Physiological, sensory, and functional measures in a model of wrist muscle injury and recovery

Evaluation of upper extremity function and its relation to curve pattern in female adolescents with idiopathic scoliosis: a pilot study

STUDY DESIGN

Cross-sectional and clinical measurement.

OBJECTIVE

To evaluate upper extremity function and its relation to the curve pattern in idiopathic scoliosis. Postural alterations and trunk distortions-caused by three-dimensional deformity itself in idiopathic scoliosis-may lead to functional changes in the upper extremity of subjects.

METHODS

Handgrip, pulp and lateral pinch strengths, hand dexterity, hand reaction time, coordination of upper extremity, upper extremity performance, throwing accuracy, and self-reported upper extremity disability were evaluated in 96 subjects. These subjects were divided into 3 groups: 47 with main thoracic curve pattern scoliosis (Lenke type 1), 31 with thoracolumbar/lumbar curve pattern scoliosis (Lenke type 5), and 18 unaffected (healthy control). Comparisons were performed between these three groups.

RESULTS

The thoracic scoliosis group showed a significant decrease in concave lateral pinch strength, concave hand dexterity of turning, coordination of the upper extremities, and concave hand reaction time than the thoracolumbar/lumbar scoliosis group (p < 0.05). Bilateral handgrip strengths decreased in thoracic scoliosis group when compared to healthy controls. Healthy individuals demonstrated greater throwing accuracy than individuals with scoliosis.

CONCLUSIONS

Upper extremity function was found to be affected based on the curve pattern. Individuals with main thoracic curves are likely to have deteriorated upper extremity function, especially for hand-specific motor skills, on the concave side, when compared to lumbar curves and healthy controls.

LEVEL OF EVIDENCE

Level III.

Quantifying forearm and wrist joint power during unconstrained movements in healthy individuals

Background

Wrist movement-related injuries account for a large number of repetitive motion injuries. Remarkably little, if any, empirical data exist to quantify the impact of neuromuscular disorders affecting the wrist or to validate the effectiveness of rehabilitation training programs on wrist functions. The aim of this project was to develop a biomechanical model for quantifying wrist and forearm kinetics during unconstrained movements, to assess its reliability and to determine its sensitivity.

Methods

Twenty healthy subjects with no history of upper arm and wrist pain volunteered for the experiment. To evaluate the reliability of the data, we quantified their forearm and wrist kinetics on two different days (minimum and maximum number of days between experimental sessions were 1 and 4 days respectively). To measure forearm and wrist kinetics, an apparatus was built to offer rotational inertia during forearm and wrist movements. An inertial measurement unit was located near the top of the device measuring its angular position along the frontal and sagittal planes. We used a mathematical model to infer forearm and wrist torque. Thereafter, we calculated the product of torque and angular velocity to determine forearm and wrist power.

Results

Results revealed that for 75% of the power and torque measurements the ICC was greater than 0.75 (range: 0.77 – 0.83). Torque and power measurements for adduction movements, however, were less reliable (i.e., ICC of 0.60 and 0.47, respectively) across testing sessions. The biomechanical model was robust to small measurement errors, and the power peaks between the first and second testing session were not different indicating that there was no systematic bias (i.e., motor performance improvement) between testing sessions.

Conclusions

The biomechanical model can be used to assess the effectiveness of rehabilitation programs, document the progression of athletes or conduct research-oriented testing of maximum forearm and wrist kinetic capacities. Nonetheless, caution should be taken when assessing forearm and wrist power adduction movements. Future studies should aim at defining a set of normative values, for various age groups, for forearm and wrist joint torque and power in healthy individuals.

Electronic supplementary material

The online version of this article (doi:10.1186/1743-0003-11-157) contains supplementary material, which is available to authorized users.