People with a transtibial amputations have greater prevalence of low back and hip joint pain compared to the general population, and factors such as altered movement, loading patterns, and neuromuscular activation during tasks such as sit-to-stand likely contribute to these high rates of pain, researchers wrote in a recent study. They suggested that muscle activation, ground reaction forces, and trunk range of motion can be affected by prosthetic alignment during sit-to-stand so investigated the alignment’s effect on hip and low back joint loading.
Kinematics, ground reaction forces, and muscle activity data were collected from ten people with transtibial amputations and ten age- and sex-matched individuals without limb loss during five self-paced sit-to-stand trials. The participants with amputations completed the sit-to-stand task with their prescribed alignment and six altered alignment conditions (±10 mm anterior/posterior, medial/lateral, and ± 20 mm short/tall). A musculoskeletal model was used to calculate hip and L4-L5 joint loading.
According to the study, there were no differences in hip or L4-L5 joint loading between alignments. Participants with amputations had a greater peak hip joint contact force on the intact side hip compared to the amputated side hip across all alignments. Participants with amputations had greater L4-L5 joint contact force compared to those without amputations.
While prosthetic alignment did not affect joint loading during sit-to-stand the researchers suggested future work on other dynamic tasks to better understand the role of prosthetic alignment on joint loading.
The study, “Altering prosthetic alignment does not affect hip and low back joint loading during sit-to-stand in people with a transtibial amputation,” was published in the Journal of Biomechanics
