Canadian
maple
Medical Alliance for the Preservation of the Lower Extremity
Surgical Offloading of Small Toes
One of the most common locations for ulcerations to develop is on the tips of the toes. This is usually a result of excessive pressure applied to the tips of the toes from the toes being contracted or crooked (see right).
Toes can become contracted and crooked for a variety of reasons--such as certain forms of arthritis, trauma, inappropriate shoes.
In the diabetic and neuropathic patient, a common reason this might occur is motor neuropathy, where abnormal nerve signals (in the diabetic caused by high sugar in the nerve) causes muscles to pull a toe abnormally (see right).
In this case, note the tight tendons (extensor digitorum longus tendons) pulling the toes upwards. They're taut and bowstrung, reminiscent of guitar strings.
However, the most common reason for a toe to become contracted and crooked--in a diabetic and non-diabetic alike) is an abnormal pull of a tendon that attaches into the toe as a result of biomechanical causes. We can't review all of the biomechanical reasons toes become contracted, so we'll just discuss the more common cause--a foot that flattens excessively in stance.
In this foot...
the heel rolls tilts... the foot rolls inwards... and the arch collapses.
Posterior Tibial Tendon
as it passes behind
and below the inside
of the ankle.
Flexor Digitorum Longus
Tendon as it passes below
the ankle into the foot.
Flexor Digitorum Longus
Tendon as it extends
down the arch towards
the toes.
A foot that flattens excessively (pronates) like the one above is not efficient for gait, so the body uses two of the leg muscles to compensate.
The major muscle that opposes excessive pronation is the posterior tibial (PT) muscle and tendon (green arrow). The PT begins high up the leg on the back of the leg bones, runs down as a tendon behind the inside of the ankle (shown with the green arrow), and attaches to the bones on the inside of the midfoot. The tendon resides within a sheath (the light blue structure on the foot model).
When this muscle contracts, it pulls the inside of the foot up, and shores up the arch.
The posterior tibial muscle carries most of the load to hold up the arch, but when it is over-worked, it enlists the aid of the adjacent muscle,the flexor digitorum longus (FDL).
The FDL muscle also begins high in the leg, on top of the posterior tibial muscle. As the FDL approaches the inside of the ankle, it turns into a tendon. (The tendon is also inside a sheath, the light blue structure on the foot model to the left).
As the FDL tendon passes into the foot, the tendon (shown in white in the photo to the left) passes obliquely across the bottom of the foot. The tendon then branches into four tendinous segments that attach to the bottom of the 2nd, 3rd, 4th, and 5th toes.
The FDL muscle is quite strong, and in trying to hold up an unstable arch, it overpowers the other muscles in the toes, causing the toes to contract.
To the right is an example. As the foot is
pictured in stance, the FDL muscle is used to help hold up the arch. In the process, the muscle pulls on the toes, and they are seen clutching the ground.
Note how the 5th toe, pulled quite obliquely by the FDL tendon, is rolling on its side. The 4th toe is also pulled obliquely, but not so much as the 5th toe. And the 3rd toe is pulled even less obliquely than the 4th.
The 2nd toe is usually aligned straight to the pull of the FDL and is usually contracted only, and doesn't typically roll on its side, as seen here.
This pattern is common because these are the angles the FDL tendon is pulling (see diagram above).
Misaligned toes like this can cause pressure spots to form on the tip of the toe where the toe hits the ground.
In the neuropathic patient with loss of sensation, a great deal of damage can occur and the patient may be unaware of the trauma.
This patient presented with a separate complaint, having no idea he had injured his toes.
Obliquity of
FDL Tendon Pull
When ulcers form, bacteria can enter. In the neuropathic individual there may be no pain so the patient does not know there is an issue.
Infections can develop.
Ulcers on the tip of the toe are extremely common after the great toe has been amputated.
Part of this is simply because the big toe is no longer present and the smaller toes are more likely to get injured.
In the example to the right you can see the degree of force that has deformed the 2nd toe.
In a patient that cannot feel pain and may have a diminished immune system to fight infections, common in diabetics and others with neuropathy, the bacteria are more likely to spread up the foot and leg, putting the patient's limb--and even life--at risk.
