Changes in plantar pressure distribution during stance in the course of fracture healing of the lower leg and the upper ankle joint

Background After a fracture of the upper ankle joint, the tibial shaft, or the tibial plateau, patients change their walking and standing behavior due to pain and therapy. According to recent studies, the plantar pressure distribution during walking also appears to change in these patients. Changes in plantar pressure distribution during standing have not yet been investigated during the healing process, though they could possibly have diagnostic and prognostic value. Aim The aim of this study was therefore to investigate the change in plantar pressure distribution during standing in the course of healing after fractures of the lower leg and upper ankle joint. Methods For this purpose, pedography (instrumented insoles with 16 pressure sensors each) was used to prospectively record various plantar parameters over time in 61 patients and 44 test subjects in a ten-second stance. Measurements were taken within 14 days postoperatively (V1) and repeated at 30-60 days (V2), 70-110 days (V3), and 130-230 days (V4). Analyzed parameters included force on the sole in % of body weight, load on specific foot zones (forefoot, midfoot, hindfoot, etc.), and the position of the center of pressure (Cop). Pain questionnaires were used to assess the relationship between pain and force load. Results Force on the injured leg increased significantly between V1-V2 and V2-V3, with no further increase between V3-V4. In period V4, patients showed a higher load on the lateral sole and a more lateral Cop compared to healthy subjects (p=0.024 and p=0.048 respectively). Significant differences between fracture types were found in V2, where tibial plateau patients loaded the forefoot and medial support beam more than other groups. A small negative correlation was found between perceived pain and force load (p=0.141). Conclusion Fractures of the upper ankle, tibial shaft, or tibial plateau characteristically influence plantar pressure distribution during standing. Pressure distribution measurements can be performed quickly in a clinical setting and can demonstrate changes in the healing process.