Stefania Fatone

Effect of Ankle-Foot Orthosis Alignment and Foot-Plate Length on the Gait of Adults With Poststroke Hemiplegia

OBJECTIVE To investigate the effect of ankle-foot orthosis (AFO) alignment and foot-plate length on sagittal plane knee kinematics and kinetics during gait in adults with poststroke hemiplegia. DESIGN Repeated measures, quasi-experimental study. SETTING Motion analysis laboratory. PARTICIPANTS Volunteer sample of adults with poststroke hemiplegia (n=16) and able-bodied adults (n=12) of similar age. INTERVENTIONS Subjects with hemiplegia were measured walking with standardized footwear in 4 conditions: (1) no AFO (shoes only); (2) articulated AFO with 90 degrees plantar flexion stop and full-length foot-plate-conventionally aligned AFO (CAFO); (3) the same AFO realigned with the tibia vertical in the shoe-heel-height compensated AFO (HHCAFO); and (4) the same AFO (tibia vertical) with 3/4 length foot-plate-3/4 AFO. Gait of able-bodied control subjects was measured on a single occasion to provide a normal reference. MAIN OUTCOME MEASURES Sagittal plane ankle and knee kinematics and kinetics. RESULTS In adults with hemiplegia, walking speed was unaffected by the different conditions (P=.095). Compared with the no AFO condition, all AFOs decreased plantar flexion at initial contact and mid-swing (P<.001) and changed the peak knee moment in early stance from flexor to extensor (P<.000). Both AFOs with full-length foot-plates significantly increased the peak stance phase plantar flexor moment compared with no AFO and resulted in a peak knee extensor moment in early stance that was significantly greater than control subjects, whereas the AFO with three-quarter length foot-plate resulted in ankle dorsiflexion during stance and swing that was significantly less than control subjects. CONCLUSIONS These findings suggest that when an articulated AFO is to be used, a full-length foot-plate in conjunction with a plantar flexion stop may be considered to improve early stance knee moments for people with poststroke hemiplegia.

Residual limb volume change: Systematic review of measurement and management

Management of residual limb volume affects decisions regarding timing of fit of the first prosthesis, when a new prosthetic socket is needed, design of a prosthetic socket, and prescription of accommodation strategies for daily volume fluctuations. This systematic review assesses what is known about measurement and management of residual limb volume change in persons with lower-limb amputation. Publications that met inclusion criteria were grouped into three categories: group I: descriptions of residual limb volume measurement techniques; group II: studies investigating the effect of residual limb volume change on clinical care in people with lower-limb amputation; and group III: studies of residual limb volume management techniques or descriptions of techniques for accommodating or controlling residual limb volume. We found that many techniques for the measurement of residual limb volume have been described but clinical use is limited largely because current techniques lack adequate resolution and in-socket measurement capability. Overall, limited evidence exists regarding the management of residual limb volume, and the evidence available focuses primarily on adults with transtibial amputation in the early postoperative phase. While we can draw some insights from the available research about residual limb volume measurement and management, further research is required.

Effect of ankle-foot orthosis on roll-over shape in adults with hemiplegia

Ankle-foot orthoses (AFOs) are intended to improve toe clearance during swing and ankle position at initial contact (IC) and midstance. Changes that lead to improved ankle-foot kinematics may result in a more biomimetic roll-over shape (ROS). ROS is the effective geometry to which the ankle-foot complex conforms between IC and contralateral IC. An effective ROS during gait may facilitate forward progression. This study investigated the effect of an AFO on ROS in adults with hemiplegia following stroke. Kinematic and force data were recorded from 13 people with hemiplegia and 12 controls. Hemiplegic subjects walked at a self-selected speed with and without an articulated AFO with plantar flexion stop. For the involved limb, the AFO significantly increased the ROS arc length (from 32.6% to 55.7% of foot length [FL]) and arc radius (67.4% to 139.3% of FL) and significantly altered the sagittal plane location of the first center of pressure (COP) point, moving it posterior to the ankle center (-1.2% to -20% of FL) (p < 0.002 for all comparisons). However, when hemiplegic patients walked with an AFO, their mean arc radius was greater, mean arc length less, and the first COP point further posterior than those of control subjects.

