Aims We aimed to assess the reliability and validity of OpenPose, a posture estimation algorithm, for measurement of knee range of motion after total knee arthroplasty (TKA), in comparison to radiography and goniometry. Methods In this prospective observational study, we analyzed 35 primary TKAs (24 patients) for knee osteoarthritis. We measured the knee angles in flexion and extension using OpenPose, radiography, and goniometry. We assessed the test-retest reliability of each method using intraclass correlation coefficient (1,1). We evaluated the ability to estimate other measurement values from the OpenPose value using linear regression analysis. We used intraclass correlation coefficients (2,1) and Bland–Altman analyses to evaluate the agreement and error between radiography and the other measurements. Results OpenPose had excellent test-retest reliability (intraclass correlation coefficient (1,1) = 1.000). The R 2 of all regression models indicated large correlations (0.747 to 0.927). In the flexion position, the intraclass correlation coefficients (2,1) of OpenPose indicated excellent agreement (0.953) with radiography. In the extension position, the intraclass correlation coefficients (2,1) indicated good agreement of OpenPose and radiography (0.815) and moderate agreement of goniometry with radiography (0.593). OpenPose had no systematic error in the flexion position, and a 2.3° fixed error in the extension position, compared to radiography. Conclusion OpenPose is a reliable and valid tool for measuring flexion and extension positions after TKA. It has better accuracy than goniometry, especially in the extension position. Accurate measurement values can be obtained with low error, high reproducibility, and no contact, independent of the examiner’s skills. Cite this article: Bone Joint Res 2023;12(5):313–320.

Aims We analyzed the acetabular morphology of Crowe type IV hips using CT data to identify a landmark for the ideal placement of the centre of the acetabular component, as assessed by morphometric geometrical analysis, and its reliability. Patients and Methods A total of 52 Crowe IV hips (42 patients; seven male, 35 female; mean age 68.5 years (32 to 82)) and 50 normal hips (50 patients; eight male, 42 female; mean age 60.7 years (34 to 86)) undergoing total hip arthroplasty were retrospectively identified. In this CT-based simulation study, the acetabular component was positioned at the true acetabulum with a radiological inclination of 40° and anteversion of 20°. Acetabular shape and the position of the centre of the acetabular component were analyzed by morphometric geometrical analysis using the generalized Procrustes analysis. Results The acetabular shapes of Crowe IV hips were distinctively triangular; the ideal position of the centre of the acetabular component was superior on the posterior bony wall. The first and second relative warps explained 34.2% and 18.4% of the variance, respectively, compared with that of 28.6% and 18.0% in normal hips. We defined the landmark as one-third the distance from top on the posterior bony wall in Crowe IV hips. The average distance from the centre of the acetabular component was 5.6 mm. Conclusion Crowe IV hips are distinctively triangular; the point one-third from the top on the posterior bony wall was a useful landmark for placing the acetabular component.

