Serial Wrist Research Articles

Time-Dependent Change in Carpal Tunnel Cross-Sectional Area and Transverse Carpal Ligament Thickness Using Serial Magnetic Resonance Imaging Studies—An Anatomical Study

Idiopathic carpal tunnel syndrome (CTS) is a common compressive neuropathy. Aging and female sex are risk factors, but the reasons are unclear. The purpose of this study was to evaluate whether identifiable radiographic changes resulting in a decrease in carpal tunnel area (CTA) over time exist. A database search of a multicenter, academic, tertiary institution from 1998 to 2021 identified 433 patients with serial wrist magnetic resonance images (MRI) at least 5 years apart. Fifty-six met the inclusion criteria with adequate films to measure CTA and transverse carpal ligament (TCL) thickness at the same slice location-the carpal tunnel inlet, hook of the hamate, and carpal tunnel outlet-independently by two observers who were blinded to each other's measurements. Rates for the change in CTA and TCL thickness were calculated at all three locations. Thickness of the TCL increased, whereas that of the CTA decreased over time. Inlet CTA decreased by 0.9 mm2 per year (95% CI: 0.34-1.5), outlet CTA decreased by 1.8 mm2 per year (95% CI: 1.2-2.5), and CTA at the hook of the hamate decreased by 1.6 mm2 per year (95% CI: 1.0-2.0 per year). The TCL thickened by 0.02 mm per year at all three sections. Taller patients had a decreased rate of CTA loss. In this select cohort, TCL thickened and CTA decreased with time. TCL thickening accounted for about half of the variation in CTA, suggesting that this is a possible contributor to this change. Hypertrophy of the carpal tunnel floor may account for the remaining variation in CTA. The question of whether these results are reliable and generalizable to the general population, or a major influence in the pathophysiology of CTS, is unknown. Small decreases in CTA and thickening of the TCL occur with aging. Whether this is a contributing factor in the development of CTS requires further study.

Wrist function recovery course in patients with scaphoid nonunion treated with combined volar bone grafting and a dorsal antegrade headless screw

BackgroundSurgical treatment is necessary for scaphoid nonunion. Open surgery with a combined volar and dorsal approach is thought to have poor functional outcomes and a prolonged recovery course. However, the detailed recovery course for this approach is rarely reported. The aim of this study was to investigate the recovery course and radiographic outcome for patients with scaphoid nonunion who underwent a combined volar bone grafting and dorsal antegrade headless screw approach.Material and methodsEighteen patients with scaphoid nonunion who underwent combined volar bone grafting and dorsal antegrade headless screw fixation were enrolled in this retrospective study. Preoperative and serial postoperative wrist functional and radiographic outcomes were collected and analysed.ResultsAll 18 patients achieved bone union at a mean time of 14.3 weeks. Compared to the preoperative status, the grip strength, wrist motion arc, and Mayo Wrist score were improved significantly 6 months after surgery, whilst the Disabilities of the Arm, Shoulder, and Hand (DASH) score did not recover until 12 months after surgery. Significant improvements were found in all scaphoid radiographic parameters.ConclusionThe surgical outcomes for scaphoid nonunion treated with a combined volar bone grafting and dorsal antegrade headless screw achieved a high union rate, with great wrist functional and radiographic outcomes. The earliest recovered wrist functional parameters were grip strength, motion arc, Mayo Wrist score and finally the DASH score at postoperative 6 months and 12 months, respectively.

Intrarater Reliability of Range of Motion Measurements of the Uninjured Wrist in Women After Distal Radius Fracture.

To determine the intrarater reliability of serial wrist and forearm range of motion (ROM) measurements of the uninjured limb, by 1 evaluator using a standardized technique of measurement, in women who have sustained a distal radius fracture. From December 2007 to December 2014, skeletally mature women who had sustained an isolated distal radius fracture routinely had sequential measurements of wrist extension and flexion as well as forearm supination and pronation in both their injured and their uninjured limbs, at a minimum of 3-week intervals. The senior author (G.H.F.J.) used a standardized technique of measurement of ROM throughout this period, and these data related to the uninjured wrist and forearm were retrospectively reviewed. Of 508 women who had a distal radius fracture, 506 had the measurements made of the uninjured wrist and forearm on 2, 300 on 3, and 128 on 4 separate occasions. The average age of the women was 61 years, with a range from 16 to 94 years. The intraclass correlation coefficients between measurements over time for extension, flexion, and supination measurements were 0.71, 0.63, 0.68, respectively, and 0.47 for pronation. The intraclass correlation coefficient varied according to patient age, but without specific progression in any age group for any ROM. Extension, flexion, and supination decreased significantly as age increased, whereas forearm pronation did not. Measurement of wrist and forearm motion of the uninjured limb can be reliably reproduced by a single rater, most so for extension, flexion, and supination, and less so for pronation. Interrater reliability assessment remains to be evaluated. Given the intrarater reliability of wrist and forearm motion measurement, the opposite (uninjured) wrist probably represents a useful reference metric for motion restoration for recovery from injury to the opposite limb.

