Wrist Kinematics Research Articles

Normal kinematics of carpal bones: A three-dimensional analysis of carpal bone motion relative to the radius

Normal carpal kinematics were studied in 22 cadaver specimens using a biplanar radiography method. The kinematics of the trapezium, capitate, hamate, scaphoid, lunate, and triquetrum were determined during wrist motion in sagittal and coronal planes. The results were expressed using the concept of the screw displacement axis and converted to describe the magnitude of rotation about and translation along three axes ( X-axis: pronation-supination axis, Y-axis; flexion-extension axis, and Z-axis: radial-ulnar deviation axis) commonly used for the wrist. The orientation of these axes is expressed relative to the radius. Within the proximal carpal row, considerable differences of carpal behavior around the Y-axis were observed during sagittal plane motion of the wrist. The scaphoid exhibited the greatest magnitude of rotation, and the lunate the least. The magnitude of rotation of the carpal bones around the X-axis during sagittal plane motion of the wrist was small. The proximal carpal bones exhibited some ulnar deviation in 60° of wrist flexion. During coronal plane motion of the wrist, the magnitude of radial-ulnar deviation of the distal carpal bones was mutually similar and generally of a greater magnitude than that of the proximal carpal bones. The proximal carpal bones experienced some flexion during radial deviation of the wrist and extension during ulnar deviation of the wrist. Translation was generally minimal in all carpal bones throughout wrist motion. This study reports results from the largest cadaver wrist kinematics study completed to date. The accuracy of the current method was improved when compared to previous studies. A sufficient number of specimens to allow statistical comparison was used and minimal interspecimen variability was noted. This study enabled a precise description of quantitative analyses of normal carpal kinematics relative to the radius.

Scapholunate dissociation: An experimental kinematic study of two types of indirect soft tissue repairs

Indirect soft tissue repairs of scapholunate dissociation (SLD) address the pathophysiology but have been criticized for significantly limiting wrist flexion and altering wrist kinematics. This study was designed to analyze and compare the kinematics of a normal cadaveric wrist to those of 2 types of soft tissue repairs performed for SLD. Ten uninjured fresh cadaver arms were evaluated by cineradiography and standard x-rays. The average scapholunate (SL) gap was 0.9 mm, with a SL angle of 50 degrees. A model of SLD was produced by sectioning the SL ligaments resulting in an average SL gap of 3.9 mm and SL angle of 66 degrees. The wrists were randomized to a dorsal capsulodesis repair and a distally based split extensor carpi radialis longus (ECRL) repair. The average SL gap after repair was 1.0 mm and the average SL angle was 47 degrees. The split ECRL repair and dorsal capsulodesis reduced scaphoid flexion with only a 10 degree and 18 degree decrease in wrist flexion, respectively. Both repairs reduced the SLD and restored normal wrist kinematics.

Load dependence in carpal kinematics during wrist flexion in vivo

Objective. The hypothesis tested was that generation of torque at the wrist affects joint kinematics. Design. An in vivo study of normal wrist kinematics during plantar flexion motion against a constant load was undertaken, using a custom-designed instrumented apparatus to track the motion of the hand during the task. Background. Despite clinical observations of a relationship between motion-loading and pain in wrists affected by rheumatoid arthritis, there is little published literature on the in vivo kinematics of the normal human wrist under load. Methods. Ten volunteers with no wrist pathology were tested while generating torques of zero, 1.1 and 2.2 N m in a planar, unidirectional flexion motion. Hand kinematics were computed using the Planar Rigid Body Method algorithm and an 8 ° angular step size. The finite radius of motion and the range and standard deviation of the residuals to a fitted second-order curve were used as indices of changes in the kinematics. Results. The magnitude of both the range and standard deviation of the residuals were found to increase significantly with torque at the 95% confidence level. Conclusions. The wrist does not behave like a smooth mechanism when generating torque. Load affects carpal kinematics.

