Evaluation of interlimb symmetry in individuals with knee osteoarthritis during gait
Richardson, R. Tyler
University of Delaware
Knee osteoarthritis is a degenerative joint disease and is one of the leading causes of disability in the United States. While the etiology is not fully understood, mechanics have been implicated in the disease initiation and progression. Previous research has found that individuals with knee osteoarthritis exhibit abnormal kinematic and kinetic gait patterns. These studies, however, have focused on the symptomatic limb in comparison with healthy individuals leaving the mechanics of the contralateral limb largely unknown. Furthermore, there has been evidence suggesting that alterations on the symptomatic limb may result in an increased risk of osteoarthritis on the contralateral limb. The objective of this study was to investigate the mechanics of the contralateral limb and associated symmetry of individuals with knee osteoarthritis during gait. Seventeen subjects with knee osteoarthritis were evaluated. Three-dimensional motion capture data was collected as each subject walked at self-selected speed on an instrumented split-belt treadmill. The symptomatic limb was selected as each subject’s self-described more painful knee and was verified radiographically to possess more severe osteoarthritis than the contralateral knee. Kinematic and kinetic analysis focused on sagittal plane knee motion during initial contact and early stance, peak vertical ground reaction force, and loading rate. In order to assess interlimb symmetry on a more global limb level, various total support moment parameters were investigated. Interlimb differences for all variables were assessed using paired t-tests. The results revealed that the symptomatic knee contacted the ground with more flexion, exhibited less excursion during stance and displayed less total excursion than the contralateral limb. In comparison with the contralateral limb, the symptomatic limb also experienced a reduced peak vertical ground reaction force and vertical loading rate. Additionally, there were no interlimb differences for peak or angular impulse of total support moment; however the symptomatic limb displayed a decreased knee contribution and an increased ankle contribution to peak total support moment when compared with the contralateral limb. The presence of interlimb asymmetries at the joint and limb levels suggests that individuals with knee osteoarthritis are using their symptomatic and contralateral limbs differently during gait. These asymmetries could represent compensation by the contralateral limb to decrease joint loading and limit knee motion for the more painful limb. Future research should focus on comparing the contralateral limb to limbs of healthy individuals in order to determine if clinical interventions should target one or both limbs to restore gait symmetry.