An In-Shoe Journey to Offload a Patient with Charcot Foot Deformity

David Sutton, Certified Pedorthist & Clinical Advisor

The case study below was provided by David Sutton, a certified Pedorthist and clinical advisor. His experience in creating custom footwear solutions is truly remarkable, especially when dealing with complex cases like the one I’ll describe today.

Fig #1: Pressure mat measurement using bilateral loading. Notice the wavering PP; highly unstable.

Customizing footwear for a patient with a Charcot foot deformity and a fused ankle presents unique challenges. It’s not just about addressing functional changes or the altered shape of the foot; it’s also about managing the history of ulcers and preventing future complications. These patients often struggle with anxiety, depression, and muscle weakness, which affects their gait significantly. Their feet tend to drop and swing forward rather than move forward in a controlled manner. Building their confidence, motivation, and reducing the risk of falls is crucial to ensuring compliance and preventing further ulceration.

Given these considerations, we must design footwear that is comfortable, easy to wear, and aesthetically pleasing. If we can’t achieve this, patient compliance will suffer, and our efforts may go to waste. To monitor progress effectively, we use in-shoe pressure mapping to ensure peak pressures (PP) stay below 200 kPa, as recommended by Schaper et al. (2019) and van Netten et al. (2017). This data helps patients see tangible improvements in real time, even if they don’t immediately feel the benefits.

During our initial visit, we measured pressure distribution using a pressure mat (see Fig #1). Normally, we’d take an in-shoe measurement, but since the patient was wearing a CAM boot on one foot and a slipper on the other, it wasn’t practical. We reviewed X-rays and conducted a clinical assessment of range of motion (ROM), leading us to decide on custom-made footwear and foot orthotics. Once we had a laser scan of the feet (see Fig #2), we created a custom last. A clear check fit was then fabricated to ensure proper fit and engage the patient in the process visually.

Fig #2: 3D LASER scan of the feet for Last making in a static moment. Visible deformity in the right foot and the inclined ankle, combined with the PP from the Mat is sufficient evidence to support that this patient will fail in a prefab shoe; client has a history of failure in prefabricated footwear.

After crafting the ankle boots and orthoses, we began the in-shoe pressure mapping journey.

We collected data from an eight-step average, with the software placing a mask over the highest peak pressure (PP) areas bilaterally. Following the first in-shoe assessment (see Fig #3) in the new custom footwear and orthoses, we adjusted the right boot based on the collected data—adding 5 mm of thickness to the sole. For the left boot, we moved the sole fulcrum more proximally and added a met dome to the orthosis. The results were evident in the second in-shoe pressure mapping assessment (see Fig #4).

Leg length discrepancies (LLDs) are frequently overlooked, particularly on the contralateral limb. Even a small discrepancy of 5 mm can have a significant impact on both feet. Adding 5 mm to the right boot reduced peak pressure loading from 335 kPa to 149 kPa under the base of the 5th metatarsophalangeal joint (MPJ) of the right foot. However, this adjustment also affected the left heel loading (see Fig #4).

Following the second assessment, we refined the left sole fulcrum further, moving it more proximally, and increased the met dome on the left orthosis. No additional modifications were needed for the right devices, though there was a slight shift in loading (see Fig #5). After the third assessment, the patient was sent home with detailed wearing instructions. It’s common for patients to push themselves too hard when trying out new footwear, so moderation is key to achieving long-term success.

Fig #3: First F-Scan assessment

Fig #4: Second F-Scan assessment.

Fig #5: Third F-Scan assessment, and the final outcome for the patient.

References:

Schaper, N. C., van Netten, J. J., Apelqvist, J., Bus, S. A., Hinchliffe, R. J., Lipsky, B. A., & IWGDF Editorial Board. (2020). Practical Guidelines on the prevention and management of diabetic foot disease (IWGDF 2019 update). Diabetes/Metabolism Research and Reviews, 36, e3266.

van Netten, J. J., Lazzarini, P. A., Fitridge, R., Kinnear, E. M., Griffiths, I., Malone, M., Perrin, B., Prentice, J., Sethi, S., & Wraight, P. R. (2017). Australian diabetes-related foot disease strategy 2018-2022: the first step towards ending avoidable amputations within a generation.

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In this webinar, David shares a case study on his approach to offloading a patient suffering from a four-year recurring diabetic ulcer, using F-Scan technology to validate his decisions.

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