Toe clearance and lower limb kinematics during swing phase of walking over the obstacles in postoperative total knee arthroplasty

Abstract

The purpose of this study was to determine minimum toe clearance and lower limb kinematics at initial swing and mid-swing phase during walking over the obstacles in patients with knee osteoarthritis after total knee arthroplasty (TKA). Twenty patients aged 65-85 years with knee OA were included to the study before surgery, three and six months following TKA and twenty age-matched healthy controls were collected the data for comparisons. All participants were asked to perform range of motion test, muscle length test, leg length, leg muscles strength test, joint position sense test, single-leg balance test, Knee Injury Osteoarthritis Outcome Score (KOOS). For gait analysis, participants were assessed while walking crossed the obstacles (2.5, 5, 10 cm) which placed at the center of an 8-m along walking path. The data were analyzed using ANOVA with repeated measure followed by Bonferroni’s multiple comparisons. The results revealed the six-month postoperative patients improved gait speed among the TKA patients. When they crossed over the obstacle (2.5 cm), it showed no significant difference in toe clearance at the initial swing phase. At obstacle heights of 5 and 10 cm, toe clearances of the six-month postoperative patients were lower than those of the controls. At the same time points, they also exhibited decreased hip flexion and knee flexion at the initial swing phase but ankle dorsiflexion was changed in a similar pattern of both groups. These altered gait movement pattern with decreased toe clearance had identified as risk factors for tripping during obstacle-crossing due to the toe trajectory closed to the ground surface. Additionally, the lower limb strength of the six-month postoperative patients was weaker than those controls and they also had slightly decreased in static balance compared with the controls. Although the TKA patients could not return to their normal gait patterns, their treatment proved to be successful in terms of knee arthritis, which delivered relatively high satisfaction because the patients experienced pain relief and functional recovery and required improvement in the quality of life. In order to maintain physical performance after TKA, training program of lower extremity such as strengthening of lower limb muscle or balance training exercise may be an important component of the effective postoperative rehabilitation programs.