Introduction Pelvic posterior tilt change (PPTC) after THA is caused by release of joint contracture and degenerative lumbar kyphosis. PPTC increases cup anteversion and inclination and results in a risk of prosthesis impingement (PI) and edge loading (EL). There was reportedly no component orientation of fixed bearing which can avoid PI and EL against 20°PPTC. However, dual mobility bearing (DM) has been reported to have a large oscillation angle and potential to withstand EL without increasing polyethylene (PE) wear against high cup inclination such as 60∼65°. Objective The purpose of this study was to investigate the optimal orientation of DM-THA for avoiding PI and EL against postoperative 20°PPTC. Methods Our study was performed with computer tomography -based three-dimensional simulation software (ZedHip. LEXI co. Japan). The CT data of hip was derived from asian typical woman with normal hips. Used prosthesises were 50mm cup and 42mm outer head of modular dual mobility system and Accolade II 127°(stryker). Femoral coordinate system was retrocondylar plane with z-axis from trochanteric fossa to intercondylar notch. Cup orientation was described as anatomical definition. The safe zone was calculated by the required hip range of motion which was defined as 130°flexion, 40°extension, 30°external rotation, and 50°internal rotation with 90°flexion and the maximum inclination of DM cup which was 60°in consideration of withstanding EL. Cup orientations withstanding 20°PPTC were defined as the primary cup orientation which changes consistently within the safe zone with the match of 20°PPTC. And among them cup orientation with lowest inclination was defined as the optimal cup orientation. result The optimal orientations could be identified only within stem anteversion from 15°to 40°. The relationship between the optimal cup orientation and stem anteversion could be automatically identified. The correlation between stem anteversion and cup anteversion was linearly distributed and could be expressed as an approximated line of the formula that (stem anteversion)+(cup anteversion)=36.8. And likewise the relationship between stem anteversion and cup inclination was curved-linerly distributed and could be expressed as an approximated curved line of the formula that (cup inclination)=0.04(stem anteversion) 2 2.18(stem anteversion)+74.8. Cup orientation calculated by the Widmer9s combined anteversion theory is easily deviated from the safe zone by PPTC. The optimal cup orientation calculated in this study could be set more inclination and retroversion than it calculated by the Widmer9s theory in contribution of large oscillation angle and admissibility of high inclination cup setting of DM. Therefore it could be possible to withstand 20°PPTC. Conclusion Performing THA with considering postoperative PPTC is necessary for good long term outcome without dislocation and PE wear. The solution for 20°PPTC after THA is to apply dual mobility bearing and the formula of combined orientation theory calculated in this study.

Background: Implantation of Kerboull acetabular reinforcement cross-plates (Kerboull plate) carries a risk for injury to vascular structures and pelvic organs. To our knowledge, there is no study assessing anatomical assessment related to this risk with this specific design. Therefore, we performed a prospective study to answer the following four questions: 1) What is the minimum distance and angle between the plate and iliac vessels? 2) What is the distance between the plate and the inner cortex of the ilium? 3) What is the ratio of views with muscle tissue present on the inner surface of the ilium? 4) What are the boundaries of the safe zone for transacetabular screw fixation for a Kerboull plate?Hypothesis: A safe zone for fixation screws would be defined by a narrow range of insertion angles.Materials and methods: This is a CT-based 3D templating prospective study. Simulations were performed for 18 patients fitted with a Kerboull plate. An original Kerboull plate (Stryker, Mahwah, NJ, USA) was placed at a 45 abduction angle relative to the X-axis (alignment A) and the palette was placed vertically to the X-axis (alignment B). We measured the distance from the centre of the plate to the inner surface of the cortex of the ilium, the shortest distance to vessels and the angle of existing vessels, and the ratio of muscles on the inner surface of the ilium.Results: The shortest distance to the vascular structures increased with increasing angle of insertion of the fixation screws, 85.8 +/- 12.1 mm for A and 111.4 +/- 12.0 mm for B at 45 degrees. The distance to the inner cortex was further increased for screws inserted in posterior direction. At insertion angles >= 40 degrees, the screws passed through muscle before invading the pelvis in most cases. However, at anterior-posterior angle (AP angles) <=-10 degrees, the risk of direct insertion of screws into the sacroiliac joint increased.Discussion: The safe zone for transacetabular screws would be insertion at an angle >= 40 degrees, with an AP angle between 0 degrees and 10 degrees (slight posterior direction). (C) 2016 Published by Elsevier Masson SAS.

