Asymptomatic Flatfeet Showed Altered Foot Motion During Walking

Among pediatric and juvenile patients with idiopathic flexible flatfeet, both symptomatic and asymptomatic flatfeet showed considerably altered foot motion during walking, according to study results published in Gait & Posture. The largest differences were found in reduced hindfoot dorsiflexion as well as in increased forefoot supination and abduction when compared with typically developing feet.

“There is an ongoing orthopedic discussion about treatment of flexible flatfeet. In clinics we are frequently confronted with severely malaligned yet asymptomatic feet,” Matthias Hösl, MSc, research associate in the Gait Laboratory at the Orthopedic Hospital for Children in Aschau, Germany, told O&P Business News. “We wanted to examine foot function during barefoot walking in symptomatic and asymptomatic flexible flatfeet which we considered to be clinical borderline cases. We aimed to find biomechanical parameters that were able to discriminate between both.”

Foot function

Researchers recruited 35 pediatric and juvenile patients with idiopathic flexible flatfeet from an orthopedic outpatient department and compared them with 11 age-matched participants with typically developing feet (TDF). Researchers captured 3-D multi-segment foot kinematics and ankle joint kinetics during barefoot gait analysis.

Although alterations in foot kinematics in flatfeet were pronounced, researchers found no differences between symptomatic flatfeet (SFF) and asymptomatic flatfeet (ASFF). Study results showed reduced hindfoot dorsiflexion and increased forefoot supination and abduction were the largest discriminatory effects between flatfeet and TDF. Although the hindfoot in flatfeet was more everted during gait, it was less flexible. Increased forefoot mobility and a hypermobile hallux compensated for limited hindfoot dorsiflexion of ASFF and SFF. Regarding ankle kinetics, researchers found SFF lacked positive joint energy for propulsion, while ASFF needed to absorb more negative ankle joint energy during loading response which may risk fatigue and overuse syndrome of anterior shank muscles.

“We supposed that symptomatic feet showed greatest deviations in 3-D foot motion with respect to our reference group. Yet that was generally not the case,” Hösl said. “On the one hand, it seems that symptoms may therefore not necessarily be linked to foot motion. On the other hand, flat footedness in asymptomatic patients also caused pronounced changes in kinetics. Interestingly, they needed to absorb about 40% more ankle joint energy during ground contact than normal feet. Consequently, foot function in asymptomatic flatfeet is already compromised when walking.”

Treating flatfeet

According to Hösl, the use of special training of inverting muscle may help prevent muscular overloading among asymptomatic pediatric and juvenile flatfeet that display functional, objectively documented limitations during shock absorption. Calf tightness should also be addressed with effective stretching regimes as it may be causal for flat footedness.

“Both restraint and excessive mobility occur simultaneously in the same flatfoot. The rearfoot, for example, might be considerably everted while also lacking mobility necessary for dampening,” Hösl said. “These deficits are likely to be more pronounced during running. Static radiographs cannot test this and a passive exam cannot simulate loadings during walking or running. This also has to be considered during surgical treatments. Using a subtalar arthroeresis implant, for example, might achieve realignment of the heel, but the heel’s already decreased range of motion into eversion may be further restricted.”

Pain associated with flatfeet may only arise when tissue wears out, causing a need to re-evaluate asymptomatic feet to find predictors for pain. Hösl recommended monitoring asymptomatic flatfeet through foot kinematics and kinetics. By evaluating a more challenging task, such as running or jumping, researchers may find more biomechanical shortcomings in asymptomatic feet. — by Casey Tingle

For more information:
Hösl M. Gait Posture. 2014;39:23-38.

Disclosure: Hösl has no relevant financial disclosures.

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