Design and characterization of the OpenWrist: A robotic wrist exoskeleton for coordinated hand-wrist rehabilitation.

Robotic devices have been clinically verified for use in long duration and high intensity rehabilitation needed for motor recovery after neurological injury. Targeted and coordinated hand and wrist therapy, often overlooked in rehabilitation robotics, is required to regain the ability to perform activities of daily living. To this end, a new coupled hand-wrist exoskeleton has been designed. This paper details the design of the wrist module and several human-related considerations made to maximize its potential as a coordinated hand-wrist device. The serial wrist mechanism has been engineered to facilitate donning and doffing for impaired subjects and to insure compatibility with the hand module in virtual and assisted grasping tasks. Several other practical requirements have also been addressed, including device ergonomics, clinician-friendliness, and ambidextrous reconfigurability. The wrist module's capabilities as a rehabilitation device are quantified experimentally in terms of functional workspace and dynamic properties. Specifically, the device possesses favorable performance in terms of range of motion, torque output, friction, and closed-loop position bandwidth when compared with existing devices. The presented wrist module's performance and operational considerations support its use in a wide range of future clinical investigations.

Spherical wrist dimensional synthesis adapted for tool-guidance medical robots

The objective of this article is to present the dimensional synthesis of serial and parallel spherical wrists, an important step in the design process of medical robots. This step is carried out to obtain optimal dimensions of tool-guidance medical robots. With this goal, we have first studied the specifications of two robots with different medical applications: one for tele-echography examination and one for minimally invasive surgery. Then, we have established that the medical needs expressed by the doctors were very different but the specifications in robotic terms have a lot of common points (kinematics, workspace, bulkiness). For both applications studied, robots need a mobility of three rotations around a fixed point (probe contact point on the patient’s skin or trocar incision). So, a spherical wrist architecture is adapted to their needs. An important constraint related to medical applications is that the robot must be compact in order to not obstruct or collide with its environment (medical personnel or patient). We perform dimensional synthesis allowing determination of dimensions of the mechanism for serial and parallel spherical wrists, for a tele-echography robot, and a serial wrist for a minimally invasive surgery robot. We use multi-criteria optimization methods minimizing a cost function to obtain both good kinematic performance and compactness for the architecture. The difficulty/challenge of this design process, depending of the studied applications, is the choice of efficient criteria describing the performances and the constraints of the robot. The design variables must faithfully represent the specifications of the robot so that its performance can respond to the medical requirements. We show, here, the different methods used for optimizing the chosen kinematic architecture for the particular medical application. These studies lead to prototypes which are validated after medical experiments. This process of dimensional synthesis will be applied to other medical applications with different sets of specified constraints.

Dynamic model of an overconstrained PKM with compliances: The Tripteor X7

This paper deals with dynamic modeling of a parallel kinematic machine tool: the Tripteor X7. This machine has a hybrid kinematic, so it presents a serial wrist attached to an overconstrained parallel unit. Two dynamic models are proposed in this paper. The first one is built with only rigid bodies. It aims at identifying the inertial parameters and those of the movement transformation devices. In the second model, joints and legs compliances are introduced. This model is then used to study the impact of elements deformations on the generated surfaces. All this simulations are compared to experimental measurements realized directly on the Tripteor. Highlights? Overconstraint Parallel Kinematic Machine tool. ? Dynamic model of PKM for machining simulation. ? Tripteor X7 Parallel Kinematic Machine tool (PKM) for High Speed Machining (HSM).

Design Process of a Robotized Tele-Echography System

This paper deals with the design process of a particular mechatronic system: a tele-echography robot. First, we describe the principle of robotized tele-echography and the prototypes already designed. Then, after having chosen the design process, we show two medical gestures analysis performed to define the required specifications of a tele-echography robot. Several kinematic synthesis allow demonstrating that the serial spherical wrist is the most adapted structure to this medical application. The kinematic performance of this structure is limited by the singularity position located at the centre of the workspace. An inclined spherical wrist structure is proposed to displace the singularity position in a less used workspace zone that the normal direction to the patients skin. In the dimensional synthesis phase, this structure is optimized. Then, a collaborative design study with designers is presented to improve aesthetic and ergonomic of the robot. This step was very interesting because it brought innovative propositions. Finally, a detailed phase allows defining the PROSIT 1 robot. It was manufactured and will be soon tested in clinical environment.

