Joint Gap Width Research Articles

The medial knee gap measured on ultrasound images is wider during a valgus stress test compared to the anterior medial knee rotation test

AbstractObjectivesPatients with injuries to the deep fibers of the medial collateral ligament (dMCL) have a worse prognosis than patients with injuries to the superficial fibers (sMCL). The anterior medial (ANTMED) rotation test has been developed to differentiate between injuries to the dMCL and sMCL. The current study tested the hypothesis that the width of the medial knee gap would be greater during the valgus stress test than the ANTMED rotation test.MethodsFifty‐three participants were included in the study. Participants did not have a history of knee injury. Ultrasound images of the participants' medial knees were collected during the valgus stress test and the ANTMED rotation test. Repeated measures ANOVA was used to test differences in the medial knee gap between the tests, stress condition, and side.ResultsNo difference between the tests in the medial knee joint gap width in the no‐stress condition. The increase in the joint gap width was greater during the valgus stress test than the ANTMED rotation test. The medial knee gap increased during both the valgus stress (4.0 ± 0.12 mm) and the ANTMED rotation test (2.9 ± 0.12 mm).ConclusionsA greater increase in the medial knee gap was seen during the valgus stress test compared to the ANTMED rotation test. Knee external rotation increases the tension within the dMCL. Increased tension in the dMCL could explain the test differences in the increase in the joint gap found in the current study. The ANTMED rotation test may prove useful to identify injury to the dMCL.

RADIOLOGICAL ASSESSMENT OF KNEE JOINT WIDTH DIFFERENCES IN OLDER ADULTS WITH SYMPTOMATIC MEDIAL KNEE OSTEOARTHRITIS

Knee osteoarthritis (OA) is a degenerative articular disease. The knee joint space width (JSW) is used for grading the severity of knee OA. However, there is a lack of research on differences in the widths of knee joints between both lower limbs in unilateral OA. The purpose of this research was to examine the radiological difference in the affected knee joint and contralateral knee joint by analyzing unilateral older adults with medial knee OA using both knees’ JSW differences. Twenty-five subjects with unilateral medial knee OA participated. X-ray radiographs were used to assess knee JSW, and the paired [Formula: see text]-test was performed to assess the knee joint gap width between the affected side and the unaffected side in the respective medial and lateral sides. The independent [Formula: see text]-test compared the differences between the lateral and medial knee JSWs on the affected side and unaffected side. The paired [Formula: see text]-test did not show a significant difference in the medial and lateral knee JSW on the affected side compared to the unaffected side ([Formula: see text]; 0.11). Meanwhile, the independent [Formula: see text]-test revealed a significant difference between the affected and unaffected sides ([Formula: see text]). This study showed no significant changes in affected knee JSWs compared to unaffected sides, but the difference between the lateral and medial JSWs was significant between the knees affected and unaffected by OA in the older adults with medial knee OA.

Comparison of Joint Space Width Determinations in Grade I and II Knee Osteoarthritis Patients Using Manual and Automatic Measurements.

Background: Examination of the knee to assess the narrowing of the joint gap or joint space width (JSW) is commonly done by manually checking radiographs and measuring the JSW using a ruler.Objective: This study aims to compare manual and automatic measurements with the diagnosis of grade I and grade II knee osteoarthritis.Material and Methods: In this cross-sectional study, 40 patients with the criteria for primary osteoarthritis (OA), aged 46 to 65 years old had knee OA grades of either I or II. The knee image was evaluated by a computer program and a radiologist manually viewing and measuring the JSW joint gap using a ruler.Results: The results showed there were no differences in the measurement of JSW medial and JSW lateral manually in grade I and grade II knee OA, at p=0.605 and p=0.344, respectively. Whereas in the automatic measurements, there was a difference between JSW medial and lateral JSW in grade I and grade II knee OA, each with p<0.001. The manual JSW measurement between medial JSW and lateral JSW in grade I and II showed that the medial and lateral knee joints have a similar distance. In the automatic, the average value of measurement lateral JSW in OA grades I and II was greater than the medial JSW.Conclusion: Automatic measurements showed that both of medial and lateral JSW at grade II OA knee were narrower than the results at grade I. Automatic measurement of JSW results was more consistent than the manual measurement method.

