Category Archives: Biomechanics

What is the Cuboid Notch used in Foot Orthotics?

Foot orthotics are custom-designed devices used to support, align, or improve the function of the foot. Among the many modifications available in orthotic design, the cuboid notch stands out as a specialized feature aimed at addressing issues related to the lateral column of the foot. Though not universally applied, the cuboid notch has gained attention among clinicians for its potential to influence foot biomechanics, alleviate pain, and enhance gait efficiency.

What Is a Cuboid Notch?

A cuboid notch is a specific modification to a foot orthotic that targets the cuboid bone—a small, cube-shaped bone located on the lateral (outer) side of the foot, between the calcaneus (heel bone) and the fourth and fifth metatarsals. The notch can be either intrinsic (built into the orthotic shell during fabrication) or extrinsic (added as a pad or elevation made from materials like EVA, cork, or Poron adhered to the dorsal surface of the orthotic).

Traditionally, the cuboid notch was created by scooping out plaster under the cuboid area during the preparation of a positive model of the foot. With modern CAD/CAM systems, orthotic shells can be digitally designed to include an elevation under the cuboid, allowing for precise customization. Most orthotic labs accept prescriptions for cuboid notches in millimeters or fractions of an inch, depending on the desired degree of support.

Biomechanical Rationale

The cuboid notch is primarily used to support the lateral column of the foot, which includes the calcaneus, cuboid, and the fourth and fifth metatarsals. This area plays a crucial role in stability and propulsion during gait. By elevating the cuboid, the notch provides an upward force that resists plantar subluxation (downward displacement) of the cuboid, especially in conditions like cuboid syndrome or calcaneocuboid fault syndrome.

Additionally, the cuboid notch can facilitate medial movement of the center of pressure during midstance, aligning with Bojsen-Moller’s “high gear” propulsion concept. This biomechanical shift promotes more efficient push-off and can reduce lateral instability.

Clinical Applications

Though research on the cuboid notch is limited and lacks consensus, several clinical scenarios suggest its usefulness:

  • Cuboid Syndrome: Characterized by pain and dysfunction in the cuboid region, often due to trauma or overuse. The cuboid notch helps stabilize the bone and prevent further subluxation.
  • Calcaneocuboid Fault Syndrome: A condition involving misalignment or dysfunction at the calcaneocuboid joint. The notch offers targeted support to this joint, improving alignment and reducing discomfort.
  • Lateral Column Collapse: Seen in flatfoot deformities or after trauma, where the lateral arch loses integrity. The cuboid notch helps restore the arch profile and redistribute load.
  • Peroneal Tendon Dysfunction: By elevating the cuboid, the notch may enhance the mechanical advantage of the peroneus longus tendon, which stabilizes the first ray and supports lateral foot function.

Influence on Gait and Joint Mechanics

The cuboid notch can influence several aspects of foot and lower limb mechanics:

  • Subtalar and Midtarsal Joint Motion: The notch introduces a pronatory moment, encouraging eversion and flexibility in these joints.
  • Calcaneal Inclination Angle: Elevating the cuboid may indirectly raise the angle of the calcaneus, contributing to improved rearfoot alignment.
  • Oblique Axis of the Midtarsal Joint: The notch helps pronate this axis, promoting plantarflexion of the fourth and fifth rays and enhancing lateral stability.

These biomechanical effects are particularly relevant in patients with rigid foot types, lateral instability, or those undergoing rehabilitation from lateral ankle sprains.

Design Considerations

Clinicians are more likely to prescribe a cuboid notch when using weightbearing or semi-weightbearing casting methods, as these techniques tend to flatten the lateral column. In traditional plaster-based manufacturing, the addition of plaster to the lateral column often lowers the arch profile, making the cuboid notch a corrective feature.

Prefabricated orthotics may also include a cuboid notch as part of their standard design, although customization remains preferable for optimal fit and function. The Feehery Modification is a variation where the notch is extended posteriorly to support the anterior lateral aspect of the calcaneus, offering broader lateral column support.

