The past two forum posts involved a case study in which a young, athletic male was diagnosed with 2nd MTPJ capsulitis (predislocation syndrome), a Morton’s Neuroma of the third intermetatarsal space and a limb length discrepancy. These are all common conditions seen in a lower extremity clinical practice, and in this case all three were initially addressed successfully with conservative care. The challenge then presents on how to manage the conditions long term on a biomechanical basis, given that the most beneficial orthotic build for one of the conditions may prove detrimental to the others. Priorities must be assigned and choices made when designing an orthotic configuration to best suit the patient’s needs. 2nd MTPJ capsulitis and intermetatarsal neuroma are probably the two most common forefoot afflictions we see, and it is not unusual to see them occurring together in the same foot. Two additional considerations in this case include a leg length discrepancy that may or may not need to be addressed, as well as the patient’s very active lifestyle which includes the repetitive stress of long distance running, the lateral movements of high intensity interval training and the high impact sport of basketball. This patient is also a professional person and has to dress accordingly Monday through Friday each week. This is how patients often present in real life, multiple considerations to factor in the orthotic build design, before we even get into the particular biomechanics of this patient.
Let’s separate out the two main pathologies in this case. My experience is 2nd MTPJ capsulitis must be addressed effectively with the orthotic device, it is often a progressive deformity, and if allowed to worsen over time often leads to plantar plate disruption and the dreaded crossover deformity of the second toe. Should it progress to the level of necessitating a surgical correction, an osteotomy, tendon transfer or plantar plate repair can all involve a prolonged recovery as well as possibilities for complications. Neuromas can also progress to needing a more aggressive treatment, many options are available, and in my experience are less amenable to successful outcomes using orthotics alone. Two cases stand out in my memory, one in which an avid hiker decided to wear only open toe shoes and no longer had to deal with the neuroma pain and the other was a woman training for her first L.A. Marathon. The neuroma was stopping her dead in her tracks during her long training runs. After we exhausted several types of treatments , including orthotics, we decided to wait until next year’s race, removed her neuroma and had her back on the road in a few weeks. She successfully ran the marathon the following year. Another topic regarding neuromas is the use of the neuroma pad (a wedge between the third and fourth metatarsal) versus a standard metatarsal pad. I tend to favor the metatarsal pad because the neuroma pad needs to be placed exactly where you intend it, so adhering it to a patient foot is fairly easy to be precise, building it into the orthotic device where the foot can shift position relative to the device is less effective.
Effective orthotic treatment of 2nd MTPJ capsulitis is far more likely to be successful, and should be prioritized in this case. Generally, it requires some sort of offloading of the second ray, often by increasing the resistance of the first ray to ground reactive force.It is imperative to know what is causing the second ray overloading, whether it is a long second metatarsal, and isolated plantarflexed second metatarsal, a dysfunction of the second metatarsal phalangeal joint due to either a biomechanical imbalance or a habitual overuse as in someone who crouches or leans forward and presses down on their forefoot repetitively with their toes in full extension. It is also common to have a convergence of the second and third metatarsals which may cause a second interspace nerve entrapment or neuroma further complicating the condition.
A hybrid type orthotic was selected in the case presentation. In reality, a patient like this may likely require more than one orthotic device to properly control his conditions across his wide range of activities. It may be wise to start with a fairly basic device, in a case like this, a semi rigid polypropylene device with a moderate heel cup, padded full length top cover, perhaps a minimal (1.5 mm) lowering of the medial arch and a simple metatarsal pad. A separate heel lift can be dispensed to accommodate the limb length discrepancy. The “bells and whistles” can be added, subtracted or adjusted as needed, or a second device can be added later depending on how the patient responds.
There is generally no “one size fits all” in the world of biomechanics and custom foot orthotics. So many variables exist that no two cases will be identical. The successful practitioner will apply the science and practice the art. Feedback is essential in achieving ultimate success, mistakes can be made, but they should be acknowledged, corrected and learned from.
