Description of Intervention1-4
An opponens splint is a type of splint that immobilizes one or more joints of the thumb while allowing the other fingers to move freely. These splints are frequently prescribed for a variety of musculoskeletal conditions involving the thumb and its supporting structures, to provide stabilization and restricting motion. Opponens splints may be recommended to alleviate pain, provide stability, prevent, or correct a deformity, or improve functional ability for traumatic injuries (e.g., fractures, strains, and sprains), congenital defects, or neurologic disorders, among other conditions.
A long opponens splint is also known as a forearm-based thumb orthosis and immobilizes the wrist, carpometacarpal (CMC) joint, and/or the metacarpophalangeal (MP) and / or interphalangeal (IP) joints of the thumb. A short opponens splint—or hand-based thumb orthosis—immobilizes the CMC joint and usually the MP joint as well. If the thumb IP joint is involved, it may also be included in a short opponens splint. This type of splint will immobilize the thumb in either extension and abduction or opposition and abduction, depending on which is more appropriate for the patient’s condition.
Opponens splints are considered a key tool in the armamentarium of hand therapists, both Occupational and Physical Therapists for several reasons, including their cost-effectiveness and simplicity. Hand-based wrist splints are also easy to apply, easy to modify, and easy to remove to assess the extent and progression of the injury.
Indications for Intervention
A long or short opponens splint is indicated for patients with musculoskeletal conditions involving the thumb that require immobilization to provide stability, alleviate pain, and/or to improve physical function.
- Ask the patient to describe their medical history, with a focus on any recent injuries to the thumb and its supporting structures. Ensure the patient provides a detailed explanation of their symptoms, including onset and duration.
- Ask if the patient has any comorbidities, including diabetes, osteopenia, cardiovascular issues, or a history of smoking.
- Perform a physical examination of the hand and wrist. If range of motion (ROM) is impaired, measure the active and passive ROM of the joint(s) involved and compare these value(s) with the contralateral side.
- Ask the patient to rate their pain on the visual analogue scale (VAS) or a similar pain scale.
- Consider using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, which is used to assess impairment of the upper extremity.
- Other parameters that may be evaluated include task performance with a hand function test, power grip with a hand dynamometer, pinch grip with a hydraulic pinch gauge, and dexterity with a pegboard.5,6
- Assign a diagnosis based on the patient’s history, symptomatology, and examination findings, and prescribe an opponens splint if it is likely to benefit the patient.
Splinting Protocol1,4,7-10
If the patient is a good candidate for a long or short opponens splint, you may select either a prefabricated, custom-fitted, or custom-fabricated splint:
- Prefabricated splint: these splints are made by a manufacturer and can be purchased over the counter at pharmacies or with a prescription from orthopedic supply stores; therefore, prefabricated splints are not individualized for the patient and do not require any special fitting services, but patients can make minimal adjustments with Velcro straps to ensure the splint fits properly
- Custom-fitted splint: this is a type of prefabricated splint that requires bending, cutting, or molding the splint to fit the patient’s hand properly; it may be necessary to apply heat to manipulate the splint
- Custom-fabricated splint: these splints are individualized for each patient by taking castings, measurements, tracings, and images of the injured area that are used to create a specialized splint; you will then fabricate the splint by molding, drilling, sewing, or bending the splint material before fitting and applying it to the patient
Most therapists prefer either a custom-fitted or custom-fabricated opponens splint, but a prefabricated splint may be sufficient for some patients with minor symptoms. Opponens splints can be constructed with a variety of materials, including plaster, fiberglass, padding, ace wraps, metal, cloth, plastic, or leather. When determining which splint design is most appropriate, consider each patient’s specific diagnosis, the expected clinical outcome, and use clinical reasoning. If fitting or fabricating the splint, ensuring that it fits comfortably is among the chief goals. Pain medications may be needed before and during the splinting process. The splint should also allow for maximal sensory perception, and the pressure of the splint should be distributed equally. It should not challenge the normal contours of the hand and forearm and allow the non-immobilized joints to function normally and allow the patient to continue daily activities. Also be sure to ensure the thumb is positioned in such a way that maintains the first webspace to prevent contracture. Proper positioning is imperative when custom fabricating these splints for correct fit. Thumb to index opposition while moulding helps keep the patient’s hand in a functional posture so they may utilize the splint during functional task performance.
After the splint is applied, provide the patient with wear and care instructions, including cleaning directions, which vary by splint. The frequency and duration of use depend on the type and severity of the condition and the patient’s comfort level. In many cases it’s appropriate to recommend wearing the splint with daily activities and at night if the patient experiences interrupted sleep. The duration of use also varies, but usually begins with a period of 4–8 weeks, which may be extended if indicated and tolerated by the patient. Avoid prolonged immobilization, which can lead to stiffness. When the splint is not worn, encourage patients to continue moving their affected wrist normally to keep muscles flexible and strong.
An opponens splint is only one component of a treatment program and should be supplemented with other interventions during and after their use, particularly stretching and strengthening exercises, manual therapy, therapeutic modalities, and functional training. It is also essential to monitor the patient and periodically assess the splint’s fit and the patient’s functional status. Custom-made opponens splints may need to be modified over time to meet the patient’s changing needs.