Quantitative Biomechanical Analysis of Wrist Motion in Bone-Trimming Jobs in the Red-Meat Packing Industry

This study was motivated by the serious impact that cumulative trauma disorders (CTDs) of the upper extremities have on industrial workers and on industry itself. To date, no quantitative data has been gathered on the kinematics of hand and wrist motion required in bone-trimming jobs in the red-meat packing industry. No information is known about what type and how much wrist motion is currently being used in bone-trimming jobs in the red-meat packing industry, or how much these motions increase the risk of occupational CTDs. The research conducted addressed this current research void and established a preliminary database of wrist and hand kinematics for a bone-trimming job in the red-meat packing industry. This kinematic database could augment the red-meat industry's efforts to reduce the severity and cost of CTDs. Ergonomics practitioners in the red-meat industry could use the kinematic methods employed in this research to assess the CTD risk of current and redesigned jobs that require repetitious, hand-intensive work. The study examined the wrist motions used by nine red-meat packing workers who performed bone-trimming jobs. These jobs are highly repetitive and hand-intensive. Quantitative measures of the kinematic parameters of wrist motions performed on the bone-trimming line were measured using goniometry. The wrist motion measures consisted of the following statistics in the radial/ulnar, flexion/extension, and pronation/supination planes: 1). mean, minimum, and maximum of wrist angle position, 2). mean, minimum, and maximum of angular velocity, and 3). mean, minimum, and maximum of angular acceleration. The kinematic data were compared to manufacturing industry's preliminary wrist motion benchmarks. These benchmarks were the means and variances of nine dependent variables of position, velocity, and acceleration from industrial workers who performed hand-intensive, repetitive work in jobs that were of low and high risk of hand/wrist CTDS (Marras and Schoenmarklin, 1993). Results of this comparison show that numerous wrist motion variables in both the left and right hands of bone-trimming workers are in the high-risk category. This quantitative analysis provides biomechanical support for the high incidence of CTDs in the bone-trimming line of the plant that was investigated.

Reprogramming of muscle activation patterns at the wrist in compensation for elbow reaction torques during planar two-joint arm movements.

The relationship between wrist kinematics, dynamics and the pattern of muscle activation were examined during a two-joint planar movement in which the two joints moved in opposite directions, i.e. elbow flexion/wrist extension and elbow extension/wrist flexion. Elbow movements (ranging from 10 to 70 deg) and wrist movements (ranging from 10 to 50 deg) were performed during a visual, step-tracking task in which subjects were required to attend to the initial and final angles at each joint. As the elbow amplitude increased, wrist movement duration increased and the wrist movement trajectories became quite variable. Analysis of the torques acting at the wrist joint showed that elbow movements produced reaction torques acting in the same direction as the intended wrist movement. Distinct patterns of muscle activation were observed at the wrist joint that were dependent on the relative magnitude of the elbow reaction torque in relation to the net wrist torque. When the magnitude of the elbow reaction torque was quite small, the wrist agonist was activated first. As the magnitude of the elbow reaction torque increased, activity in the wrist agonist decreased significantly. In conditions where the elbow reaction torque was much larger than the net wrist torque, the wrist muscle torque reversed direction to oppose the intended movement. This reversal of wrist muscle torque was directly associated with a change in the pattern of muscle activation where the wrist antagonist was activated prior to the wrist agonist. Our findings indicate that motion of the elbow joint is an important consideration in planning wrist movement. Specifically, the selection of muscle activation patterns at the wrist is dependent on the relative magnitude and direction of the elbow reaction torque in relation to the direction of wrist motion.

Wrist kinematics during pitching. A preliminary report.

