As Psoriatic Arthritis Disease Activity Increases, Hand Functionality Decreases

Busra Candiri

For the first time, results from a study showed that psoriatic arthritis (PsA) negatively affects hand strength. As disease severity increased, grip strength decreased, along with skill, coordination, and the functionality of the hand.

Investigators sought to evaluate the strength, proprioception, skill, coordination, and functional condition of the hand in patients with psoriatic arthritis. They measured these functions in correlation with disease activity.

This study was conducted by a team of investigators led by Busra Candiri, Faculty of Health Sciences, Physiotherapy and Rehabilitation Department, Inonu University.

Understanding the Objective

Tissue biomechanical stress and microtraumas lead to activation of abnormal innate immune responses in psoriatic arthritis, which can trigger joint inflammation. Inflammation in peripheral joints are more exposed to trauma.

Investigators referenced an evaluation that was conducted on 28 hand joints in patients with psoriatic arthritis. The ultrasound showed abnormal synovial thickening in all patients included.

It was determined that abnormal ultrasound findings in the hand joints correlated with disease activity measured by the Disease Activity Score 28 (DAS28).

“Although evaluations have been made on the strength of the hand in patients with PsA,” investigators wrote, “if we examine hand functions as a whole, the research on hand proprioception is limited and there is no research in the literature on hand skills.”

Evaluating disease severity and level of strength

At the conclusion of the study, after multiple exclusions of individuals who were not eligible for various reasons, there were a total of 36 patients in the group with psoriatic arthritis and 20 individuals in the control group.

The hand functions of the individuals were examined according to their dominant hand and without including dominance. In the psoriatic arthritis group, 94.4% were right-hand dominant and 80% were right-hand dominant in the control group.

Results show that right and left grip strength and lateral pinch, two-point pinch, and three-point pinch strength were significantly lower in the group with psoriatic arthritis compared with the control group.

No significant difference was found between the groups when comparing flexion, extension, and radial deviation joint position sensation error amounts. The ulnar deviation error amount was significantly higher in the psoriatic arthritis group.

There was no significant difference in the right and left hands when examined according to the dominant hand. The only difference was found between the left-hand ulnar deviation error amounts of the right-dominant individuals between both groups.

Measuring Disease Activity

This study consisted of individuals who were aged 18-65 years. The group of patients with psoriatic arthritis consisted of 36 outpatients who were diagnosed with psoriatic arthritis, under regular medical supervision, and received drug therapy.

Healthy individuals were evaluated to be part of the control group. Participants in each group were selected by a random sampling method.

Criteria for exclusions were neurological diseases causing sequelae in the hand, upper extremity surgeries, neuropathies, traumas and history of nerve damage, psychiatric disorders, and reluctance to continue the evaluation as well as patients with chronic pain in the upper extremity joints.

The disease activity of patients with psoriatic arthritis was determined by using the Disease Activity Score 28 (DAS28).

This measurement method allowed investigators to classify patients with psoriatic arthritis into categories including remission (less than 2.6), mild activity (2.6-3.2), moderate activity (3.2-5.1), and high activity (≥ 5.1).

“The results show that all subparameters of grip and pinch strength were significantly lower in patients with PsA,” investigators wrote, “and were moderately associated with disease activity.

This study, “Effect of psoriatic arthritis on the strength, proprioception, skill, coordination, and functional condition of the hand” was published in the International Journal of Rheumatic Diseases.