Learning the forward kinematics behavior of a hybrid robot employing artificial neural networks

SUMMARYHybrid robots, composed of a parallel platform and serial wrist, achieve a compromise of stiffness and dexterity. Thus, they are well suited for applications such as aircraft component machining and automotive assembly, where high accuracy and large workspace movements are required. However, their forward kinematics can be highly coupled and be nonlinear. To reduce the time required to define the forward kinematics of a robot with parallel–serial structure, this paper introduces the use of neural networks. Two radial basis function networks are trained to learn the parallel and serial kinematics separately, and then integrated into a complete model. The error of this network model is analyzed and identified by a particle swarm optimization algorithm. Simulation and experiment results are obtained from the hybrid robot, Exechon, which shows that the developed kinematic model is able to produce accurate position and orientation estimates of the end-effector. The computation time of the neural network model is greatly reduced when compared to the time achieved by the numerical model.

Mapping similarity between parallel and serial architecture kinematics

First the principles of mapping spatial points to surfaces is introduced in the context of the inverse kinematics of a general six revolute serial wrist partitioned robot. Then the advantage of choosing ideal frames is illustrated by showing that in the case of some architectures an image space formulation, though possible, may be an impediment to clear geometric insight and a satisfactory and much simpler solution. After showing how the general point mapping transformation is reduced to classical Blaschke-Grunwald planar mapping a novel three legged planar robot’s direct kinematics is solved in image space and then using conventional “distance” constraints. The purpose is to show why the latter approach yields spurious solutions and how the displacement pole rotation performed with kinematic mapping reliably avoids this problem. In conclusion certain other new and/or interesting reduced mobility parallel robots are discussed briefly to point out some advantages and insights gained with an image space approach. Particular effort is made to expose in detail how mapping simplifies and extends the solution of direct kinematics pertaining to Calvel’s “Delta” 3D translational robot.

A gravitational deflection compensation strategy for HPKMs

Hybrid parallel kinematic machines (HPKM) are prone to structural deflection under the influence of gravity, both in the serial wrist joints and in the upper tripod structure. The deflection results in errors at the tool tip, leading to manufacturing inaccuracies and performance outside the manufacturer's quoted accuracy. To further increase the take-up of HPKMs robust online compensation strategies are required that return and maintain the HPKM to the quoted accuracy level under production conditions. This paper addresses the problem of mass-induced errors in the positional accuracy of hybrid parallel kinematic machines (HPKMs) and describes the development of a novel robust polar compensation methodology for the reduction of these errors. The strategy developed significantly reduces the level of error observed. A full implementation of the gravitational error compensation strategy on the Neos Robotics TR600 at the University of Nottingham has seen the measured system’s gravitational error reduced by 70% and the system performance returned to the quoted manufacturer’s accuracy level.

Dynamics of a Class of Parallel Wrists

This paper presents a dynamic model of parallel wrists with all links constrained to have a spherical motion with the same center. The model can also be applied to serial wrists. The model, based on Lagrangian formulation of dynamics, exploits the feature that all the links have the same fixed point. Three parameters defining the platform orientation are used as generalized coordinates. This choice allows the use of the generalized inertia matrix (GIM) appearing in the model to calculate effective dynamic performance indices proposed in a previous paper. The model can solve both the direct and the inverse dynamic problems. It also contains the Jacobian matrix useful to characterize the kinematic behavior of parallel manipulators. By the model it is shown that the best performances are reached in the workspace regions where the manipulator has a good kinematic and dynamic isotropy, whereas the incidence of nonlinear forces on performances is relevant at high end-effector speed. A numerical example is provided.

