1992 Volume 11 Pages 319-330
The ankle joint moment in the saggital plane, dorsi and plantar flexion of the ankle joint, flexion and extension of the knee joint, and temporal factors of gait were measured continuously for 10 hemiplegic patients under two conditions: with and without AFO. The ankle joint moment was measured by a capacitive transducer which detected vertical floor reaction forces during the gait. All devices were attached to the subject's body, so that 8 to 20 strides could be measured continuously during 30 seconds. A specially disigned AFO was used in order to decompose the total ankle joint moment into two factors, the moment due to muscle forces and the moment due to the corrective forces generated by the AFO. The data were analyzed with special focus on the corrective moment of the AFO. The maximum dorsi-flexion moment due to the AFO in the early stage of the stance phase was less than 5Nm, and the maximum plantar-flexion moment in the late stage of the stance phase was less than 8Nm. These values were small in comparison with the total ankle joint moment, which ranged up to 70Nm. In regard to the effect of the AFO, the following general tendencies were statistically found. 1. The gait cycle decreased. 2. The single stance phase duration of the affected leg increased. 3. The swing phase duration of the affected leg decreased. 4. The maximum dorsi-flexion angle of the ankle joint during stance phase decreased. 5. The maximum plantar-flexion angle during swing phase of the ankle joint decreased. 6. The maximum dorsi-flexion of the ankle joint occurred in the ealier stage of the stance phase. 7. The maximum extension of the knee joint occurred in the later stage of the stance phase. 8. The maximum dorsi-flexion moment increased. 9. The maximum plantar-flexion moment increased. 10. The maximum dorsi-flexion moment occurred later. 11. The activities of dorsi-flexor muscles and plantar-flexor muscles decreased. However, hemiplegic gait showed extremely large variation depending on the subject. Thus, a case where the ankle joint moment increased with the AFO, a case where the ankle joint moment decreased with the AFO, and cases that showed a change in the knee joint angular pattern are reported and examined in more detail individually.