The effect of trunk-flexed postures on balance and metabolic energy expenditure during standing.

Study Design. This study analyzed force plate, kinematic, and metabolic energy data of 14 able-bodied subjects standing statically with upright and trunk-flexed postures. Objective. To explore the effect of trunk-flexed postures on balance and metabolic energy expenditure during standing. Summary of Background Data. Abnormal trunk posture often occurs in the presence of spinal deformities, such as lumbar flatback. It is unclear whether alterations in trunk posture affect energy expenditure and the location of the body’s center of mass in the transverse plane (BCOMtrans) during standing. Methods. Kinematic, kinetic, and energy expenditure data were collected with upright trunk alignment and with 25° ± 7° and 50° ± 7° of trunk flexion from the vertical. The mean location of the BCOMtrans was estimated from the net center of pressure (COP), which is a weighted average of the COP beneath both feet. Results. The fore-aft position of the net COP under the base of support was not significantly different between postures (P < 0.08). At each posture, the net COP was located 16% of the foot length anterior to the ankle joint centers. However, with increasing trunk flexion, there was a significant increase in oxygen consumption rate (P < 0.001 for all postures). Conclusion. Compensatory actions, such as ankle plantarflexion and hip flexion, allowed the mean position of the net COP to remain within a narrowly defined region irrespective of trunk posture. Changes in muscle activity associated with a trunk-flexed posture and the associated compensations likely contributed to the increased energy expenditure.

A kinematic model to assess spinal motion during walking

Study Design and Objectives. A 3-dimensional multi-segment kinematic spine model was developed for noninvasive analysis of spinal motion during walking. Preliminary data from able-bodied ambulators were collected and analyzed using the model. Summary of Background Data. Neither the spine’s role during walking nor the effect of surgical spinal stabilization on gait is fully understood. Typically, gait analysis models disregard the spine entirely or regard it as a single rigid structure. Data on regional spinal movements, in conjunction with lower limb data, associated with walking are scarce. Methods. KinTrak software (Motion Analysis Corp., Santa Rosa, CA) was used to create a biomechanical model for analysis of 3-dimensional regional spinal movements. Measuring known angles from a mechanical model and comparing them to the calculated angles validated the kinematic model. Spine motion data were collected from 10 able-bodied adults walking at 5 self-selected speeds. These results were compared to data reported in the literature. Results. The uniaxial angles measured on the mechanical model were within 5° of the calculated kinematic model angles, and the coupled angles were within 2°. Regional spine kinematics from able-bodied subjects calculated with this model compared well to data reported by other authors. Conclusions. A multi-segment kinematic spine model has been developed and validated for analysis of spinal motion during walking. By understanding the spine’s role during ambulation and the cause-and-effect relationship between spine motion and lower limb motion, preoperative planning may be augmented to restore normal alignment and balance with minimal negative effects on walking.

Erratum to: Describe the outcomes of dysvascular partial foot amputation and how these compare to transtibial amputation: a systematic review protocol for the development of shared decision making resources

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Biomechanical and energetic effects of a stance-control orthotic knee joint

Users of traditional knee-ankle-foot orthoses (KAFOs) walk with either locked or unlocked knee joints depending on the level of stability required. Some users may benefit from new stance-control KAFOs that prevent stance-phase knee flexion but allow swing-phase flexion. We collected data from nine nondisabled adults who walked with KAFOs that incorporated the Horton Stance-Control Orthotic Knee Joint (SCOKJ) in the locked, unlocked, and auto (which provides knee stability during stance phase and knee flexion during swing phase) modes to investigate the biomechanical and energetic effects of stance-control orthoses. Studying nondisabled subjects allowed us to analyze the effects of stance-control orthoses in a homogenous population. In general, gait kinematics for the auto and unlocked modes were more similar than for the auto and locked modes. Despite the elimination of hip hiking in the auto mode, oxygen cost was not different between the auto and locked modes (p > 0.99). The SCOKJ allowed our nondisabled subjects to walk with a more normal gait pattern; however, future research should explore the effect of stance-control orthoses on persons with gait pathology.

