Causes and Treatments for Muscle Contracture

A muscle contracture, also known as a contracture deformity, is a permanent shortening and tightening of muscle fibers that reduces flexibility and makes movement difficult. It is caused when a muscle loses elasticity. If a muscle cannot move and be stretched, the nearby joints also lose mobility and become painful.

When trying to stretch the contracted muscle, a person will feel the muscle become very rigid, which will cause increased pain.

Muscles Affected

Muscles that are flexors, those that bend the joints to bring body parts closer to the body, are the ones most affected by contractures. The stiffening and tightening of these muscles prevent the body parts from being moved out and away from the body.

The most common muscles affected by muscle contractures are:

• Wrist and finger flexors: Groups of muscles that bend the wrist and fingers
• Biceps brachii: The main elbow flexor that bends the arm
• Gastrocnemius and soleus: The calf muscles that allow the ankle to point the foot (plantarflexion)
• Hamstrings: A group of three muscles at the back of the thigh that bend the knee

Causes

Muscle contractures, or muscle tissue that is stiffer than normal and difficult to stretch, are caused by permanent shortening of muscle fibers and the change in normal muscle structure. 

Sarcomeres are fundamental units of muscles that cause muscle fibers to contract. With muscle contractures, sarcomeres overly lengthen when muscle fibers tighten. This increase in sarcomere length prevents the muscle from contracting normally, resulting in muscle weakness.

Muscle fibers are encased in an extracellular matrix, a mesh-like web composed of collagen and other proteins that help transmit force and provide muscle contraction. With muscle contractures, the amount of collagen within the extracellular matrix increases, causing a stiffening of fibers that restricts movement.

Muscle contractures also form from a decrease in satellite cells. Satellite cells, which are specialized stem cells that can rebuild muscle, are necessary for muscle regeneration and repair. Without an adequate amount of satellite cells, other cells like fibroblasts significantly increase inside muscle tissue, causing muscle fibers to become stiff and fibrotic (more fibrous).

These changes to the sarcomeres, collagen within the extracellular matrix, and satellite cells all result from conditions in which neurological input to the muscles from the brain and spinal cord is reduced. This is caused through lack of use, from injury, or from neurological and neuromuscular conditions, such as in the following list.

Cerebral Palsy

Contractures often occur from upper motor neuron lesions that prevent signals from traveling from your brain and spinal cord to the motor neurons that control muscle contraction. When these signals are weakened or blocked, muscles become stiff and weak due to a lack of stimulation.

Cerebral palsy is a group of disorders affecting mobility that are caused by an upper motor neuron lesion. Cerebral palsy is present at birth and is the most common motor disability in children. It causes cognitive impairment, decreased muscle strength, and problems with movement, coordination, and functional motions like walking.

Because cerebral palsy prevents the muscles of the legs from being sufficiently stimulated, contractures commonly develop in the hips, knees, and ankles.

Clinical research suggests that patients with cerebral palsy can have as much as a 75% decrease in satellite cells that help repair muscle tissue and prevent muscle fibrosis, or stiffening. Specific genes linked to collagen production are also altered, causing irregular changes to the extracellular matrix of muscles.

Muscular Dystrophy

Muscular dystrophy is a group of inherited neuromuscular disorders characterized by muscle weakness and wasting. Lack of nerve supply to muscles causes them to become stiff and tight, which inhibits the functional range of motion needed to move joints and activate muscles to move the arms and legs.

Clinical research also suggests that people with muscular dystrophy have decreased levels of satellite cells that help repair muscles, increasing the risk of developing muscle contracture.

Lack of Use

When muscles are not used for a long time because of prolonged bed rest, hospitalization, or immobilization from wearing braces, splints, or casts after injuries, blood flow and electrical signaling from nerves to muscles decrease. This results in weakness, increased muscle tightness and stiffness, and muscle wasting, called atrophy.

Over time, stiff and tight muscles can progress to contractures that become very difficult to stretch. 

Trauma or Injury

Injury to muscles or tendons can cause contractures as scar tissue develops, joining muscle fibers and joints together. This development significantly restricts movement. Large burns also can cause contractures of the skin, muscles, and joints. Without aggressive treatment, range of motion can become significantly limited, and these changes can become irreversible. 

Other Causes

Other forms of upper motor neuron lesions that can cause contractures from a lack of electrical input to muscles as a result of brain or spinal cord damage include strokes, traumatic brain injuries, and spinal cord injuries.

Other conditions that are characterized by muscle and joint contractures are neuromuscular disorders like spinal muscular atrophy (SMA) and conditions that cause inflammation and the stiffening of joints, such as juvenile rheumatoid arthritis. A long history of diabetes also increases the risk of developing contractures that affect the finger flexors, such as Dupuytren’s contractures and trigger finger.

Symptoms

Symptoms of contractures include incredibly stiff and tight muscles that are resistant to stretching, which causes pain, decreased range of motion, and impaired joint mobility.

When contractures are severe, they can interfere with the functional range of motion needed to move joints to complete daily tasks and movements like standing up from a chair and walking. 

Treatment

Physical Therapy

Physical therapy can help decrease the severity of muscle contractures through stretching and soft tissue mobilization to decrease muscle tightness.

Exercise

Regular exercise can help maintain proper joint mobility and range of motion to reduce joint stiffening and muscle tightening. Exercise also improves blood flow and activates muscles, which helps prevent contractures from forming.

Braces or Splints

Specialized braces or splints can be custom-made to fit different body parts and provide a prolonged low-intensity stretch over a long period of time to increase muscle length. Once muscle length has increased, a new brace or splint may need to be made to adjust to the changing range of motion.

Surgery

Surgical release of contracted muscle tissue may be necessary in severe cases in which muscle contractures limit the functional range of motion needed for activities of daily living (ADLs). This type of surgery also can improve functional movements like walking and getting in and out of bed and up from chairs. Tight muscles can be surgically cut and tendons can be lengthened to allow for more mobility.

Summary

Muscle contracture causes muscles to become tight and difficult to move and stretch. The causes of muscle contracture are not always avoidable, but a wide range of treatment options is available to help loosen up tight muscles and preserve or restore the range of motion of your muscles.

A Word From Verywell

Contractures often develop after prolonged bed rest, inactivity, or lack of use of certain muscle groups. To reduce the risk of muscle tightness and to prevent contractures from developing, it’s important to move daily and stretch common areas like the fingers, arms, and legs. 

For contractures that are severe or develop from neuromuscular disorders, it is important to seek medical treatment, including physical and occupational therapy, to prevent contractures from worsening and to try to regain as much functional range of motion as possible. Delaying treatment can potentially cause irreversible symptoms.