Implantation of Kerboull acetabular reinforcement cross-plates (Kerboull plate) carries a risk for injury to vascular structures and pelvic organs. To our knowledge, there is no study assessing anatomical assessment related to this risk with this specific design. Therefore, we performed a prospective study to answer the following four questions: (1) What is the minimum distance and angle between the plate and iliac vessels? (2) What is the distance between the plate and the inner cortex of the ilium? (3) What is the ratio of views with muscle tissue present on the inner surface of the ilium? (4) What are the boundaries of the safe zone for transacetabular screw fixation for a Kerboull plate? A safe zone for fixation screws would be defined by a narrow range of insertion angles. This is a CT based 3D templating prospective study. Simulations were performed for 18 patients fitted with a Kerboull plate. An original Kerboull plate (Stryker, Mahwah, NJ, USA) was placed at a 45° abduction angle relative to the x-axis (alignment A) and the palette was placed vertically to the x-axis (alignment B). We measured the distance from the centre of the plate to the inner surface of the cortex of the ilium, the shortest distance to vessels and the angle of existing vessels, and the ratio of muscles on the inner surface of the ilium. The shortest distance to the vascular structures increased with increasing angle of insertion of the fixation screws, 85.8 ± 12.1 mm for A and 111.4 ± 12.0 mm for B at 45°. The distance to the inner cortex was further increased for screws inserted in posterior direction. At insertion angles ≥ 40°, the screws passed through muscle before invading the pelvis in most cases. However, at anterior-posterior angle (AP angles) ≤ −10°, the risk of direct insertion of screws into the sacroiliac joint increased. The safe zone for transacetabular screws would be insertion at an angle ≥ 40°, with an AP angle between 0° and –10° (slight posterior direction). Level IV prospective diagnostic study.

It has recently been reported that the transverse acetabular ligament (TAL) is helpful in determining the position of the acetabular component in total hip replacement (THR). In this study we used a computer-assisted navigation system to determine whether the TAL is useful as a landmark in THR. The study was carried out in 121 consecutive patients undergoing primary THR (134 hips), including 67 dysplastic hips (50%). There were 26 men (29 hips) and 95 women (105 hips) with a mean age of 60.2 years (17 to 82) at the time of operation. After identification of the TAL, its anteversion was measured intra-operatively by aligning the inferomedial rim of the trial acetabular component with the TAL using computer-assisted navigation. The TAL was identified in 112 hips (83.6%). Intra-observer reproducibility in the measurement of anteversion of the TAL was high, but inter-observer reproducibility was moderate. Each surgeon was able to align the trial component according to the target value of the angle of anteversion of the TAL, but it was clear that methods may differ among surgeons. Of the measurements of the angle of anteversion of the TAL, 5.4% (6 of 112 hips) were outliers from the safe zone. In summary, we found that the TAL is useful as a landmark when implanting the acetabular component within the safe zone in almost all hips, and to prevent it being implanted in retroversion in all hips, including dysplastic hips. However, as anteversion of the TAL may be excessive in a few hips, it is advisable to pay attention to individual variations, particularly in those with severe posterior pelvic tilt.

Mitsubishi Heavy Industries (MHI) has developed SOFC with tubular type cell stack since 1984. In this study, we report the current status toward commercialization of SOFC-GTCC power generation system at MHI. To Redox robustness of a cell stack, the sintering characteristics of interconnect was improved. To improve durability of cell stack, long-term change of the electrochemical characteristics had been measured, and analyzed the interface of cathode and electrolyte by SIMS. For compact module, the packing density of the cell stack was increased from 400 to 700 stack/m2, and confirmed I-V characteristics and the temperature distribution of improved module. The generation performance of improved module is roughly comparable to that of conventional type module, and the temperature distribution is also roughly agreement of simulation result.

SOFC is able to attain extremely high efficiency over 70% as LHV, as gas turbine combined cycle system. Mitsubishi Heavy Industries (MHI) has been developing SOFC since 1984. Based on developed technologies, now MHI is on the step of integrating SOFC power generation system. MHI has improved the components and the control technology for the combined cycle system, that is, improvement of cell stack, verification of pressurized operation and control of SOFC module and the combustor for low- calorie fuel. In 2006, MHI managed to operate the combined cycle system with maximum combined power output of 75kW, for the first time in Japan. And now, MHI is ready to manufacture a 200kW class SOFC-MGT combined cycle system, which will be operated in 2007.

