Tibialis Posterior Tendon Rupture

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Good morning everyone!!!
I have an 81 year old man with a tibialis posterior tendon rupture that is not able to be surgically repaired due to poor circulation and healing.
He has associated tib ant and peroneal contractures which are causing a fair amount of pain.
I have been treating with orthotics, ankle brace, supportive footwear, mobilising and dry needling. His lovely wife is religious with the stretching regime and also daily massage to the peroneals and the tibialis anterior.
The toes are now contracting and he is having considerable pain all day and night.

Does anyone have any other suggestions for us apart from pain relief?

Thanks!

 

A custom Arizona type gauntlet brace generally works quite well for these patients.

 

That's really interesting Kevin. I googled Arizona Gauntlet brace and it says that there is a moulded plastic shell between the leather and the lining. We do something very similar with a leather stiffener which is non-occlusive and micro-adapts to the wearer over time.
We do it as a whole boot but I like the idea of a brace that would fit into a shoe.

 

The Arizona brace is very popular here in the USA with both podiatrists and orthopedic surgeons.

 

Thanks Kevin and Bill. I gather the Arizona brace has a much more solid plastic shell than the plastic supports in the current ankle brace. I had tried a brace with a more solid plastic support but it irritated the medial side of the foot in particular the navicular which was quite prominent. Kevin, do you mould the medial side of the Arizona to the patients ankle and foot?
Thanks
Rebecca

 

I have been thinking about this question with respect to the 3 forces principle. This principle says that to counter a turning force you need to have 2 forces pushing against it, either side of it.

Perhaps you could help me here Kevin. I have made a drawing with 4 diagrams each a simplified section through the mid-talar joint.

A is the intact PT muscle and tendon which counteracts the pronation force by pulling upwards against the insertion slips in the navicular and 123 cuneiforms cuboid and 234 met bases which pull on the other side of the pronation force. I know there is a lot going on the the saggital plane as well but I am keeping it simple here.

B is a conventional orthotic, which is limited by the width of the footwear at the waist and so tries to control the pronation force by 2 ground reaction forces, both lateral to the pronation force. This puts a painful pressure on the navicular as you pointed out Rebecca.

C shows a bespoke orthopaedic shoe which has a very wide heel base and a medial cup that surrounds the tarsus and so 2 ground reaction forces can push either side of the pronation force. This can be very successful but requires expensive bespoke footwear and can look a bit clumsy around the rear-foot.

D is a section through the Arizona Brace which is a thin, rather elegant device which can be worn inside a conventional shoe which allows corrective forces to apply above the pronation force and on the other side of it by reason of the lateral turning of the brace up around the plantar lateral aspect of the foot.

Is that how you would see it Kevin?

 

Bill:

I did not see any images in your posting, just some x's in boxes.

I have included a new illustration with the external forces from the brace on the foot, ankle and leg which would occur when using the Arizona Brace in a foot with a medially deviated subtalar joint (STJ) axis. These three external forces would create an external STJ supination moment which would, in turn, reduce the tension force on the posterior tibial tendon during weightbearing activities.

 

Thanks Kevin. That's very similar to the drawing. The lateral force at the base is as important as the force on the leg. Very Clear. My problem is I can't figure out how to put a picture onto my reply without having a URL for it so I tried going through twitter but obviously it didn't work.

Oh, Yes. I have to go advanced. OK here it is.


A is the intact PT muscle and tendon which counteracts the pronation force by pulling upwards against the insertion slips in the navicular and 123 cuneiforms cuboid and 234 met bases which pull on the other side of the pronation force. I know there is a lot going on the the saggital plane as well but I am keeping it simple here.

B is a conventional orthotic, which is limited by the width of the footwear at the waist and so tries to control the pronation force by 2 ground reaction forces, both lateral to the pronation force. This puts a painful pressure on the navicular as you pointed out Rebecca.

