Many individuals with lower-limb amputations experience problems with the fitting of the socket of their prosthesis, which can lead to dissatisfaction or device rejection. Osseointegration (OI), the implantation of a shaft directly interfacing with the remaining bone, is seen as a promising alternative for some of these patients.
In an observational study, researchers investigated how bone anchoring influences neuromuscular parameters during balance control in a patient with a unilateral transfemoral amputation.
Center of pressure (CoP) and electromyography (EMG) signals from muscles controlling the hip and the ankle of the intact leg were recorded during quiet standing six months before and one-and-a-half years after the volunteer patient underwent OI surgery. The results were compared to a control group of nine individuals who did not have an amputation.
Results of the study showed that muscle coactivation and EMG intensity decreased after OI, approaching the levels of able-bodied individuals, according to the authors. Muscle coactivation controlling the ankle decreased in the high-frequency range, and the EMG intensity spectrum decreased in the lower-frequency range for all muscles when vision was allowed. With eyes closed, the ankle extensor muscle showed an increased EMG intensity in the high-frequency range after surgery. CoP length increased in the mediolateral direction of the amputated leg.
