Key Points
- ZeroSole redistributes pressure by removing individual hexagonal cells beneath a focal pressure point to create a targeted offloading cavity.
- The pressure point is identified, the corresponding cells are removed, and the patient’s response is assessed while standing and walking.
- The size and position of the pressure point should guide how many cells are removed.
- Pressure-mapping research found up to a 32% reduction in peak plantar pressure when ZeroSole was customised for targeted offloading.
Plantar calluses develop when skin is exposed to repeated mechanical stress and friction.
When pressure becomes concentrated in one area of the foot, the resulting callus can become painful and may return after treatment.
To offload a plantar callus, you should identify the area where pressure is concentrated before selecting an appropriate pressure-redistribution method.
The right approach depends on the patient's presentation, footwear, biomechanics and how long the offloading needs to be maintained.
How do you identify pressure beneath a plantar callus?
A focal area of hyperkeratosis, usually directly beneath a bony prominence such as a dropped metatarsal head, can indicate where pressure is being concentrated.
When deciding where to offload, the offload site should cover the entire callus, including its borders and any localised erythema.
Other clinical signs that can help identify where pressure needs to be reduced include:
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Tenderness on direct palpation
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Localised erythema
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Joint limitations or fixed structural deformities
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Areas where weight is concentrated on one specific spot during the gait cycle
Looking at the whole affected area helps ensure the offload is positioned appropriately.
Is debridement enough to treat a plantar callus?
No. Debridement removes the hyperkeratotic tissue, but it doesn’t address the underlying mechanical pressure contributing to the callus.
Sharp debridement removes the callus and immediately reduces the physical mass pushing into the underlying tissue.
However, if you don’t address the underlying mechanical load, the callus can return quickly.
Debridement only treats the symptom, whereas pressure redistribution treats the cause.
In healthy patients, ignoring mechanical pressure can lead to recurring pain and increasingly frequent clinic visits, reducing patient satisfaction.
In high-risk patients, such as those with diabetes or neuropathy or peripheral vascular disease, failing to deflect focal pressure can allow the tissue underneath to break down, potentially escalating a simple callus into ulceration.
This is why you need to treat the callus itself and address the pressure contributing to it.
What are the options for offloading a plantar callus?
The main offloading options include semi-compressed felt, modular offloading insoles and bespoke orthotics.
The most appropriate choice depends on the patient's presentation and the purpose of the intervention.
Semi-compressed felt
Semi-compressed felt can provide temporary or acute relief around a localised pressure point.
It can also be used to test an offloading layout before moving to a longer-term insole solution.
Where footwear has limited space and can’t accommodate an insole, felt may be the more practical option.
Its main limitation is longevity. Felt is a temporary intervention, so it may not suit cases requiring ongoing plantar offloading.
Modular silicone offloading insoles
Modular silicone offloading insoles can provide immediate, longer-lasting offloading while allowing the pressure-relief area to be customised.
Individual cells can be removed to create an offloading cavity beneath the area requiring pressure relief.
This can be carried out directly from the clinic chair without specialist equipment, allowing the insole to be fitted during the appointment and the patient's response assessed under weight-bearing.
Correctional or Bespoke orthotics
Correctional / Bespoke orthotics may be appropriate where targeted pressure relief needs to be combined with significant biomechanical realignment and functional correction.
This makes them more suitable for complex cases where pressure relief must be part of a wider biomechanical intervention.
When is a silicone offloading insole useful for plantar callus?
A modular silicone insole can help when you need immediate, longer-lasting plantar offloading and the insole needs to be customised during the appointment.
ZeroSole was developed to bridge the gap between temporary felt pads and the complexity of bespoke orthotics.
The insole can be customised and fitted during the appointment, creating an offloading cavity directly beneath the lesion.
This can be particularly useful for chronic or stubborn lesions that require longer-term targeted offloading.
The cushioned layers and lower profile also make the insole practical for use within the patient's footwear.
How do you choose the right offloading approach?
The right offloading approach depends on the location of the pressure, the patient's presentation, their footwear and the level of support or correction required.
Key considerations include:
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Location and extent of the callus: Offloading should cover the area requiring pressure reduction.
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The pressure point: Tenderness, localised erythema and the relationship between the callus and underlying structure can help identify where pressure is concentrated.
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Footwear: Available space can influence which interventions are practical.
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Foot structure and biomechanics: Structural changes can concentrate weight in a particular area.
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Duration of offloading: Temporary and longer-term interventions have different applications.
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Need for functional correction: Some patients require targeted pressure relief, while others need greater biomechanical correction.
No single offloading method suits every plantar callus. The choice should reflect the individual presentation and the level and duration of offloading required.
How can ZeroSole be used to offload a plantar callus?
ZeroSole provides a customisable option for targeted plantar offloading that can be modified and fitted chairside.
Clinicians can remove individual cells from the silicone insole to create an offloading cavity directly beneath a defined pressure point.
The insole can then be fitted and the patient's response assessed under weight-bearing.
For chronic or stubborn plantar callus, this provides a longer-term offloading option between temporary padding and a bespoke orthotic.