Gait kinematics and kinetics are affected more by peripheral arterial disease than by age

Abstract

Peripheral arterial disease (PAD) produces abnormal gait and disproportionately affects older individuals. The current study investigated PAD gait biomechanics in younger (<65 yr) and older (>/=65 yr) subjects. The study included 61 patients with PAD (31 younger, age: 57.4 +/- 5.3 yr, and 30 older, age: 71.9 +/- 5.2 yr) and 52 nondisabled age-matched control subjects. Patients with PAD were tested during pain-free walking and compared with control subjects. Joint kinematics and kinetics (torques) were compared using a 2 x 2 analysis of variance (groups: patients with PAD vs control subjects, age: younger vs older). Patients with PAD had significantly increased ankle and decreased hip range of motion during the stance phase as well as decreased ankle dorsiflexor torque compared with control subjects. Gait changes in older individuals are largely constrained to time-distance parameters. Joint kinematics and kinetics are significantly altered in patients with PAD during pain-free walking. Symptomatic PAD produces a consistent ambulatory deficit across ages definable by advanced biomechanical analysis. The most important finding of the current study is that gait, in the absence of PAD and other ambulatory comorbidities, does not decline significantly with age based on advanced biomechanical analysis. Therefore, previous studies must be examined in the context of patients with potential PAD being present in the population, and future ambulatory studies must include PAD as a confounding factor when assessing the gait function of elderly individuals.

Trial registration: ClinicalTrials.gov NCT00094575.

Keywords: aging; biomechanics; gait; gait decline; joint angles; joint torques; older adults; peripheral arterial disease; peripheral vascular disease; walking.

Figure 1

Representative joint angle curves from a younger healthy control for the a) Ankle, b) Knee, and c) Hip during the stance phase. The bar graphs represent total flexion-extension range of motion of the corresponding curve. It is obvious that the peripheral arterial disease patients have more ankle range of motion while also exhibiting less knee and hip range of motion than controls. Note: AROM: Maximum ankle range of motion during the stance phase. KROM: Maximum knee range of motion during the stance phase. HROM: Maximum hip range of motion during the stance phase. Y-PAD: Peripheral arterial disease patients less than 65 years of age. O-PAD: Peripheral arterial disease patients 65 years of age or older. Y-CON: Healthy control subjects less than 65 years of age. O-CON: Healthy control subjects 65 years of age or older. *p < 0.5, significant main effect for group (PAD groups vs. CON groups).

Figure 2

Representative joint torque curves from a younger healthy control for the a) Ankle, b) Knee, and c) Hip during the stance phase. A positive (+) value indicates a net internal extensor/plantarflexor torque, and a negative (−) value indicates a net internal flexor/dorsiflexor torque. Torques are normalized to body mass. The bar graph values represent the peak torque of the corresponding curves (units = %BW X BH). It is obvious that patients with PAD have lower response of the hip extensors during early stance, suggesting weakness of the hip extensor muscles. Patients with PAD also have reduced ankle dorsiflexor and knee extensor torque during early stance and decreased hip flexor torque during late stance. Note: ADT: Maximum Ankle Dorsiflexor Torque, APT: Maximum Ankle Plantarflexor Torque. KET: Maximum Knee Extensor Torque, KET: Maximum Knee Flexor Torque. HET: Maximum Hip Extensor Torque, HFT: Maximum Hip Flexor Torque. Y-PAD: Peripheral arterial disease patients less than 65 years of age. O-PAD: Peripheral arterial disease patients 65 years of age or older. Y-CON: Healthy control subjects less than 65 years of age. O-CON: Healthy control subjects 65 years of age or older. *p < 0.5, significant main effect for group (PAD groups vs. CON groups).