Is functional hallux limitus due to a problem at the retrotalar pulley?

Hello everyone!!
Unfortunately I arrive a little late! you have been talking about this article for years and I did not know!!
I am one of the co authors and would be very happy to answer any questions you might have and hopefully continue learning from your perspective of the problem. I must say that many articles published in your journal have allowed me to advance in Mayita understanding od Functional Hallux Limitus and sagittal plane blockade.

Some of the questions were:

1-Prevalence of FHL. I think it is very high, probably more thant 60% of people out there, however the vast majority of them are or remain asymptomatic.

2- Symptoms associated:
Metatarsalgia, plantar fascitis, tendonitos of acchilles tendon and posterior tibialis, Primum metatarsus elevatus, anterior knee pain....

3-Causes. Multiple causes, some of which you have mentioned.... one of them that we have identified is a blockage of the muscular belly of the Flexor Hallucis Longus at the retrotalar pulley. Either because the muscular insertion is very distal in the tendon or too bulky to go through.

4- Main diagnostic test: stetcth test. Dorsal fleion of the MTP joint limited when foot in dorsal flexion. (no limitation when foot in plantar flexion other wise this would mean presence of arthrosis of the MTP (Hallux Rigidus)).

5-Hoover cord. Yes someone said it, we thought of the cable of the "hoover" jamming against a 90 deg angle despite having a cable that is long enough..... the sub talar manipulation would loosen the "cable" at the retrotalar pulley allowing us to recover MTP dorsal flexion.

6- Treatment . 9/10 physio and inner soles. When it fails, arthroscopic release of the subtalar pulley.

Look forward to any questions!!


S

Santiago ECHEVERRI
FMH Chirurgie Orthopedique et Traumatologie
Lausanne Switzerland.

 

Video showing arthroscopic release of subtalar joint.
you should see:
1-tight muscular belly of Flexor Hallucis Longus blocked at the pulley when temting dorsal flexion of the ankle and MTP.
2-Release of the pulley facilitating sliding motion of the tendon.

 

One of the other explanations of functional hallux limitus (FnHL) is the reverse windlass effect. That is, with arch flattening the medial slip of the plantar fascia becomes tighter and this limits hallux dorsiflexion. The test you describe for identifying FnHL caused by loss of movement of the Flexor Hallucis Longus (FHL) tendon would not differentiate between loss of motion from the plantar fascia and loss of motion from the FHL tendon. I believe the loss of motion that you see with this test will be caused by the medial slip of the plantar fascia and not the FHL tendon the vast majority of the time.

One clinical test you can do is to have the patient stand and then grab their toe and attempt to dorsiflex the hallux at the same time you palpate the plantar arch. You can easilly palpate the increase in tension in the medial slip of the plantar fascia when you do this. I have seen some texts misidentify the palpable structure that becomes tight, as the FHL tendon when it is fact the plantar fascia. You can verify that this structure is not the FHL tendon by having the subject, in a chair, plantar flex their 1st IPJ and you will see the tendon does not become prominent when this happens.

You discuss limitation of motion of the STJ when the FHL tendon becomes caught in the canal. I'm not sure that I understood exactly how you are saying the FHL tendon limits STJ motion. I find it very unlikely that it does because the FHL tendon has very limited leverage on the STJ. The studies that look at tendon excursion show that the posterior tibial, FDL and the peroneal muscles have much greater excrusion than the FHL tendon with inversion and eversion.

Eric

 

Identification of the retrotalar pulley of the Flexor Hallucis Longus tendon
Chris Tzioupis Anthony Oliveto Silke Grabherr Jacques Vallotton Beat M. Riederer
Jnl Anatomy: 05 July 2019

 

Functional hallux rigidus in high level athletes: Arthroscopic repair by flexor hallucis longus debridement
Brian Carpenter, DPM, FACFAS et al
Journal of the International Foot & Ankle Foundation