The Impact of Muscle Contracture on Joint Mobility

Can physical therapies help relieve muscle contractures in individuals who have endured prolonged bed rest, inactivity, or lack of use of certain muscle groups?

Muscle Contracture

A muscle contracture, or contracture deformity, is caused when a muscle loses elasticity. This causes permanent shortening and tightening of muscle fibers, which reduces flexibility and makes movement difficult. Muscles that cannot move and stretch cause the surrounding joints to lose mobility and develop pain symptoms. When trying to stretch the contracted muscle, the individual will feel the muscle become very rigid, which can increase pain. (Lieber, R. L., and Fridén, J. 2019) Delaying treatment can potentially cause irreversible and chronic symptoms.

Commonly Affected Muscles

Flexor muscles bend the joints and are those most affected by contractures. The stiffening and tightening prevent the body parts from moving out and away. The most common include:

Wrist and Finger Flexors

• Muscle groups that bend the wrist and fingers.

Biceps

• The primary elbow flexor that bends the arm.

Gastrocnemius and Soleus

• The calf muscles which allow the ankle to point the foot/plantarflexion.

Hamstrings

• A group of three muscles behind the thigh that bend the knee.

Causes

The permanent shortening of muscle fibers and changes in muscle structure cause muscle contractures or stiffer-than-normal tissue that is difficult to stretch. Sarcomeres are structural units of muscles that cause fibers to contract.

With contractures, the sarcomeres overly lengthen when the muscle fibers tighten. This increase in sarcomere length prevents the muscle from contracting normally, resulting in weakness. Muscle fibers are encased in an extracellular matrix, a mesh composed of collagen and other proteins that help transmit force and provide muscle contraction. Muscle contractures cause the amount of collagen within the extracellular matrix to increase, causing a stiffening of fibers that restricts movement. (Lieber, R. L., and Fridén, J. 2019)

Muscle contractures also form from decreased satellite cells. Satellite cells are specialized stem cells that can rebuild muscle and are necessary for muscle regeneration and repair. Without the proper amount of satellite cells, other cells like fibroblasts significantly increase in the muscle tissue, causing the fibers to become stiff and fibrotic or more fibrous. These changes to the sarcomeres, collagen within the extracellular matrix, and decreased satellite cells all result from conditions in which neurological input to the brain and spinal cord muscles becomes reduced. This is caused by lack of use, injury, or neurological and neuromuscular conditions. (Lieber, R. L., and Fridén, J. 2019)

Cerebral Palsy

Contractures often occur from upper motor neuron lesions, which prevent signals from the brain and spinal cord from reaching the motor neurons that control muscle contraction. When these signals are weakened or blocked, muscles become stiff and weak from lack of stimulation. (Lieber, R. L., and Fridén, J. 2019)

Cerebral palsy is a group of disorders affecting mobility caused by an upper motor neuron lesion that is present at birth and is the most common motor disability in children. It causes:

• Cognitive impairment
• Decreased muscle strength
• Problems with movement, coordination, and functional motions.

Because cerebral palsy prevents the muscles of the legs from being sufficiently stimulated, contractures commonly develop in the hips, knees, and ankles.  Individuals can have a 75% decrease in satellite cells to 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. (Lieber, R. L., and Fridén, J. 2019)

Muscular Dystrophy

Muscular dystrophy is a group of inherited neuromuscular disorders characterized by muscle weakness and wasting. Deficient nerve supply to muscles causes them to become stiff and tight, inhibiting the functional range of motion needed to move joints and activate muscles to move. Clinical research suggests that individuals with muscular dystrophy have decreased levels of satellite cells to repair, increasing the risk of developing muscle contracture. (Lieber, R. L., and Fridén, J. 2019)

Disuse-induced Muscle Wasting or Disuse Atrophy

When muscles are not used for some time because of hospitalization, prolonged bed rest, or immobilization from wearing braces, splints, or casts after injuries, the blood circulation and electrical signaling from nerves to muscles decreases. This results in weakness, increased muscle tightness and stiffness, and muscle wasting/atrophy. Over time, stiff and tight muscles can progress to contractures that become extremely difficult to stretch.

