Objective: The aim of this study was to compare clinical and ultrasound findings of thumb joints in young adults with and without thumb pain associated with text messaging.

Methods: In this case-control study, 117 students with thumb pain associated with text messaging were evaluated clinically and with ultrasound analysis of the thumb. Age- and sex-matched controls received ultrasound evaluation to note any subclinical changes.

Results: Clinical examination in the cases identified tenderness most commonly in the metacarpophalangeal joints, followed by the carpometacarpal joints, and then the interphalangeal joints. Tenderness was noted in the web space and the anatomic snuff box. Hypermobility on the Beighton scale was recorded as 2. Grind tests were positive in 21% of participants. Grip strength did not differ, but lateral and tip pinch strength were significantly reduced in the cases compared with controls. Fluid was detected in the metacarpal joints by ultrasound but not in the carpometacarpal or interphalangeal joints. No changes were detected in the controls.

Conclusion: Clinical examination indicated involvement of all joints of the thumb, but ultrasound evaluation could identify changes only in metacarpal joints, indicating signs of possible subclinical changes taking place in the thumb in these participants as a result of repetitive use.

Author keywords: Thumb; Carpometacarpal Joints; Metacarpophalangeal Joint

Author affiliations:  CE: Department of Physiotherapy, KMC Mangalore, Manipal University, Mangalore, Karnataka, India; BK, AKB: Department of Orthopaedics, KMC Manipal, Manipal University, Manipal, Karnataka, India; AV: Department of Radiodiagnosis, KMC Mangalore, Manipal University, Mangalore, Karnataka, India

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