Plantar fasciitis is the most common cause of heel pain in adults, affecting an estimated one in ten people at some point during their lifetime. Characterised by degeneration and inflammation of the plantar fascia at its proximal insertion on the medial calcaneal tubercle, the condition produces a well-recognised clinical pattern: sharp, stabbing heel pain that is most intense with the first steps of the morning or after periods of prolonged rest. This "post-static dyskinesia" is the hallmark of the condition and provides the conceptual basis for one of its most widely used conservative treatments — the night splint.
Night splints have been a mainstay of plantar fasciitis management for several decades. By maintaining the foot and ankle in a position of dorsiflexion throughout sleep, they aim to counteract the pathological processes that underlie morning pain. Understanding why night splints work requires an appreciation of the biomechanical and histological mechanisms driving the condition, and their clinical application is best understood within the broader context of evidence-based conservative care.
## Pathophysiology and the Rationale for Night Splints
The plantar fascia functions as a passive tension band along the undersurface of the foot, supporting the medial longitudinal arch and facilitating efficient propulsion during gait. Repetitive mechanical loading — particularly in individuals with limited ankle dorsiflexion, excessive body weight, prolonged weight-bearing occupations, or biomechanical abnormalities such as pes planus or pes cavus — leads to cumulative microtrauma at the fascial origin. This produces a cycle of failed healing and degenerative change rather than true acute inflammation, a process more accurately termed plantar fasciopathy in contemporary literature.
During sleep, the foot naturally rests in a position of plantarflexion. In this position, the plantar fascia and the intrinsic musculature of the foot are in a shortened, relaxed state. When the individual rises and bears weight, the sudden tensile loading of these contracted structures produces the characteristic pain of the first steps. Over time, nocturnal shortening may contribute to ongoing fascial tightness and impair the tissue's capacity for repair.
The night splint directly addresses this mechanism. By holding the ankle in a neutral or mildly dorsiflexed position — typically five to fifteen degrees — throughout the sleeping hours, the device maintains a gentle, sustained stretch on both the plantar fascia and the Achilles tendon-gastrocnemius-soleus complex. This prolonged low-load stretching promotes fascial elongation, reduces morning contracture, and — according to some researchers — may facilitate the remodelling of collagen fibres within the healing tissue. The result, for many patients, is a meaningful reduction in first-step pain and an improvement in overall function.
## Types of Night Splints
Night splints are available in two principal designs: posterior splints and anterior (or dorsal) splints.
Posterior night splints are the traditional design, consisting of a rigid or semi-rigid shell that runs along the back of the lower leg and under the foot, secured with straps. They hold the ankle in dorsiflexion and are effective at maintaining the desired position throughout the night. However, their bulk and rigidity are frequently cited by patients as uncomfortable, leading to poor compliance — a critical limitation in any treatment that requires nightly use over an extended period.
Anterior or dorsal night splints address this concern by positioning the shell along the front of the lower leg and the dorsum of the foot, leaving the heel and posterior calf free. Patients generally report these to be more comfortable and less disruptive to sleep, and compliance rates tend to be higher. A third variant, the sock-style or "strassburg sock," applies a gentle dorsiflexion force through a strap connected from the toe of a compression sock to the knee. While less rigid than splinted designs, it is particularly well tolerated and has demonstrated efficacy in clinical trials.
The choice between designs should be guided by individual patient factors, including tolerance, sleep position, and the degree of ankle dorsiflexion restriction. Fitting and patient education are essential: the splint must be worn consistently — ideally every night — for a minimum of one to three months to achieve meaningful benefit.
## Clinical Evidence
The evidence supporting night splints for plantar fasciitis is generally positive, though the quality of available research is variable. Multiple randomised controlled trials and systematic reviews have demonstrated that night splints produce significant reductions in pain and improvements in function compared to baseline, and are broadly comparable to other conservative interventions such as stretching programmes, orthotics, and corticosteroid injections in terms of short-to-medium-term outcomes.
A landmark study by Batt, Tanji, and Skattum demonstrated that patients using night splints alongside a standard stretching programme achieved superior outcomes compared to stretching alone. Similarly, a well-cited trial by Powell and colleagues found that night splints were significantly more effective than anti-inflammatory medication and activity modification in reducing first-step pain at eight weeks. The Strassburg sock has been evaluated in a prospective controlled trial, with results showing resolution of symptoms in the majority of participants within a mean of approximately eight weeks.
Notably, night splints appear to be particularly effective for patients with chronic plantar fasciitis — defined as symptoms persisting for more than six months — who have failed to respond to other conservative measures. In this subgroup, the addition of a night splint to an existing treatment programme frequently produces the breakthrough improvement that other modalities alone had not achieved.
## Integration into a Treatment Plan
Night splints are rarely employed in isolation. Best practice dictates their use as part of a multimodal conservative approach that may include calf and plantar fascia stretching, load management, foot orthoses, footwear modification, and — where indicated — shockwave therapy or physiotherapy-guided exercise rehabilitation. Patient education regarding the chronic, self-limiting nature of the condition, combined with realistic expectations about the timeline for recovery, is fundamental to engagement and adherence.
Compliance remains the single greatest barrier to success with night splint therapy. Clinicians should discuss this openly with patients, acknowledge the challenges of wearing a device during sleep, and explore which design is most likely to suit the individual's lifestyle and sleeping habits.
Night splints represent a well-established, biomechanically rational, and evidence-supported intervention in the conservative management of plantar fasciitis. By maintaining a sustained dorsiflexion stretch throughout the night, they directly target the nocturnal fascial shortening that underlies the condition's most disabling symptom — first-step morning pain. When appropriately selected, correctly fitted, and used consistently as part of a comprehensive treatment programme, night splints can produce meaningful clinical improvement and accelerate recovery, particularly in patients with chronic or refractory symptoms. They remain a valuable and accessible tool in the podiatric and sports medicine clinician's armamentarium.