Key Insights On Intractable Plantar Keratoses

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Author(s): 
William Fishco, DPM, FACFAS

   To that end, surgery planning is difficult since the intractable plantar keratosis may be in part due to multiple factors. For example, how do you address the lesion that is located under the second metatarsal head in a patient who has hallux valgus, a long second metatarsal and a non-reducible hammertoe? Those who believe in the structural etiology would recommend shortening the second metatarsal. Those who believe in the biomechanical etiology would recommend a bunionectomy to restore function of the first ray and repair of the hammertoe to reduce retrograde buckling.

   Certainly, there are other factors to consider when developing a surgical plan. In the older population, there may be lack of fat padding to the sub-metatarsal region. In this patient population, I am more likely to perform something simple such as addressing a structural problem versus a more global functional reconstruction.

   For example, a geriatric patient with an intractable plantar keratosis under the fifth metatarsal head generally does well with a fifth metatarsal head resection. Obviously, I would not entertain this procedure in a young and/or highly active patient.

   It is difficult for me to come up with a foolproof algorithm for you to determine the ideal surgical procedure(s) for intractable plantar keratoses. I would like to share with you the way I think about surgery for this condition. In my mind, I feel the simplest way to come up with a treatment plan depends on the location of the skin lesion.

   To illustrate, for intractable plantar keratoses under the first metatarsal head, I will generally consider a Jones tenosuspension if there is a flexible contracture at the interphalangeal joint and/or metatarsophalangeal joint. However, if there is a rigid plantarflexed first metatarsal, then I will do a dorsiflexory base wedge osteotomy. This scenario typically occurs in the pes cavus foot type. I rarely do anything with the sesamoids, such as sesamoid planning or sesamoidectomy.

   When the skin lesion is under the fifth metatarsal head, one should assess for a plantarflexed first metatarsal. Additionally, I will determine whether there is in an associated tailor’s bunion deformity. If there is a significant plantarflexion deformity of the first metatarsal (forefoot valgus), I will consider a dorsiflexory base wedge osteotomy of the first metatarsal to reduce compensatory stress on the fifth metatarsal head (i.e., remove the “teeter-totter” effect).

   If there is no structural sagittal plane deformity of the first metatarsal, I will typically address the fifth metatarsal with an osteotomy at the neck to dorsiflex and also medialize the bone if there is an associated tailor’s bunion.

Treating Intractable Plantar Keratoses Under The Central Metatarsals

The most difficult area to address and come up with an appropriate surgical plan for is typically the intractable plantar keratosis under the central metatarsals. When the hyperkeratotic lesion is under the second and third metatarsals, it is typically due to a pes valgus foot type with an insufficient first ray.

   There may also be concomitant hammertoe deformities and structurally long metatarsals. I typically will stabilize the medial column with a first ray procedure, fix the hammertoe(s) with digital stabilization (proximal interphalangeal joint fusion) and shorten/elevate metatarsal heads as needed, depending on the radiographs.

   A hyperkeratotic lesion under the fourth metatarsal head is typically a scenario similar to the lesion under the fifth metatarsal head. I will assess for a plantarflexed first metatarsal and determine whether that is causing lateral overload. If so, I will address the first metatarsal as I have previously described. If there is a hammertoe deformity and/or structural problem with the fourth metatarsal, I will perform an osteotomy of the metatarsal with hammertoe repair.

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Ian Reillysays: April 4, 2012 at 4:53 am

Nice review Dr. Fishco. I have come to all the same conclusions and have a similar toolbox of procedures. The one thing I do with a Weil now is take a wedge of bone out to shorten and slightly elevate. There is some evidence that a pure Weil plantarflexes the capital fragment somewhat. In the U.K., we call this a Schweil – a Weil-Schwartz combo!

Best wishes

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William D. FIshco, DPMsays: April 5, 2012 at 11:22 pm

I do take a dorsal wedge as well if I am going to shorten the metatarsal more than 3 mm.

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