Isometric strength for flexion and extension decreased by 29.3% and 32.5%, respectively ( 14). The cross-sectional area of the forearm muscle decreased by 4.1%. In one study, subjects spent 9 days wearing a cast suspended from the neck by a sling that immobilized muscles acting on the wrist. These changes may lead to situations such as persistent stiffness and pain, muscle atrophy, and decreased range of motion-conditions that inevitably produce dysfunction and/or disability ( 12, 13). Immobilization has clearly detrimental effects on the surrounding tissues, including shortening, decreased tensile strength, edema formation, venous stasis, and atrophy ( 11). It is important to understand the negative consequences of joint immobilization and the need for early motion. Skeletal muscle strength declines by 1% to 1.5% per day after strict bed rest ( 9), and the decline in strength is even more profound (1.3% to 5.5% per day) with cast immobilization ( 10). This decrease in muscle mass is accompanied by decreases of 6% to 40% in muscle strength ( 8). Research has shown that a dramatic change in muscle mass occurs within 4 to 6 weeks of bed rest. It has been shown that changes in the mechanical properties of the spine occur after only 4 days of bed rest ( 7). As the tissue contracts and reorganizes, it becomes denser and, usually within a week, results in restricted range of motion ( 6).ĭegenerative changes to bones and muscles also occur rapidly during immobilization. By the third day ( 5), degenerative changes are seen in chondrocytes in the areas of contact between articular surfaces, and by the fourth day, there is a marked decrease in proteoglycan content ( 4). The second day brings a noticeable decrease in proteoglycans ( 4), which contribute to the stiffness of cartilage.
Within the first day of immobilization, chondrocyte activity changes, signaling the beginning of degeneration ( 1). Connective tissue, which tends to shorten very slowly and progressively if it is not opposed by a considerable force ( 2), contains chondrocytes that are responsible for the formation, maintenance, and repair of articular cartilage ( 3). When a joint is immobilized, the muscles, bones, and surrounding connective tissue begin to degenerate quickly ( 1). We encourage the development of consistent discharge instructions that will promote early mobility and a safe and rapid return to normal activities. Based on these results in a small group of patients, it appears that requiring the use of a joint immobilization sling is overly restrictive, promotes fear, and hinders recovery. No lead displacement occurred after the weightlifting exercises were performed.
As an adjunct to the study, we queried clinicians at 48 US hospitals about sling immobilization and activity restrictions after pacemaker/ICD implantation at their institutions. For each subject, an electrophysiology nurse specialist used a noninvasive device programmer to evaluate surgical lead placement before and after the exercises.
Ten subjects who had undergone pacemaker/ICD surgery performed four individual resistive range-of-motion exercises (three sets of 10 repetitions for each: one warm-up set without weight and two sets with a 1- or 2-pound hand weight) with the affected arm prior to hospital discharge. We examined whether performing a resistive range-of-motion exercise protocol after pacemaker/ICD surgery would result in lead displacement and, therefore, whether sling immobilization and activity restrictions are justified. After pacemaker/implantable cardioverter-defibrillator (pacemaker/ICD) implantation, patients are often required to immobilize the affected arm with a sling to minimize the risk of lead displacement.
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