Adaptive control of the filler wire rate during laser beam welding of squared butt joints with varying gap width

Adding filler wire control to autogenous laser beam welding of squared butt joints offers a means to widen up the tight fit-up tolerances associated with this process. When the gap width varies, the filler wire rate should be controlled to assure a constant geometry of the resulting weld seam. A dual mode sensing system is proposed to estimate the joint gap width and thereby control the filler wire rate. A vision camera integrated into the welding tool together with external LED illumination and a laser line projection enables two sensing modes, one surface feature extraction mode and one laser triangulation-based mode. Data from the both modes are fused in a Kalman filter, and comparisons show that the fusing of the data gives more robust estimation than estimates from each single mode. A feed-forward control system adaptively adjusts the filler wire rate based on the estimations of the joint gap width in front of the keyhole. The focus is on keeping the data processing simple and affordable, and the real-time performance of the sensor and control system has been evaluated by welding experiments. It is shown that the proposed system can be used for on-line control of the filler wire rate to achieve a constant weld geometry during varying joint gap widths.

A low-cost infrared sensing system for monitoring the MIG welding process

In this study, a low-cost infrared sensing system based on the analysis of the surface temperature distribution is proposed for monitoring the perturbations occurring during the aluminum alloy metal inert gas (MIG) welding process. A galvanometer scanner is employed in this real-time infrared sensing system to continually reflect the infrared energy to the point infrared sensor. By controlling the scanning mirror of the galvanometer scanner rotating in a high speed, the infrared energy at different points of the welding seam and the heat-affected zone on the surface of the plate will be continually captured by the point infrared sensor. Different conditions (changes in the welding speed, welding current, and joint gap width) of the welding process have been simulated to perturb the welding process. Three representative geometric defects such as undercut, humping, and lack of fusion were produced to validate our infrared sensing system. Experimental results showed that the sensing system is useful for monitoring perturbations that arise during the welding process and identifying welding defects.

Monitoring of Varying Joint Gap Width During Laser Beam Welding by a Dual Vision and Spectroscopic Sensing System

A vision and spectroscopic system for estimation of the joint gap width in autogenous laser beam butt welding is presented. Variations in joint gap width can introduce imperfections in the butt joint seam, which in turn influence fatigue life and structural integrity. The aim of the monitoring approach explored here is to acquire sufficiently robust process data to be used to guide post inspection activities and/or to enable feedback control for a decreased process variability. The dual-sensing approach includes a calibrated CMOS camera and a miniature spectrometer integrated with a laser beam tool. The camera system includes LED illumination and matching optical filters and captures images of the area in front of the melt pool in order to estimate the joint gap width from the information in the image. The intensity of different spectral lines acquired by the spectrometer has been investigated and the correlation between the intensity of representative lines and the joint gap width has been studied. Welding experiments have been conducted using a 6kW fiber laser. Results from both systems are promising, the camera system is able to give good estimations of the joint gap width, and good correlations between the signal from the spectrometer and the joint gap width have been found. However, developments of the camera setup and vision algorithm can further improve the joint gap estimations and more experimental work is needed in order to evaluate the robustness of the systems.

Distinctions of introarticular force distribution between genesis-II posterior stabilized and cruciate retaining total knee arthroplasty: An intraoperative comparative study of 45 patients

BackgroundAlthough both the posterior stabilized and cruciate retaining total knee arthroplasty have been proven to effectively relieve pain and restore basic functions, the joint gap width during flexion was reported to be different due to the presence or absence of posterior cruciate ligament, which may lead to different intra-articular force distribution. In this study, we investigated the distinctions in intra-articular force distribution between the two types of TKA designs in patients with varus knee osteoarthritis. MethodsForty five patients (50 knees) with varus knee osteoarthritis were prospectively included, with each 25 knees receiving cruciate retaining and posterior stabilized total knee arthroplasty, respectively. With an intra-articular force measurement system, the intra-articular force distribution with knee flexion at 0°, 30°, 45°, 60°, 90°, and 120° were recorded in all patients. FindingsThe total force was similar for posterior stabilized and cruciate retaining knees at all flexion degrees. However, force in the medial compartment accounted for 59.8%–84.0% of total force in posterior stabilized knees, while 27.4%–65.7% in cruciate retaining knees. In cruciate retaining knees, no significant difference was found between forces in the two compartments at 30° flexion (P=0.444), but force was significantly concentrated in the lateral side during 45°–120° flexion (P=0.000–0.028). InterpretationAlthough the entire intra-articular forces were similar between CR and PS knees at different flexion angles, medial part had higher force than lateral part when PS knee was used. The posterior cruciate ligament do a role in soft balance, and make the force more evenly distributed.

