Predicting flexible flatfoot symptoms
A recent paper on variations in midfoot alignment offers a tantalizing new piece of information in the treat-or-don’t-treat puzzle that has long been an issue in management of asymptomatic pediatric flexible flatfoot.
By Emily Delzell
Although there is wide agreement on the treatment of symptomatic patients, clinicians are still challenged to differentiate between the physiologic and pathological manifestations of asymptomatic flexible flatfoot. Asymptomatic physiologic flexible flatfoot is normal and self-correcting, whereas its pathological counterpart leads to a cluster of structural problems as children age, put on weight, and participate in organized sports and other physical activities.
The surgeon authors of the paper published in the Journal of Pediatric Orthopaedics in June retrospectively identified 135 patients aged seven or older with a diagnosis of idiopathic flexible flatfoot. They divided the population into three groups: 45 asymptomatic patients; 45 symptomatic patients treated conservatively; and 45 symptomatic individuals treated with surgery.
The authors assessed 13 radiographic measurements that describe the alignment of the hindfoot, hindfoot, and forefoot, but found a large effect size for only one: talonavicular coverage. This measure describes the alignment of the midfoot and is defined as the angle created by lines drawn through the medial and lateral margins of the articular surfaces of the talus and the navicular.
According to the authors’ key finding, talonavicular coverage angle was significantly greater in both symptomatic groups than in the asymptomatic group, suggesting that lateral displacement of the navicular is linked to onset of symptoms. In turn, the findings may have implications for interventions in asymptomatic patients.
“Further research is need to confirm this finding, but it offers a clue to the pathology linked to pain in children with flexible flatfoot,” said study co-author Scott J. Mubarak, MD, director of Rady Children’s Hospital’s pediatric orthopedic program and clinical professor of orthopedic surgery at University of California, San Diego. “Although there is no evidence that orthotics can prevent talonavicular uncoverage from occurring, if practitioners see this finding on x-ray, it could support interventions to modify footwear, including the recommendation that patients wear high-quality athletic shoes with good support that takes stress off the midfoot.”
Russell G. Volpe, DPM, who is in private practice at the Foot Clinic of New York in Farmingdale and New York City and professor of pediatrics and orthopedics at the New York College of Podiatric Medicine, noted that the talonavicular coverage finding is an interesting step forward in the debate over how to best identify the at-risk asymptomatic flexible flatfoot.
“The authors have taken a serious scientific look at this potential predictor,” Volpe said, but it’s important to point out that no one measure can be used to exclude asymptomatic patients from risk of progression or from treatment.”
The big picture is key to identifying the pathological pediatric flexible flatfoot, Volpe said.
“When I evaluate a child with flat feet, I look at a host of biomechanical lower extremity factors that may be contributing to flat foot morphology,” he said. “This might include analyzing angles seen on x-ray, but identifying at-risk children requires more than looking at a single angle.”
Volpe also noted that the retrospective analysis included a window of only six years for symptoms to develop, meaning the oldest child at the study’s cut-off was just under 18 years, an age at which there are still many years of potential symptomology ahead.
Despite the study’s limitations, Volpe said its findings, which confirm prior knowledge of the link between midfoot compensation and deformities of bone and soft tissues, gave him a sense of cautious optimism that as practitioners learn more they will become even better at identifying the at-risk foot.