A computerized hand and wrist motion analysis system was modified to capture data at a rate of up to 1000 Hz. Using this system, wrist flexion and extension data were collected on five right-handed professional pitchers (75 pitches). A wrist position versus time graph was generated for each pitch. The pitch data produced a reproducible analysis of motion for the majority of the pitches regardless of pitcher. Based on the graphic display of data points, four phases of wrist motion during a pitch were identified. The first phase is the cocking phase, or the motion of the wrist as it moves into maximum extension. This is then followed by the most explosive phase, the acceleration phase, which represents ball propulsion. At ball release, the wrist progresses through flexion and there is a consistent decrease in wrist velocity, known as the deceleration phase. Finally, there is the recovery phase, or the return of the wrist toward neutral. Average values for wrist range of motion, length of phase, and angular velocity (degrees per second) were calculated for each phase of the pitch. This study represents a major step toward quantifying motion of the wrist during a pitch. The ability to quantify this motion may prove valuable in the assessment of throwing athletes after injury and rehabilitation.

Wrist kinematics: Row, column or both?

Analysis of radiographs of 52 wrists showed that, from ulnar to radial deviation, the amount of scaphoid shortening and ulnar translation of the scaphoid varies in a normal distribution. There is a significant correlation between the two measurements, such that the more the scaphoid shortens the less it translates and vice versa. Females subjects were more likely to have greater scaphoid shortening and less translation. It is felt that carpal kinematics thus cover a spectrum from the "row" theory to the "column" theory which is normally distributed and that women are more likely to have a column type wrist. This variation may affect the result of treatment of scapholunate dissociation by techniques such as scapho-lunate fusion. A "CR index" is proposed so that the tendency of a wrist towards row or column theory can be quantified. This may be used to predict the success of some surgical procedures in the treatment of scapho-lunate dissociation.

Wrist kinematics differ in expert and novice tennis players performing the backhand stroke: Implications for tennis elbow

Investigators have suggested that the greater prevalence of lateral humeral epicondylitis (tennis elbow, TE) in novice tennis players compared to expert players may reflect the novice players' use of faulty mechanics for the backhand stroke. We investigated the wrist kinematics (flexion/extension), grip pressures, and wrist muscle electromyographic activity in novice ( N = 8) and expert ( N = 8) tennis players performing the backhand stroke. Experts performed the backhand stroke with the wrist extended (re: neutral alignment of the forearm and hand dorsum). Collision of the ball and racket occurred with the wrist extended an average of 0.41 rad (about 23° from neutral alignment) in the expert players; moreover, their wrists were moving further into extension at impact. In contrast, novice subjects struck the ball with the wrist flexed 0.22 rad (about 13°) while moving their wrists further into flexion. Wrist extensor EMGs showed similar levels of activity during the 500 ms interval before ball-racket impact, whereas expert subjects displayed greater EMG levels after contact, consistent with the accompanying wrist extension. The wrist kinematic and EMG data together show that the novice subjects eccentrically contracted their wrist extensor muscles throughout the stroke. We argue that conditions exist for novice subjects that assist stretch of wrist extensor muscles upon collision of the ball and racket. The resulting eccentric contraction of wrist extensor muscles may contribute to lateral TE in novice players, given previous research indicating that eccentric muscle contraction facilitates muscle fiber injury.

Determination of wrist kinematics using a magnetic tracking device

The objective of this work is to present a method to determine the three-dimensional kinematics of the human wrist joint under physiological loading conditions using a magnetic tracking device. Euler angles were used to determine wrist extension-flexion, radial-ulnar deviation and supination-pronation. The screw displacement axis (SDA) method was used to describe the relative motion between carpal bones. Computer graphics were also used to obtain a better visualization of the three-dimensional motions of the carpal bones. This was accomplished by combining motion data and digitization data describing the geometry of the articular surfaces of the carpal bones. Geometric data included the locations of several points located on the articular surfaces forming the radio-scaphoid and radio-lunate joints. The SDA axes describing the motions of the capitate or the lunate or the scaphoid with respect to the radius during flexion-extension were found almost parallel to the medial-lateral direction. Translations along any SDA did not exceed 2 mm. One can thus consider the motion of each carpal bone as a pure rotation about a screw axis. Also, the SDA axis describing the motion of the capitate with respect to the radius was found to pass through the proximal end of the capitate. The graphical display of carpal motions shows that, as the wrist is flexed, the surface of the lunate within the radio-lunate articulation moves from palmar to dorsal. On the other hand, the palmar-dorsal location of the proximal surface of the scaphoid within the radio-scaphoid articulation remains almost unchanged.

