Treating Stress Failure Injuries In Young Athletes

By Patrick Agnew, DPM

Is the term “overuse injuries” really appropriate? After all, many so-called “overuse” injuries of the lower extremity are unilateral. In most cases, the right foot is used just as much as the left foot so the term becomes illogical. Perhaps stress failure phenomena would be a more accurate description of these injuries. Some examples of mechanisms leading to stress failure problems include repetitive motion, repetitive loading and repetitive impact. Your patients might encounter repetitive motion injuries in endurance sports like swimming or sports such as cross-country running or basketball. Athletic injuries are often blamed on training, technique or equipment errors. I would add biological errors to the mix. Training errors occur when a child goes too far, too fast, too heavy or too soon. Technique errors often occur in the absence of good coaching. An example might be when an athlete’s improper kicking in swimming breaststroke leads to knee derangement. Equipment errors, such as worn out shoes, can lead to repetitive impact injuries. Unfortunately, biological errors are all too often discovered after the fact. For example, a child who sustains a repetitive loading injury to the second metatarsal head may later be recognized as one who overpronates. If a practitioner had recognized the injury early on, he or she could have used an orthotic to stop the overpronation from destabilizing the first ray and allowing overloading of the second ray. However, stress failure injuries are tough to detect as they often have an insidious onset. This is because the repetitive nature of the damage builds gradually to the point that the “straw that breaks the camel’s back” may occur. Prodromal signs and symptoms of an impending stress failure might include vague or mild discomfort, similarly mild edema, erythema, ecchymosis and eventually a loss of use of the involved anatomy. These are the same signs and symptoms associated with acute trauma but they are more gradually developing with stress failure injuries. Some examples of stress failure in children might be categorized by tissue type. These certainly could include failure of bone, soft tissues or skin. A Primer On The Intricacies Of Bone Failure Failure of bone in children is controversial subject. The actual etiology of injuries is often unclear. These injuries are characterized by what appears to be a failure of vasculature to a bone or part of a bone, which results in death of bone cells and often culminates in failure of bone structure. Also be aware that the terminology is awkward. Naming the injury is often complex and terms such as avascular necrosis, osteonecrosis, osteocondritis, infarction and infraction are sometimes used interchangeably. The proposal of a convention on this controversy is beyond the scope of this article. The signs and symptoms of this type of injury are those listed above. You’ll usually see these symptoms focused in a predictable area such as the second metatarsal head, the navicular, the base of the fifth metatarsal, the heel, etc. A typical bone failure patient may be a teenage gymnast or cheerleader who has experienced a recent increase in activity level. The activity has overloaded an area such as the second metatarsal head. Other predisposing factors might include a short first metatarsal, a degree of equinos, overpronation, a cavus foot type and/or inappropriate footwear. Radiographs of the affected area may reveal deformation of the metatarsal head but this would presumably indicate late recognition. For example, you may see that a child’s dorsal planar foot radiograph demonstrates delayed growth of the third metatarsal from a stress failure injury. Treating these type of injuries involves resting the injured part for a sufficient time, both to alleviate symptoms and to allow redevelopment of adequate strength in the bone to prevent failure. If failure (deformation) has already occurred, complex individualized treatment is likely to be necessary. Be aware that failing to identify these injuries early and prevent subsequent deformation of the affected bone can have far reaching consequences. The resulting changes in joint surfaces may result in early and often severe degenerative joint disease. The controversy regarding stress failure of bone in children overflows into the discussion of stress failure of soft tissue. Repeated stress failure injuries of bone may indicate a collagen disease like osteogenisis imperfecta.

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