I have been intrigued by sesamoiditis since I suffered from it as a resident. I lived with the condition for 10 years before finally realizing I was creating the problem by the way I was running and walking.
After making this discovery, my outlook on treating sesamoiditis changed. I no longer relied on treating it through inserts and offloading devices. I began focusing on strengthening the foot, proper walking and running form, and shoe gear.
I realized I was placing excessive force on my first metatarsophalangeal joint (MPJ). Contrary to my previous belief, when I began experimenting with barefoot running on a treadmill, I put less strain on the joint and my painful sesamoids. This was because I had adapted a shorter stride and began landing with a flatter, more midfoot and forefoot type of foot strike. I was landing more laterally (as I should be) so there was direct force to the first MPJ.
More importantly, I had eliminated the propulsion phase of gait. I realized that it was during the propulsion phase that I felt pain in my sesamoid complex. I was focusing on heel striking laterally and then allowing my foot to pronate and toe off during propulsion. I no longer accept this as a proper phase of gait.
When teaching running form, I advocate landing with a midfoot strike. Instead of pushing off with the forefoot, one should drive the knee forward and use the momentum from a forward lean at the ankles. The propulsion will come from the entire foot and spring mechanism of the leg (Achilles and quadriceps) with a lesser degree of flexion on the first MPJ.
It takes many weeks of running with this form to see a reduction in pain. I typically will introduce a period of rest and anti-inflammatories before commencing this, depending on the severity of the injury. If patients can run without severe pain that would be changing their form, I will allow them to run easy with no speed workouts and only slow base training. If they can't run pain-free, then the rest period continues until they can demonstrate a relatively pain fee gait, one that doesn't alter form to relieve the pain.
I have also noticed that many patients who present to me with either sesamoiditis, a bipartite or fractured sesamoid perform some type of propulsion activity for the forefoot. This is usually from playing volleyball or watching exercise videos such as the infamous P90X or the Insanity workout. Doing repetitive dynamic planks can really load the MPJ excessively, creating pain. Treating these patients with rest, casting and orthotics may help. However, once patients return to the activity that places force on the MPJ, the pain reoccurs.
I also advise modifications in walking and standing. Taking long strides on rigid dress shoes with a solid heel can also increase the force to the MPJ as the body needs to pass over the foot and the force ends up on the first MPJ that is now behind the body passing over it. With a shorter stride or smaller step, the foot does not end up behind the body and the stress to the MPJ is undoubtedly minimized.
Even standing can play a role. Instead of standing in a relaxed posture leaning back onto a cushioned heel, one should disperse the weight over the feet with a slight lean toward the forefoot, which will recruit foot intrinsics to stabilize one’s posture. This obviously takes time and patients cannot learn it overnight.