A 46 year-old Mexican gentleman visited me on referral by two top NYC foot orthopedists. He'd had surgery six months previously to release pressure on the nerves in his ankle. The problem began after he'd started running to lose weight in four-year old running shoes, which offered little support. This condition, called "tarsal tunnel syndrome," causes pain, burning, and aching further down into the foot. It feels like something is wrong with the arch and big toe, when actually the problem stems from forces compressing the nerve in the ankle that distributes to the arch and toe. It's similar to "carpal tunnel syndrome," which you may remember was prevalent in the early days of computers when so many people took up keyboarding. Remember how this started some new keyboard designs?
He was distressed when he reported. He was complaining of pain not only in the arch and toe, which was supposed to have been resolved by the tarsal tunnel release surgery, but also by ever worsening pain at the balls of his feet behind the toes. He'd never had any injury or pain before at this site, and could hardly walk by the time he came to see me. The orthopedists who referred him asked me to look into making him orthotics with large metatarsal pads on them, to relieve these pains at the balls of his feet (metatarsal pads are mounds fixed to the tops of orthotics which are supposed to be located just rearwards of the ball of the foot, thereby lifting the ball from the ground and reliving painful pressure).
The key to this case was both in his history and his physical exam. He was an internet surfer, and had learned a lot about his tarsal tunnel via the world wide web. He discovered that orthotics are supposed to help tarsal tunnel (this is true), and that custom orthotics are usually better than over the counter devices at correcting pronation (sagging of the arch) which often contributes to a painful tarsal tunnel syndrome (this is also true). He discovered a company on the internet which creates orthotics from a casting of the foot; the company sends a casting kit to the customer, who follows instructions and mails the foot casts to the company. My patient received his custom orthotics one month after he had his tarsal tunnel surgery, and began using them immediately. His tarsal tunnel pain at the arch and great toe was initially completely relieved by the surgery.
One month after beginning the orthotics, he began to get walking pain at the ball of the foot that had had the tarsal tunnel surgery. Then his tarsal tunnel operative site began to swell. One month after that, he began to get the original tarsal tunnel pain. One month after that, he began to get walking pain at the ball of his non-operated foot. Two weeks after that, his opposite foot unoperated tarsal tunnel began to swell. Shortly thereafter, he began noticing tarsal-tunnel-like symptoms (pain in the arch and beneath the great toe) on the unoperated side. Six weeks later, barely able to walk due to pain in both feet, he came to see me.
The operative site at the inside of his ankle looked swollen, but not infected. The incision was intact. When I lightly compressed the swelling, I caused the uncomfortable sensation of tarsal tunnel syndrome down into his arch and big toe. When I palpated the ball of his foot, there was tenderness at the second, third and fourth joints. This was all very strange because neither his history, his shoes, nor his foot type fit the characteristics that should cause this type of pain at the ball of his foot. His toes were perfectly strong, his calves flexible, his foot and toe motions normal. There was no reason so far to have such pain at the balls of both feet.
When I watched him walk, he displayed the typical gait of someone with pain at the ball of the foot: "apropulsive." This means the person does not finish each step by pushing off at the ball of the foot, but rather abruptly stops the step as the weight is about to transfer to the ball, pulling the foot up with the muscles in the front of the ankle. Among other things, an apropulsive gait will disable the "soleus pump." The soleus muscle, the largest muscle in the calf, has many one-way valves in it. Every time the calf contracts and thus throws weight to the ball of the foot, the soleus squeezes blood back up through these one-way valves towards the heart. It helps the heart defeat gravity and assists with circulation. This was not happening in this gentleman's case, because he was walking apropulsively. But why?
I took a look at his orthotics. They already had large metatarsal pads as requested by the orthopedists, large enough to off-load the balls of his feet. But when I matched the orthotics to his feet, the met pads found homes squarely under the painful joints at the balls of his feet. They'd been poking into the balls of his feet for six months. He had no choice but to keep his weight back on his heels to avoid the artificial mountains under the balls of his feet. This disabled his soleus pumps, caused swelling in the tarsal tunnels, and left him with pains in the fore and rear parts of both feet.
His solution? On the first day I saw him, I took him out of the orthotics with the big met pads and gave him a pair of over the counter arch supports that had no met pads. I casted him for orthotics to support his tarsal tunnels and asked the lab to rush the order. The next day he informed me that the pains at the balls of his feet were already 75% better, but his tarsal tunnels were worse. I asked him to wait one more day till his new supports came in.
One week after receiving the new orthotics he e-mailed me: all pains nearly gone.