A kinematic method to calculate the workspace of the trapeziometacarpal joint

Estimating the Thumb Rotation Angle by Using a Tablet Device With a Posture Estimation Artificial Intelligence Model

MediaPipe Hand (MediaPipe) is an artificial intelligence (AI)-based pose estimation library. In this study, MediaPipe was combined with four machine learning (ML) models to estimate the rotation angle of the thumb. Videos of the right hands of 15 healthy volunteers were recorded and processed into 9000 images. The rotation angle of the thumb (defined as angle θ from the palmar plane, which is defined as 0°) was measured using an angle measuring device, expressed in a radian system. Angle θ was then estimated by the ML model by using parameters calculated from the hand coordinates detected by MediaPipe. The linear regression model showed a root mean square error (RMSE) of 12.23, a mean absolute error (MAE) of 9.9, and a correlation coefficient of 0.91. The ElasticNet model showed an RMSE of 12.23, an MAE of 9.95, and a correlation coefficient of 0.91; the support vector machine (SVM) model showed an RMSE of 4.7, an MAE of 2.5, and a correlation coefficient of 0.99. The LightGBM model achieved high values: an RMSE of 4.58, an MAE of 2.62, and a correlation coefficient of 0.99. Based on these findings, we concluded that the thumb rotation angle can be estimated with high accuracy by combining MediaPipe and ML.

The effect of rheumatoid arthritis on upper extremity functions: A kinematic perspective

AIM

To examine the global upper extremity kinematics in 3D while performing "jar opening motion" in Rheumatoid Arthritis (RA) and to compare these with healthy individuals.

METHOD

Twenty-four women (12 healthy, 12 RA) were included. Evaluations were made with a JAMAR dynamometer, Health Assessment Questionnaire, and 3D kinematic analysis of global upper extremity during "jar opening motion." The time taken during "jar opening motion" was analyzed in 2 parts (Part 1, Part 2), with total time: part 1 + part 2. In addition, shoulder-to-table distance; elbow flexion angle; wrist extension angle; the area scanned and angular rotation by arm, forearm and hand were used in the analysis.

RESULTS

Between groups, there was a statistical difference in: bilateral hand grip strength; part 1, part 2, total time; shoulder-to-table distance; elbow flexion angle; the area scanned by hand; angular rotation of arm and hand in favor of the healthy group (P < .05). In stepwise multiple regression analysis, the most predictive variable for disability was elbow flexion, explaining 53.9% of disability.

CONCLUSION

Compared to healthy individuals, individuals with RA have slower motion, more elbow flexion, less hand grip strength, circular pattern in hand, rotation in arm and hand. Increased disability may result in greater load on elbow flexion.

How kinematic disturbance in the deformed rheumatoid thumb impacts on hand function: a biomechanical and functional perspective

Purpose This study investigates the effects of kinematic disturbances in rheumatoid thumb on patient's hand functions via objective and patient-perceived measurements. Method Twenty-one patients with rheumatoid arthritis (RA) and 21 healthy age- and gender-matched individuals were recruited to receive the objective evaluations, including the Purdue Pegboard Test, Jamar dynamometer, pinch-meter, Permanent Impairment Scale and self-administrated measurements, including the Health Assessment Questionnaire (HAQ) and Manual Ability Measure-36 (MAM-36). An electromagnetic tracking system was used to measure thumb kinematics. The differences in the measures between the RA and control groups and the dominant and non-dominant hands of the RA group were examined. The relationships between the thumb kinematics and hand functional capabilities, as well as impairment levels, were also explored. Results The RA group showed significantly smaller thumb movement capabilities and hand strength, as well as worse scores in hand dexterity, MAM-36 and HAQ than healthy controls. The movement workspace of the RA thumb showed moderate correlations with the factors of hand strength, dexterity, impairment scale, MAM-36 and HAQ scores. Conclusions The findings indicate deficits related to the movement capability of the RA thumb may negatively influence hand dexterity and functional hand performance, as well as life quality, for the patients with RA. Implications for Rehabilitation A deformed rheumatoid thumb might limit the movement workspace of the thumb and consequently impair the hand performance as well as the life quality. The dominant thumb of the RA patients might have greater structural and functional deterioration than the non-dominant side. Suitable joint protection strategies, exercises and orthotics should be early applied to the RA patients for preserving hand functions.

