Plantar pressure distribution in patients with Müller-Weiss disease

Background: Müller-Weiss disease (MWD) is a rare pathological entity of unclear etiology that occurs in middle aged individuals and is characterized by midfoot pain and typical radiographic findings of navicular compression between the talar head and lateral cuneiform. Pes planovarus is a hallmark of advanced disease. The purpose of this study was to characterize the plantar pressure distribution in patients with this diagnosis. Methods: Eight symptomatic feet in six patients with MWD, between the ages of 40 and 60 years, were compared to 18 feet of nine normal individuals. Midfoot scores were recorded according to the American Orthopaedic Foot and Ankle Society scale. Radiographic staging of navicular fragmentation and talar head displacement was done according to the Meary-Tomeno lines. Plantar pressure was measured during walking on a level floor at a natural preferred cadence. All subjects used the same shoe model, and plantar pressure data were collected over four cycles. For each step, the mean pressure and mean normalized pressure impulse were calculated for each of 10 foot zones. The mean of the four steps was computed for comparison between groups. Statistical analysis was performed using a t-test, and the level of significance was set at 0.05. Results: All patients with MWD had advanced radiographic characteristics, and their midfoot scores did not exceed 47 points. Plantar pressure measurements demonstrated significantly higher values (p < 0.05) in the midfoot segments of patients with MWD than the control group, while significantly lower values (p < 0.01) were recorded in the toe segments. Conclusions: Müller-Weiss disease is characterized by increased plantar pressures at the midfoot, combined with reduction in toe pressures. This abnormal pressure distribution may be at least partially responsible for patients' pain and discomfort. Considering these foot characteristics in treatment plans may help choose appropriate nonoperative treatment (i.e. insoles, arch support, hard platform shoes), as well as operative alternatives (appropriate fusion procedures).