Part of this, too, is the biomechanical consequence of losing the great toe's function.
When the great toe is amputated, the flexor tendon to the great toe is lost and the foot loses push off power.
As a result, the flexor tendons to the lesser toes are recruited to aid in push off. Over time the additional use of the tendons causes the lesser toes to contract into hammertoes.
This can cause trauma to the lesser toes that may present in the form of thick skin (corns) at the tip of the toe as seen to the right.
This pressure may lead to ulcers to form at the tip of the lesser toes.
To the right is a relatively superficial ulcer of the 2nd toe.
Ulcers on the 2nd toe are the most common lesser toe ulcer as it is the longest toe and has no protection from the great toe.
To the right we see the effects of pressure on the 3rd toe. The bruising and blistering is developing here because the 2nd toe is more flexible and the 3rd toe is more rigid, causing more pressure to be borne on the tip of the 3rd toe.
Blisters like this will often become ulcers in short order.
Here is an ulcer of the tip of the 3rd toe.
In this case the 2nd toe is not just contracted, but pulled back towards the top of the foot, placing the greatest force on the tip of the 3rd toe.
Pressure is also deforming the nail.
New ulcers in new locations place the foot at risk for new infection and additional amputations.
To the right we see a foot where the great toe developed an ulcer. Little effort was devoted to offloading the great toe, and it was amputated.
The 2nd toe then developed an ulcer, and it, too, was then removed.
Then the 3rd.
The incremental amputations is sometimes known as the sausage-ization of the foot, where it is cut repeatedly like cutting a sausage.
Saving these last two toes does nothing for the foot mechanically, and puts the patient at risk for additional medical problems.
This is why diabetic foot specialists try to avoid amputating the great toe whenever possible.
Misshapen toes can also cause pressure and ulcerations to develop on the top of the toe, where a shoe may rub, as in the images below left and below center (an example so severe, the bone has popped through the skin). Or it may cause an ulcer between the toes, as seen below right.
It can be difficult to offload (remove pressure from) contracted toes with an orthotic, particularly if the ulcer is on the top of a toe or between the toes. A shoe with a deep toe box may get pressure off the top of a toe, but won't likely help an ulcer on the tip of a toe or between a toe. Specialized supports can lift a toe off the ground, but can cause irritation to the toe, and can cause the toe to elevate and the shoe may rub against the top of the toe, causing a new ulcer.
So doctors have tried to develop surgical procedures to correct the contracted toes. These procedures are so powerful, they can actually cure the ulceration in many cases.
The main procedure we'll discuss is a very simple procedure called a tenotomy (meaning tendon cut).
This procedure may be appropriate if one can readily straighten a toe manually, as seen to the right. This means there is little arthritis present in the joints of the toe. When the toe can be straightened like this, the toe is considered "reducible."
In this case, surgical correction could be as simple as cutting the flexor tendon (identified in the diagram at the top of this page) that is causing the deformity.
This procedure can be done very quickly and cleanly, either with a scalpel or with a needle.
For the scalpel procedure, the scalpel is inserted horizontally under the toe bone. The blade is then turned sharp edge down to cut the tendon, then turned back flat and removed--a procedure requiring just a single stitch (right). It's a clean cut and it's arguably easier to make sure you've released the full tendon.
For the needle procedure, a needle is inserted from the bottom of the toe and the sharp edge is used to cut the tendon. This procedure has the advantage as having a pinpoint incision that doesn't usually require any stitches.
Either way, the procedure is minimally invasive, and holds the possibility of a cure to the ulcer. Thus, for most ulcer patients with a flexible deformity, it should
be strongly considered.
There are numerous studies that describe the effectiveness of this procedure. We'll review meta-analyses--studies that looked at multiple studies and combined their results, then some selected individual studies at the bottom of this page.
Meta-analyses (Studies that look at other studies, combine the results and try to draw conclusions)
In 2023, Calvo-Wright et al examined 11 studies. These papers reported a healing rate of 92-100%, with healing times ranging from 2-4 weeks. They found few complications--transfer lesions onto adjacent toes being most common, for which they suggested performing simultaneous tenotomies as a way to eliminate that risk. They concluded the procedure was simple effective and safe.