Trauma or Injury

Muscle or tendon injuries can cause contractures as scar tissue develops, joining muscle fibers and joints together. This can significantly restrict movement. Large burns can also cause skin, muscles, and joint contractures. The range of motion can become significantly limited, and the changes can become irreversible if not aggressively treated.

Other Causes

Other forms of upper motor neuron lesions that can cause contractures because of weak or blocked electrical input to muscles as a result of brain or spinal cord damage include:

• Stroke
• Traumatic brain injuries
• Spinal cord injuries (Lieber, R. L., and Fridén, J. 2019)
• Neuromuscular disorders like spinal muscular atrophy – SMA.
• Conditions that cause inflammation and joint stiffening, like juvenile rheumatoid arthritis.
• A history of diabetes also increases the risk of developing contractures affecting finger flexors, like Dupuytren’s contractures and stenosing tenosynovitis
  or trigger finger. (Lieber, R. L., and Fridén, J. 2019)

Symptoms

Symptoms include:

• Extremely stiff and tight muscles resistant to stretching.
• Pain from the inability to stretch.
• Loss of range of motion.
• Impaired joint mobility.
• Severe contractures can interfere with the functional range of motion needed to move joints to complete normal tasks and movements, such as standing up from a chair and walking.

Treatment

Physical Therapy

• Physical therapies can help reduce the severity through stretching and soft tissue mobilization to decrease tightness. (Lieber, R. L., and Fridén, J. 2019)

Exercise

Regular exercise can:

• Reduce joint stiffening and muscle tightening.
• Help maintain joint mobility and range of motion.
• Improve blood circulation and muscle activation. (Lieber, R. L., and Fridén, J. 2019)

Braces and Splints

• Specialized braces or splints can be custom-made to fit different body parts.
• These provide a prolonged low-intensity stretch over a period of time to increase muscle length.
• Once the muscle has stretched, a new brace or splint may be needed to adjust to the increased range of motion. (Lieber, R. L., and Fridén, J. 2019)

Surgery

In severe cases where muscle contractures limit the functional range of motion needed for activities of daily living or ADLs, surgical release of the contracted tissue may be recommended. This surgery can improve functional movements like walking, getting in and out of bed, and standing up from chairs. The tight muscles can be surgically cut, and the tendons can be lengthened to allow more mobility. (Lieber, R. L., and Fridén, J. 2019)

The causes of muscle contracture are not always avoidable, but various treatment options are available to help loosen up tight muscles and preserve or restore the range of motion. It’s important to move daily and stretch common areas like the fingers, arms, and legs to reduce the risk of muscle tightness and prevent contractures from developing. It is imperative to seek medical treatment for severe contractures resulting from neuromuscular disorders, including physical and occupational therapy, to prevent contractures from worsening and regaining as much functional range as possible.

Injury Medical Chiropractic and Functional Medicine Clinic uses an integrated approach personalized to the individual that focuses on what works for them and treats injuries and chronic pain syndromes through personalized care plans that improve ability through flexibility, mobility, and agility programs to relieve pain. Our providers use an integrated approach to create personalized care plans for each patient, including Functional Medicine, Acupuncture, Electro-Acupuncture, and Sports Medicine principles. Our goal is to relieve pain naturally by restoring health and function to the body. If other treatment is needed, Dr. Jimenez has teamed up with top surgeons, clinical specialists, medical researchers, and rehabilitation providers to provide the most effective treatments.

Chiropractic Treatment for Cerebral Palsy

References

Lieber, R. L., & Fridén, J. (2019). Muscle contracture and passive mechanics in cerebral palsy. Journal of applied physiology (Bethesda, Md. : 1985), 126(5), 1492–1501. doi.org/10.1152/japplphysiol.00278.2018