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Canadian Medical Alliance for the Preservation of the Lower Extremity

Surgical Offloading of Small Toes

Toes can become contracted and crooked for a variety of reasons--

such  as certain forms of arthritis, trauma, inappropriate shoes. 

However, the most common reason for a toe to become contracted

and crooked is an abnormal pull of a tendon that attaches into the

toe.   One reason this might happen is a motor neuropathy, where

abnormal nerve signals cause muscles to pull a toe abnormally. 

But the most common reason contracted and misshapen digits occur

is because of an underlying biomechanical abnormality.  We can't

review all of the biomechanical reasons a toe can become contracted,

so we'll just discuss one of the more common causes.

 

Imagine a normal foot that flattens excessively in stance.  

The heel rolls tilts.                      The foot rolls inwards.                                                     And the arch collapses.

 

 

 

 

 

 

A foot that flattens excessively (pronates)

like the one above is not efficient for gait,

so a couple of the muscles on the inside of the ankle are used to compensate.  

The major muscle that opposes excessive pronation is the posterior tibial (PT) muscle. 

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, and attaches to the bones on the inside of the midfoot.  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 inside a sheath, which is the blue structure in the photo on the left.)

 

As the FDL tendon moves 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.  

 

Misaligned toes like this can cause pressure spots to form on the tip of the toe where the toe hits the ground, as seen in the three examples below.  Ulcers on the tip of the toe are extremely common after the great toe has been amputated, as seen in the examples below center and below right.  This is why diabetic foot specialists try to avoid amputating the great toe whenever possible.

 

 

 

 

 

 

 

 

 

 

 

 

It can also cause issues on 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 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.

But what if there is a relatively simple procedure that could be performed to correct the problem? 

 

 

In many cases there are simple surgical procedures

that may resolve the issue.

If one can readily straighten a toe manually, as seen

to the right, the toe is considered "reducible." 

 

Surgical correction could be as simple as cutting the

flexor tendon.  

     

 

This procedure can be done very quickly and cleanly

with a scalpel inserted from the side, turned to cut

the tendon, then removed--a procedure requiring

just a single stitch (right).

It can even be done with a needle inserted from the

bottom of the toe, a procedure that usually doesn't

require any stitches.

The procedure is surgical, but it's minimally invasive,

and for most ulcer patients with a flexible deformity,

it should be strongly considered.

References in the medical literature for this procedure

can be found immediately below. 

 

It's worth pointing out that while the studies below

show good results, most do not seem to specify

that the procedure was performed on reducible

deformities, which would be the deformities for

which the flexor tenotomy procedure would be

most likely to work.

 

 

References on a flexor tenotomy for reducible contracture deformities.

In a 2013 Danish study, 65 toes from 38 patients were treated with a flexor tenotomy to treat toe ulcers.  All healed uneventfully.  There were no infections and no amputations.  There were 3 recurrences.

 

Rasmussen A, Bjerre-Christensen U, Almdal TP, Holstein P. Percutaneous flexor tenotomy for preventing

and treating toe ulcers in people with diabetes mellitus.  J Tissue Viability. 2013 Aug;22(3):68-73.

doi: 10.1016/j.jtv.2013.04.001. Epub  2013 Jun 26. PubMed PMID: 23809991.

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.  35 of the 38 ulcers healed (92%) 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(1):3.

Published 2013 Jan 24. doi:10.1186/1757-1146-6-3

 

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


 

In a 2008 Canadian study of 34 toes in 14 patients, a tenotomy was performed.  All 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.  All 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

 

 

In a 2010 Dutch study, 42 toes from 23 patients were treated with a flexor tenotomy.  All ulcers healed in an average of 4 weeks.  The mean follow up was 11 months. There was one recurrence and one complication.

 

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 Mar-Apr;49(2):119-22. doi: 10.1053/j.jfas.2009.12.001.

Epub 2010 Feb 4. PubMed PMID: 20137983.

 

If we combine the results of these studies, we get a chart that looks like the one below.  Of the 248 procedures performed in these studies, 244 digits healed with 6 complications.  There were 18 total recurrences, representing 7.25%.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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. 

 

If a contracted toe cannot be straightened manually, as in the case to the left, this means the joint has adapted to being held in a crooked position for too long.  The joint has become arthritic.  The toe is called "non-reducible." 

In this case, it is a fixed deformity, and simple tenotomies are not able to straighten the toe. 

Surgical correction of fixed deformities requires addressing the bone.

 

For fixed deformities like this,

surgical correction usually requires

removing a small section of bone

in the joint so the toe can be

straightened.  

Hardware (like pins and specialized

screws) are usually avoided in ulcer

patients in order to make healing

quicker and easier, and to minimize

risks of infection.  Further, in order

to avoid future ulcers, we'd prefer

the toe to be more flexible, not

more rigid.

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.

 

 

 

Conclusion

 

No one relishes the idea of surgery, particularly in a diabetic foot. 

However, in many cases these are procedures that can be safer than allowing an ulcer to return repeatedly.  We discuss why surgical offloading should be considered here.  

On other pages we'll discuss procedures that could be considered to surgically correct ulcers on the great toe, and procedures to correct ulcers on the ball of the foot.

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.

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This page written by Dr. S A Schumacher
Podiatric Surgeon
Surrey, British Columbia  Canada

All clinical photographs are owned and provided
by Dr. S A Schumacher.  They may be reproduced
for educational purposes with attribution to: 
Dr. S A Schumacher, Surrey, BC Canada

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