Calvo-Wright MM, López-Moral M, García-Álvarez Y, et al. Effectiveness of percutaneous flexor tenotomies for the prevention and management of toe-related diabetic foot ulcers: a systematic review. J Clin Med. 2023;12(8):2835.
In 2017 Bonanno et al reviewed six studies with 264 flexor tenotomies. They found 97% healed in an average of 29.5 days with 6% recurrence.
Bonanno DR, Morrison JB, et al. Flexor tenotomy improves healing and prevention of diabetes-related toe ulcers: a systematic review. J Foot Ankle Surg. 2017;56(3):600–604.
In a 2016 review, Scott et al examined 5 studies involving 250 flexor tenotomy procedures on 163 patients. They found 92-100% healing, reported 0-18% recurrence at 22 months. They noted few infections or new deformities but some transfer ulcers.
Scott JE, Menz HB, Perraton LG, et al. Effectiveness of percutaneous flexor tenotomies for the management and prevention of toe‐related diabetic foot ulcers: a systematic review. J Foot Ankle Res. 2016;9:55. doi:10.1186/s13047-016-0159-0.
Additional references to individual studies on the efficacy of flexor tenotomies for ulcers on the tips of toes are provided at the bottom of this page.
Non-Reducible Deformities
In the section above, we discussed performing a flexor tenotomy for toes with a reducible deformity, that is, a toe contracture that can be readily straightened manually.
In those toes, cutting the tendon allows the toe to heal because the tendon is the deforming issue, and the bones are not holding the toe in a contracted position.
However, in many cases the toe is stuck in a contracted state--held in place by an arthritic joint that will not bend, as seen to the right.
For fixed deformities like this, where the joint is arthritic and fused, cutting the tendon would not fully correct the issue. Surgical correction usually requires removing a small section of bone in the joint so the toe can be straightened.
The procedure usually chosen is called an arthroplasty. This is more involved than simply cutting a tendon, but it's still a rather simple, quick-healing procedure requiring about five stitches.
Hardware (like pins and specialized screws) are sometimes used to fuse the toe, making it very straight. But the author usually avoids fusions of toes in ulcer patients to lower the odds of future ulcers and to make healing quicker and easier, and to minimize risks of infection. Below left: Intra-op. Below right: 1 week post-op.
Aren't these procedures risky in this population?
Sometimes patients or doctors shy away from these procedures, thinking they are dangerous in a diabetic patient.
Their caution is, "What if they don't heal? What if they get infected? Maybe it's better not to do anything."
However, as you see in the papers provided on this page, the procedure is very successful at resolving the ulcer and has few complications.
So long as the blood sugar is controlled reasonably, so long as the blood supply is sufficient to allow for uneventful healing, the case can be made that living with recurrent ulcerations puts the patient at significantly higher risk of infection and amputation than doing a simple procedure once in a sterile environment.
Read through the summaries of these papers and consider the success rates of the procedures and the few complications noted. Then consider that most untreated ulcers will recur time and again, each time putting the patient at risk of infection and amputation.
Additional studies:
In a multi-centered, randomized controlled study from 2022, patients were randomized to tenotomy vs standard of care (non-surgical). Healing rates were 100% in the tenotomy group vs 35% in the non-surgical group, and healing was quicker in the surgical group as well. There were no significant complications in the surgical group.
Andersen JA, et al. Flexor Tendon Tenotomy Treatment of the Diabetic Foot: A Multicenter Randomized Controlled Trial. Diabetes Care. 2022;45(11):2492–2500. PubMed: https://pubmed.ncbi.nlm.nih.gov/36151947/ (DOI shown in abstract source: 10.2337/dc22-0085)
In a follow up study in 2024, pressure was measured in the surgical group pre-surgery vs 3 months post surgery. Following surgery, average pressure on the toes declined from 205.6 KPa to 61.3 KPa. That's a 70% reduction in pressure on the toe.
Andersen JA, et al. Effect of flexor tendon tenotomy of the diabetic hammertoe on plantar pressure: a randomized controlled trial. BMJ Open Diabetes Research & Care. 2024.