Workspace Modeling and Analysis for Dexterous Hands

The workspace is a fundamental feature for a dexterous hand to grasping plan, motion control, and mechanical design. Although the graphic, numerical, or analytical methods are valid to generate the workspace of dexterous hands, but there exist several defects for these methods to describe the workspace characteristics, such as forms, boundaries, volumes, and intersection workspaces. We propose a combined modeling approach to visualize and analyze the workspace of YWZ dexterous hand, which has five fingers, 20 degrees of freedom (Dofs). The proposed approach is also fit for similar dexterous hands to generate their precise workspaces. After a brief mechanism introduction of YWZ dexterous hand, a displacement equation of its index finger is deduced to calculate the fingertip positions in three-dimension (3D) Euclidean space. Then, a two-dimension (2D) boundary figure enclosing the flexion–extension motion field of the finger is drawn by the displacement equation. Taking this boundary figure as a sketch in a CAD modeling environment, we further model a vivid 3D finger workspace, which is relative with the abduction–adduction motion of the finger. Besides, we generate the whole workspace of YWZ dexterous hand and analyze its volumes and intersection workspaces. The kinematic simulations and physical prototype experimentations are carried out to validate this approach can construct perfect workspace of dexterous hands. Compared with the Monte Carlo method, the form and boundary of the 3D finger workspace generated by our proposed approach have more accurate, integrated, vivid, and intuitional.

In vivo kinematics of the thumb carpometacarpal joint during three isometric functional tasks

BACKGROUND

The thumb carpometacarpal (CMC) joint is often affected by osteoarthritis--a mechanically mediated disease. Pathomechanics of the CMC joint, however, are not thoroughly understood due to a paucity of in vivo data.

QUESTIONS/PURPOSES

We documented normal, in vivo CMC joint kinematics during isometric functional tasks. We hypothesized there would be motion of the CMC joint during these tasks and that this motion would differ with sex and age group. We also sought to determine whether the rotations at the CMC joint were coupled and whether the trapezium moved with respect to the third metacarpal.

METHODS

Forty-six asymptomatic subjects were CT-scanned in a neutral position and during three functional tasks (key pinch, jar grasp, jar twist), in an unloaded and a loaded position. Kinematics of the first metacarpal, third metacarpal, and the trapezium were then computed.

RESULTS

Significant motion was identified in the CMC joint during all tasks. Sex did not have an effect on CMC joint kinematics. Motion patterns differed with age group, but these differences were not systematic across the tasks. Rotation at the CMC joint was generally coupled and posture of the trapezium relative to the third metacarpal changed significantly with thumb position.

CONCLUSIONS

The healthy CMC joint is relatively stable during key pinch, jar grasp, and jar twist tasks, despite sex and age group.

CLINICAL RELEVANCE

Our findings indicate that directionally coupled motion patterns in the CMC joint, which lead to a specific loading profile, are similar in men and women. These patterns, in addition to other, nonkinematic influences, especially in the female population, may contribute to the pathomechanics of the osteoarthritic joint.

WORKSPACE OF DIGITAL HUMAN LOWER EXTREMITIES

This paper presents an applicable formula for determining the workspace of digital human lower extremities. The digital human model has over 100 degrees of freedom (DOF): 94 in the upper body, 14 in the lower extremities, 5 in the neck, 4 in the eyes, and 25 for each hand. The Jacobian row rank deficiency criteria are implemented to determine the singular surfaces that finally form the workspace. The use of this digital human model for determining workspace offers several advantages over direct measurement: (1) the workspace can be visualized in real-time based on offline computation, (2) the workspace can be used for the ergonomic design of products in the virtual prototyping stage, and (3) the calculated workspace includes complete information about the envelope and inside characteristics.

In vivo kinematics of the first carpometacarpal joint after trapezectomy

First carpometacarpal osteoarthitis is frequent and surgery may be necessary if medical treatment is not efficient. Trapeziometacarpal arthroplasty, trapeziometacarpal arthrodesis and trapezectomy may be proposed. These surgical solutions may modify the carpometacarpal kinematics of the thumb. However, no clinical tools are currently available to assess these modifications. The goal of our study is to assess the TM kinematics, with an optoelectronic system, in patients after trapezectomy. Ten women, average age 53 (range 45 to 67) underwent trapezectomy with ligamentoplasty for trapeziometacarpal osteoarthritis. An optoelectronic device (Polaris(®)) was used to analyse postoperative range-of-motion of the thumb. Splints were used in order to isolate the trapeziometacarpal joint and retroreflective markers were placed both on the splints and on the thumb. Mean flexion-extension, abduction-adduction, axial rotation and circumduction were calculated.

