Physical Therapy for Cast Immobilization

Often after an injury or surgery, a patient undergoes a period of immobilization to allow the injured area or surgical site to heal properly and to reduce the risk of further damage. Cast immobilization is useful in a variety of situations, however, a number of problems can arise from this form of treatment. In particular, patients often suffer decreased cardiovascular fitness, muscle strength, and range of motion to the injured limb. Physical therapy counters these adverse effects, reduces recovery time, and allows the patient to return to normal activities quickly and safely.

Cardiovascular Fitness
Cardiovascular or aerobic fitness can be lessened if your immobilized limb leads to a decrease in physical activity. For example, a patient with a long leg cast who must use crutches finds it difficult to do many of the daily activities that he or she did before the injury. To improve cardiovascular fitness, a physical therapist can design an aerobic program that fits your needs and injury. You may use a stationary bike if you have an immobilized upper extremity, or an upper extremity arm bike can be used if you cannot use your legs. If you want to return to an active lifestyle, a cardiovascular program accelerates your rate of return and helps if you are less active by increasing the blood flow and oxygen to the healing tissue to speed the healing process.

Loss of Muscle Strength
Another significant problem related to immobilization is muscle atrophy, or loss of muscle strength and size, which often begins around day 10 of immobilization (Fig. 1). To combat atrophy, a physical therapist often prescribes isometric exercises which are done by contracting the muscle against resistance but without moving the joint (Fig 2). Although the muscle does not work through the normal range of motion, the contraction and hold improves muscle strength and slows the results of muscle atrophy.

Regaining Movement
After cast removal, regaining movement is the next step in physical therapy. The immobilized body part is generally stiff and difficult to move depending on the length of immobilization. Typically, 6 to 8 weeks of immobilization are required for adequate healing of bone fractures. During this time, muscle tissue and other connective tissues affected by the immobilization often undergo changes. These tissues not only weaken due to lack of normal use, but they can also shrink, thereby limiting normal motion. With daily use, your motion is usually regained, however, a physical therapist can help you progress faster and more safely through exercise, stretching, and other therapies. The physical therapist helps you regain normal use of the extremity, pushes for a speedier recovery, and decreases the risk of injury to the weakened tissue. For the active or athletic population, this phase of therapy includes higher level exercises such as plyometric (vigorous drills), proprioceptive (receiving stimuli with the muscles and tendons), and sport specific training. These activities ensure a safe return to your desired activity level.

If you require some type of immobilization, physical therapy can speed your return to full activity, improve function, and decrease the risk of future injuries.

William Larkin, SPT and James A. Mullennax, MS, PT
Columbus, Georgia

Additional Readings:
Andrews JR, Harrelson GL, Wilk KE. Physical Rehabilitation of the Injured Athlete. Philadelphia, PA: WB Saunders Co; 1999:18-34.
McLatchie GR. The Soft Tissues: Trauma and Sports Injuries. Oxford, England: Butterworth-Heinemann Ltd; 1993:83-87. Perrin DH. The Injured Athlete. 3rd ed. Philadelphia, PA: Lippincott, Williams & Wilkins; 1999:123-124.
Scully RM., Barnes MR. Physical Therapy. Philadelphia, PA: JB Lippincott Co; 1989:166-167, 715-719.