Tengyu Zhang1, Xuefei Bai2, Fei Liu3, Yubo Fan4. 1. School of Biological Science and Medical Engineering, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China; National Research Center for Rehabilitation Technical Aids, No.1, Ronghuazhonglu, BDA, Beijing, China; Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, No. 1, Ronghuazhonglu, BDA, Beijing, China. 2. National Research Center for Rehabilitation Technical Aids, No.1, Ronghuazhonglu, BDA, Beijing, China; Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, No. 1, Ronghuazhonglu, BDA, Beijing, China. 3. National Research Center for Rehabilitation Technical Aids, No.1, Ronghuazhonglu, BDA, Beijing, China. 4. School of Biological Science and Medical Engineering, Beihang University, No.37, Xueyuan Road, haidian district, Beijing, China; National Research Center for Rehabilitation Technical Aids, No.1, Ronghuazhonglu, BDA, Beijing, China; Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, No. 1, Ronghuazhonglu, BDA, Beijing, China; Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, No. 37, Xueyuan Road, haidian district, Beijing, China. Electronic address: yubofan@buaa.edu.cn.
Abstract
BACKGROUND: Inappropriate biomechanical loading usually leads to a high incidence of hip and knee osteoarthritis (OA) in individuals with lower-limb amputation, and prosthetic alignment may be an important influencing factor. The effect of alignment on the lower limb loading remains quantitatively unclear, and the relationship between malalignment and joint diseases is undefined. RESEARCH QUESTION: How does alignment affect spatiotemporal gait parameters and ground reaction force (GRF) in individuals with transfemoral amputation? METHODS: Gait tests of 10 individuals with transfemoral amputation were performed with recommended alignment and eight malalignments, including 10 mm socket translation (anterior, posterior, medial, and lateral) and 6° socket angular changes (flexion, extension, abduction, and adduction). Fifteen individuals without amputation were recruited as a control group. The differences in spatiotemporal and GRF parameters under different alignments were analyzed and compared with those of the control group. Statistical analyses were performed by one-way ANOVA, repeated measure multivariate ANOVA, and paired t tests. RESULTS: The medial GRF peaks and impulse on both sides and load rate on the intact side are significantly higher than those of the control group (P < 0.0056). The propulsive and braking peaks, vertical impulse, and medial and vertical load rates of GRF on the intact side are higher than those on the residual side (P < 0.05). The alignment of socket adduction significantly increases medial GRF peak and impulse on both sides (P < 0.0056). SIGNIFICANCE: Alignments exert remarkable and complicated effects on the biomechanical performance. The considerably higher GRF on the intact side of the individuals with transfemoral amputation may lead to internal stress changes of the intact joint, which may be an inducement for high incidence of joint diseases. Probably due to the increased lateral deviation of the center of gravity, the socket adduction alignment significantly increases medial GRF, which may lead to an increased risk of knee OA.
BACKGROUND: Inappropriate biomechanical loading usually leads to a high incidence of hip and knee osteoarthritis (OA) in individuals with lower-limb amputation, and prosthetic alignment may be an important influencing factor. The effect of alignment on the lower limb loading remains quantitatively unclear, and the relationship between malalignment and joint diseases is undefined. RESEARCH QUESTION: How does alignment affect spatiotemporal gait parameters and ground reaction force (GRF) in individuals with transfemoral amputation? METHODS: Gait tests of 10 individuals with transfemoral amputation were performed with recommended alignment and eight malalignments, including 10 mm socket translation (anterior, posterior, medial, and lateral) and 6° socket angular changes (flexion, extension, abduction, and adduction). Fifteen individuals without amputation were recruited as a control group. The differences in spatiotemporal and GRF parameters under different alignments were analyzed and compared with those of the control group. Statistical analyses were performed by one-way ANOVA, repeated measure multivariate ANOVA, and paired t tests. RESULTS: The medial GRF peaks and impulse on both sides and load rate on the intact side are significantly higher than those of the control group (P < 0.0056). The propulsive and braking peaks, vertical impulse, and medial and vertical load rates of GRF on the intact side are higher than those on the residual side (P < 0.05). The alignment of socket adduction significantly increases medial GRF peak and impulse on both sides (P < 0.0056). SIGNIFICANCE: Alignments exert remarkable and complicated effects on the biomechanical performance. The considerably higher GRF on the intact side of the individuals with transfemoral amputation may lead to internal stress changes of the intact joint, which may be an inducement for high incidence of joint diseases. Probably due to the increased lateral deviation of the center of gravity, the socket adduction alignment significantly increases medial GRF, which may lead to an increased risk of knee OA.