DIAGNOSTIC APPLICATION OF MULTIROW COMPUTED TOMOGRAPHY OF THE HIP JOINT OF JAPANESE QUAILS (COTURNIX JAPONICA)

The morphological assessment of selected parts of the hindlimb of Japanese quails (Temminck & Schlegel, 1849), with particular emphasis on hip joint structures, was performed, using a 128-row scanner (GE Optima Aquilion, Toshiba, Japan). Eight dead 3-month-old Japanese quails were evaluated. During intravital examination of those birds, no hindlimb abnormalities or locomotion disorders were detected. Bird body, which hip joints and other structures of hindlimbs were studied, was examined in posterioranterior position. The following hip joint structures, on both sides, were assessed in this study: hip joint gap width, acetabulum width, femoral head diameter, and femoral shaft width. The applied imaging method allowed accurate assessment of the selected structures. There was low variability between left and right hindlimbs and among individuals. Modern imaging techniques, such as multirow computed tomography (MCT) allows quick intravital assessment of normal and pathological structures of poultry bones and joints.

Lumbar Facet Joint Orientation in Degenerative Spondylolisthesis: The Role of Ethnic Variation in Asia Pacific—A Study from the AOSAP Research Collaboration

Introduction Degenerative spondylolisthesis (dSpl) can lead to various symptoms, including low back pain. Lumbar facet joint orientation has been reported to be associated with the development of dSpl. The role of ethnicity regarding facet joint orientation remains uncertain. As such, the following study was performed across a wide-ranging population base to assess the role of ethnicity in facet joint orientation in patients with dSpl in the Asia Pacific region. Materials and Methods A multinational, multiethnic cross-sectional image-based study was performed in 34 institutions in Asia Pacific, identifying 448 cases. Lateral standing X-rays and axial MRIs and/or CT scans were obtained for patients with lumbar dSpl. Magnitude of slip displacement, level of dSpl, and left/right facet joint angulation, width-curvature ratio, and gap width were noted on image assessment. Facet joint measurements were performed at each level from L3-S1. Gender, age, BMI, and ethnicity were also noted. Results The study included 389 patients with known ethnic origin (mean age: 61.4 years; 36.7% males, 63.3% females). The mean BMI was 25.6 kg/m2. The level of dSpl was most prevalent at L4/L5 (72.4%). There were 28.8% Indian, 28.5% Japanese, 17.5% Chinese, 8.2% Korean, 6.2% Thai, 4.6% Caucasian, 2.3% Filipino, 2.3% Malay, and 1.3 were of mixed Asian origin. Accounting for patient demographics and displacement, there was a statistically significant difference between ethnicity to that of left/right facet joint angulations, width-curvature ratios, and gap widths from L3-S1 between specific ethnic groups ( p &lt; 0.05). Conclusion This is the largest study to address the role of ethnicity upon lumbar facet joint orientation in dSpl. Ethnicity plays a role in facet joint orientation and may influence the occurrence and severity of dSpl or be a potential consequence. An understanding of ethnic variability may be one factor which assists in identifying those patients at risk of postsurgical development or progression of dSpl. Acknowledgments This study was funded by AOSpine Asia Pacific. Disclosure of Interest None declared

Seam Tracking Monitoring Based on Keyhole Features during High-Power Fiber Laser Welding

Seam tracking is an important field to obtain good welding quality. During the high-power fiber laser welding, the laser beam focus must be controlled to track the welding seam accurately. A method of detecting the offset between the laser beam focus and the welding seam based on analyzing the keyhole features was researched during high-power fiber laser butt-joint welding of Type 304 austenitic stainless steel plates at a continuous wave fiber laser power of 10 kW. The joint gap width was less than 0.1mm. An infrared sensitive high speed camera was used to capture the thermal images of a molten pool in welding process. Two parameters called the keyhole centroid and keyhole shape were defined as the eigenvalues of seam tracking offset to determine the offset between the laser beam focus and the desired welding seam. The welding experiments confirmed that the offset between the laser beam focus and the welding seam could be monitored and estimated by the keyhole centroid and keyhole shape parameters effectively.

Effect of ultrafine particles of activating fluxes on the laser welding process

It is established that use of activating flux superdispersed powders in laser welding of steels allows for improvement of the quality of welded joints, for reducing joint gap width and increasing penetration depth: in so doing, process productivity goes up by 7–45%.

Is the effect of a posterior cruciate ligament resection in total knee arthroplasty predictable?

It is broadly supposed that in total knee arthroplasty, the flexion/extension gap ratio is increased after resection of the posterior cruciate ligament (PCL). However, studies are rare and results are inconsistent. Therefore, this study was conducted to determine whether PCL release regularly increases the flexion gap. Data from 50 consecutive posterior stabilised knee prostheses were analysed retrospectively. Using imageless computer navigation, the joint-gap width was measured over the entire range of motion before and after PCL release. PCL release had no effect on the extension gap, but it increased the flexion gap significantly. An increase of >3 mm occurred in 36% of patients and of >5 mm in 12%. No clinically relevant effect (<2 mm) was found in 44% of patients. PCL release increased the flexion/extension gap ratio on average, but the individual effect could not be predicted. Therefore, we recommend PCL release before the femoral resections are performed, as this step mainly determines the ratio between extension and flexion gap.