C shows a bespoke orthopaedic shoe which has a very wide heel base and a medial cup that surrounds the tarsus and so 2 ground reaction forces can push either side of the pronation force. This can be very successful but requires expensive bespoke footwear and can look a bit clumsy around the rear-foot.

D is a section through the Arizona Brace which is a thin, rather elegant device which can be worn inside a conventional shoe which allows corrective forces to apply above the pronation force and on the other side of it by reason of the lateral turning of the brace up around the plantar lateral aspect of the foot.

 

Bill, you need to think about equilibrium and all the forces acting. You need to draw a free body diagram and all the forces acting need to add up to zero when the body in question is not accelerating. As you look at Kevin's drawing the forces from lateral to medial applied to the foot and leg by the brace have to equal the forces from medial to lateral. If these forces weren't equal then the brace would have to accelerate relative to the foot and leg. (A small knit pic:, Kevin did not make the arrows different lengths in his drawing.)

In the case of the PT tendon in the frontal plane there is an upward force on the navicular and a downward force from the tibia. The muscle pull on both the origin and the insertion.

B. The medial heel skived orthotic works by shifting the center of pressure or the average point of force. The center of pressure is the average point of force. A varus wedge will apply more force medially than laterally. A good way to understand this is to view the projection of the STJ axis in the transverse plane. In this view the force will be pointed toward you and be a dot rather than an arrow. The moment from that force will be dependent on the distance that force is from the joint axis. The varus wedge will move the force more medial and, at the heel, farther from the STJ axis thus increasing the supination moment from the ground.

C. Whereas, in B the force was only from underneath the foot, the shoe with the medial build up can apply a force to the foot from medial to lateral. The problem, in free body diagram analysis, comes when do a free body diagram analysis of the shoe. If the shoe applies a medial to lateral force to the foot/leg, then there is an equal and opposite force from leg/foot applied to the shoe (draw only the shoe and the forces acting on it.) So, that force, acting on the shoe, will tend to rotate the upper of the shoe, or if the buildup is rigid enough the whole shoe. Imagine reaching inside the empty shoe with your finger and pushing the medial wall of the shoe in a lateral to medial direction. The shoe will tend to evert with the applied force. Now with a person standing in the shoe, there will be more weight to resist the eversion and attempted eversion of the shoe will shift the center of pressure under the shoe more medial and this will help the forces and moments balance out. This explains why the shoe buildup has to be so stiff and why the additional medial flare is helpful.

D. Kevin's diagram pretty much sums it up. You cans see why the gauntlet can be relatively thinner than the shoe build up. The gauntlet won't tend to rotate relative to the foot and leg as the center of pressure from the lateral side of the gauntlet will directly oppose the force from the medial side of the foot applied to the gauntlet.

Eric

 

Thank you Eric. That is very helpful. Here is a picture of 2 ankle boots both for an orthopaedic surgeon who suffered a ruptured PT tendon. He was reluctant to go down the surgical solution having seen the results over the years. The dark boot was the first pair with an external wedge heel and the light colour was a second pair with the wedge concealed as a cradle inside. He is now on his third pair.
I am very taken with the Arizona Brace and want to learn the technique. I presume it is done on a cast of the whole lower limb, then a vacuum formed polypropylene shell that is shaped and skived for comfort before being sandwiched between a lace up lining and upper.

 

Of course, in a limited reimbursement environment you could take patient outside and shoot him. I can tell you the Arizona brace works like a champ generally with minor fitting issues. The one warning is that an elderly man who can't get down to his feet probably can't put the thing on without the aid of someone else.

 

Yes, inability to reach down or do up laces is a real problem. Arthritis in the hands can cause this as well. The slip on shoes with a long shoe horn can usually be managed. Shoe repairers often have untapped skills and if the 81 year old gentleman has a slip on shoe that he could get on, a skilled shoe repairer, with the guidance of an communicative podiatrist, could build the medial border up and out to ease the condition. That should be affordable on any budget.