Plantar pressure displacement after anesthetic motor block and tibial nerve neurotomy in spastic equinovarus foot

The aim of this study was to analyze the displacements of center of pressure (COP) using an in-shoe recording system (F-Scan) before and after motor nerve block and neurotomy of the tibial nerve in spastic equinovarus foot. Thirty-nine patients (age 45 ± 15 yr) underwent a motor nerve block; 16 (age 38 ± 15.2 yr) had tibial neurotomy, combined with tendinous surgery (n = 9). The displacement of the COP (anteroposterior [AP], lateral deviation [LD], posterior margin [PM]) was compared between paretic and nonparetic limbs before and after block and surgery. At baseline, the nonparetic limb had a higher AP (17.3 vs 12.3 cm, p < 0.001) and LD (4.0 vs 3.3 cm, p = 0.001) and a smaller PM (2.9 vs 4.7 cm, p = 0.001). For the paretic limb, a significant increase of AP was observed after block (13.5 vs 12.3 cm, p = 0.02) and after surgery (13.7 vs 12.3 cm, p = 0.03). A significant decrease of PM was observed after surgery (4.5 vs 3.3 cm, p < 0.001) with no more difference between two limbs (2.8 vs 3.3 cm; p = 0.44). This study shows that the F-Scan system can be used to quantify impairments and be useful to evaluate the effects of treatment for spastic foot. It suggests that changes in AP displacement following block may predict the effects of neurotomy.