Longitudinal radiographic analysis of rheumatoid arthritis in the hand and wrist

Purpose: To assess the longitudinal radiographic osseous changes of the wrist and hand other than interphalangeal joints in rheumatoid disease. Methods: Serial wrist and hand x-rays in 96 patients with long-standing rheumatoid disease were reviewed. The average number of years between initial and most recent x-rays was 15.1. The Larsen scoring system was used to assess the degree and severity of joint involvement. We identified patterns of involvement in the wrist, thumb, and finger metacarpophalangeal (MCP) joints. Results: The radioscaphoid and radiolunate joints had the earliest and most severe progression of all joints studied. Scaphoid erosions often were seen early (27%) and their presence was a predictor of progressive involvement. Ulnar styloid erosions commonly were seen as early isolated findings (25%). The distal radioulnar joint showed a rapid increase in Larsen score and was involved in 78% of patients on late x-rays. The thumb showed considerable late MCP joint disease that often led to boutonniere deformity and the trapeziometacarpal joint had the least rate of progression of all joints studied. The most severely and frequently involved MCP joints were the radial (index and middle), which also had the greatest increase in score over the span of the study. Finger MCP joint disease was observed to progress temporally in a predictable pattern: first radial MCP joints of the dominant hand, followed by the nondominant radial MCP joints, and last the ulnar MCP joints of the nondominant hand with small finger involvement preceding that of the ring finger. Of all MCP joints, the ring finger was least affected. Conclusions: This study clarified the longitudinal osseous radiographic changes of the wrist and hand (excluding interphalangeal joint) in rheumatoid disease. (J Hand Surg 2003;28A:427-434. Copyright © 2003 by the American Society for Surgery of the Hand.)

Planar Translational Cable‐Direct‐Driven Robots

AbstractWe present the simulated dynamics and control of a planar, translational cable‐directdriven robot (CDDR). The motivation behind this work is to improve the serious cable interference problem with existing CDDRs and to avoid configurations where negative cable tensions are required to exert general forces and moments on the environment and during dynamic motions. Generally for CDDRs the commanded rotations are more demanding than commanded translations in terms of slack cable conditions. Therefore we propose a translational CDDR whose end‐effector may be fitted with a traditional serial wrist mechanism to provide rotational freedom (assuming proper design to resist the moments). Only the translational CDDR is considered in this article, including kinematics and statics modeling, statics workspace (wherein all possible Cartesian forces and moments may be exerted with only positive cable tensions), plus a dynamics model and simulated control for planar CDDRs. Here we focus only on planar CDDRs, to clearly demonstrate our dynamics and control work; we will extend this work to spatial CDDRs in the future. Examples are presented to demonstrate simulated control including feedback linearization of the four‐cable CDDR (with one degree of actuation redundancy) performing a Cartesian task. An on‐line dynamic minimum torque estimation algorithm is introduced to ensure all cable tensions remain positive for all motion; otherwise slack cables can result from CDDR dynamics and control is lost. © 2003 Wiley Periodicals, Inc.

Workspace Atlases for the Design of Spherical 3-DOF Serial Wrists

In this paper, the physical model of the solution space of spherical 3-DOF serial wrists is established. The reachable workspaces are classified. The dexterous workspaces for such wrists are investigated based on the rotatability conditions for the spherical 4-bar mechanism. Using the theory of conformal transformation, we obtain plane figures of the reachable and dexterous workspaces. The atlases of the workspaces in the physical model of the solution space are plotted. These results are useful not only for designer overall to understand the relationship between the workspaces and link lengths of spherical 3-DOF serial wrists, but also for the design of the wrists.

Effects of methotrexate on radiologic progression in juvenile rheumatoid arthritis.

To assess the effects of methotrexate (MTX) therapy on radiologic progression in juvenile rheumatoid arthritis (JRA). We evaluated serial wrist radiographs for carpal length in 23 JRA patients with bilateral wrist involvement, before and during MTX treatment. These carpal length measurements were compared with established norms for carpal length in a healthy pediatric population. Both clinical responders to MTX (17 of 23 patients) and nonresponders (6 of 23) had decreasing carpal length prior to initiation of the treatment. Eleven of the 17 clinical responders had improved carpal length after a mean of 2.5 years of MTX treatment. All 6 clinical nonresponders had progressive loss of carpal length. MTX treatment resulted in radiologic improvement, as measured by carpal length, in the majority of children with JRA who had a clinical response to MTX.

A Global Performance Index for the Kinematic Optimization of Robotic Manipulators

In this paper, a novel performance index for the kinematic optimization of robotic manipulators is presented. The index is based on the condition number of the Jacobian matrix of the manipulator, which is known to be a measure of the amplification of the errors due to the kinematic and static transformations between the joint and Cartesian spaces. Moreover, the index proposed here, termed global conditioning index (CGI), is meant to assess the distribution of the aforementioned condition number over the whole workspace. Furthermore, the concept of a global index is applicable to other local kinematic or dynamic indices. The index introduced here is applied to a simple serial two-link manipulator, to a spherical three-degree-of-freedom serial wrist, and to three-degree-of-freedom parallel planar and spherical manipulators. Results of the optimization of these manipulators, based on the GCI, are included.