A torque-controlled device to measure passive abduction of the thumb carpometacarpal joint

The passive biomechanics of the thumb carpometacarpal joint: An in vitro study

The thumb carpometacarpal (CMC) joint facilitates multidirectional motion of the thumb and affords prehensile power and precision. Traditional methods of quantifying thumb CMC kinematics have been largely limited to range-of-motion (ROM) measurements in 4 orthogonal primary directions (flexion, extension, abduction, adduction) due to difficulties in capturing multidirectional thumb motion. However, important functional motions (e.g., opposition) consist of combinations of these primary directions, as well as coupled rotations (internal and external rotation) and translations. Our goal was to present a method of quantifying the multidirectional in vitro biomechanics of the thumb CMC joint in 6 degrees-of-freedom. A robotic musculoskeletal simulation system was used to manipulate CMC joints of 10 healthy specimens according to specimen-specific joint coordinate systems calculated from computed tomography bone models. To determine ROM and stiffness (K), the first metacarpal (MC1) was rotated with respect to the trapezium (TPM) to a terminal torque of 1 Nm in the four primary directions and in 20 combinations of these primary directions. ROM and K were also determined in internal and external rotation. We found multidirectional ROM was greatest and K least in directions oblique to the primary directions. We also found external rotation coupling with adduction-flexion and abduction-extension and internal rotation coupling with abduction-flexion and adduction-extension. Additionally, the translation of the proximal MC1 was predominantly radial during adduction and predominantly ulnar during abduction. The findings of this study aid in understanding thumb CMC joint mechanics and contextualize pathological changes for future treatment improvement.

Validity and reliability of a smartphone inclinometer app for measuring passive upper limb range of motion in a stroke population

Purpose: To demonstrate the validity and reliability of a smartphone app to measure ROM after stroke.Materials and methods: Twenty-one stroke survivors with a diagnosis of stroke that affected the motor cortex or subcortical motor pathways and were hospital inpatients at one of two metropolitan hospitals were recruited. A within-session test-retest design was used to compare ROM measurements taken using the GetMyROM app for iPhone to those taken by a digital inclinometer. Torque-controlled passive elbow and wrist extension were collected and statistical analysis of concurrent validity and test-retest reliability performed.Results: GetMyROM app was valid when compared to the digital inclinometer for measuring passive ROM of the elbow (r = .98, p = .0001, ICC  =  0.97) and wrist (r = .97, p = .0001, ICC  =  0.96) in individuals with acute stroke. Both the GetMyROM app and inclinometer demonstrated excellent test-retest reliability: ICC values are 0.84 to 0.93, and standard error of measurement between 6° to 10°.Conclusion: The GetMyROM app may be implemented in a clinical setting similar to that where the study was conducted, enabling rehabilitation physicians and therapists to use a smartphone to take precise measurements of ROM in daily clinical practice.Implications for rehabilitationApproximately half of all stroke survivors experience reduced passive upper limb range of movement.Accurate measurement of passive upper limb range of movement using validated assessments and/or instruments is paramount.This study demonstrates that the GetMyROM app is valid and reliable compared to the gold standard comparison (digital inclinometer), and is therefore appropriate to use in clinical settings to take precise measurements.

Examination of the torque required to passively palmar abduct the thumb CMC joint in a pediatric population with hemiplegia and stroke

Many activities of daily living involve precision grasping and bimanual manipulation, such as putting toothpaste on a toothbrush or feeding oneself. However, children afflicted by stroke, cerebral palsy, or traumatic brain injury may have lost or never had the ability to actively and accurately control the thumb. To translate insights from adult rehabilitation robotics to innovative therapies for hand rehabilitation in pediatric care, specifically for thumb deformities, an understanding of the torque needed to abduct the thumb to assist grasping tasks is required. Participants (n=16, 10 female, 13.2±3.1 years) had an upper extremity evaluation and measures were made of their passive range of motion, anthropometrics, and torques to abduct the thumb for both their affected and non-affected sides. Torque measures were made using a custom wrist orthosis that was adjusted for each participant. The torque to achieve maximum abduction was 1.47±0.61inlb for the non-affected side and 1.51±0.68inlb for the affected side, with a maximum recorded value of 4.87inlb. The overall maximum applied torque was observed during adduction and was 5.10inlb. We saw variation in the applied torque, which could have been due to the applied torques by the Occupational Therapist or the participant actively assisting or resisting the motion rather than remaining passive. We expect similar muscle and participant variation to exist with an assistive device. Thus, the data presented here can be used to inform the specifications for the development of an assistive thumb orthosis for children with "thumb-in-palm" deformity.

