Annals of Long Term Care

Joint contractures impair quality of life and lead to further complications and disability. In severe dementia, many patients are seen in a fetal position. This position causes flexion of the muscles at joints, causing the muscles to undergo shortening, resulting in degenerative tissue changes, and then leading to potential irreversible deformity. The authors discuss the development of joint contractures in Alzheimer’s disease (AD), where it is thought that the natural progression of AD terminates with patients in the fetal position. It has been postulated that this fetal position causes the high incidence of contractures seen in end-stage AD. However, in many situations it is the absence of adequate prevention strategies that produces contractures. (Annals of Long-Term Care: Clinical Care and Aging 2010;18[8]:26-33)

Joint contractures are well recognized in the geriatric community as a disabling complication of dementia. They impair quality of life and lead to further complications and disability. In severe dementia, patients are commonly seen in a fetal position. The flexion of the muscles at joints causes the muscles to undergo shortening, resulting in degenerative tissue changes, and then leading to potential irreversible deformity. The upper limb is seen in a flexed position with adduction at the shoulder joint and flexion at the elbow, wrist, and fingers. In the lower limb, the hip is usually flexed with inversion of the feet. Earlier intervention with regular passive movements of the affected limbs may prevent contracture development.¹Prevention is thought to be the best medicine for contracture management.

In this article, we will discuss the development of joint contractures in Alzheimer’s disease (AD). It is thought that the natural progression of AD terminates with patients in the fetal position. It has been postulated that this fetal position causes the high incidence of contractures seen in end-stage AD. However, in many situations it is the absence of adequate prevention strategies that produces contractures, resulting in patients assuming the fetal position.

Joint Development and Physiology
Joints are organs with the function of providing skeletal articulation and allowing movement of the skeletal frame. A joint is stabilized by its capsule, tendons, and ligaments. The ligaments, which are dense connective tissue, provide connection between bones, whereas the tendons connect muscle to bone, which is integral in stabilizing the joint.

Joints first appear at six weeks of gestation. The external mesenchymal tissue forms the joint capsule and tendon, and the internal layer forms the synovial membrane and meniscus. This typically occurs at seven weeks. In a week’s time, cavitation usually occurs, with the end result of an articular cavity.²

Skeletal muscle is comprised of muscle fibers and connective tissue. Each muscle fiber contains thousands of myofibrils, which in turn comprise thick and thin filaments, called myosin and actin, respectively. It is these thick and thin filaments that account for muscle contractions.³ Muscles contain both contractile tissue and connective tissue.⁴ The contractile component contains filaments that move past each other to cause contraction or lengthening. The connective tissue is what contains the filaments, fibrils, and fibers together. Connective tissue is made up of both collagen and elastic fibers. The collagen provides tensile strength, whereas the elastic fibers are elastic.⁴ During normal development, muscles grow by adding sarcomeres to the ends of myofibrils. Growth is influenced by rate of bone growth, amount of stretch, presence or absence of hormones, and nutritional status.⁴ A muscle contains multiple motor units that are involved in contraction of muscle fibers.