Some aspects of the early collapse biomechanics of the segmentally necrotic adult human femoral head were studied, using a small-deformation plane strain, elasto-plastic finite element model. The computational procedure used was based upon the initial stress technique, and permitted study of stress and strain fields and of the progression of failure regions as a function of incrementally applied joint loads. The results consistently demonstrated both subchondral and deep cancellous failure patterns similar to those seen clinically. There was a clear distinction, however, between these two failure regimes, dependent primarily upon the relative strength deficits input for the subchondral versus the deep cancellous regions. Usually, the failure zone was appreciable only at significantly supra-physiological loads, reflecting the likely importance of fatigue events in the clinical collapse process. Although subchondral failure was always limited to the entire base region of the infarction wedge, the zones of deep failure varied considerably with changes in lesion geometry, usually being concentrated within the infarct near the underlying necrotic/viable interface.

OBJECTIVESTo clarify the initial onset time of osteonecrosis after the start of steroid treatment and its relation to the onset of abnormal lipid metabolism.METHODSAnimal models were prepared by administering methylprednisolone to rabbits using five different steroid regimens.RESULTSA single, acute ischaemic event suggested by the frequency, size or number of necrotic foci within the proximal femur was not different among the groups. Histological evidence of osteonecrosis first occurred 1-2 weeks after initial steroid administration. At the same time there were significantly abnormal elevations in serum lipids, which persisted for between 1 and 2 weeks after the initial corticoid treatment. Triglycerides, total cholesterol and free fatty acids were markedly elevated in all groups; these lipid abnormalities were significantly present in the rabbits with osteonecrosis but not in the rabbits without osteonecrosis.CONCLUSIONSThis study shows that (i) osteonecrosis appears in rabbits shortly after corticoids are first administered, and (ii) osteonecrosis in rabbits is chronologically associated with the onset of hyperlipaemia and increased free fatty acids. This supports the occurrence of intraosseous fat embolism as a cause of osteonecrosis.

BACKGROUND:Nonunions of a juxta-articular lesion with bone loss, which represent a challenging therapeutic problem, were treated using external fixation and distraction osteogenesis. METHODS:Seven juxta-articular nonunions (five septic and two aseptic) were treated. The location of the nonunion was the distal femur in four patients, the proximal tibia in one patient, and the distal tibia in two patients. All of them were located within 5 cm from the affected joints. Preoperative limb shortening was present in six cases, averaging 2.9 cm (range, 1-7 cm). The reconstructive procedure consisted of refreshment of the nonunion site, deformity correction, stabilization by external fixation, and lengthening to eliminate leg length discrepancy or to fill the defect. Shortening-distraction was applied to six patients and bone transport to one patient for reconstruction. Intramedullary nailing to reduce the duration of external fixation was simultaneously performed in two cases. All the patients had at least 1 year of follow-up evaluation. RESULTS:Osseous union without angular deformity or leg length discrepancy greater than 1 cm was achieved in all patients. The mean amount of lengthening was 5.8 cm (range, 2.2-10.0 cm). The mean external fixation period was 219 days (range, 98-317 days), and the mean external fixation index was 34.4 days/cm (range, 24.5-47.6 days/cm). All patients reported excellent pain reduction. There were no recurrences of infection in five patients with prior history of osteomyelitis. The functional results were categorized as excellent in two, good in three, and fair in two. CONCLUSION:Despite the length of postoperative external fixation, distraction osteogenesis can be a valuable alternative for the treatment of juxta-articular nonunions.

Deformity combined with shortening of 18 lower limb segments of 17 patients was treated with the Ilizarov method. Limb lengthening was done at the same treatment (monofocal treatment) or a separate osteotomy (bifocal treatment) was done after acute or gradual correction of the deformity using the Ilizarov hinge system. The external fixation time, amount of deformity correction, length gained, and incidence of complications were examined. Results were compared between monofocal versus bifocal treatment groups and between femoral versus tibial procedures. The average deformity corrected was 22.3 degrees, and the average lengthening was 44.4 mm. The external fixation index was 49.3 days/cm on average, ranging from 24.4 to 90 days/cm, and the mean duration of external fixation was 198 days, ranging from 77 to 352 days. Major complications requiring surgical treatment, such as premature consolidation and fracture, were seen in four patients. There were no statistically significant differences between the results for monofocal and bifocal treatment or treatment indices for femoral and tibial operations. The Ilizarov method was very effective for treatment of limb deformity combined with shortening. Monofocal treatment might be better if the total amounts of lengthening required are short to reduce surgical invasion. Longer treatment indices for tibial operations could not be verified from the current study.