Determination of passive moment-angle relationships at the trapeziometacarpal joint

While modeling the trapeziometacarpal (TMC) joint for determination of tendon forces, the TMC has been considered frictionless and passive moments created by soft tissues neglected. This, however, becomes inaccurate when reaching the joint end range of motion and considering that the TMC is entirely crossed by a complex network of skin, ligaments, soft tissues, and tendons. The objective of this study was to evaluate the passive moments with respect to joint posture in order to further include this relationship in biomechanical modeling. An experimental method was proposed to estimate in vivo a global passive moment including the sum of the actions of each passive anatomical structure. An external force was applied at the level of the metacarpophalangeal joint in various directions ranging from neutral position to full extension and full adduction to full abduction. The passive moment was computed and expressed as a function of the adopted joint angles. An exponential regression was then developed to fit the experimental data and to propose a generic passive moment model. Results showed a good agreement between the proposed exponential regression model and the experimental measures. Moreover, it was shown that joint stiffness could represent more than 60% of the net joint moment during a typical pulp grip task. These results showed the necessity to include the data in biomechanical modeling. The results may help predict more realistic tendons force especially in abduction/adduction muscles.

Palmar abduction measurements: reliability and introduction of normative data in healthy children

PURPOSE

Previously, we studied normative and reliability data of palmar thumb abduction measurements (conventional goniometry, the Pollexograph thumb, the Pollexograph metacarpal, the Inter Metacarpal Distance, the American Society of Hand Therapists method, and the American Medical Association method) in healthy adults. Because many interventions aiming to improve palmar abduction are performed at an early age, the goal of this study was to assess normative and reliability data of these measurement methods in children.

METHODS

We performed measurements with the Pollexograph thumb, the Pollexograph metacarpal and Inter Metacarpal Distance in 100 healthy children to acquire normative data. A retest was performed in 63 children to assess intraobserver reliability.

RESULTS

Mean active and passive palmar abduction measured with the Pollexograph thumb was 62 degrees (range, 40 degrees to 76 degrees). The range of motion of the Pollexograph metacarpal was smaller (mean 49 degrees, range, 32 degrees to 64 degrees). The mean Inter Metacarpal Distance was 50 mm (range, 36-70 mm). Intraclass correlation coefficients of the Pollexograph thumb, Pollexograph metacarpal, and Inter Metacarpal Distance indicated excellent reliability (intraclass correlation coefficients between 0.85 and 0.92).

CONCLUSIONS

Normative Pollexograph thumb and Pollexograph metacarpal data showed that means measured in children are comparable to values found in healthy adults. Reliability data indicated that the Pollexograph thumb, the Pollexograph metacarpal, and Inter Metacarpal Distance are also reliable measurement methods in children.

The Pollexograph: a new device for palmar abduction measurements of the thumb

STUDY DESIGN

Clinical measurement, cross sectional.

PURPOSE

To introduce a new measurement device, the Pollexograph, to easily measure palmar thumb abduction, and to compare its reliability with conventional goniometry.

METHODS

Fourteen hand therapists measured palmar abduction of the same healthy subject with the Pollexograph and a conventional goniometer. In addition, intrarater reliability of the Pollexograph was studied in 21 patients with a hypoplastic thumb.

RESULTS

Variance between measurements of the same subject measured by the hand therapist was 2-6 times smaller with the Pollexograph compared to conventional goniometry. Pollexograph intrarater reliability in hypoplastic thumb patients was excellent (intraclass correlation coefficient (ICC)=0.98-0.99).

CONCLUSIONS

A new tool to measure palmar abduction in clinical care, the Pollexograph, has been introduced. The Pollexograph reduces variability between raters when measuring the same subject compared with conventional goniometry and excellent measurement reliability in hypoplastic thumb patients.

LEVEL OF EVIDENCE

Not applicable.