In 2018, Lee and Chung of Korea took a retrospective review of 54 toes in 42 patients. 93.5% healed of toe tip ulcers healed without incident.
Lee DH, et al. Outpatient percutaneous flexor tenotomy for diabetic toe ulcers: healing outcomes in 46 cases. J Korean Foot Ankle Soc 2018;22(4):151-155. Published online: 19 January 2018 DOI: https://doi.org/10.14193/jkfas.2018.22.4.151
A 2019 study by Schmitz et al looked at 101 feet with 84 for an ulcer.
95% healed in a median of 27 days. 13% reulcerated and 1 suffered an amputation.
Schmitz P, Scheffer R, de Gier S, Krol RM, van der Veen D, Smeets L. The effect of percutaneous flexor tenotomy on healing and prevention of foot ulcers in patients with claw deformity of the toe. J Foot Ankle Surg. 2019;58:1134-1137. doi:10.1053/j.jfas.2019.03.004.
In a 2013 Danish study, Rasmussen et al performed the procedure on 65 toes from 38 patients were treated. with ulcerated or impending ulcerations. They reported that all ulcers healed uneventfully. 93% healed in median 21 days. 3 ulcers recurred. They considered the procedure simple, safe and effective.
Rasmussen A, et al. Percutaneous flexor tenotomy for preventing and treating toe ulcers in people with diabetes mellitus. J Tissue Viability. 2013.
in a 2013 Dutch study, 38 ulcers were treated with a flexor tenotomy to treat a toe ulcer and followed for an average of 23 months. 92% healed with a mean time of 22-26 days. The other 3 had a bone infection at the time the flexor tenotomy was performed and ultimately required amputation. 7 of the 35 re-ulcerated.
van Netten JJ, Bril A, van Baal JG. The effect of flexor tenotomy on healing and prevention of neuropathic diabetic foot ulcers on the distal end of the toe. J Foot Ankle Res. 2013;6:3.
In a 2010 US study, 58 tenotomies in 48 patients were treated with flexor tenotomies. 98.3% of the ulcers healed in 40-52 days. 12.1% recurred, with a recurrence taking 13.9 months on average. 5% had a post-operative infection. 2 patients with pre-existing bone infection had amputations. Average follow up was 28 months.
Kearney TP, Hunt NA, Lavery LA. Safety and effectiveness of flexor tenotomies to heal toe
ulcers in persons with diabetes. Diabetes Res Clin Pract. 2010;89:224–6.
doi: 10.1016/j.diabres.2010.05.025
A 2010 study of 42 ulcers found 100% healing in an average of 4 weeks. Mean follow up was 11 months, where they noted there had been 1 recurrence, with 1 going on to amputation.
Schepers T, Berendsen HA, Oei IH, Koning J. Functional outcome and patient satisfaction after flexor tenotomy for plantar ulcers of the toes. J Foot Ankle Surg. 2010;49(2):119-122. doi:10.1053/j.jfas.2009.12.001.
In a 2008 Canadian study of 34 toes in 14 patients, a tenotomy was performed. 100% healed in an average of 3 weeks and were followed for an average of 13 months. There were no major complications and no recurrences.
Tamir E, McLaren AM, Gadgil A, Daniels TR. Outpatient percutaneous flexor tenotomies for management of diabetic claw toe deformities with ulcers: a preliminary report. Can J Surg. 2008;51(1):41–44.
In a 2007 US study, 28 ulcers in 18 patients were treated with flexor tenotomies. 100% healed. All lesser toe procedures recurred. 3 of 17 great toe ulcers recurred. 2 of the 3 had a second tenotomy that did not recur. There were no infections, amputations or other complications. Average follow up was 36 months.
Laborde JM. Neuropathic toe ulcers treated with toe flexor tenotomies.
Foot Ankle Int. 2007;28:1160–4. doi: 10.3113/FAI.2007.1160
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This page written by Dr. S A Schumacher
Podiatric Surgeon
Surrey, British Columbia Canada
Unless otherwise indicated, all clinical
photographs owned and provided by
Dr. S A Schumacher.
They may be reproduced for educational
purposes with attribution to:
Dr. S A Schumacher