Knee extension strengthening is one of the cornerstones of rehabilitation in prosthesis users with transtibial amputation. It is recommended in terms of increasing functional mobility, preventing the risk of fall and knee osteoarthritis. Therefore, there is a need for objective measurements to evaluate changes in functional strength and walking through the rehabilitation process. Muscle thickness measured by ultrasound was found to be valid and highly correlated with magnetic resonance imaging and dual-energy X-ray absorptiometry measurements and shown to reflect the strength and functional outcomes in various diseases. The first aim of this study is to reveal the rectus femoris muscle thickness alteration in prosthesis users with transtibial amputation compared to able-bodied controls and establish its correlation with functional strength and walking tests. The second aim is to determine intra- and inter-rater reliability and construct validity of the rectus femoris muscle thickness measured by ultrasound in prosthesis users with transtibial amputation.
Bilateral rectus femoris muscle thickness was measured by two independent examiners using an ultrasound. Bilateral knee extension strength was measured via handheld dynamometer (Jamar, Bolingbrook, IL, USA). Functional strength and walking were assessed by Step-up-over (SUO) and Walk-across (WA) tests of NeuroCom Balance Master® device (NeuroCom International, Clackamas, OR, USA).
Study Type
OBSERVATIONAL
Enrollment
28
Marmara University
Istanbul, Turkey (Türkiye)
Ultrasonographic cross-sectional area of rectus femoris measurement
Images were obtained at the bulkiest area of muscle at mid-thigh (midway between the anterior superior iliac spine and the upper pole of the patella) while the participant lay in the supine position with lower limbs are extended and relaxed. The probe was held axially with a light touch in order not to cause any difference in the muscle volume. The rectus femoris cross-sectional area of both limbs (CSA-RF) (mm2) was calculated.
Time frame: through study completion, an average of 6 months
Knee extension strength measurement via handheld dynamometer
The dynamometer was located 5 cm above the intermalleolar line to measure bilateral knee extension strength. All participants were tested while lying supine position with a support behind the knees to achieve approximately 30° of flexion. For the amputated-limb, the prosthesis was used in place.
Time frame: through study completion, an average of 6 months
Step-up-over Test
All participants were asked to stand still behind the box placed on the pressure platform and to move immediately after seeing the sign on the computer screen. The movement was defined as three phases: first stepping onto the box with one limb, second carrying the body over the box, and third landing with the other limb on the opposite side of the box. The average lift-up index (%), movement time (s), and the impact index for both limbs calculated after three repetitions.
Time frame: through study completion, an average of 6 months
Walk-across Test
All participants were asked to stand still and to walk as fast as possible along with the pressure platform after seeing the sign on the computer screen. The average step width (cm), step length (cm), and speed (cm/s) were calculated after three repetitions.
Time frame: through study completion, an average of 6 months
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