Foot Pressure Changes Before and After Ankle Fusion: A Pedobarograph Study

We performed a case-control study with the purpose of establishing the pressure patterns in the soles of the feet of patients with ankle osteoarthritis, determining whether the pattern changed after treating the arthritis with ankle joint fusion (arthrodesis), and whether the change is significant. We also studied the benefits of ankle fusion with respect to the Short-Form 36-item Health Survey and the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale. The study included 18 participants (9 in the study group and 9 in the control group) to reach statistical significance with a 95% confidence interval (CI). A demonstrable increase was found in both forefoot and hind-foot pressures in the study group preoperatively compared with the control group. Also, a demonstrable increase was found in the pressure in both the forefoot (mean difference 50.56 ± 267.39 kPa) and the hindfoot (mean difference 57.44 ± 160.27 kPa) from preoperatively to postoperatively. This difference was not statistically significant (p = .59 [t(8) = 0.57]; 95% CI 256.10 to -154.98) for the forefoot pressures and for the hindfoot pressures (p = .31 [t(8) = 1.08]; 95% CI 180.64 to -65.76). The Short-Form 36-item scores significantly improved from preoperatively to postoperatively (p = .000054 for the physical component and p = .018 for the mental component). The American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scale score also improved significantly (p = .0000005). The foot pressures, as measured by using the insole sensors, showed an increase in forefoot and hindfoot pressures that was not statistically significant.