Changes in the pressure distribution by wrist angle and hand position in a wrist splint

Palmar Dislocation Fracture of the Hamate: A Case Report and Review of Literature

Objective  Hamate dislocations are rare lesions of the carpus, which make their diagnosis difficult or even missed, and their management non-standardized. Case Description  We report the case of a 34-year-old victim of a high kinetic traffic accident. The initial evaluation revealed multiple fractures of both upper limbs, including a palmar fracture dislocation fracture of the hamate, without any vascular or nerve complications. Open surgical treatment via a dorsal approach allowed reduction and fixation of the hamate by temporary multiple pinning. At 12-month follow-up the patient had pain free motion of the wrist with a DASH score of 3. Radiographs showed evidence of proximal pole hamate sclerosis and carpo-metacarpal narrowing. Literature Review  Owing to its rarity, literature on this topic is extremity limited. Various mechanisms have been described to explain these injuries, including dorsal pressure on the carpus associated with traction of the annular carpal ligament on its hamate insertion. Symptoms can be minimal and only three cases of nerve complications have been reported. Long-term outcomes following these injuries usually result in decrease in wrist motion and grip strength. Clinical Relevance  The rarity of dislocations with or without hamate fracture favors the absence or the delay of diagnosis, which must lead to a precise radiographic analysis and to the implementation of a CT scan in case of high kinetics carpal trauma, even if it is poorly symptomatic. Level of Evidence  Level 5, case study.

Does thermoplastics' thickness influence joint stabilization and movement coordination? An inferential study of wrist orthoses

BACKGROUND

Given the existence of multiple low-temperature thermoplastics, clinicians fabricating can readily modify an orthoses' thickness, weight and flexibility, among other properties. However, there is limited evidence on the impact of such different materials on upper extremities' biomechanics.

OBJECTIVE

Our study aimed to investigate differences in joint stabilization and movement coordination provided by upper extremity orthotics fabricated with low-temperature thermoplastics of different thicknesses.

STUDY DESIGN

Inferential, cross-sectional study.

METHOD

We conducted a kinematic analysis of a standardized task through a three-dimensional motion capture system. Ten participants (5 female) performed the same task under three circumstances: 1) wearing a volar wrist immobilization orthosis, made with a 3.2-mm thick low-temperature thermoplastic; 2) using the same orthotic fabricated with a 1.6-mm thick material; and (3) without orthoses. We divided the standardized task into five logical phases for data analysis, obtaining the active range of motion of the shoulder, elbow, forearm, and wrist joints as the primary outcome. Secondary outcomes included movement smoothness and coordination, measured by the number of motor units, time, and distance travelled by the upper extremity.

RESULTS

Despite changes in thermoplastic thickness, both orthotics significantly restricted the wrist motion during task performance (F(2,16) = 14.32, P < .01, and η2p = 0.797), with no difference between the 2 devices and no significant changes to proximal joints' active range of motion. Although orthoses use increased the time required for task performance (F(2,16) = 23.05, P < .01, and η2p = 0.742), no significant differences in movement smoothness or coordination were noted.

CONCLUSION

Our results indicate that wrist orthoses fabricated with a 1.6-mm thick low-temperature thermoplastic can provide joint stabilization similar to a device made from a 3.2-mm thickness material, suggesting thinner thermoplastics' efficacy to stabilize joints in the absence of contractures or preexisting chronic conditions.

A Soft Pressure Sensor Skin to Predict Contact Pressure Limit Under Hand Orthosis

Customized static orthoses in rehabilitation clinics often cause side effects, such as discomfort and skin damage due to excessive local contact pressure. Currently, clinicians adjust orthoses to reduce high contact pressure based on subjective feedback from patients. However, the adjustment is inefficient and prone to variability due to the unknown contact pressure distribution as well as differences in discomfort due to pressure across patients. This paper proposed a new method to predict a threshold of contact pressure (pressure limit) associated with moderate discomfort at each critical spot under hand orthoses. A new pressure sensor skin with 13 sensing units was configured from FEA results of pressure distribution simulated with hand geometry data of six healthy participants. It was used to measure contact pressure under two types of customized orthoses for 40 patients with bone fractures. Their subjective perception of discomfort was also measured using a 6 scores discomfort scale. Based on these data, five critical spots were identified that correspond to high discomfort scores (>1) or high pressure magnitudes (>0.024 MPa). An artificial neural network was trained to predict contact pressure at each critical spot with orthosis type, gender, height, weight, discomfort scores and pressure measurements as input variables. The neural networks show satisfactory prediction accuracy with R² values over 0.81 of regression between network outputs and measurements. This new method predicts a set of pressure limits at critical locations under the orthosis that the clinicians can use to make orthosis adjustment decisions.

Work-related risk factors for Carpal Tunnel Syndrome among Majmaah University female touchscreen users

Objectives:

This study aimed to explore the prevalence of carpal tunnel syndrome symptoms among female touchscreen users at Majmaah University, Saudi Arabia and to make a comparison for the wrist range of motion between probable CTS and non-CTS female touchscreen users.

Methods:

Two hundred and twenty-two female touchscreen users were enrolled in the present study. Among this cohort, fifty-two were academic members, 40 were employees and 130 were undergraduates. A Digital Inclinometer device was used to assess ROM of the wrist movements. A computer-based questionnaire, Phalen’s test, and Tinel’s sign were used to investigate the presence of CTS symptoms. The study was conducted between November 2018 and February 2019 at Majmaah University.

Results:

The prevalence of probable CTS was 34.2% among touchscreen users; the percent of probable CTS was significantly higher in undergraduates compared to other touchscreen users. There was a significant reduction in wrist flexion between the tested groups.

Conclusion:

Female touchscreen users at Majmaah University tended to have a high-risk for CTS. Wrist ROM measurements, particularly wrist flexion, could be a beneficial indicator for anticipating deviations in wrist posture after long-term touchscreen use. It is necessary to consider the job nature, age, BMI, and duration of using touchscreen as risk factors for CTS symptoms.