The cuboid notch is a prominent specialized feature in foot orthotics design, aimed at providing targeted support to the lateral column of the foot, and, more specifically, to the cuboid bone itself. The use of the cuboid notch is both nuanced and significant, particularly when addressing complex biomechanical pathologies and optimizing functional movement in various patient populations.
Anatomy and Biomechanical Role
The cuboid bone serves as a static and rigid lateral element of the foot, conferring inherent stability to the lateral arch. Its strategic location, bridging the calcaneus and the metatarsals, makes it susceptible to mechanical stresses, subluxations, and dysfunctions, particularly in active individuals or those with planar foot deformities. When the cuboid becomes unstable or subluxed, conditions such as “cuboid syndrome” or “calcaneocuboid fault syndrome” may arise, with symptoms including lateral foot pain, swelling, and altered gait mechanics.
What is a Cuboid Notch?
A cuboid notch (sometimes called a cuboid raise, pad, elevation, or modification) is a more specific form of lateral column support in foot orthotics. It can be incorporated intrinsically into the orthotic shell during fabrication, or added extrinsically to the shell later using materials such as EVA, cork, or Poron. Traditionally, it was formed by shaving or scooping out plaster under the cuboid on the positive foot model, but modern computer-aided design systems (CAD) allow for elevation under the cuboid in millimetric precision.
Clinical Indications and Applications
The cuboid notch is primarily indicated when a clinician seeks to:
- Support the cuboid to counteract plantar subluxation, resisting downward movement of the bone in cases of cuboid syndrome.
- Provide lateral column stabilization, thus improving overall foot function and reducing lateral foot pain resulting from instability or subluxation.
- Facilitate the medial movement of the center of pressure in midstance, leveraging the high gear propulsion concept.
- Enhance pronatory moment at the subtalar and midtarsal joints, benefiting patients with excessive supination or lateral instability.youtube
- Elevate the inclination angle of the calcaneus, which is a modification sometimes referred to as the Feehery Modification.
Mechanisms and Effects
The cuboid notch imparts a directed upward force beneath the cuboid, resisting its tendency to subluxate or “drop” during dynamic activity. It plays a key role in redistributing forces across the foot’s lateral column, and altering the mechanical advantage of crucial tendons like the peroneus longus, which stabilizes the first ray. Additionally, it can help prevent the foot from sliding laterally off an orthotic, especially in instances where other features (e.g., medial skive) are incorporated to increase supinatory moments.
Intrinsic vs. Extrinsic Application
An intrinsic cuboid notch is part of the shell’s actual design, shaped into the orthotic at the time of fabrication and not easily modified post-production. On the other hand, an extrinsic notch or pad can be attached to the surface of the orthotic later and adjusted or removed as needed — providing flexibility for clinicians to test or fine-tune the effect through adhesive felt padding as a “treatment direction test”.
Evidence and Controversies
Despite its widespread clinical use, published research on the cuboid notch is limited, and there remains no strong consensus on its precise effectiveness or indications. Some clinicians report excellent clinical outcomes — pain reduction, improved stability — while others encounter adverse results, such as increased pain due to misplacement of the notch or pad. It has been suggested that moving the notch or pad medially under the cuboid (rather than too lateral) offers an inversion force to the bone, which may be more beneficial biomechanically, considering the cuboid both everts and plantarflexes as part of calcaneocuboid joint function.
Manufacturing and Prescription Considerations
Manufacturers accept prescriptions for cuboid notches in various specifications, often measured in millimeters, and can incorporate them either in custom or prefabricated orthotics. Clinicians who model foot casts through weightbearing or semi-weightbearing methods are more likely to use a cuboid notch, as this approach affects the lateral arch profile, often necessitating additional lateral support.
Related Modifications
There are several well-documented shell modifications related to the cuboid notch, including:
- Feehery Modification: Extends the cuboid support posteriorly to include the lateral calcaneus.
- Denton and Fettig Modifications: Variations in shape and placement for targeted effects.
Clinical Use: Cuboid Syndrome and Beyond
A cuboid notch can be particularly valuable in managing cuboid syndrome, lateral ankle instability, and peroneal tendon pathologies. By supporting the cuboid, the orthotic aids in restoring functional alignment, reducing pain, and possibly improving propulsion mechanics during gait.
Materials and Adjustability
A variety of materials can be used for cuboid notch modifications:
- EVA (Ethylene-vinyl acetate): Commonly used for extrinsic pads due to ease of shaping and adjustment.
- Cork, Poron: Other materials offering different densities and support characteristics.
- Myolite: Sometimes used for offloading applications, providing cushioning and lateral stability.
Extrinsic cuboid pads are favored for initial trials and adjustments, given their removability and fine-tuning capability. If symptoms worsen, the cuboid pad can be repositioned or removed altogether.
Practical Clinical Approach
In practice, clinicians often employ adhesive felt pads as provisional tests to determine the therapeutic effect before committing to permanent orthotic modifications. This trial-and-error approach helps identify individuals who will benefit from targeted lateral column support without risking exacerbation of symptoms
The cuboid notch remains a versatile and important modification in foot orthotics, especially for lateral column stabilization, managing cuboid subluxation, and improving overall foot biomechanics. Its application requires thorough understanding of foot anatomy, pathology, and individual gait mechanics, as well as careful consideration during prescription and design. As more research emerges, clinicians may gain better insights into optimal placement and efficacy, ensuring improved outcomes for patients with complex lateral column problems.