The previous post on this blog presented a hypothetical case involving pain in the sesamoid area of a medium built, middle aged female. Included in the presentation are several factors that should assist in determining what type of orthotic device should be most beneficial in successfully controlling the sesamoiditis. The assumption is this is a very typical case with no extraneous factors such as arthritic condition, occult fracture, AVN, or ligamentous, tendinous or capsular rupture. We have the following considerations;
- Medium weight and height, moderately active, wears both casual and dress shoes.
- Mild to moderate Hallux Abducto Valgus deformity
- A semi circular callus plantar to the second metatarsal head
- Evidence of over-pronation upon gait analysis, including abductory twist during propulsion
- Lateral displacement of the sesamoids on the AP radiograph, but anatomically aligned on the sesamoid axial radiograph
- Elevated 1st metatarsal relative to the second metatarsal on the lateral radiograph
Temporary biomechanical control over the foot pronation was achieved with the use of low dye taping with an added dancer’s pad. This substantiates the etiology of the deformity and should guide long term treatment plans with functional orthotics. The associated conditions listed above indicate the presence of both frontal plane as well as transverse plane motion being excessive during propulsion in the form of forefoot eversion and abduction.
Model P-14 orthotic on the KevinRoot website is our suggested solution to sesamoiditis. It features a polypropylene frame, extrinsic rearfoot post, 18 mm heel cup, no frame filler, balanced forefoot correction, a 1.5 mm Spenco top cover and a 3 mm Myolite padded extension with a sesamoid aperture. I would like to add the following suggestions to enhance this device for more challenging cases.
- Minimal arch fill- by maintaining as high a medial arch as possible in the flexible pronated foot, this enhances the ability of the orthotic device to maintain the first ray as plantarflexed (stable) as possible when the foot as progressing from midstance into propulsion
- Add a frame filler, minimize the effect torque or twisting longitudinally of the orthotic within the shoe
- Use a more rigid frame material, for the same reasons as above
- First ray cutout- there are three options for the first ray cutout, 45 degrees, 65 degrees and full cutout.
- Varus extrinsic bar or forefoot tip post- this will create a solid, flat surface on the distal edge of the orthotic and will help to maintain the forefoot correction which may be lost while using the first ray cut out. It is not necessary to create more forefoot correction with this extrinsic post, just maintain the correction you achieve with the intrinsic posting. This may create a bit of a step off from the front edge of the orthotic, which may in turn be alleviated with augmented padding under the sesamoids.
- Dancer’s pad or metatarsal punch for the sesamoids- generally the dancer’s pad will encourage more stable plantarflexion of the 1st ray, and alleviate some of the elevatus of the 1st metatarsal seen on the lateral view. Please be sure to mark the location of the sesamoid in question in your cast or scan of the foot.
The P-14 model on the website is most closely represented as a Performance profile Root type orthotic. The modifications described above can be added to any KevinRoot orthotic device type with any frame material, including Dress, Control, and UCBL depending on the individual patient needs. In the case study presented here, I would highly recommend two devices for this patient, one for her casual and sport shoe needs, and a second dress shoe model for her professional attire.
The next Forum post will be further discussion on the 1st metatarsal-sesamoid joint complex. For those of you who are not surgeons, this is currently a very hot topic in the bunion surgery world, the frontal plane rotation of the 1st metatarsal being the primary deformity in HAV, very interesting!
Please remember, the team at KevinRoot Medical is always ready to assist you!
