Why Night Splints May Not Help Plantar Fasciitis?

Why is every plantar fascial sufferer told to wear a night splint?  Because, in this evidence based world, although not always the truest evidence, it has become an essential part of the “Menu Treatment Algorithm.”  So, everyone, no matter what foot function they have, are told to use one.  Although it may help some, I’ve seen many that it has not.  There is a reason for that.

ANATOMY:  The achilles tendon consists of one tendon that originates from two muscles.  One muscle attaches above and behind your knee to the femur (thigh bone).  The other attaches to the lower leg below the knee. Both of these muscles attach to the achilles tendon that inserts to the lower aspect of the back of the heel bone (calcaneus).  There are also some fibers of the achilles tendon that attach around the heel to the plantar fascia.  The plantar fascia then attaches to soft tissue about the base of your toes.

Thus, bending the big toe joint affects one long unit consisting of the plantar fascia, heel bone and the Achilles tendon unit.  The theory behind the night splint is to stretch this entire unit.


So why does it fail?  Besides not being able to fall asleep or sleep well with your foot/toes up in that position, it typically is only helpful for those who have a tight achilles tendon. Since not all plantar fasciitis sufferers have a tight Achilles tendon, it is unlikely to help them. However, even if you have a tight achilles tendon, the answer goes back to understanding the anatomy.

Most tight achilles tendon sufferers are due to a tight gastrocnemius muscle.  This muscle attaches above the knee.  Most of us sleep with our knees bent so this bending relieves any tension on it that the splint is supposed to be stretching.  So, if your knee is bent while sleeping then the splint is really not stretching the achilles tendon.   Furthermore, an argument can be made that cold muscles should not be stretched. Some believe a cold muscle will rebound back due to the muscle fibers not being as elastic as they would be if the muscle was warm.

But can you stretch the plantar fascia?  Is there really evidence of such?  Not really.  The fascia is a thick fibrous band that attaches to the heel bone on one end and soft tissue on the other.  There is no muscle to stretch.  Those who have surgically seen, palpated and tested the strength of the plantar fascia know that it will not stretch like a muscle tendon unit.

But why does stretching sometimes work?  Because you’re not actually stretching the plantar fascia. You’re compressing the area of inflammation/pain that reduces buildup of fluid, thus relief. That is why I believe compression sleeves/socks as well as certain types of taping seem to help better than splints.

Therefore, if you don’t really have a tight achilles tendon or sleep with your knees bent, the chances of failure of night splinting are higher than normal.

So, what should you do? I recommend seeking the help of a professional who can evaluate your gait and tell you the cause of your problem.  You may be able to lessen the pain with compression socks, night splints, etc. but unless you find the cause of the problem, it will most likely keep coming back or you may end up with some other problem.


David J. Sables, D.P.M., C. Ped

ArchMasters-Orthotics, Shoes & Footcare, LLC