Analyzing the precision of JSW measurements using 3D scans and statistical models

One of the methods to diagnose rheumatoid arthritis (RA) is measuring joint space narrowing over time. A method is presented to analyze the sensitivity of this measurement to positioning of the hand. Micro-CT scans are used to generate projections of a joint under varying angles of rotation. A semi-automatic method is used to measure the joint space width (JSW) for each projection. A Statistical model is used to investigate whether the rotation can be detected from a 2D radiograph. It is shown that rotation of the hand has a significant influence on the measured JSW

In vivo contact stresses at the radiocarpal joint using a finite element method of the complete wrist joint

A small number of cadaveric studies have been carried out looking at the force transmission through the radiocarpal joint. In this study subject specific finite element models were created of the whole wrist joint using measured biomechanical data to capture the forces acting on the wrist with the hand generating a maximum gripping force

Segmentation of Radiographs of Hands with Joint Damage Using Customized Active Appearance Models

This paper is part of a project that investigates the possibilities of automating the assessment of joint damagein hand radiographs. Our goal is to design a robust segmentationalgorithm for the hand skeleton. The algorithm is\ud based on active appearance models (AAM) [1], which have been used for hand segmentation before [2]. The results will be used in the future for radiographic assessment of rheumatoid arthritis and the early detection of joint damage. New in this work with respect to [2] is the use of multiple object warps for each individual bone in a single AAM. This method prevents modelling and reconstruction defects caused when warping overlapping objects. This makes the algorithm more robust in cases where joint damage is present. The current implementation of the model includes the metacarpals, the phalanges, and the carpal region. For a first experimental evaluation a collection of 50 hand radiographs has been gathered. The image data set was split into a training set (40) and a test set (10) in order to evaluate the algorithm’s performance. First results show that in 8 images from the test set the bone contours are detected correctly within 1.3 mm (1 STD) at 15 pixels/cm resolution. In two images not all contours are detected correctly. Possibly this is caused by extreme deviations in these images that have not yet been incorporated in the model due to a limited training set. More training examples are needed to optimize the AAM and improve the quality and reliability of the results

Quantitative sensory testing in painful hand osteoarthritis demonstrates features of peripheral sensitisation.

Hand osteoarthritis (HOA) is a prevalent condition for which treatments are based on analgesia and physical therapies. Our primary objective was to evaluate pain perception in participants with HOA by assessing the characteristics of nodal involvement, pain threshold in each hand joint, and radiological severity. We hypothesised that inflammation in hand osteoarthritis joints enhances sensitivity and firing of peripheral nociceptors, thereby causing chronic pain. Participants with proximal and distal interphalangeal (PIP and DIP) joint HOA and non-OA controls were recruited. Clinical parameters of joint involvement were measured including clinical nodes, VAS (visual analogue score) for pain (0-100 mm scale), HAQ (health assessment questionnaire), and Kellgren-Lawrence scores for radiological severity and pain threshold measurement were performed. The mean VAS in HOA participants was 59.3 mm ± 8.19 compared with 4.0 mm ± 1.89 in the control group (P < 0.0001). Quantitative sensory testing (QST) demonstrated lower pain thresholds in DIP/PIP joints and other subgroups in the OA group including the thumb, metacarpophalangeal (MCPs), joints, and wrists (P < 0.008) but not in controls (P = 0.348). Our data demonstrate that HOA subjects are sensitised to pain due to increased firing of peripheral nociceptors. Future work to evaluate mechanisms of peripheral sensitisation warrants further investigation

Trust, Organizational Controls, Knowledge Acquisition from the Foreign Parents, and Performance in Vietnamese International Joint Ventures

Successful adaptation in strategic alliances "calls for a delicate balance between the twin virtues of reliability and flexibility" [Parkhe 1998]. On one hand, the joint venture must be flexible enough to respond to the uncertainties of competitive business environments because it is not feasible to plan for every possible contingency. Yet, on the other hand, unfettered flexibility invites dysfunctional behavior, such as opportunism and complacency. This delicate balance accompanies a parallel balance between trust and control of the joint venture. The primary goal of this study is to empirically examine this relationship in the context of Vietnamese international joint ventures (IJVs) by building on the model of knowledge acquisition and performance in IJVs established by Lyles and Salk [1996]. This study makes three major contributions to the literature. First it confirms several findings of the original Lyles and Salk study [1996]. Second, we strengthen Lyles and Salk's original model by incorporating multiple measures of both interorganizational trust and control as independent variables. Finally, this study represents one of the first in-depth examinations of business in the emerging Vietnamese economy.http://deepblue.lib.umich.edu/bitstream/2027.42/39713/3/wp329.pd

A Three-dimensional Finger Motion Measurement System of a Thumb and an Index Finger Without a Calibration Process

Various wearable systems have been investigated to measure hand motion, but some challenges remain. Many systems require a calibration process to map sensor signals to actual finger joint angles by the principle of measuring the length change of the finger, or bending sensors. Also, few studies have investigated how to measure thumb motion accurately using the wearable systems. This paper proposes an exoskeleton system with linear Hall sensors to measure three-dimensional hand motion without a calibration process. The calibration process is avoided by measuring finger joint angles through an absolute rotation measurement. A new wearing method with lower parts underneath the hand joints and rubber bands is proposed to fix the structure to the hand and adapt it for various hand sizes. As the thumb has a complex biomechanical feature at carpometacarpal (CMC) joint, a new measuring method of the CMC joint is proposed to directly calculate the orientation of the metacarpal. The prototype of the thumb and index finger was manufactured, and the performance was verified experimentally by using an optical motion capture system