• 한국정밀공학회지
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• 제25권3호
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• pp.165-175
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• 2008

An ankle-foot orthosis(AFO) is a brace for persons with gait disabilities to support or replace the function of ankle joint. Ankle-foot orthoses(AFO's) are usually prescribed to alleviate the drop-foot by constraining the excessive plantar flexion. The shape and the strength of the AFO are often based on 'trial and error' due to a lack of knowledge of the stress distribution in the AFO. In this study, an improved stress-freezing method was proposed to measure the stress distribution characteristics in the AFO. As a result, a photoelastic material with low freezing temperature was developed to measure the stresses under a person's direct contact loading condition. The three-dimensional stress-1rozen photoelastic models of AFO's for five stages of stance phase such as heel contact, foot flat, mid stance, heel off, and toe off were produced. The results of photoelastic analysis revealed that the stresses developed in the AFO were varied considerably from tensile to compressive or vice versa, during walking. At the posterior part of ankle joint in the AFO, the maximum compressive stress of 1.81MPa was observed in the mid stance, and the maximum tensile stress of 0.74MPa was observed during heel contact. The overall stress levels in the AFO's were low in the toe off phase. The results suggested that the posterior part of ankle joint might be the most fragile part in the AFO.

• 대한물리의학회지
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• 제15권1호
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• pp.1-9
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• 2020

PURPOSE: Many patients with stroke have difficulties in walking with foot-drop. Various types of ankle-foot orthoses (AFOs) have been developed, but their weight needs to be reduced with the assistance of the ankle dorsiflexor. Therefore, an elastic AFO (E-AFO) was devised that not only improves the stability and flexibility of the ankle but also assists with ankle dorsiflexion while walking. This study examined the effects of an E-AFO, on the walking patterns of foot-drop patients with stroke. METHODS: Fourteen patients walked with and without an E-AFO, and the gait parameters were assessed using the GAITRite system. The spatiotemporal data on the gait patterns of stroke patients with foot-drop were compared using paired t-tests; the level of statistical significance was set to α<.05. RESULTS: No significant differences were observed in the velocity (p=.066) and affecte+d step length (p=.980), but the affected and less-affected stance (p=.022, p=.002) and swing time (p=.012, p=.005) were significantly different. The E-AFO produced a significant difference in the less-affected step length (p=.032). CONCLUSION: The E-AFO has a significant effect on the walking patterns of individuals with foot-drop and stroke. The E-AFO could be a useful assistive device for gait training in stroke patients.

• The Journal of Korean Physical Therapy
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• 제13권3호
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• pp.693-699
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• 2001

The use of AFO in the management of patients with hemiplegia has been somewhat controversial. The purpose of the study was to identify the influence of the plastic ankle foot orthoses(AFO) on the characteristics of pelvic tilt in the patients with hemiplegia. Sixteen hemiplegic patients participated. The angle of pelvic tilt were measured using the BROM II . Results showed that the hemiplegia who weared plastic AFO, the angle of pelvic tilt was significantly less than not weared subjects. However. duration of wearing a plastic AFO and the degree of spasticity were not affected to the angle of pelvic tilt. Therefore the patients with hemiplegia should consider using the brace for the right purpose, also need to maintain the mobility of ankle joint while wearing the plastic AFO.

• Journal of Biosystems Engineering
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• 제34권1호
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• pp.57-62
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• 2009

Kinematic analysis of MTC (Muscle-Tendon Complex) units is a key indicator for diagnosis of patients with musculoskeletal disorders because the contracture or shortening of musculo-tendinous units is known to produce pathological gaits. Therefore, the principal objective of this study was to assess the length change in the triceps surae prior to and after wearing an AFO (Ankle-Foot Orthoses) in patients with musculoskeletal disorders during a gait. In this study, analyses were conducted using a Muscle Tendon Complex model coupled with the trajectory data from markers attached to anatomical landmarks. As a result, the maximum length change in the triceps surae during a gait was 4.87% when a barefoot walking group and a walking group with AFO were compared. In particular, the difference in length changes between both groups in Soleus MTC units was found to be statistically significant in all gait phases. Our results revealed that MTC length in the AFO walking group was clearly increased over that of the barefoot walking group. In the future, further studies will be required in order to more adequately assess musculoskeletal disorders using many cases studies with regard to agricultural working conditions because this study deals with the kinematic analysis of musculo-tendinous units in the case of clinical experiments.

• 한국운동역학회지
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• 제20권4호
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• pp.469-477
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• 2010

The purpose of this study was to evaluate the effects of insole-equipped ankle-foot-orthoses (AFO) on gait. 10 healthy males who had no history of injury in the lower extremity participated in this study as the subjects. The foot of each subject was first scanned, and the insole fit to the plantar was made using BDI-PCO(Pedcad Gmbh, Germany). The subject then was made to walk on a treadmill under four experimental conditions: 1) normal walking, 2) walking wearing AFO, 3) walking wearing AFO equipped with the insole, 4) walking wearing pneumatic-ankle-foot-orthosis (pAFO) equipped with the insole. During walking, foot pressure data such as maximum force, contacting area, peak pressure, and mean pressure was collected using Pedar-X system (Novel Gmbh, Germany) and EMG activity of lower limb muscles such as gastrocnemius medial head, gastrocnemius lateral head, and soleus was recorded using MP150 EMG module (BIOPAC System Inc., USA). Collected data was then analyzed using paired t-test in order to investigate the effects of the insole. As a result of the analysis, when insole was equipped, overall contacting area was increased while both the highest peak pressure and the mean pressure were significantly decreased, and EMG activity of the lower limb muscles was decreased. On the contrary, the cases of wearing AFO showed the decreased contacting area and the increased pressures. Therefore, the AFO equipped with a proper insole fit well to the foot can help comfortable walking by spreading the pressure over the entire plantar.

• The Journal of Korean Physical Therapy
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• 제16권3호
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• pp.161-175
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• 2004

The purpose of this study was to determine the effect of HPAFO(Hinged Plastic Ankle Foot orthosis) and SPAFO(Solid Plastic Ankle Foot Orthosis) on standing balance and step moving in hemiplegia patients. Twenty hemiplegic patients were either inpatient or outpatient at the Rehabilitation medicine, MokPo J General Hospital and JeonJu J Medical Center from July 15, 2002 to September 15, 2002. Patients were able to ambulate independently for at least 10 meters and to stand independently for at least 10 minutes with balance measurement tool. The static balance and dynamic activity measurement was determined by SAKAI active balancer(Japan) with wearing HPAFO and wearing SPAFO. The static balance and dynamic activity analysis was analyzed by independent t-test. The results were as follows: 1. There were no significant difference in body weight bearing percent between wearing HPAFO and wearing SPAFO(p>0.05). 2. There were significant difference in whole path length between wearing HPAFO and wearing SPAFO(p<0.05). 3. There were significant difference in Effective Value Area between wearing HPAFO and wearing SPAFO(p>0.001). 4. There were significant difference in repeated functional time between wearing HPAFO and wearing SPAFO(p>0.001). 5. There were significant difference in cadence between wearing HPAFO and wearing SPAFO(p>0.001). The result of this study showed that wearing HPAFO and wearing SPAFO gave fair amount of improvement to static standing balance and dynamic movement ability of hemiplegic patients. The comparison result showed significant differences in between HPAFO and SPAHFO. The result of this study had a general limitation due to the restricted number of cases. The future study needs more detailed research and comparison with various variance between these two orthoses.