OBJECTIVE:We investigated apoptosis, i.e., programmed cell death, in steroid induced osteonecrosis in a rabbit model.METHODS:Forty-four adult Japanese White rabbits were divided into 3 groups: Group A were untreated controls and had a subsequent 8 week no-treatment period; Group B received intramuscular injection of methylprednisolone 4 mg/kg once weekly for 4 weeks; and Group C received the same treatment and had a subsequent 8 week no-treatment period. At the end of each period, all animals were sacrificed and tissue samples were obtained from the femur and humerus for histopathologic examination. Terminal deoxynucleotidyl transferase (TdT) mediated deoxyuridine triphosphate (dUTP) biotin nick end labeling (TUNEL) was used to detect fragmented DNA known to be associated with apoptotic cell death.RESULTS:Group A rabbits did not develop osteonecrosis-like lesions (ONL) in the femur and humerus, and few TUNEL positive cells were observed in bone marrow cells. In Group B, ONL developed in 11/15 rabbits, and many TUNEL positive cells were found in the area surrounding ONL. In Group C, ONL were found in 6/10 rabbits, but only a few TUNEL positive cells were present around the lesion.CONCLUSION:These findings revealed that apoptosis occurs in the early stage of steroid induced osteonecrosis.

A new type of electrode has been prepared by the coating method from a solution mixture of polyaniline(PANI) and V2O5. The composite electrode exhibited high capacity density of 200 mAh cm−3, favorable redox activity explainable by the bi-ion-transfer mechanism, and high redox stability against the over-discharging. This result was supported from X ray diffraction patterns of the composite electrode.

We have newly developed multi-porous sheets fabricated from chemically polymerized polyaniline which are applicable for positive electrodes of ion rechargeable batteries. We have also developed novel multi-porous sheets for negative electrodes made of carbon material which are derived from synthetic organic polymer. Both sheets fabricated to have an area of maximum 1000cm2 and thickness of 0.3-3.0mm are reinforced by synthetic short fiber.Because of fiber-reinforcement, these sheets show excellent mechanical properties and easy handling in spite of their high porosity. The polyaniline positive electrodes have been combined with the carbon negative electrodes to produce high energy density cells having excellent cycle life and a high working voltage. Preliminary prototype CR 2016 cells made of these electrodes in welded steel can have demonstrated up to 17 mWh/cell.

Complexes of polyaniline (PANI) with various organic r-electron acceptors such as TCNQ and others were prepared by the automatic doping method. The relationship between current and applied voltage was linear and ohmic in argon atmosphere at voltages below 5 V, but in air it was non-linear. A field-effect current was observed at PANI-chloranil complex on silicon substrate.

Electrochemical doping of polyaniline (PANI) can be carried out in solid polymer electrolyte (SPE) with a high ionic conductivity, 4 × 10−5S/cm. Cyclic voltammograms on PANI in SPE are different from those in liquid electrolyte solutions. Dependency of cyclic voltammograms on the conditions such as type and concentration of supporting electrolyte or the potential applied suggests the existence of two types of doping processes derived from the different solvation effect.

In in situ measurements of ESR during electrochemical doping in polyaniline, the maximum spin density is observed at 3.25 V. ESR linewidth decreases upon doping, but after exhibiting a minimum value at 3.5 V, it increases again, tending to saturation. On the other hand, in situ conductivity measurement demonstrates the maximum value (1.6 S/cm) at around 3.5 V. Taking into consideration the complex absorption spectral change upon doping, the results are discussed in terms of polaron and bipolaron models. At higher doping levels, suppression of the interchain transfer of polaronic species due to Coulomb interaction is introduced to explain the decrease of conductivity.