An approach to determining the kinematic parameters of biomechanical systems with applications to the wrist.

This paper presents an accurate and robust approach for determining the kinematic parameters of biomechanical systems. A computationally efficient algorithm is given for estimating the translation vector and rotation matrix of a moving body from measurements of the position of at least four spatially distributed points on the body. This algorithm provides an estimation of the spatial location and orientation of the body which is less sensitive to measurement error than other methods. It is indicated how the kinematic parameters can be used to determine the linear translation and angular rotation of the moving body in terms of an anatomically relevant coordinate system. The design, fabrication and calibration of an inexpensive, serial-link, three-dimensional mechanical digitizer for use in data acquisition is described. This device is kinematically optimized and is easy to use for accurate data collection. An implementation of this approach to quantifying certain aspects of the kinematics of the human wrist is discussed.

Biomechanics of the golf swing in players with pathologic conditions of the forearm, wrist, and hand

Golf is an activity generally stressful to the hands and wrists and particularly can produce increasing symptoms in players with underlying problems such as hand and wrist arthritis or tendinitis. The purpose of this study was to quantitate wrist motion and club head/ball impact force in subjects with pathologic conditions of the hand, wrist, or forearm, within a laboratory environment. A regular straight-handled golf club was compared to a new BioCurve handle design that has a 19 degrees ulnar bend. We measured and compared the effect of the two grips on wrist motion, club head velocity, ball impact force, ball impact location, and isometric torsional strength in 20 subjects who had a variety of upper extremity disorders. This data was then compared to data collected in an identical fashion from golfers without such conditions. The results of our study show that there were no differences related to club handle design on impact force or impact location, club head velocity, or club head path and face angle. Wrist kinematic differences were minimal between handle designs. The differences that were significant (P less than 0.05) centered around the decreased ulnar deviation of the left hand that resulted when subjects used the BioCurve handle design, which also allowed greater resistance to torque than the straight grip club. In addition to collecting objective data, we asked subjects for their opinions of the two grips. As a whole, the normal group and the group with pathologic conditions noted more comfort, improved grip, and less shock transmission with the BioCurve handle.

A closed‐loop jacobian transpose scheme for solving the inverse kinematics of nonredundant and redundant wrists

AbstractThe solution of the inverse kinematic problem is of the utmost importance in robotic manipulator control. This article proposes a closed‐loop scheme for solving the inverse kinematic problem for nonredundant and redundant wrists based on the computation of the Jacobian transpose. The manipulability measure is suitably introduced as a constraint for redundant wrists, by taking advantage of the null space of the Jacobian matrix. The resulting algorithm provides a computational tool to solve a specified orientation trajectory into a joint trajectory. Numerical results with two spherical wrists show the excellent performance of the scheme.

Wrist kinematics after limited intercarpal arthrodesis

Two limited intercarpal fusions, scapho-trapezial-trapezoidal and scapho-capitate, were simulated in six fresh human cadaver wrists by means of two Herbert screws. By use of a biplanar radiographic measurement system, the relative kinematic behavior of selected carpal bones, before and after the simulated limited fusions could be analyzed. Both scapho-trapezial-trapezoidal and scapho-capitate fusions produced a similar reduction in global range of motion and comparable effects on the relative intracarpal motion. In both fusions, a significant reduction in relative motion at the lunocapitate joint was recorded. The scaphoid, being fused to the distal carpal row, was shown to lose its role in the adaptative mechanism that allows preservation of articular congruency to the always changing space between the distal carpal row and the radius. After both types of fusion, increased sliding motion of the lunate on the radius was found. These kinematic changes are likely to enhance shear stresses on the lunate and tension on the surrounding ligaments, potentially diminishing long-term functional results.