RESULTS

The mean range-of-motion of trapeziometacarpal joint was 50 degrees for flexion-extension, 47 degrees for abduction-adduction and 11 degrees for axial rotation. The mean angle between rotation axes was 90 degrees and the mean distance d between the axes was 3 millimeters. Comparisons between patients and healthy subjects showed no significant differences in flexion-extension, abduction-adduction and axial rotation. Circumduction in patients was reduced compared to healthy subjects. No significant differences were noted between the operated side and the contralateral side.

DISCUSSION AND CONCLUSION

Our study showed that this protocol can be used in the postoperative follow-up of patients after trapezectomy. We did not find any significant differences compared to the contralateral side. However, circumduction after trapezectomy was reduced compared to healthy subjects.

Effects of age and gender on the movement workspace of the trapeziometacarpal joint

While researchers have suggested that joint mobility would probably be affected by age and gender, research findings often present discrepancies. Little research has been performed on the factors which effect mobility of the trapeziometacarpal (TMC) joint. The purpose of this study was to address the effects of age and gender on the ranges of motion of the normal TMC joint. Eighty normal subjects divided into four age groups participated in this study. The TMC joint motions were recorded using an electromagnetic tracking system. In order to achieve a maximal range of TMC joint motion which was defined as the maximal workspace, each subject was asked to perform actively maximal circumduction, flexion-extension, and abduction-adduction of the TMC joint. Numerical and statistical methods were used to compute the TMC workspace and to detect significant differences. A workspace-to-length ratio was determined as an index to examine the effects of the age and gender on the joint mobility. The results demonstrated that age and gender had significant influences on the TMC workspace among the groups studied. The understanding of TMC joint mobility under different age and gender conditions is achieved through this study. The findings can be used to report clinical measures in the determination of the extent of impairment of osteoarthritis as well as the outcomes between pre- and post-surgical (or non-surgical) interventions.

Operational and maximal workspace of the thumb

The purposes were to examine the workspace of the thumb during its operational (submaximal and random) movement and to compare the operational workspace with its maximal workspace. Fifteen female subjects with asymptomatic hands performed the thumb circumduction and operational motion. Linear and angular measurements of the thumb were obtained by a marker-based motion analysis system. During the circumduction, the linear ranges of motion of the thumb tip were 102.8 +/- 9.9 mm and 130.7 +/- 14.1 mm in abduction/adduction and flexion/extension directions, respectively, and the corresponding values for the operational motion were 67.3 +/- 16.1 mm and 73.1 +/- 18.0 mm, respectively. The angular ranges of motion of the carpometacarpal (CMC) and metacarpophalangeal joints during the operational motion were less than 65% of their maximal motion ranges. In addition, the CMC joint tended to move in directions oblique to its anatomical defined axes. The results of operational motion may provide guidelines for ergonomic design of thumb-operated tools and hand-held electronics devices.

Joint kinematics after thumb carpometacarpal joint reconstruction: an in vitro comparison of various constructs

PURPOSE

Osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint causes pain and limits thumb motion. Different surgical procedures exist to treat thumb CMC OA; however, kinematic analyses of thumb reconstructions are limited. The purpose of this study was to evaluate kinematic changes of the thumb CMC joint as the result of different thumb reconstruction procedures.

METHODS

Fifteen cadaveric forearms were prepared and instrumented with an electromagnetic tracking device to measure the motion of the thumb metacarpal with respect to the trapezium (thumb trapeziometacarpal joint). Kinematics of the intact thumb and the thumb after trapeziectomy under passive motion were recorded. Specimens then had joint reconstruction consisting of either a ligament reconstruction with tendon interposition (LRTI), Weilby arthroplasty, or Thompson arthroplasty. The kinematic data collection analysis was repeated. The radius of joint motion and 3-dimensional (3D) work area were calculated for each surgery and were used for statistical analysis.

RESULTS

The type of surgical treatment significantly affected the joint radius of motion and the 3D work area. The Thompson and LRTI techniques produced a larger joint radius of motion than the other techniques (Weilby technique and total trapezial resection) and was similar to that of the intact joint. The Weilby and LRTI techniques produced a 3D work area similar to those of the intact joint and trapeziectomy and was also larger than that of the Thompson reconstruction.

CONCLUSIONS

Kinematic analysis of the thumb CMC joint is effective in differentiating surgical treatments used for end-stage of OA. Only the LRTI reconstruction produced a joint radius of motion and a 3D work area similar to the those of an intact thumb. Additional research is needed to define the optimal surgical techniques to treat the end-stage OA thumb CMC joint.