Deformity of foot often missed at birth

Conway McLean, DPM, Journal columnist

The vagaries and varieties of the human form never cease to amaze me. So many people living on this planet, and no two are just alike. Predictably, this extends to our skeletal structures, its shape and form, from facial anatomy right down to our feet. The former means we each look different, either slightly or markedly unique. The latter means some variation from the norm usually results in less than optimal function, which is weight bearing and ambulation. That is what our feet do for us.

Some foot deformities are quite obvious, while others are subtler on visual inspection. Take, for example, Sarah, a fairly normal, middle-aged woman, with no particularly memorable medical history.

The only pertinent part of her medical history as a youth was having to wear special shoes due to her in-toeing. This is a clinical finding which means, as stated, her toes point in when they stand or walk. This is not a specific diagnosis and can be the result of a host of different conditions, originating from different structures, from the pelvis to the metatarsal bones.

Let’s talk about Sarah’s medical history, and the associated relevant components of her past. Obviously, she doesn’t recall much of her childhood, beyond the use of these “special” shoes. Sarah was not particularly athletic, as far as her favorite childhood activities go.

Upon further questioning, it seemed this was not due to disinterest, but more so the result of an inability to compete. She has distinct and specific memories of a general failure to keep up. It would appear she sought out pursuits requiring a minimum of physical demands.

Does she have specific memories of experiencing pain? No, but therein lies one of the problems. Children do not relate pain like adults. Even when they have some medical condition that causes pain, often they will say nothing. How is a parent or medical provider to know? Obviously, some children naturally prefer more sedate pursuits, but, on occasion, it is due to their inability to keep up. Or, if they can compete, the activity causes some form of discomfort.

As Sarah grew, she chose a career, as well as hobbies, requiring less activity, primarily only sitting. Even though she was less active, Sarah experienced back pain regularly, and was beginning to have knee pain on a regular basis as well.

The back pain was relieved temporarily by chiropractic treatments, of which she was very appreciative, but was also frustrated at the transient relief. Standing for longer periods reliably resulted in more pain from these two areas. Try as hard as she might, she had to have at least three chiropractic treatments a month to achieve even a moderate level of comfort.

At the time Sarah presented to my office, her knee pain seemed to be directly related to amount of standing she did. The recent development of moderately severe arch and heel pain added to her woes and initiated her search for appropriate care. Little did she suspect my exam would reveal a congenital condition profoundly affecting her musculoskeletal system and how (well) it functioned.

I have kept you waiting in suspense long enough and am able to now the reveal the diagnosis you have all been waiting for. Sarah suffered from abnormal alignment of the metatarsal bones, those bones which are found at the front of the foot and connect the toes to the feet. The condition is termed Metatarsus Adductus, although a variety of terms have been used, adding to the confusion. When someone is born with metatarsals excessively angulated inwards towards the middle of the body, but are not angulated in any other way (labeled adduction), they will often be told they are simply “pigeon-toed”. It doesn’t take a rocket scientist to recognize this is not much of a medical diagnosis.

It’s all a matter of degrees. If the amount of angulation is not particularly severe, most physicians will dismiss it summarily, and label it unimportant. And sometimes it is. Unfortunately, the consequences of this foot malalignment often take decades to manifest. The human body does not work well, specifically walk well, when the metatarsal bones are pointed in. As compensation, the foot tends to twist outward in a process called pronation. With sufficient amounts of pronation, the arch lowers and the front of the foot swings outward. Voila! The Metatarsus Adductus is corrected…..sort of. This situation, adducted metatarsals and excess pronation look vaguely like a ‘Z’. Thus, it’s also referred to as a Z-foot.

The real problem with this condition is the stress placed on the body by this excess rolling of the arch. The abnormally positioned bones, tendons, ligaments and other structures which function in walking and standing become inflamed and “diseased” over time. Supporting and moving the human body is an incredibly complex process. With hyper-pronation (ie excessive amounts of this motion), the lower leg is turned too far in, placing excessive physical stress on the knee joint, the hips and low back. The arch is also directly affected, often leading to pain. But the pain which ensues is rarely traced back to the origin of the problem, the adducted metatarsal bones.

Treatment for this condition is directly related to the age at which it is diagnosed. In an infant, simple manipulation exercises performed by a caregiver can frequently result in correction of the abnormal adduction. Various braces have been available for many years directed at achieving the same goal. At a certain age, the deformity becomes fixed and manipulation is no longer possible. Only when it is truly severe will surgery be considered. But many do not fall into this category, and receive little to no treatment, and often no education about this problem.

For many adults who are suffering the complications from years of metatarsus adductus, and the associated by-products of hyper-pronation, an accurate diagnosis is the first step. X-rays, taken with the individual standing, as well as a careful and thorough clinical exam, are usually all that are needed. Reducing the amount of abnormal pronation is best achieved with a pair of prescription, customized arch supports, medically termed foot orthotics. Still, many will have already suffered from a variety of the degenerative changes of the musculoskeletal system form years with a Z-foot deformity.

This is a surprisingly common condition, with some estimates claiming the incidence is actually much higher than reported due to the confusion over terminology, and the prognosis. Regardless, if you have chronic pain, perhaps it is mild to moderate Metatarsus Adductus that has gone unrecognized too long? A detailed exam by an expert should reveal the presence of this deformity. If you are responsible for the well-being of a child, have them evaluated by a physician who knows foot alignment, and function, over the years.

Maybe you’ll be saving them from a knee replacement on down the line.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula, with an upcoming move of his Marquette office to the downtown area. McLean has lectured internationally on wound care and surgery, being double board certified in surgery, and also in wound care. He has a sub-specialty in foot-ankle orthotics. Dr. McLean welcomes questions or comments