Can iliopsoas muscle contribute stiff knee gait pattern? A preliminary study

Abstract

s / Gait & Posture 39S (2014) S1–S141 S99 Table 1 Principal component scores (mean (SD)) for the hindfoot kinematics and the activation of M. gastrocnemius medialis. Features (PCj, explained variance (%)) Leg Controls (n=15) Ankle OA (n=7) Follow-up (short) (n=7) Follow-up (long) (n=7) P value ANOVA (post hoc tests*) Hindfoot plantarflexion during push-off (PC1, 35.7%) Affected 9.59 (12.32) −5.92 (14.73) −18.57 (15.31) −11.62 (9.26) <0.001 (0.018, <0.001, 0.001) Non-aff. 6.82 (11.28) 1.94 (13.84) −6.52 (17.04) 5.50 (15.54) 0.214 Amount of hindfoot inversion during stance (PC1, 32.5%) Affected −5.67 (10.94) 11.37 (18.89) 10.48 (14.43) 15.47 (17.84) 0.009 (0.014, 0.009, 0.003) Non-aff. −7.93 (12.22) −4.66 (10.31) −0.57 (12.86) −2.95 (7.44) 0.515 Peak activation gastrocnemius medialis (PC1, 46.8%) Affected 2.16 (3.19) −1.76 (2.81) −2.67 (2.18) −0.36 (3.41) 0.005 (0.011, 0.002, 0.107) Non-aff. 1.72 (3.14) −2.21 (3.17) −2.06 (1.99) 0.74 (3.70) 0.017 (0.013, 0.009, 0.527) * P values: (i) controls vs. ankle OA; (ii) controls vs. follow-up (short); (iii) controls vs. follow-up (long). Fig. 1. Sagittal plane knee kinematics. Discussion and conclusions: This study indicated that equines gait decreases peak knee flexion in swing phase and knee ROM in gait cycle itself. Furthermore hip flexor weakness contribute reducing peak knee flexion in swing and knee ROM and may cause more severe stiff knee problem. Hip flexor muscle weakness which is commonly encountered after iliopsoas and adductormuscle lengthening for children with equinus gait may increase knee extension demand and cause stiff knee gait pattern. The claim of hip flexor weakness causing stiff knee pattern in heel–toe gait is still need detail investigation.