SLR - October 2016 - Matthew Snow

Gait Patterns in Children with Limb Length Discrepancy

Reference: Aiona M, Do KP, Emara K, Dorociak R, Pierce R. Gait Patterns in Children with Limb Length Discrepancy. J Pediatr Orthop. 2015 Apr–May;35(3):280–4.
Scientific Literature Review
Reviewed By: Matthew Snow, DPM
Residency Program: MedStar Washington Hospital Center
Podiatric Relevance: It is estimated that one out of every thousand people have a limb length discrepancy (LLD). A discrepancy of greater than two centimeters has been shown to cause premature pain and arthritis in the spine, knee, hip and ankle. There are very few articles that describe compensation mechanisms in gait caused by limb length discrepancies. Accurately recognizing early compensation patterns in the pediatric population can prevent long-term sequela that lead to debilitating pain and arthritis. The purpose of the study was to define the various gait patterns in patients with LLD and the impact of these compensations on gait kinetics.

Methods: A total of 43 children with inclusion and exclusion criteria of LLD >2cm without neuromuscular disease were enrolled. Underlying diagnosis included Legg-Calve-Perthes disease, developmental hip dysplasia, growth plate damage due to trauma or infection and congenital deformities causing shortening of the femur or tibia. A cohort of 20 developing children of similar ages was used as a control group. Gait analysis was examined in a motion lab utilizing an advanced motion system and force plates. Scanograms measured the interval segment lengths of the lower extremities. Compensatory mechanisms were then stratified dependent on the extremity affected. Short side included ankle plantarflexion or pelvic obliquity. Long side included knee flexion or pelvic obliquity. Paired t-tests were used to analyze differences in work between the short and the long sides.

Results: Average discrepancy was 4.6 cm with an average of 6.1 percent difference in LLD. Patients with >7cm LLD used multiple compensatory mechanisms while an average of 3.7 cm used a single compensatory mechanism. If the major LLD was located in the femur, increased work was primarily in the contralateral ankle. Those with tibial LLD usually produced increased work in the contralateral hip with pelvic obliquity maneuvers. Total mechanical work was significantly increased on the uninvolved limb.

Conclusions: The authors conclude that more patients walk with pelvic obliquity compensation mechanisms than previously perceived. They demonstrated that dependent upon the pathology location, compensatory mechanisms could be anticipated in specific joints. Of particular value, when femoral discrepancies were noted, there was a significant increase in mechanical work at the shorter side ankle joint. This potentially leads to long-term mechanical problems that directly affect the foot and ankle. Early recognition of the exact locations of pathology early can help better direct care to the appropriate anatomic level to increase joint preservation and functionality. Performing accurate and thorough clinical examinations along with appropriate scanogram analysis will help guide the most efficient multidisciplinary intervention.

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