Should You Use A Fifth Ray Cutout For Lateral Column Overload?

A colleague called asking about an orthotic prescription for lateral column overload. He was wondering if I would try a fifth metatarsal or fifth ray cutout. This would be similar to a first ray cutout that one might use for hallux limitus. This is an interesting idea and I actually have not tried it myself.

The primary goal in this situation is to transfer pressure off the lateral column and onto the medial column. If we can accomplish that, then that should reduce the pain the patient is having from excessive lateral load. See below for the prescription I recommended.

• Semi-rigid polypropylene.
• Standard heel cup.
• A wide width so there is more surface area under the medial column in order to transfer pressure off of the lateral column
• A minimum cast fill. A minimally filled orthosis will conform closer to the medial arch in order to transfer pressure off the lateral arch. We have to be careful in this situation that the orthosis does not conform so closely to the medial arch that it supinates the foot, pushing the patient onto the lateral column. Usually, a minimum fill with no inversion will work well to transfer pressure off the lateral column without excessively supinating the foot. If we do a minimum fill with inversion, then I think there is some risk of excessive supination. If this occurs, however, all we need to do is to grind the medial arch thinner to increase the flex of the orthosis.
• Polypropylene 0/0 rearfoot post. We want a polypropylene post. An ethylene vinyl acetate (EVA) post would compress laterally over time and let the patient roll more onto the lateral column. We want a flat 0/0 post to encourage the patient to pronate a little faster in order to get the foot off the lateral column.
• A cushion top cover such as 3 mm soft EVA with 1.5 mm Poron glued to the bottom. The extra cushion is to cushion the lateral column.
• Glue cover heel only. By gluing the cover heel only, we can easily adjust the front of the orthosis such as grinding the lateral side to allow the fifth ray to plantarflex.

That should be quite an effective prescription and still allow us the ability to do a fifth ray cutout if necessary. I am hesitant to recommend a fifth ray cutout initially as it will narrow the orthosis and the device may not sit correctly in the shoe. However, I think having the ability to do it if the initial orthosis does not provide adequate relief is a benefit.

Editor’s note: This blog was first published at https://prolaborthotics.com/Blog/tabid/90/EntryID/316/Default.aspx and has been adapted with permission from Lawrence Huppin, DPM, and ProLab Orthotics. For more information, visit www.prolaborthotics.com .