Palmar abduction: reliability of 6 measurement methods in healthy adults

PURPOSE

The aim of the current study was to assess reliability of 6 palmar thumb abduction measurement methods: conventional goniometry, the Inter Metacarpal Distance, the method described by the American Medical Association, the method described by the American Society of Hand Therapists, and 2 new methods: the Pollexograph-thumb and the Pollexograph-metacarpal.

METHODS

An experienced hand therapist and a less-experienced examiner (trainee in plastic surgery) measured the right hands of 25 healthy subjects. Palmar abduction was measured both passively and actively. Means and ranges for palmar abduction were calculated, and intrarater and interrater reliability was expressed in intraclass correlation coefficients, standard errors of measurement, and smallest detectable differences.

RESULTS

Mean active and passive angles measured with goniometry resembled values measured with the Pollexograph-thumb method (approximately 60 degrees). Mean angles found with the Pollexograph-metacarpal method were approximately 48 degrees. Mean active and passive distances for the Inter Metacarpal Distance were 64 mm. Mean active and passive distances found with the American Society of Hand Therapists method were 97 to 101 mm, and mean distances found with the American Medical Association method were 67 to 70 mm for active and passive measurements. Intraclass correlation coefficients for the Pollexograph-thumb, Pollexograph-metacarpal, and the Inter Metacarpal Distance indicated good and significantly higher intrarater agreement for active and passive measurements than intraclass correlation coefficients of conventional goniometry, the American Society of Hand Therapists method, and the American Medical Association method, which showed only moderate agreement. For interrater reliability, the same measurement methods were found to be most reliable: the Pollexograph-thumb, Pollexograph-metacarpal, and the Inter Metacarpal Distance.

CONCLUSIONS

We found that the Pollexograph-thumb, Pollexograph-metacarpal, and the Inter Metacarpal Distance are the most reliable measurement methods for palmar abduction.

Design of a continuous passive and active motion device for hand rehabilitation

This paper presents the design of a novel, portable device for hand rehabilitation. The device provides for CPM (continuous passive motion) and CAM (continuous active motion) hand rehabilitation for patients recovering from damage such as flexor tendon repair and strokes. The device is capable of flexing/extending the MCP (metacarpophalangeal) and PIP (proximal interphalangeal) joints through a range of motion of 0 degrees to 90 degrees for both the joints independently. In this way, typical hand rehabilitation motions such as intrinsic plus, intrinsic minus, and a fist can be achieved without the need of any splints or attachments. The CPM mode is broken into two subgroups. The first mode is the use of preset waypoints for the device to cycle through. The second mode involves motion from a starting position to a final position, but senses the torque from the user during the cycle. Therefore the user can control the ROM by resisting when they are at the end of the desired motion. During the CPM modes the device utilizes a minimum jerk trajectory model under PD control, moving smoothly and accurately between preselected positions. CAM is the final mode where the device will actively resist the movement of the user. The user moves from a start to end position while the device produces a torque to resist the motion. This active resistance motion is a unique ability designed to mimic the benefits of a human therapist. Another unique feature of the device is its ability to independently act on both the MCP and PIP joints. The feedback sensing built into the device makes it capable of offering a wide and flexible range of rehabilitation programs for the hand.

Twelve weeks of nightly stretch does not reduce thumb web-space contractures in people with a neurological condition: a randomised controlled trial

QUESTION

What is the effectiveness of 12 weeks of nightly stretch in reducing thumb web-space contracture in people with neurological conditions?

DESIGN

Assessor-blinded, randomised controlled trial.

PARTICIPANTS

Forty-four (one dropout)community-dwelling patients with a neurological condition (14 stroke, 7 traumatic brain injury, 23 spinal cord injury) who had uni or bilateral thumb web-space contractures (60 thumbs).

INTERVENTION

The experimental thumbs were splinted into a stretched,abducted position each night for 12 weeks. The control thumbs were not splinted.

OUTCOME MEASURES

Thumb web-space was measured as the carpometacarpal angle during the application of a 0.9 Nm abduction torque before and after intervention.

RESULTS

The mean increase in thumb web-space after 12 weeks was 1 deg (95% CI, -1 to 2).

CONCLUSION

Intensive stretch administered regularly over three months does not reduce thumb web-space contractures in neurological conditions.