Superimposed Electrical Stimulation Real-time Effects on Repeated Muscle Contractions Enable to Increase Recovery From Thumb Joint Stiffness After Surgery of the Ulnar Collateral Ligament

Background

One of the potentially debilitative complications of operative repair and subsequent immobilization is stiffness that appears secondary to inflammation and adhesions. To prevent such a physical impairment, active joint mobilization has shown to be efficient. However, adhesions sometimes remain despite the therapy. Due to the viscoelastic nature of the biological tissues, if a technique can enable to extend the muscle ability to impose a maximal steady stress on adhesions, adhesion deformation should be greater and range of motion deficit should be reduced. Within that context, the purpose of the present study was to assess the real-time effects of superimposed electrical stimulation (SES) on maximal voluntary muscular contraction (VOL) over time and to assess SES effects on range of motion recovery in thumb stiff joint.

Methods and Findings

The aim of the first experiment was to examine the real-time effects of tetanic SES on the maximal volitional level of force over repeated contractions of the triceps brachii muscle. To address this goal, seventeen subjects participated voluntarily in this study. Two features of the muscular force were assessed: The peak force (1) and the impulse (2). These two dependent variables were measured during 500 sec - including 50 maximal force productions of 4 sec each- in two randomized conditions of VOL and SES. When considering the 50 trials as a whole, exerted force was higher in the SES than in the VOL condition for both peak force and impulse (P<.05). Over time, peak force and impulse decreased consistently in VOL starting between the 20th and 30th trials whereas they were maintained in SES condition (P<.05).

The aim of the second experiment was to compare the effects of VOL and SES on the range of flexion recovery of the stiff metacarpophalangeal joint following operative repair of the ulnar collateral ligament of the thumb. To address this goal, eight patients participated voluntarily. Range of motion, oedema and pain were assessed before and after the two randomised conditions of VOL and SES.