Peripheral arterial disease affects ground reaction forces during walking

Objective: Claudication is the most common manifestation of peripheral arterial disease (PAD), producing significant ambulatory compromise. The gait of claudicating patients has been evaluated using primarily temporal and spatial parameters. With the present study, we used advanced biomechanical measures to further delineate the ambulatory impairment of claudicating patients. We hypothesized that the claudicating legs of PAD patients have an altered kinetic gait pattern compared with normal legs from control subjects. Methods: Ambulation kinetics (ground reaction forces) were evaluated in claudicating patients and compared with age-matched healthy controls. Forces were analyzed in the vertical, anterior-posterior, and medial-lateral directions. Time from heel touch-down to toe-off (stance time) and time spent in double-limb support were also evaluated. Results: The study recruited 14 PAD patients (age, 58 ± 3.4 years; weight, 80.99 ± 15.64 kg) with femoropopliteal occlusive disease (ankle-brachial index [ABI], 0.56 ± 0.03) and five controls (age, 53 ± 3.4 years; weight, 87.38 ± 12.75 kg; ABI, ≥1.00). Vertical force curve evaluation demonstrated significant flattening in claudicating patients resulting in a lower and less fluctuant center of mass when ambulating. In the anterior-posterior direction, claudicating patients demonstrated significantly decreased propulsion forces. In the medial-lateral direction, they had significantly increased forces consistent with wider steps and an inability to swing their legs straight through. Claudicating patients demonstrated a greater stance time and time in double limb support compared with healthy controls. Most importantly, gait abnormalities were present before the onset of claudication, with gait worsening after the onset of claudication. Conclusion: Claudicating patients demonstrate significant gait impairments that are present even before they experience any limb discomfort. These alterations may make them feel more stable and secure while attempting to minimize use of the affected limb. Advanced biomechanical analysis, using ambulation kinetics, permits objective and quantitative evaluation of the gaits of claudicating patients. Such evaluation may point to new rehabilitation strategies and provide objective measurement of functional outcomes after medical and surgical therapy.