Potential Limitations and Risks

Despite its benefits, the cuboid notch is not universally suitable. In some cases, it may exacerbate symptoms, especially in individuals with hypersensitivity or pain around the cuboid region. Overcorrection or improper placement can lead to discomfort, altered gait, or new biomechanical issues.

Because there is no standardized protocol or robust clinical research validating its efficacy, the cuboid notch should be used judiciously and tailored to the patient’s specific anatomy and pathology. Regular follow-up and adjustments are essential to ensure therapeutic success.

The cuboid notch is a nuanced yet impactful modification in foot orthotic design. By targeting the cuboid bone and supporting the lateral column, it offers a biomechanical solution for a range of conditions—from cuboid syndrome to lateral instability and gait dysfunction. While its use requires clinical expertise and careful customization, the cuboid notch exemplifies how small design features in orthotics can yield significant improvements in foot function and patient comfort.

As orthotic technology continues to evolve, further research and clinical trials may help establish clearer guidelines for the use of cuboid notches, enhancing their role in evidence-based podiatric care.

Sources:
PodiaPaedia – Cuboid Notch
Podiatry FAQ – What is a Cuboid Notch?

Do Flip-flops with arch support work?

Foot orthotics really are a effective modality used by podiatric physicians to manage a wide range of foot problems. All the clinical experiences and research evidence is that they are very effective. Nevertheless, one trouble with them is that they have to be worn in footwear. That is naturally a lifestyle option, but sometimes the options and the environment do not necessarily accommodate the use of the right footwear which foot supports could be worn in.

One query which you see asked frequently is that are those flip flops that come with an arch support built into them, can they be used instead of foot supports. There are a variety of manufacturers available on the market of flip flops that have different amounts of arch support built into them.

Are they as effective as foot supports?

That’s doubtful. The support that is included in them is just like what you will receive from a premade foot orthotics or one of the typical over-the-counter kind of foot supports. That is fine if you have an average arch shape. However, that is not good if you don’t. Foot orthotics usually are built to be specific to your foot type.

Should you use them?

There’s no harm in using these and they certainly might be used as an adjunct to foot supports when you’re not wearing footwear. As if they may be utilized as an alternative, you should discuss that with your foot doctor.

I do keep hearing about the Archies on the internet, however I haven’t seen them because they are from Australia. Evidently numerous podiatry clinics around Australia retail them.

The Abductory Twist

The abductory twist is an observation which is found during an observation of the walking. Just as the heel starts to unweight or raise up the ground there’s a fast sudden abduction or twist seen of the heel. This is a commonplace finding during a gait evaluation, but its clinical value is of some discussion.

There are a number of reasons for an abductory twist. The first is that because rearfoot is pronating (rolling medially at the rearfoot) this is attempting to internally rotate the leg. Simultaneously the other leg is in the swing period moving forward and is wanting to externally turn the lower limb. The lower limb is ‘battling’ with these two opposite motions. Friction between the floor and the heel holds the heel from moving. The instant weight starts to come off the heel, the external rotation force from above can now abduct the rearfoot and it does so easily. A second explanation is that there is a condition at the great toe joint in which it fails to enable dorsiflexion correctly. This might be a hallux rigidus, a functional hallux limitus or a issue with the windlass mechanism that affects movement at the great toe joint. As this dorsiflexion is difficult to start, the body abducts the heel to maneuver sideways around that joint. Another reason which is often only found in the physical therapy literature is that the problem is as a result of control of motion around the hip joint. In that literature this is described as a medial heel whip.

The cause of debate about the clinical significance of an abductory twist is that it is merely an observation observed when doing a gait assessment that is the result of another thing (for example, the loss of friction with the ground, an issue at the big toe or hallux joint or the hip joint). If it is a problem, then therapy is directed at what is triggering the abductory twist or medial heel whip rather than aimed at the abductory twist itself. The treatment choices to do away with it is going to be very diverse dependent on what is the preferred treatment decision for what’s causing it.