Validity and Reliability of the Berg Balance Scale for Community-Dwelling Persons With Lower-Limb Amputation

OBJECTIVE To evaluate the validity and reliability of the Berg Balance Scale (BBS) for use in people with lower-limb amputation. DESIGN Cross-sectional study. SETTING Research laboratory. PARTICIPANTS Individuals (N=30; age, 54±12y; 20 men) with unilateral transtibial (n=13), unilateral transfemoral (n=14), or bilateral (n=3) lower-limb amputation of dysvascular (n=7), traumatic (n=14), infectious (n=6), or congenital (n=3) origin. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES BBS, 2-minute walk test, L test, Prosthesis Evaluation Questionnaire-Mobility Subscale, Activities-specific Balance Confidence Scale, and Frenchay Activities Index; self-reported descriptors were also collected, including frequency of prosthesis use, number of falls in 12 months before the visit, fear of falling, and daily mobility aid use. RESULTS The BBS had high interrater reliability (intraclass correlation coefficient =.945) and internal consistency (α=.827). Relations between the BBS scores and those of other outcome measures were all statistically significant (P≤.001). Significant group differences in BBS scores were observed for fear of falling (P=.008) and mobility aid use (P<.001), but not for multiple (≥2) falls in the previous 12 months (P=.381). BBS items involving reaching forward, turning 360°, tandem standing, and standing on 1 leg had relatively greater frequencies of lower scores across participants. CONCLUSIONS The BBS appears to be a valid and reliable clinical instrument for assessing balance in individuals with lower-limb amputation, but it may not be able to discriminate between individuals with greater or lesser fall risk. Limitations in prosthetic motion and control may be responsible for the challenges experienced on items of lower performance. Future studies would be useful to assess the responsiveness of the BBS to interventions aimed at improving balance in individuals with lower-limb amputation.

Walking Mechanics of Persons Who Use Reciprocating Gait Orthoses

Although ambulation with a reciprocating gait orthosis (RGO) may provide physical benefits to people with lower-limb paralysis, the high metabolic energy cost associated with ambulation limits orthosis use. The purpose of this case series was to investigate the dynamics of ambulation with RGOs to identify and better understand the potential causes of the high energy cost. Data were acquired from five regular users of RGOs. Kinematics and kinetics were measured, and the moments and powers acting at the hips and shoulders calculated. All RGO users walked with a flexed trunk and bore a large proportion of body weight through the arms during single support. Moments at the shoulder encouraged trunk extension, while moments at the hip encouraged trunk flexion. An extension moment acted on the hip at the beginning of swing, which was antagonistic to the goal of swing and contradicted the intent of the reciprocal link: to advance the swing leg. These results suggest that characteristics of RGO ambulation are consistent across users. The relationship between posture, forces acting on the walking aids, and the action of the RGO reciprocal link should be further explored because these factors likely contribute to the high metabolic cost of ambulation with an RGO.

Effects of prosthetic foot forefoot flexibility on oxygen cost and subjective preference rankings of unilateral transtibial prosthesis users

The investigators conducted a double-blind randomized crossover study to determine the effects of prosthetic foot forefoot flexibility on oxygen cost and subjective preference rankings of 13 unilateral transtibial prosthesis users. Five experimental feet were fabricated for use in the study: F1, F2, F3, F4, and F5. F1 was most flexible, F5 was least flexible, and F3 was designed to conform to a biomimetic ankle-foot roll-over shape. The experimental feet were modeled after the Shape&Roll prosthetic foot (originally produced by Northwestern University, Chicago, Illinois; now in public domain) but had different numbers of saw cuts within the forefoot members, allowing more or less flexibility during walking. Participants walked at the same comfortable, freely selected speed on the treadmill for 7 min with each foot while energy expenditure was measured. No significant difference was found in oxygen cost (mL O(2)/kg/m) between the different feet (p = 0.17), and the order of use was also not significant (p = 0.94). However, the preference ranking was significantly affected by the flexibility of the feet (p = 0.002), with the most flexible foot (F1) ranking significantly poorer than feet F3 (p = 0.003) and F4 (p = 0.004). Users may prefer prosthetic feet that match the flexibility of an intact ankle-foot system, even though we did not detect an energetic benefit at freely selected speeds.