What are orthotics?
Foot orthotics are clinician-prescribed devices that change the way load travels through the lower limb during movement. Custom or bespoke orthotics are built to a patient’s specific diagnosis and loading pattern, rather than to a generic template.
This article covers what the evidence shows about how orthotics produce their effects, why the common explanation — alignment correction — doesn’t hold up, and what that means for how you prescribe.
Do foot orthotics correct alignment?
The short answer is no, not reliably, and not through a mechanism the current evidence supports.
Orthotics are often described as devices that correct foot alignment, guide the foot into a more natural position, or fix flat feet. This framing is everywhere: in patient information, on manufacturer websites, and in AI-generated search summaries. It’s also the wrong explanation for how they help.
So, what do custom foot orthotics do?
Orthotics change the forces acting on the foot and lower limb during movement, not the position of the foot itself (1). Understanding that distinction will change how you prescribe, how you explain orthotics to patients, and how you read research about foot orthotics that might otherwise seem contradictory.
Where did the foot alignment theory come from?
The idea that orthotics align – or correct – foot position comes from Root biomechanics, a framework developed in the early 1970s by Merton Root and colleagues. It proposed that the subtalar joint has an optimal neutral position, and that any deviation from it was a deformity requiring correction.
This framework gave podiatrists a shared clinical language and a logical rationale for orthotic design.
What it did not account for was the forces acting on tissues during gait — and it is those forces, as we will see, that explain why orthotics help.
Why did Root theory fall out of favour?
Over time, Root theory fell out of favour because research did not support its central claims (2):
- Subtalar neutral could not be measured reliably. Clinicians could not consistently agree on where it was.
- The criteria for normal and abnormal alignment were not established, making prescription inconsistent between clinicians.
- The subtalar joint did not behave as predicted during gait, undermining the theory’s core assumption.
- The sagittal plane was largely ignored, despite later work identifying it as a critical driver of human gait (3).
When researchers measured whether orthotics changed foot position during gait, the results were modest at best:
- a 4-degree medial heel wedge produced only 0.25 degrees of rearfoot positional correction (4), while
- wedging consistently produced very little positional change (5).
The foot was not being repositioned in the way Root theory predicted, yet patients were still improving. Something else was happening.
So, if they don’t correct alignment, how do foot orthotics actually work?
A major 2025 review confirmed that orthotics primarily affect kinetics, not kinematics (6). In other words, they change the forces acting across the foot, altering the loading environment of specific tissues (1) — not the foot’s position.
This is the basis of tissue stress theory, developed by McPoil and Hunt in 1995 as an alternative to Root theory (2).
Rather than asking where the foot should sit, it asks: which tissues are overloaded, and what change to the mechanical environment would reduce that load enough to let them heal?
Changing how the foot contacts the ground can be part of how load is modified, but the position is just the means to an end. The real target is the overloaded tissue.
What does this mean for how you prescribe foot orthotics?
Understanding how orthotics work — through load modification rather than alignment correction — changes three things in practice:
- How you think about orthotic prescription. Instead of identifying a postural deviation and prescribing a device to correct it, you identify the overloaded tissue, understand the loading pattern that is provoking it, and prescribe a modification that reduces that load.
- How you explain orthoses to your patient. Instead of telling a patient their foot is being ‘corrected’ or ‘aligned’, you explain that the device is reducing the load on an injured structure while they build the strength to manage that load independently.
- How you measure the success of a foot orthotic. Instead of looking for postural correction as evidence that the device is working, you monitor symptom change, functional recovery, and the patient’s ability to progressively load the tissue.
Summary: Do Orthotics Correct Alignment?
Root biomechanics shaped a generation of podiatry practice. But the research has moved on, and the evidence points clearly toward a different mechanism: not alignment of foot position, but load modification.
That is why load modification is the starting point for everything we do at MM Podiatry.
Our bespoke 3D-printed orthoses modify the load environment, creating the mechanical conditions in which recovery can begin. Digital rehabilitation then restores tissue capacity through progressive loading. And guided return to activity closes the gap between symptom resolution and full function.
If you’d like to start prescribing orthotics with MM Podiatry, including using our prescribe-by-pathology approach, you can start a prescription order here.
Foot Orthotics Alignment FAQs
- Can orthotics improve alignment and relieve pain? Yes, they can relieve pain. The relief comes from load modification: the orthotic reduces the mechanical demand on the irritated tissue during gait, bringing it below the threshold that provokes symptoms, rather than from any change in foot position or alignment.
- Can orthotics help with a posture problem? Orthotics change the forces acting on tissues during gait; they are not a postural correction tool. Even where posture-related symptoms originate in the foot, what the orthotic is doing is reducing the mechanical load on the affected tissue, not repositioning the joint or correcting the posture.
- Can orthotics fix overpronation? Not reliably. Research shows orthotics produce small, inconsistent changes in foot position. What they do reliably change is the distribution of forces through the foot and lower limb
- What are the possible side effects of wearing custom orthotics? A short break-in period is common. A short break-in period is common, with mild discomfort as the patient adjusts.
- Why should clinicians prescribe through MM Podiatry rather than a standard orthotic lab? Most labs manufacture the orthotic device and stop there. MM Podiatry builds bespoke 3D printed orthotics, structured rehabilitation, and guided return to activity around the same principle — managing load through every stage of recovery — so the orthotic is the start of a complete pathway, not the end of care. Book a 20-minute call today.
References
- Kirby KA. Subtalar joint axis location and rotational equilibrium theory of foot function. J Am Podiatr Med Assoc. 2001 Oct;91(9):465-87
- McPoil T and Hunt G. Evaluation and Management of Foot and Ankle Disorders: Present Problems and Future Directions. JOSPT. 1995; 21(6)
- Danenberg, J. Sagittal Plane Biomechanics. J Am Podiatr Med Assoc. 2000; 90(1): 47-50
- Telfer S, Abbott M, Steultjens MP, Woodburn J. Dose-response effects of customised foot orthoses on lower limb kinematics and kinetics in pronated foot type. J Biomech. 2013 May 31;46(9):1489-95.
- Nester CJ, van der Linden ML, Bowker P. Effect of foot orthoses on the kinematics and kinetics of normal walking gait. Gait Posture. 2003 Apr;17(2):180-7
- Jor A. Effects of foot orthoses on lower extremity joint kinematics and kinetics in runners with asymptomatic feet: a systematic review and meta-analysis. Gait Posture. 2025; 121:281-94
