Biomechanical Behavior of the Flexor Tendon in Patients with Trigger Finger

Abstract

Trigger finger (TF) also called stenosing tenosynovitis is a disease commonly seen in hand clinics The disease may affect one or several digits impairs hand function and is likely to negatively affect working ability and quality of life According to the current clinical observation the cause of TF is attributed to the disparity in size between the flexor tendon and the A1 pulley The pathophysiologic mechanism behind trigger digits remains controversial It has generally been ascribed to primary changes in the first annular pulley However in recent findings the gene expression and the pathology of TF resemble that of tendinosis in the Achilles tendon and thus it has been speculated that TF may be a form of tendinosis and the mechanical properties of tendon may be affected Previous studies investigated the tendon’s mechanical properties in vivo and focused on the lower-extremity The results indicated that tendinopathy might change the mechanical and material properties of the tendon The purpose of this study is to better understand the mechanical properties of flexor tendons and variations in the morphologies of the flexor digitorum tendon between normal and trigger fingers when in various positions Sonographic and custom-designed isokinetic dynamometer are used to measure tendon force at different finger flexion angles The measurements of the force and tendon displacement are used to learn more about the mechanical properties of flexor digitorum superficial (FDS) and profound tendons (FDP) In this study we recruited 15 healthy controls who did not have any hand disease or injury and 6 patients with trigger finger The results demonstrate that both the FDP and FDS tendons of the patients with trigger finger are significantly thicker and stiffer than in the controls As a result greater tendon forces were needed for the trigger finger patients to reach the same amount of tendon displacement Our research also explored the effects of different joint postures on force production and tendon stiffness between the two groups In both the distal and proximal interphalangeal joints of the healthy participants the tendon force decreased when the joint angle was increased and tendency not seen in the patient group In conclusion this study used imaging technology and the mechanical design to investigate the effects of different finger-joint positions on tendon force production and tendon displacement between healthy participants and patients with trigger finger It is hoped that the findings from this experiment may provide some information to be used in clinical diagnosis assessment and care for patients suffering from trigger finger in the future

Date of Award	2016 Aug 5
Original language	English
Supervisor	Fong-chin Su (Supervisor)