Literature Review
What is Ultrasound?
Ultrasound imaging is a widely used non-invasive diagnostic technique that employs high-frequency sound waves to generate real-time images of internal body structures. The technology operates by transmitting ultrasonic pulses into the body, where they interact with tissues of varying densities, producing echoes that are captured and processed to create an image. The primary advantages of ultrasound imaging include its ability to provide real-time visualization, lack of ionizing radiation, and relatively low cost compared to other imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI) (Bushberg et al., 2011).
What is the advantage to Ultrasound?
In musculoskeletal and orthopedic applications, ultrasound has gained prominence in assessing soft tissue integrity, joint kinematics, and bone movement. Dynamic sonography, in particular, is a valuable tool for evaluating musculoskeletal disorders that are best or only seen during motion, muscle contraction, or changes in patient positioning (Bianchi and Martinoli). This capability makes ultrasound ideal for monitoring biomechanical interactions and anatomical changes during dynamic tasks. Recent advancements have expanded the role of ultrasound in prosthetic research. Studies have demonstrated the feasibility of using B-mode ultrasound to monitor in vivo residual bone movement within prosthetic sockets, providing insights into prosthetic fit and alignment (Jonkergouw et al.). Additionally, ultrasound elastography techniques have been developed to assess the mechanical properties of musculoskeletal tissues, offering potential for early diagnosis and therapy monitoring (Drakonaki et al.).As ultrasound technology continues to evolve, its applications in prosthetic research and biomechanical assessments are expected to grow, offering a promising avenue for improving patient outcomes and optimizing prosthetic designs.
What is Bone displacement?
This displacement often occurs during the swing phase of gait and is reversed when the limb is bearing weight during stance. Despite its importance and impact on the performance and patient’s satisfaction with a prosthetic device, pistoning in lower limb prosthesis has not been widely studied. At present, the available literature on the socket fitting and suspension is mainly focused on pressure distribution,shear force and friction.
Why is it significant to obtain a measurement of bone displacement during dynamic activity?
There is a gap in literature because most of the studies focused on a static condition, while it is extremely difficult to evaluate the displacement of the bone during a dynamical activity (Maikos et al., 2024).Why is it important and what have people done?
Here is a comprehensive overview of the studies done to understand parts of the research question:
|
Study |
Method |
Activity |
How was the interface pressure measured? |
Where did they measure it? (front, back or side) |
Notes |
| Maikos et al., 2024 | Dynamic Stereo X-Ray | Walking on a treadmill | shear and compression will be measured | - | It is just a protocol for the study, they are still doing the experiments |
| Convery and Murray, 2001 | ultrasound transducers | Walking on incline, turning, stepping up and down, standing up and down,weight transfer | - | Two transducers: one near the top and one near the bottom of the socket → parallel to each other | |
| Paterno` et al, 2024 | Pressure sensors | horizontal, ascent, and descent walking, upstairs and downstairs | exploiting plantar pressure | anterior, lateral, posterior, and medial areas of the socket | Sensors compromise vacuum in socket |
| Childers et al., 2012 | Limb/Socket Measurement (LSM) Device | Cycling on a stationary electromagnetically braked ergometer at 150 W and 90 rpm | - | Device’s frame is attached to the lateral side.The prosthetic socket had a hole cut into the anterior/distal portion to allow for attachment of the LSM device. | |
| Papaioannouet al., 2010 | Biplane Dynamic Roentgen Stereogrammetric Analysis DRSA (X-rays) + force plate instrumentation | Strenuous activities”: 6 movement tasks (three trials for sudden fast stop and three for coming down from stairs) while landing on the prosthesis | Tantalum markers & mesh patterns were used to assess skin deformation and slippage → skin strain & shear were estimated | several 4 mm tantalum markers were placed on the external surface of the socket based on a predefined pattern | |
| Jonkergouw et al., 2024 | B-mode ultrasound to monitor in vivo residual bone movement | forward, backward, sideways steps, and in-place weight shifts | US was applied to the distal portion of the tibial anterior crest | ||
| McLean et al., 2019 | inductive sensors | Walking on a treadmill | Panels were located overthe anterior medial and anterior lateral tibial flares,and posteriorly along the midline. | They tried to adjust the socket size and studied limb fluid volume | |
| Sanders et al., 2006 | A photoelectric sensor | Walking on a flat surface | - | The sensor was placed in a small frame attached just below the prosthetic socket. A hole was made in the bottom of the socket to fit most of the sensor inside. The sensor was held in place vertically, and a small adjustment mechanism allowed it to be moved up or down without removing the prosthesis. |
Why do we want to measure it and why measure the interface pressure?
During the cyclical loading and unloading of the residual limb during the gait cycle, the skin of the residual limb is exposed to nonphysiological stresses and strains, including excessive shear forces. Although the skin is well adapted to compressive force, excessive shear force can be damaging, leading to abrasions, wounds, and ulcers (Maikos et al., 2024).However, whole-limb skin strain analysis is complicated by the heterogeneous composition of the skin and its anisotropic mechanical properties. Some investigations have used 3D digital image correlation (DIC) to create full-field deformation and strain maps of an unsupported residual limb. Lin et al examined skin strain in a flexed biological residual limb from an individual with transtibial limb loss and showed that the anterior patella region of the limbs exhibited predominantly tensile strains, whereas the posterior patella region exhibited predominately compressive strains. Although 3D DIC evaluations have provided critical data to help improve the mechanical interface of sockets and liners to limit relative motion and shear forces on the skin surface, these investigations only considered strain on an unloaded residual limb (Maikos et al., 2024).
What would be the most optimal positioning of the Ultrasound probe?
In Jonkerguow 2024 the hole and probe positioning was the distal portion of the tibial anterior crest, and as seen in the picture the gap was on the front/shin. The correct probe position was determined by visually optimizing the contrast between the socket, liner, skin, and residual bone within the ultrasound image.
- US gel was applied in the gap of the liner and gel sock to compensate for the lost material and to prevent air to creep inside the socket
- The probe was rigidly fixed, perpendicular to the stump, in a custom-made 3D-printed clamp (Ultimaker 3, Utrecht, the Netherlands) that was glued (+PLUSe- ries 60 Second Adhesive, Fabtec, Everett, Washington, USA) to the socket. Gel was inserted in the cavity between
- The clamp and the socket wall to fill the remaining gaps and prevent air between probe and socket. Duct tape was applied around the clamp to prevent the US gel to run out from under the probe during the measurements.
References
Maikos, J. T., Chomack, J. M., Herlihy, D. V., Paglia, D. N., Wetterstrand, C., O’Connor, J. P., Hyre, M. J., Loan, J. P., & D’Andrea, S. E. (2024). Quantifying bone and skin movement in the residual Limb-Socket interface of individuals with transtibial limb loss using dynamic stereo X-Ray: Protocol for a lower limb loss cadaver and clinical study. JMIR Research Protocols, 13, e57329. https://doi.org/10.2196/57329