Plantar fasciitis is a common source of heel and foot pain, caused by strain on the thick band of tissue running along the bottom of the foot, known as the plantar fascia. This fibrous band connects the heel bone to the toes and supports the arch of the foot. Repetitive stress can cause micro-tears and irritation in the tissue, leading to pain. The condition is characterized by a sharp, stabbing pain near the heel, typically worst with the first steps in the morning or after periods of rest. External supports, such as braces, splints, or orthotics, are widely used as part of conservative treatment. These devices mechanically alter the forces on the foot by stretching the fascia or redistributing weight.
Categorizing Common Support Devices
Support devices for managing foot pain are categorized based on their function and when they are worn. Night splints are used while the patient is non-weight-bearing, typically during sleep. These rigid, boot-style splints encase the foot and lower leg, holding the ankle at a fixed angle, often near 90 degrees of dorsiflexion.
The Strassburg Sock is a related nighttime support made of tubular knit material worn over the calf with adjustable straps attached to the toes. This design maintains the foot in a neutral or slightly dorsiflexed position by applying tension to the toes. Both the sock and the boot splints prevent the fascia from contracting and stiffening overnight, providing a continuous, gentle stretch.
Daytime supports are worn inside footwear during walking and bearing weight, and their primary function is load redistribution. These include prefabricated or over-the-counter arch supports, which offer cushioning and general arch support to reduce impact forces.
Custom-molded orthotics are devices specifically made from a mold of the patient’s foot to provide precise biomechanical control and arch contouring. Athletic taping, often called low-dye taping, is another common method that mechanically supports the arch and limits excessive pronation. Unlike the more rigid orthotics, taping is a temporary intervention that requires regular reapplication.
Evidence for Nighttime Immobilization
The primary mechanism for nighttime devices is preventing the plantar fascia from shortening during sleep, which causes severe first-step pain upon waking. When the foot is pointed downward during rest, the fascia contracts. Night splints and Strassburg Socks hold the foot in a neutral or slightly dorsiflexed position, maintaining a prolonged, passive stretch on the plantar fascia and Achilles tendon.
Scientific evidence, including systematic reviews, generally supports the use of night splints as an effective component of conservative treatment, particularly for reducing morning pain. Studies indicate that maintaining this nighttime stretch helps reduce the micro-trauma that occurs when the shortened fascia is abruptly loaded with the first steps of the day. The gentle, continuous tension helps the tissue heal in a lengthened state over time.
While both rigid splints and the Strassburg Sock share the goal of dorsiflexion, the sock-style device is often more tolerable, improving patient adherence to the treatment regimen. Combining night splints with other therapies, such as insoles, has been shown to enhance improvement in pain relief and foot function compared to using either device alone. Patients may experience significant relief in four to eight weeks, though severe cases may require three months or longer of consistent use.
Evidence for Daytime Support and Load Redistribution
Daytime supports, such as orthotics and taping, function by controlling the biomechanical forces that stress the plantar fascia during weight-bearing activities. These supports aim to redistribute pressure across the foot and limit excessive motion, specifically pronation, which can over-stretch the fascia. Systematic reviews confirm that foot orthoses are effective in alleviating pain symptoms for patients with plantar fasciitis.
Contoured full-length insoles are more effective in relieving symptoms than simple heel cups, highlighting the importance of arch support and motion control. Orthotics provide significant pain relief in the short, medium, and long term, though data on their ability to improve foot function is less consistent.
Prefabricated, over-the-counter arch supports are a beneficial and cost-effective initial treatment option. Custom-molded orthotics are designed to match an individual’s specific contours and theoretically offer superior control. However, high-quality studies suggest no significant difference in pain and function outcomes between custom and prefabricated devices. Athletic taping provides excellent short-term relief by mechanically lifting the arch, useful for acute pain episodes or intense activity.
Practical Considerations for Device Use
The practical reality of using these supports greatly influences treatment success. Patient compliance is a significant challenge, especially with night splints, which can be bulky, warm, or interfere with sleep. To maximize adherence, healthcare providers often recommend a gradual introduction, starting with a few hours of wear per night and slowly increasing the duration.
Adverse effects are a factor, particularly with orthotics, which can initially cause soreness or discomfort as the body adjusts to the altered alignment. Improperly fitted orthotics can lead to blisters, skin irritation, or, rarely, nerve compression. Night splints may also cause skin irritation or pressure points if not properly padded and adjusted.
Night splints are typically worn for one to three months, depending on symptom severity, until symptoms are significantly reduced. Orthotics are often worn continuously in all shoes during the day and may be needed for several months or longer to maintain comfort. The most successful outcomes occur when supports are combined with other conservative treatments, such as targeted stretching exercises and physical therapy.