Long-term study of chronic scapho-lunate instability treated by scapho-trapezio-trapezoid arthrodesis

The effect of scapho-trapezio-trapezoid arthrodesis on wrist kinematics was studied in 25 patients with chronic static scapho-lunate instability and in 16 patients with dynamic instability, with follow-up ranging from 24 to 101 months (average, 56 months). Postoperative planar and cineradiographic examination in patients returning to heavy labor reveal an absence of carpal shift-influence of the scaphoid proximal pole on the lunate-triquetral unit in ulnar deviation. Scapholunate diastasis present before operation persists in ulnar deviation as the STT fusion mass, capitate, and hamate rotate with the hand into ulnar deviation; the lunate-triquetral unit is not physiologically "pulled" radially into the lunate fossa of the radius. Triquetro-hamate mechanics remain normal as active engagement along the helicoidal triquetro-hamate interface initiates proximal row dorsiflexion. Clinical postarthrodesis wrist motion is a combination of intercarpal and radiocarpal mechanics, with energy in the flexion and extension arc dissipated through the scapho-lunate interface. The paucity of arthritic changes after up to 101 months after surgery is based on the kinematic changes presented in these data.

Mathematical analysis of computed carpal models.

The computed carpal models from digital computed tomography (CT) data obtained in this study compare favorably to natural anatomy. A new application of algebraic analysis of this data provides mathematical markers from which to calculate the position and orientation of each carpal bone. When the origin of the spatial coordinates of a carpal bone is transferred to the centroid of the bone, the data can be treated as three-dimensional pattern vectors describing its surface. It is then possible to calculate vectors that are the principal axes of the geometry. These axes provided references that were used to calculate position and orientation of the carpal bones in three wrist specimens. Comparisons of volumes, surface areas, and sizes and proportions of five computed images of each carpal bone from two of these wrists demonstrate the reliability of the technique. The analysis of CT scans of ceramics with known boundaries allows an estimation of its accuracy. The technique is well suited to the future study of normal wrist kinematics and pathological conditions.

The effect of scapholunate ligament section on scapholunate motion

Although the scapholunate interosseous ligament has been studied anatomically and functionally by several investigators, its exact role in wrist kinematics is still controversial. We designed and executed an experimental study with four cadaver specimens to compare various carpal motions before and after section of this ligament. Our results suggest that injury to this structure significantly changes carpal motion especially between the scaphoid and lunate.

External fixation across the wrist

External fixation is a method useful for the immobilization of the wrist after injury. The biomechanics of the wrist are discussed together with the treatment of simple injuries with uniaxial frames. Complex injury patterns cause more extensive disruption of wrist kinematics and therefore require more complex external fixation configurations that restrict motion in more than one plane. Internal fixation can also be combined with external fixation to solve special fracture problems. Eight cases are presented in which external fixation was applied 4 weeks after internal fixation because of poor alignment following closed reduction. Thereafter all the fractures united. The complexity of fixation technique should match the complexity of the fracture problem.

The in-vivo kinematics of the rheumatoid wrist

The in-vivo kinematics of the rheumatoid wrist

Kinematics of Robot Wrists

Robots for use in assembly and other interactive tasks must be able to respond to both forces and velocity com mands within their workspace. By considering a general six-joint robot we show that all such robots are limited in their ability to respond in orientation to feedback commands. We also show that it is simple to predict, if not to avoid, these regions of degeneracy in which the manipulator loses a degree of freedom.

An in-vivo study of normal wrist kinematics.

The motion of the hand relative to a reference frame embedded in the radius is described using the screw displacement axis (SDA) concept. A three-dimensional sonic digitizer was utilized in a study of the dominant wrist of 15 normal subjects to determine the location and orientation of the SDAs based on the endpoints of flexion-extension motion (FEM) and radial-ulnar deviation (RUD) of the hand. The length of the common perpendicular between the SDAs of FEM and RUD was as large as 6 mm in some individuals; however, in some subjects the FEM SDA was distal of the RUD SDA while in others it was proximal. Considering the group of 15 subjects, the SDAs of FEM and RUD for the normal group nearly intersect in the head of the capitate in the neutrally positioned wrist and forearm.