by Bob Longworth MSc DPodM

Duncan first came to see us in January 2023 in need of some insoles. He had an interesting story of foot and ankle problems since he broke a 5th metatarsal when in the Army aged 21 (he’s now 59). Back then he was given insoles by a Podiatrist which took a lot of getting used to but he persevered with them and eventually “my body got used to them”

In his 40’s he started with knee pain after running a half marathon and had his insoles reviewed by another Podiatrist who was horrified at the treatment he had received. “He told me I had a Supination problem and I’d been given Pronation insoles”.

Unfortunately, the insoles that this and other Podiatrists over time have tried, never got to grips with his problem and all failed to give him comfort – so he resorted to making his own, which did the trick to some extent.

From Kim (2017)

With time his problems got worse to the point where he was unable to even walk a mile. So a couple of years ago, he saw an Orthopaedic surgeon who said “I’ve never seen feet like yours before!” and suggested major surgical correction was the only answer.

Myerson et al (2019)

In October 2021 he had his right foot operated on “they sawed my heel in half and straightened it so it was in line with my Achilles, which they lengthened, and they lowered the arch”. In November 2022 he had the left treated in the same way and when he came to see us, he was still in a walking cast and recovering from the surgery.

Similar example of surgical correction from Mayou et al (2017)

Duncan had what we class as Cavus type feet which tend to roll to the outer edge of the foot (invert) when walking and are prone to ankle sprains and issues with the 5th metatarsal. Duncans was so extreme that even after corrective surgery, it was obvious that he still had issues with ankle inversion.

Following his lead, we managed to make some insoles that have worked in both being comfortable and reducing his tendency to invert. Previously he’d just put padding at the heel but looking at him walk, there was an inversion moment occurring in midstance, so the wedging needed to extend to the midfoot too. They are not like any insoles I’ve made before and took a bit of to-ing and fro-ing to get them right, but he is now able to walk for 3 miles which is amazing so soon after his surgery.

So why have we succeeded where others have failed?

I think the original Podiatrist must have just looked at the shape of his feet and not look at him walking or considered their function. They saw he had very high arches to his feet, so put a big arch on the insoles. The fact that Duncan was able to get used to something that was totally wrong for him, shows how adaptable humans can be.

When we fit insoles, comfort is king – if it doesn’t feel right, we change it. You are not going to walk normally if there’s something that hurts in your shoe. The advice to ‘break insoles in slowly and persevere with them if they’re not immediately right’ can lead to issues like Duncan’s.

Chatting with him, the problem with the other failed insoles was that they always had some kind of arch on them. He felt that feature always caused him to invert and was uncomfortable. We actually used TPD Xline insoles (which have a high arch) and switched them left for right so the bulk was on the outside edge, and the inside of the insoles were reduced to nothing.

Finished insole and prototype, using the left insole on the right and vica versa

You get a lot of Podiatrist who go on and on about how casted insoles are superior but that’s just not the case. There is no way I could have got a casted insole anything like the final devices we ended up with. The ability to adapt, add and grind away material that responded to the patients needs is what gave us success here.


Kim BS (2017) Reconstruction of caus foot: A review. The Open Orthopaedics Journal 11, (Suppl-4, M5) 651-659

Maynou C, Szymanski C, Thiounn A (2017) The Adult Cavus Foot. European Federation of National Associations of Orthopaedics and Traumatology Open Review 2, 221-229

Myerson MS and Myerson CL (2019) Cavus Foot. Deciding Between Osteotomy and Arthrodesis Foot and Ankle Clinics 24(2):347-360

Article by Bob Longworth