The therapeutic benefit of night splints is based on maintaining the length of the plantar fascia while the patient sleeps. Normally, muscle tone within the triceps surae causes the ankle joint to assume a plantarflexed position while at rest. With the foot in the plantarflexion position, the plantar fascia and intrinsic plantar musculature shorten, relax and adapt overnight to a nonfunctional state. The shortened, tight plantar fascia and intrinsic musculature would explain the phenomenon of post-static dyskinesia in which the first few steps after long periods of rest are extremely painful.
The posterior night splint retains the tension within the plantar fascia and intrinsic musculature, maintaining their functional lengths and decreasing the sudden stress that ambulation places on the plantar aspect of the foot after periods of rest. One can position splints with the foot dorsiflexed at 5 to 15 degrees to the leg. In addition, podiatrists may add a pad to the anterior aspect of the night splints to maximize the stretching of the plantar fascia and intrinsic musculature.
Night splints provide constant, consistent strain. This not only maintains functional length but eventually provides a net reduction of stress within the plantar fascia and intrinsic muscles.
Patient adherence with these splints can be a challenge. Most patients will tolerate them for about two weeks. At this point, some patients get uncomfortable and may start removing them at night. Wearing night splints may adversely affect patients’ sleeping habits and consequently their lives and work productivity. In these cases, patients often prefer to abandon the splints.1
To gauge the range of treatment options utilized by experienced podiatrists, various practitioners provided feedback. These DPMs use a large volume of night splints in their practice and some are Fellows of the American Academy of Podiatric Sports Medicine (AAPSM). The results reveal broad differences of opinion in terms of how and when DPMs use night splints.