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Oct 20

Written by: Larry Huppin, DPM
10/20/2011 7:52 AM

I had a ProLab client call me today with a question regarding orthotics for a patient who has mild to moderate hallux limitus pain while cross-country skiing. In a previous blog, I had written about orthotics for downhill ski boots, and you can read that here. Cross-Country is a significantly different sport, however, primarily because of the need for motion at the metatarsophalangeal joints in some (but not all) boots. 

Cross-Country Ski boots can be somewhat narrow in the heel. This means we have to limit the size of the orthotic in the heel. In addition, heel control is not particularly important while cross-country skiing. Thus, there is not much need for deep heel cups or the use of rearfoot posts.

This patient is an active cross-country skier and, as I mentioned, he has hallux limitus. He has a little limitation to dorsiflexion, but he still has about 60 to 70 degrees of dorsiflexion available at the first metatarsophalangeal joints bilateral. There is no crepitus noted. He is a moderate pronator showing late midstance pronation in gait. Below is the orthotic we recommended:

  • Direct-milled polypropylene, 3 mm. I recommended the direct-milled because it is thinner for the same strength than is the vacuum formed version of the polypropylene. I like it better than the carbon fiber or graphite devices because it is much easier to adjust and less prone to fracture.
  • No rearfoot post. As I mentioned rearfoot control is not very important during cross-country skiing, so we are not going to use a rearfoot post. Leaving the post off also makes it easier to fit the orthosis into the boot.
  • Spot Grind. Instead of the post, we will do a flat grind on the bottom of the orthosis to help stabilize it in the frontal plane. This also allows the orthosis to sit lower in the shoe.
  • Shallow heel cup. Again, he is not going to require much rearfoot control and the shallow heel cup will also allow the orthosis to fit easily into the boot.
  • Minimum cast fill. Minimum cast fill orthoses will conform tighter to the arch of the foot and more effectively let the first ray plantarflex to help decompress the first metatarsophalangeal joint.
  • Wide width. The wide width will provide the best control. I did advice the client that this may be somewhat too wide for the boot and he may need to grind it a little bit to get it to fit. Another option will be to send the boot into the lab and we can fit it to the boot.
  • Full length sport top cover.
  • Reverse Morton’s extensions bilateral to help the first ray plantarflexed and decompress the first metatarsophalangeal joint.
  • Fill under the first metatarsal head with 3 mm poron for a more finished look and comfortable orthotic. 
  • A bottom cover. The bottom cover will finish the orthosis off and make it easier to slide in and out of the shoe. For cross-country ski boots, I find vinyl is a good material for the bottom cover as it makes it easier to move the orthosis in and out of the boot.
You can read more about pathology specific orthosis for functional hallux limitus here.

ProLab takes a scientific approach with our orthoses by integrating evidence-based medicine into orthotic therapy. Our team of Medical Consultants regularly evaluates the medical literature pertaining to orthotic therapy and biomechanics. ProLab clients are encouraged to contact a medical consultant whenever they have questions about an orthotic prescription.

For an easy way to stay up-to-date on evidence-based orthotic therapy, subscribe to our free E-Journal. Your will receive a monthly email synopsis of the research that impacts your practice.

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