Conway McLean, DPM

Another top athlete felled in his prime, succumbing to the rigors of professional sports. So goes the more sensational headlines when the news leaked of Rafael Nadal’s condition. Apparently, the best tennis player in the history of the sport, if judged by the number of Grand Slam tennis tournaments won, had suffered a potentially career-ending malady of his left foot.

But this was not a result of the hazards of his sport, the typical ankle sprain or tendonitis. His is a condition considered a mysterious disease, whereby an important bone in the middle of the arch dies, quite literally. Apparently, Nadal has suffered from pain in this region of his foot for over 15 years. Many therapies have been attempted over time, some more successful than others.

The disease is called Mueller Weiss syndrome and was first described over a century ago. Yet, the specific mechanism remains unknown. It’s considered quite rare. But how rare? No one can say and the reason is simple; we aren’t certain how many people have it. In its milder forms, it is rarely recognized. Much more common in women than men, it develops generally in middle age, although of course, these are only tendencies. It can cause severe pain but typically does not hurt all the time.

In Mueller-Weiss, the navicular bone loses its blood supply. When blood flow to the navicular is cut off, it loses its structural integrity and collapses under the compression force exerted by the adjacent bone nearer to the ankle (the talus). The navicular bone flattens or distorts, slowly, over time, altering the articulation between the two bones. This is an important and very functional joint. And these destructive changes generally lead to inflammation and pain over time.

Depending on the degree of deformity prior to any modification, the architecture of the foot may be altered. These changes in foot anatomy are always one of succumbing to gravity, a collapsing of the arch. Mueller-Weiss seems to occur more often to a flatter foot type, but typically results in a greater degree of deformity.

A similar problem occurs in children, whereby the navicular loses its blood supply and dies. In this version, called Kohler’s disease, the bone becomes more compressed and flattened as compared to the changes seen in the adult. Once again, the reason for these changes, an exact mechanism or explanation, this continues to elude us.

Being a professional athlete, Rafael Nadal has access to the most advanced therapies available. Although specifics are rarely provided, treatment did include local anesthetic injections so he could continue competing in a recent tournament. But this is a very temporary approach, the medication effective only long enough for a few sets. Without the nerves being numbed, Nadal said he couldn’t have continued.

Following the French Open this year, Nadal was scheduled to undergo a radio-frequency nerve ablation procedure, which attempts to destroy the nerves sending the pain signals coming from his left foot. (Again, another wonderful use of radio-waves in soft tissue surgery). He has had surgery on the foot, or so say various sources. Others disagree, insisting the treatment wasn’t surgical.

Any therapy which helps support the arch is going to reduce pain levels in those suffering from Mueller-Weiss syndrome. This means a supportive device for the arch, of which there are thousands of makes and models, may be helpful….depending on the design and materials. The more precise, the most effective biomechanically, the more it is going to help. Obviously, this means a custom device (in its billions of incarnations) should do significantly more. Another healthy way to reduce stress on the arch is to stretch out the Achilles, an extremely time-consuming effort, requiring months to achieve measurable gains.

A review of the literature on the topic reveals an interesting finding. Some reputable, respected sources put the egg before the chicken, proverbially speaking. They claim the loss of a blood supply is the primary event, leading to death of the bone and the subsequent deformity. Others, also equally reliable, believe the compressive forces experienced by the navicular bone are unique to the foot. Perhaps the compression of this bone, in certain foot types, is what leads to bone death and eventually further deformity.

The fact that this seems to occur in both children and adults, the same process of navicular death, may indicate the condition is rooted in an individual’s biomechanics. We know that how the bones of the arch are shaped will greatly affect how the foot works. And if it’s not quite right, some structure, be it a tendon or ligament, nerve or joint, will be stressed. But these stresses aren’t experienced just for a day. Or even just a month. These are chronic conditions, the result of one’s foot shape and function.

Faulty biomechanics are the cause of many orthopedic conditions. Perhaps both Mueller Weiss syndrome and Kohler’s disease are the result of abnormal arch function. Difficult to say when we’re not sure how many people have the condition, nor what causes it. Many of these individuals end up with a triple arthrodesis, in which all the major joints of the mid- and rear-foot are fused. This does get rid of a painful joint, but it also eliminates any joint function, any motion. Anyone versed in body mechanics will tell you, stop the motion of one joint, and the neighboring joints are going to be affected.

Rafael Nadal’s tennis future is uncertain. But fear not, you need not lose sleep over Nadal’s future foot health. (At least he’s getting the best care that money can buy.) What we don’t know is why this bone death occurs. Why the navicular? Is this a process that we can intercede in, via the provision of some preventative therapy? If each person that was in the initial stages of Mueller-Weiss was treated with stretches, foot orthotics, appropriate shoe gear, etc, what would be the course of their disease? Would they develop any deformity? Once again, we just don’t know. Another medical mystery for which we have no answer.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula. Dr. McLean’s practice, Superior Foot and Ankle Centers, has offices in Marquette and Escanaba, and now the Keweenaw following the recent addition of an office in L’Anse. McLean has lectured internationally, and written dozens of articles on wound care, surgery, and diabetic foot medicine. He is board certified in surgery, wound care, and lower extremity biomechanics.