Growing pains remain a mystery

Pain is part of the human experience. As should be predictable, pain is a more frequent companion as we age, the ravages of time taking its toll. Many of us manage to damage some body part or experience a malfunction of a bodily system, and pain is generated as a result. This unpleasant sensation is generally not associated with the vitality of youth, which has not been subjected to the degradation of the years.

Children can experience pain, of course, but they relate to it differently than adults. Children will often not be able to verbalize these unpleasant sensations or, perhaps, are sometimes unwilling. A particularly common example are the ubiquitous growing pains, a frequent condition for many American youth. Although extremely common, modern medicine has no definitive or concrete explanation for this phenomenon. (Some will find it surprising but there is much modern science does not know.)

Growing pains are defined as recurrent, self-limiting episodes of limb pain in children, usually affecting the lower extremities. It is a benign condition, causing no complications, occurring usually during early childhood. Often experienced at night, various designations have been applied. Some examples include ‘benign nocturnal limb pain of childhood’ and ‘recurrent limb pain of childhood.’ Regardless of the name, this appears to be a more frequent ailment than once thought, affecting one in three youths.

The condition was first described in 1823 in a text on ‘diseases of growth’ by a French physician. Yet, despite its long history as a recognized medical malady, the cause remains unclear. There are theories in abundance, as should be predictable for such a ubiquitous and long-standing pathology.

One commonly held belief is referred to as the anatomic theory. Variations in foot, ankle and leg structure and function will alter a body’s biomechanics, increasing stress to some soft tissue structure. Things like hypermobility conditions (where ligaments are too loose), a flatfoot deformity, or an abnormal curvature of the spine, can all lead to altered gait mechanics and pain.

This concept is supported by the frequent finding of pain reduction when utilizing in-shoe supportive devices in some suffering individual. Obviously, there are a million iterations on the theme, but when done correctly, “arch supports” have proven to be of great benefit. Many practitioners of musculoskeletal medicine make use of the beneficial effects of arch/foot/body supports when treating growing pains.

The fatigue theory postulates increasing amounts of physical activity are the cause for these troubles. The finding that these pains seem aggravated by days of greater activity provides some encouragement for this theory. But logically speaking, this would also be the case with some type of anatomic or biomechanical explanation.

Joint hypermobility is a frequent finding in this age group, occurring in about 34% of children and adolescents. This occurs when multiple joints have excess mobility, meaning the articulation can move too far out of position. Weight bearing can wreak havoc in the presence of this variation in soft tissue physiology. This impairment in “restraint” causes multiple structures to move out of a healthy position. This is the principle behind the hypermobility theory for growing pains.

How about the skeletal fatigue theory for this condition, whereby an “overuse syndrome” develops? Research has shown that kids with growing pains have reduced bone density of the tibia as compared to their peers. It has been proposed that increased activity, in combination with the decreased bone density, is what results in growing pains.

Clearly, much suffering results from ‘benign nocturnal limb pain of childhood,’ aka growing pains, or whatever pseudonym is applied. Traditional medicine has little to offer beyond massage and non-prescription analgesics, the ubiquitous acetaminophen and ibuprofen, in their many manifestations. The experience of many clinicians, along with an emerging body of evidence, supports the use of the aforementioned in-shoe bracing, whether it be a prefabricated device (by nature somewhat generic) or a prescription pair of foot orthotics.

The logic for such an effort seems easily grasped in the presence of biomechanical or functional abnormalities. If, indeed, growing pains are in some way associated with musculoskeletal function, “bracing,” i.e. arch supports, would lessen stress to the body parts involved in weight bearing. Other candidates benefitted are those whose foot pronates too much.

Indeed, studies have borne out this approach. Some recent research demonstrated a significant reduction in pain and reduced fatigue within one month of wearing supports, with relief maintained at the 3 month end point of the study. One study not yet performed would evaluate the association of childhood growing pains and biomechanically induced problems as an adult. The duration required for such an experiment would make this challenging.

The question remains unanswered: are growing pains a problem with bone health? Or is it the result of poor skeletal alignment leading to poor function, the all-important body biomechanics? Clearly the act of weight bearing is a critical component in this discussion since it is experienced almost exclusively in the legs.

Numerous studies have been performed and sufficient data gathered. Conservative intervention in the form of in-shoe bracing, in conjunction with an appropriate physical therapy regimen, is recommended for the short term and long term management of growing pain in the presence of any abnormality of motion or mechanics. And yet why do foot supports help even when there isn’t a problem with function? Like so many other questions in medicine, it may for some time remain a mystery.

Dr. Conway McLean, DABFAS, FAPWHc, has offices in L’Anse and Marquette. He is a physician who specializes in treating lower leg, ankle and foot problems.


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