Detection of seam tracking offset based on infrared image during high-power fiber laser welding

Seam tracking is a significant precondition to obtain good welding quality. During the laser welding, the laser beam focus must be controlled to follow the welding seam accurately. A novel approach to detecting the offset between the laser beam focus and the welding seam based on infrared image processing is investigated during high-power fiber laser butt-joint welding of type 304 austenitic stainless steel plates at a continuous wave fiber laser power of 10 kW. The joint gap width is less than 0.1 mm. An infrared sensitive high speed camera arranged in off-axis direction of laser beam is used to capture the dynamic thermal images of a molten pool. The characteristics of thermal distribution and infrared radiation of the molten pool, when the laser beam focus is deviated from the welding seam center, are analyzed. Two parameters called the keyhole morphological parameter and the heat accumulation effect parameter are defined as the characteristic values of seam tracking offset to determine the offset between the laser beam focus and the desired welding seam. Also, the image processing technique is used to analyze the infrared images of the molten pool, which indicates the presence of mathematic correlation between the defined two parameters and the seam tracking offset. The welding experiments confirm that the offset between the laser beam focus and the welding seam can be estimated by the keyhole morphological parameter and the heat accumulation effect parameter effectively.

Development of adaptive control system for alternating current pulsed metal inert gas welding parameters

A three-dimensional laser sensor is combined with an alternating current pulsed metal inert gas welding robot system to detect information about the variation of joint gap width and deviation of the joint position relative to the welding torch. Together with the joint tracking and torch direction adjustment, electrode negative polarity ratio and welding speed are also controlled adaptively according to the variation of joint gap width during welding. As a result, a high tolerance of joint gap variation is obtained and bead shape becomes more uniform and of reasonable quality in welding of aluminium alloy sheets.

Reduction of blowholes in high-speed arc welding of hot-dip galvanised steel sheets

Summary This paper describes an investigation of the blowhole formation mechanism and the substances causing blowholes during high-speed arc welding of galvannealed steel sheets extensively used in the chassis components of motor vehicles. Based on these results, it clarifies the effect of the shielding gas composition on suppression of zinc vaporisation and also examines suitable preventive measures. The results obtained may be summarised as follows: 1. Provided the organic substances adhering to the base material amount to around 1 mg/cm2, they are not the main cause of blowhole formation. 2. Even after thorough degreasing in such a way that the amount of organic substances present is equivalent to less than 1 in 500 parts of the zinc coating weight, numerous blowholes are formed to much the same extent as those found in the base material before degreasing. 3. The gas collected through the blowhole zone being broken apart reveals its main components to be hydrogen and hydrocarbons, including methane. Hydrogen is present at the level of around 1 in 10 parts of methane. 4. Sinewy traces of zinc are found in the blowhole origins of the root zone extending from the heat affected zone of sheet fit-up. A zinc concentration gradient is found on the blowhole face walls extending from these origins towards the bead surface. 5. On the basis of (1)-(4), there is little possibility of hydrogen being the cause of blowholes, which appear to be due to the vaporisation of zinc. 6. An oxygen-containing shielding gas promotes zinc oxidation and suppresses zinc vaporisation and is therefore effective for blowhole reduction. The optimum addition rate is around 5% for a shielding gas consisting of 80%Ar + 20%CO2 mixed gases. Oxygen addition is especially effective at a joint gap width of 0.2–0.4 mm. 7. Suitable selection of filler materials with a melting point below 1400°C intended to ensure that the weldpool temperature is kept low and the application of an oxygen-containing shielding gas are effective for blowhole reduction.

Influence of joint gap width on strength and fracture toughness of copper brazed steels

AbstractThe strength of brazed butt joints is commonly assessed in terms of the tensile performance of defect-free laboratory testpieces. In practice, brazed joints often contain crack-like defects which dominate the mechanical performance. The present work examines the strength and fracture toughness of copper brazed joints in steel. It is shown that the tensile strength of defect-free joints increases as the joint gap decreases and as the strength of the steel increases. Conversely, the fracture toughness is observed to decrease to a very low level as the joint gap decreases and as the strength of the steel increases. As a result, thin brazed joints are very susceptible to the presence of defects and, in practice, it is difficult to take advantage of the potential strength available. The reason for the relationship between toughness and joint gap is that toughness is determined by the extent of crack tip plasticity which, for a brazed joint, is controlled by the thickness of the braze metal.MST/1124

Influence of joint gap width on strength and fracture toughness of copper brazed steels

Influence of joint gap width on strength and fracture toughness of copper brazed steels