Thumb Strength and Mobility in deQuervain's Disease

Purpose: deQuervain's disease is caused by a stenosis of the first dorsal compartment of the wrist, which contains extensor pollicis brevis and abductor pollicis longus tendons, resulting in thickening of the overlying retinaculum. The most incapacitating symptom is pain over the radial side of the wrist. Other symptoms can include impaired function of the thumb, stiffness, neuralgia-like complaint, limited range of motion (ROM) and decreased strength. In clinical settings, frequent evaluations in this population consist in assessing ROM, with either a goniometer or the distance between two anatomical landmarks, and grip or pinch strength with a hand-held dynamometer or a pinch gauge. Unfortunately, these “standard” evaluations assess mostly the movement and strength of the flexor and adductor muscles of the thumb and may overlook some deficits present in pathologies, such as deQuervain's disease, involving the extensor and abductor apparatus. Furthermore, when the injury is unilateral, the usual clinical practice is to compare the symptomatic to the asymptomatic limb to quantify the severity of the deficits. However, some studies demonstrate significant differences between the capacities of asymptomatic limbs and those of limbs of control groups. The aim of the present study is to verify the adequacy of comparing strength and mobility of the symptomatic thumb to those of the asymptomatic one in subjects presenting unilateral deQuervain's disease. The study hypotheses are that the strength and mobility of the symptomatic thumb of subjects with deQuervain's disease will be diminished compared to the asymptomatic one and that the capacities of the asymptomatic thumb will be similar to those of the control group.