Center of pressure in a walking boot shifts posteriorly in patients following lower leg fracture.

BACKGROUND

Studies have shown that the ambulatory behavior and amount of weight bearing performed by lower leg fracture patients, increases over time. It is likely that gait features, such as center of pressure (CoP), also change over time.

RESEARCH QUESTION: The purpose of this study was to characterize changes in CoP exhibited by lower leg fracture patients wearing a walking boot during the recovery period.

METHODS

Approximately 2 weeks post-surgery, seven lower leg fracture patients were fitted with a MaxTrax walking boot which was integrated with the Ambulatory Tibia Load Analysis System, an underfoot load monitoring system. Patients wore the walking boot for 2-12 weeks resulting in continuous load data during the recovery period. Ambulation was filtered from the raw data and daily average CoP values were calculated by averaging the CoP vectors from all steps in a given day.

RESULT: In general, the CoP vector varied in both the x and y directions during the initial stages of recovery but was more uniform during the later stages of healing. In 6/7 patients, the CoP in the y direction was closer to the forefoot during the initial stages of healing but shifted posteriorly as time post-surgery increased. The single patient that did not exhibit a posterior shift in CoP was also the only patient to develop a non-union. CoP in the x direction show a less clear trend. CoP in the x direction exhibited a medial shift in 5 patients and a lateral shift in 2 patients.

SIGNIFICANCE: During lower leg fracture recovery in a walking boot, the CoP in the y direction shifts posteriorly as time post-surgery increases and CoP monitoring may become a useful tool to monitor individual patient healing progression.