A splint is an external device used to support, immobilize, or protect a body part. A dynamic splint is a specialized orthosis designed for rehabilitation that applies controlled, gentle forces to improve joint mobility and tissue length. Unlike a static splint, which holds a joint in a fixed position, the dynamic version incorporates a moving component to facilitate a therapeutic stretch, restoring function and range of motion following injury, surgery, or disease.
The Mechanism of Controlled Movement
The foundational principle behind dynamic splinting is the application of continuous low-load force (CLLF), also known as low-load prolonged stretch (LLPS). This method contrasts with aggressive, short-duration stretching, which can cause pain, tissue microtrauma, or rebound stiffness. Dynamic splints use adjustable components, such as integrated springs, elastic cords, or rubber bands, to exert a constant, measurable tension on the affected joint or shortened soft tissue.
The controlled force encourages a biological process in the connective tissues called creep or plastic deformation. Connective tissues, such as ligaments, tendons, and joint capsules, are composed largely of collagen fibers. When exposed to a sustained load, the collagen fibers gradually rearrange, leading to a permanent increase in tissue length. This gentle, sustained stretch remodels shortened or scarred connective tissue that forms contractures, allowing the joint to achieve a greater passive range of motion. The force applied is relatively small, but its effectiveness comes from the extended duration of its application.
Conditions Requiring Dynamic Splinting
Dynamic splinting is primarily prescribed for patients experiencing joint stiffness or a loss of passive range of motion, medically termed a joint contracture. These contractures occur when connective tissue is scarred or shortened due to prolonged immobilization, trauma, or disease. Post-operative recovery is a significant indication, particularly following procedures like joint replacement, ligament repairs, or complex tendon grafts, as the splint helps prevent the formation of dense adhesions and scar tissue.
Following flexor or extensor tendon repairs in the hand, a dynamic splint protects the repair site while initiating controlled movement to prevent the tendon from adhering to surrounding structures. It is also used for peripheral nerve injuries, such as radial nerve palsy, where the splint provides functional positioning and prevents contractures while the nerve regenerates. Common joints that benefit include the small joints of the hand and wrist, the elbow, and the knee, where restricted mobility significantly impacts daily function.
Practical Considerations for Use
Effective use of a dynamic splint relies heavily on patient adherence to the prescribed wearing schedule. To achieve the desired tissue remodeling effects, the splint must typically be worn for a minimum of six to twelve hours daily, frequently during periods of rest or sleep. A physical or occupational therapist determines the precise schedule, which may involve several shorter sessions or a single prolonged period.
Because the device applies sustained pressure, monitoring skin integrity is an ongoing requirement to prevent pressure sores or skin breakdown. Patients and caregivers must regularly inspect the skin underneath the splint’s cuffs and straps for redness or irritation. The splint must also be kept clean, often involving mild soap and water, to maintain hygiene. As the joint’s range of motion improves, the tension provided by the dynamic components requires regular adjustment by the prescribing therapist to maintain the low-load force at the new end-range of motion.