Effect of prosthetic alignment on gait and biomechanical loading in individuals with transfemoral amputation: a preliminary study

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  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.