revealed 18 grade III lateral menisci and 1 grade II lateral menisci. Even with 6 medial-dominant OAs, lateral meniscal involvement was more obvious than medial meniscal involvement on MRI. Subtotal lateral meniscectomy accompanied with coagulation of the bleeding points was performed on 17 cases. For 2 PF OA cases, synovectomy and a histologic examination of synovium were performed. Remission was obtained for 18 cases. The unsuccessful case had cirrhosis of the liver. A majority of the patients (17 of 19) had degenerative torn lateral menisci confirmed with MRI and at arthroscopy. Successful outcomes were achieved by meniscectomy and coagulation. Most so-called spontaneous recurrent hemarthroses in OA knee joints appear to be attributable to torn lateral menisci. Level IV, therapeutic case series.
    To evaluate the clinical outcomes of a new arthroscopic procedure, arthroscopic posteromedial release (PMR), and its potential use as a treatment option for medial-type osteoarthritic (OA) knees. Retrospective analysis of clinical... more
    To evaluate the clinical outcomes of a new arthroscopic procedure, arthroscopic posteromedial release (PMR), and its potential use as a treatment option for medial-type osteoarthritic (OA) knees. Retrospective analysis of clinical outcomes of a case series. Knees with medial-type OA and flexion contracture were treated with PMR. They were classified using the Kellgren and Lawrence (K/L) radiographic grading system and classified using magnetic resonance imaging (MRI) into smooth (S) or irregular (IR) groups, based on the subchondral contour of the medial femoral condyle. Clinical outcome was evaluated using the Japanese Orthopaedic Association knee score (JOA score), verbal rating scale (VRS), and patient satisfaction. Fifty-two patients with 58 OA knees were included in the study. The mean age of the patients at the time of surgery was 71.6 years, the average ROM was from 13 degrees to 129 degrees , and the average follow-up period was 3.3 years. Most of the knees were classified as K/L grade III or IV. Overall, the average JOA score improved to 71.6 points from 56.3 points preoperatively. VRS scores decreased in most patients, and 76% of patients were satisfied at their last follow-up. The JOA score of the K/L grade III knees improved to 76.9 from 60.4 points preoperatively and that of the K/L grade IV knees improved to 69.5 from 55.3 points. The improvement in JOA score was less for the IR group, from 54.5 to 66.2 points, than for the S group, from 62.3 to 79.6 points. Five knees from the IR group and 1 from the S group were converted to total knee arthroplasty. Knees with relatively advanced OA, for which arthroscopic debridement has conventionally been contraindicated, can be treated with PMR if they are selected properly based on MRI findings. Level IV, case series.
    The purpose of this study was to further our understanding of the normal appearance of the popliteomeniscal fasciculi (PMF) on MRI after the determination of finely tuned imaging parameters. For this purpose we performed the study in two... more
    The purpose of this study was to further our understanding of the normal appearance of the popliteomeniscal fasciculi (PMF) on MRI after the determination of finely tuned imaging parameters. For this purpose we performed the study in two stages. Stage I was to determine suitable parameters for depicting the popliteomeniscal fasciculi. Stage II was to classify the "normal" image. The findings presented in this article will contribute to the understanding of the normal appearance of the popliteomeniscal fasciculi on MRI, and of the degree of variation of this structure among the population.