Plantar fasciitis, when it occurs at the heel, typically causes pronounced pain in the morning. This is called post-static dyskinesia. There are several reasons why this occurs. One reason is that without the weightbearing pressure of being on your feet during the day, the plantar fascia becomes more inflamed and more fluid accumulates in this area-swelling or edema (overnight). Fluid will also accumulate because the foot is in a relaxed position (plantar flexion or flexion of the ankle) and there is minimal tension on the fascia allowing for more "engorgement". So upon arising, you get up and walk on this inflamed fluid-filled plantar fascia at the heel level. Until some extra fluid is literally "worked out", there is severe pain and often limping.
By holding the foot and calf muscle under tension (extension or more accurately - dorsi flexion of the ankle) it is not possible for fluid to accumulate as much. As a result, this pain upon arising in the morning does not occur. Another reason why this occurs is because the calf muscle is held in a more stretched position and is not allowed to tighten up overnight. The more you can stretch out the calf muscle the less tension in the whole system that includes the calf muscle, Achilles tendon, heel bone and plantar fascia. See also our blog on stretching for plantar fasciitis. (Part One, Part Two)
Night splints range from a classic posterior night splint to the front of the foot and shin style night splint. They are very padded and should be fairly comfortable. But nonetheless they are fairly bulky. The anterior (front of the foot and shin style) is much less bulky and can be more comfortable. The disadvantage to the anterior style of night splint is that does not hold the foot up as
effectively as a posterior night splint. But again the posterior night splint is fairly bulky. For severe cases plantar fasciitis a posterior night splint is the best option.
Another option is not to have the foot held in a dorsiflexed position overnight at all. But instead, to allow for some compression on the plantar fascia so that this area is not allowed to become swollen. This does not address the tight calf but it does address the fluid accumulates overnight. Therefore this can be effective at reducing the pain first thing in the morning. The most effective but light weight splint in this case is the Bledsoe brace.
One of the last options is to use a Strasburg sock. A Strasburg sock is fairly inexpensive and spans from the calf to the foot and out to the toes, then attached back to the front of the shin. These are available on line and at some athletic shoe stores.
For people who sleep on their backs or the sides night splints are fairly easy to use. However if you sleep on your stomach, this alone can be a big factor in why plantar fasciitis just won't go away. The foot is forced into a plantar-flexed or relaxed position and the calf muscle always tightens up overnight and the plantar fascia is allowed to become more swollen overnight. One way to address this is to have your feet hanging out over the end of the foot of the bed so that they are not forced into this position. Another option is to have a fairly thick pillow that suspends the tip of their foot off the bed when you sleep on your stomach.
One problem with a posterior night splint is that the heel tends to lift up and the foot is not held in ideal position. However, just by having the foot at 90° there is some benefit. Ideally speaking it should be and 5-10° of dorsiflexion. But again another problem is individuals with a high arch foot are prone to nerve irritation overnight and your feet may seem to go numb. Potentially this could be a problem and usually causes enough irritation that goes individuals with high arch feet or nerve irritation will have to discontinue the use of the night splints. There are many different types of night splints because patient's have different preferences and foot types. One reason why there are so many types of night splints, is that they are an effective adjunct to long-term treatment for plantar fasciitis.