Immobilization has beneficial effects in the early phase of muscle regeneration and is crucial for fracture healing. However, lengthy immobilization has detrimental effects: it causes
- Joint stiffness
- Degenerative changes in articular cartilage
- Muscle atrophy
- Weakness and stiffness
Complete immobilization is primarily required for acute fractures. Certain stress fractures, For example, tarsal navicular fractures, also require immobilization. Occasionally in severe soft tissue injuries, it may be helpful to immobilize the injured area for upto 48 hours to limit pain and swelling.
Immobilization can be obtained through the use of rigid braces, air splints, and taping, thermoplastic materials or, most commonly, with the use of a plaster cast. Plaster casts have the disadvantages of being relatively heavy, prone to damage and not water -resistant. For undisplaced fractures and immobilization of soft tissue injuries, fiberglass casts are preferred. Fiber glass casting material is light, strong and waterproof. A waterproof under wrap is available that enables the athlete to bathe without the need to protect the cast. This allows those with lower limb casts to exercise in water to maintain fitness.
Protected Mobilization
Mobilization on the other hand, has numerous tissue benefits.
- One way to achieve early, but safe, mobilization is by protected mobilization.
- This term refers to use of protective taping or bracing to prevent movement in a direction that would cause excessive stress on an injured structure. For example, a hinged knee brace prevents valgus strain in a second degree medial collateral ligament injury.
- Non-injured structures are allowed to move (i.e. the knee joint continues to function), and this feature distinguishes protected mobilization from complete immobilization.
- This allows enough movement to prevent stiffness, maintain muscle strength and improve the nourishment of the articular cartilage, while still protecting the damaged ligament.
- Early mobilization in patients with acute limb injuries (e.g. ankle sprain, stable fractures and after surgical tendon repair).decreases pain and swelling, and improves functional outcomes compared to cast immobilization.
Continuous Passive Motion
Continuous Passive Motion (CPM) may be used after surgery using a specific CPM machine. It is particularly beneficial when pain limits active range of motion exercises or when there is a need to control the range of movement to allow wound healing.CPM may also encourage nourishment of articular cartilage and minimize joint stiffness.CPM may have a role in the early stages of treatment of second or third degree muscle tears, for example, in the hamstring or quadriceps to encourage alignment of healing fibers.
Mobilization and Exercise Therapy
Whether early mobilization or exercise therapy is treatment or rehabilitation remains a gray area. However, we emphasize that exercise therapy itself may provide a tissue regenerative stimulus. For example, with respect to muscle, early mobilization promotes rapid and intensive capillary ingrowths into the injured area, regeneration of muscle fibers and more parallel orientation of myofibers compared with immobilization. In tendon it appears that certain strengthening protocols (e.g. heavy resistance training heel drops) may stimulate collagen synthesis among tendon cells which, in turn, strengthen tendon.
