Imbalance in Lower Extremity Amputees Associated With Asymmetrical Load Distribution

According to a literature review, lower extremity amputees experience greater postural imbalance compared with the able-bodied population. Researchers attributed the difference to load distribution asymmetry, in which more load is applied to the non-amputated leg.

“The aim of this review was to summarize and update readers on the current published research explicitly related to balance variables in lower extremity amputees,” the researchers wrote. “Given the intricate interaction among balance domains, the understanding in measured balance variables is crucial for improving postural control and helps in rehabilitation.”

Review of LEA balance

In May 2013, researchers searched PubMed, Web of Science, Medline, Scopus and CINAHL and found 23 full-text articles for inclusion in their review.

The review showed lower extremity amputees exhibit greater postural imbalance compared with healthy individuals. Although mean center of pressure position for able-bodied individuals was only slightly toward the dominant side, lower extremity amputees generally veered toward the non-amputated side. Lower extremity amputees also had higher center of pressure velocities vs. healthy individuals.

Among seven articles that investigated body load distribution, four studies showed weight distribution of the non-amputated leg was larger vs. the amputated leg and that load distribution was generally asymmetrical among lower extremity amputees. Researchers found, compared with healthy individuals who had equal distribution between both legs, load distribution asymmetry for first-fitted users was greater than for experienced prosthetic users.

According to most of the studies reviewed, the absence of visual input increased the postural sway among lower extremity amputees and balance performance was significantly increased with the aid of visual and somatosensory inputs. Individuals with a short residual limb had a larger sway area vs. individuals with a medium residual limb.

“[These results could be] used to update the current findings of amputees’ postural balance, and for the comparison purpose of their results,” Ku Pei Xuan, a doctoral student of the department of biomedical engineering at the University of Malaya, Kuala Lumpur, Malaysia, told O&P Business News.

Future studies

According to the researchers, few of the studies in this review reported the association between postural control and reason of amputation, which may cause an absence of balance-related factors. One such balance-related factor not explored by the review articles was the effect of residual limb length and type of prosthesis. Other factors of balance that were not investigated include confidence level of the amputee and sleep quality, which the researchers suggested should be tested in future research. Age should also be included in future studies as postural sway will increase among the elderly in the normal population.

“Insufficient information prevents the analysis of related measured variables. The application of measured variables is recommended to include details such as stump length, prosthetic type, patients’ confidence level, sleep quality, age effect and gender effect,” the researchers concluded. “Hence, further research for the aspects mentioned above is required to enhance and provide a better understanding for lower extremity amputation postural control.” — by Casey Tingle

For more information:
Pei Xuan K. Gait Posture. 2014;39:672-682.

Disclosures: The study was funded by the Malaysia UM/MOHE/HIR grant. Pei Xuan has no relevant financial disclosures.

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