Description of Intervention1,2
A blocking splint is a versatile type of splint designed to restrict the amount of active and passive movement of one or more joints in the fingers and/or wrist. These splints may be used as a short-term measure in the emergency room to account for continued swelling or for longer periods to treat a variety of injuries that require immobilization. The type and amount of immobilization, as well as the exact wrist and finger joint placement, can differ significantly depending on the injury or condition. For example, a dorsal blocking splint is used to prevent wrist extension while keeping the metacarpophalangeal (MP) joints in flexion and the interphalangeal (IP) joints in extension. Conversely, a volar blocking splint is used to prevent wrist flexion and maintain the MP joints in extension and the IP joints in flexion.
Limiting extension or flexion of these joints effectively inhibits the activity of certain muscles, tendons and ligaments while promoting the activity of others. Over time, this facilitates healing of damaged bones and/or soft tissue and protects the involved structure(s) from further trauma, which also alleviates pain and improves physical function in the process. Hand therapists, both Occupational and Physical Therapists, frequently use blocking splints when this type of immobilization is sought.
Indications for Intervention
A blocking splint is indicated for hand and wrist injuries/conditions in which a period of immobilization of one or more joints is required. A dorsal blocking splint is typically used to prevent wrist extension and maintain MP joint flexion and IP joint extension, while a volar blocking splint is typically used to prevent wrist flexion and maintain MP joint extension and IP joint flexion.
- Ask the patient to describe their medical history, with a focus on any recent injuries to the hand or wrist. Ensure that the patient provides a detailed description of their symptoms and the duration of these symptoms.
- Ask if the patient has any comorbidities, including diabetes, osteopenia/osteoporosis, 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 assesses impairments 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.3,4
- Assign a diagnosis based on the patient’s history, symptomatology, and examination findings.
- Prescribe a dorsal or volar blocking splint if deemed appropriate.
Orthoses Guidelines1,5-9
If the evaluation indicates that the patient is a good candidate for a blocking 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 orthopaedic 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 it to the patient
Custom-fitted and custom-fabricated splints are strongly recommended for most patients, but a prefabricated splint may be sufficient in some cases when symptoms are mild. Blocking splints can be constructed with a variety of materials, including plaster, fiberglass, padding, ace wraps, metal, cloth, plastic, or leather. If fitting or fabricating the splint, ensure that it fits the patient comfortably. 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 or forearm. Pain medications may be needed before and during the splinting process.
Additional tips for fabricating a dorsal blocking splint of thermoplastic material are listed below:
- Ask the patient to sit with both elbows on a table; let him/her make a fist with the uninvolved hand and support the involved hand to ensure the wrist is in the desired position and the MP joints are supported in flexion, with the fingers in extension
- Cut a rectangular piece of thermoplastic material wide enough to capture the widest part of the patient’s hand and forearm
- Stretch the material distally over the fingertips and pull proximally towards the elbow; in effect, the material will stretch and conform to the flexion of the MP joints and the wrist position
- Avoid excessive handling of the material, which will cause fingerprints and marks that can irritate the patient’s skin; only minimal handling is needed to secure the position of the material around the wrist and forearm
- Let the material harden sufficiently before removing to trim; when hardened, remove the splint and trim all sharp edges and corners away; there should be no material on the volar surface of the palm and forearm, and the patient should be able to passively flex each finger joint into the palm and actively extend each finger inside the splint shell
After the splint is fitted and applied, provide the patient with wear and care instructions, including cleaning directions, which vary by splint. The frequency of use depends on the type and severity of the condition. Following flexor tendon repair, the splint must be worn at all times for protection, as taking the splint off prematurely could lead to a rupture of the repair site. Less frequent use may be adequate for rheumatoid arthritis flare-ups and certain overuse conditions. The duration of use also varies widely. Typically, minimum duration of 3-8 weeks for mild diagnoses but 5-6 weeks continuous wear for tendon injuries may be necessary. When the splint is not worn, patients should be encouraged to continue moving the non-immobilized joints normally to keep muscles flexible and strong.
A blocking splint is only one component of a complete 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.
