Approach for gait analysis in persons with limb loss including residuum and prosthesis socket dynamics.

Musculoskeletal modeling and marker-based motion capture techniques are commonly used to quantify the motions of body segments, and the forces acting on them during human gait. However, when these techniques are applied to analyze the gait of people with lower limb loss, the clinically relevant interaction between the residual limb and prosthesis socket is typically overlooked. It is known that there is considerable motion and loading at the residuum-socket interface, yet traditional gait analysis techniques do not account for these factors due to the inability to place tracking markers on the residual limb inside of the socket. In the present work, we used a global optimization technique and anatomical constraints to estimate the motion and loading at the residuum-socket interface as part of standard gait analysis procedures. We systematically evaluated a range of parameters related to the residuum-socket interface, such as the number of degrees of freedom, and determined the configuration that yields the best compromise between faithfully tracking experimental marker positions while yielding anatomically realistic residuum-socket kinematics and loads that agree with data from the literature. Application of the present model to gait analysis for people with lower limb loss will deepen our understanding of the biomechanics of walking with a prosthesis, which should facilitate the development of enhanced rehabilitation protocols and improved assistive devices.

Relationship between clinical measurements and motion of the first metatarsophalangeal joint during gait.

BACKGROUND: The range of joint motion is a commonly reported outcome measure in assessment of the great toe. Although motion of the first metatarsophalangeal joint during gait is of primary functional importance, clinicians rely on relatively static clinical measures to assess this joint. The relationship between the results of commonly used clinical tests of motion of the first metatarsophalangeal joint and motion of this joint during gait was assessed in a study of thirty-three subjects who had no history of a pathological condition of the foot or ankle. METHODS: An electromagnetic tracking device was used to acquire three-dimensional orientation data on the hallux with respect to the first metatarsal. Receivers were secured to the skin overlying the proximal phalanx of the hallux, the first metatarsal, and the medial aspect of the calcaneus. Measurements were recorded during four clinical tests. These tests assessed the active range of motion of the first metatarsophalangeal joint with the subject weight-bearing, the passive range of motion with the subject weight-bearing, the passive range of motion with the subject non-weight-bearing, and the motion during a heel-rise. The data collected with these tests were compared with motion of the first metatarsophalangeal joint during walking. The focus of the analysis was the dorsiflexion component of rotation. RESULTS: With the exception of the passive range of motion with the subject weight-bearing, the ranges of motion measured during all of the clinical tests exceeded the motion of the first metatarsal joint that is required during normal walking. The motion measured during heel-rise (r = 0.87, p < 0.001) and the active range of motion with the subject weight-bearing (r = 0.80, p < 0.001) had the strongest correlations with motion of the first metatarsophalangeal joint during gait. The mean dorsiflexion during the test of the active range of motion (44 degrees) was closer to the mean dorsiflexion during gait (42 degrees) than was the mean value measured during the heel-rise test (58 degrees). This study also demonstrated that the clinical tests are not interchangeable as their mean results differed by as much as 21 degrees. CONCLUSIONS: The selection of a reliable and valid clinical test and an understanding of the relationship of the results of this test to the motion requirements during normal gait will help to standardize reporting techniques and will improve the ability of the clinician to determine the outcomes of treatment. This study showed that measurement of the active range of motion with the subject weight-bearing was a reliable and valid test and that the results were strongly correlated with motion of the first metatarsophalangeal joint during gait.

Reliability and validity of first metatarsophalangeal joint orientation measured with an electromagnetic tracking device.

OBJECTIVE: To establish the reliability and validity of measurements of sagittal plane orientation of the first metatarsophalangeal joint using the Flock of Birds electromagnetic tracking device. DESIGN: Different joint orientations were reproduced on cadaver specimens in a specially designed jig with skin and skeletal application of the sensors. BACKGROUND: The Flock of Birds provides a means for quantifying first metatarsophalangeal joint motion, however, the reliability and validity of such an application has not been determined. METHODS: Joint orientation was measured in five cadaver feet with skin and skeletal sensor application. A specially designed jig allowed simulation of clinical tests of range of motion. Sagittal plane orientation was determined from 3-D, anatomically-based, reference frames embedded in the first metatarsal and proximal hallux. RESULTS: Reliability of all measurements was high for skin and skeletal sensor application. There were no significant differences in joint orientation between either technique for any of the simulated motion tests. CONCLUSIONS: The Flock of Birds provides reliable and valid measures of first metatarsophalangeal joint orientation with the sensors applied to the skin over the first metatarsal and proximal hallux. RELEVANCE: An electromagnetic tracking device is suitable for measuring sagittal plane motion of the first metatarsophalangeal joint. This motion can easily be expressed using 3-D, anatomically-based reference frames.