Our patient is a 39 year old female with a chief complaint of burning and occasional throbbing pain in the ball of her right foot. The pain started approximately six months prior and manifested initially as a cramp in her lesser toes during a long run. The problem was alleviated when she stopped running and removed her shoe, and was then able to continue her run. She noticed the problem recurring during her running and hiking activities and became more frequent and more intense over time. Eventually the problem started to recur during non athletic activities, especially when wearing dress shoes required for her employment as an executive. In the past two months she has noticed an occasional clicking feeling in her third and fourth toes, and now has noticed a pain behind the second toe which is worsened when she is on hard surfaces or barefoot, and the second toe is starting to stick up and drifts over towards the big toe. She visited her local running shoe store and was told by the salesperson she has a “Morton’s Neuroma” and should try wider shoes for running and hiking. If that did not work she should seek professional help for evaluation and treatment.
The patient is 5” 4” tall and weighs 120 pounds. She states she is in perfect health, takes no prescription medication and denies allergies to food or medications. No prior surgical history. She denies smoking, and recreational drug use. She drinks a glass of wine or can of beer 2-3 times per week. She reports being very physically active, running approximately 5 miles several times per week, frequent hiking in the nearby mountain trails, biking, swimming and various cardio and strength training at the gym. She works as an executive at a local corporation, is married but has no children. She is distressed that the pain in her right foot is preventing her from training for an upcoming triathlon, and the condition is worsening despite her attempts to mitigate the problem.
Lower extremity examination is performed bilaterally. Circulatory findings are WNL and non-contributory. Dermatological findings are also WNL other than superficial callous formation on the plantar aspect of both feet under the second metatarsal and around the rim of both heels. No unusual skin lesions are otherwise noted. Neurological findings are all negative with the exception of a positive Mulder sign in the third interspace of the right foot. Musculoskeletal findings include limb length discrepancy of 1 cm, measured from the anterior superior iliac spine to the medial malleolus, right side greater than left, the right foot larger than left, measuring size 10 medium on the right and 9.5 medium on the left using a Brannock device. There is a slight medial dorsal excursion of the right second toe, with slight swelling and pain to palpation of the plantar plate of the right 2nd metatarsophalangeal joint. The Lachman drawer sign is present.
Biomechanical examination reveals ankle dorsiflexion greater than degrees bilateral with both knee extension and flexion, normal range of motion of bilateral subtalar, midtarsal joints and 1st metatarsal phalangeal joints. She has a neutral Calcaneal Stance position of 2 degrees inverted bilaterally, resting calcaneal stance position of 2 degrees everted on the left and 4 degrees everted on the right. The is noted to be the left forefoot is perpendicular to the calcaneal bisection on the left and 4 degrees varus on the right foot. The first is minimally hypermobile bilaterally. Walking gait analysis reveals slightly greater pronation on the right side than left during midstance and propulsion, running gait analysis on the treadmill with shoes on reveal mild internal position of the knees and midfoot strike.
Weight bearing x-rays of both feet reveal slightly hypermobile 1st ray, 1st metatarsal elevated relative to second metatarsal) elongated second metatarsal bilateral, and medial-dorsal deviation without subluxation of the 2nd MTPJ of the right foot. Bone density appears normal, and radiological findings are otherwise WNL
Discussion
The diagnosis of neuroma of the third interspace and capsulitis (pre-dislocation syndrome) of the 2nd Metatarsophalangeal joint of the right has been established. A secondary diagnosis of limb length discrepancy, right greater than left has also been established. After consultation with the patient regarding the diagnoses and possible treatment options, she had decided she wants to try to alleviate the conditions with custom foot orthotics and forgo other treatment options.
Questions regarding an orthotic build for this patient should include;
What rearfoot, midfoot and forefoot options should we include? What materials for the frame, potential frame filler, top cover and extension should we choose? What extra padding, accommodations, or cushions should we add? How rigid or flexible should we make this device? Wide, narrow or medium width? Since we have two different primary diagnoses, and one secondary diagnoses how do we prioritize one over the others, if necessary? Do we need to make more than one pair of orthotics for this patient? If so, what types and for what purposes?
This is a very common scenario presented here. Of course a case like this in the real world would include many other treatment options other than orthotic devices, including non-invasive ones that would not interfere with the patient's desire to remain in active training. How would you handle this case?
