• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.1
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• pp.35-40
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• 2011

Purpose: This study was performed to evaluate the diagnostic usefulness of ankle stress radiograph for evaluation of chronic lateral ankle instability. Materials and Methods: Among patients undergoing the modified-Brostrom procedure, 42 cases with complete rupture of the anterior talofibular ligament were enrolled in this study. Sixty Korean adults (120 cases) were recruited as the control group. Radiologic measurement of talar tilt and anterior talar translation was performed through stress radiographs using Telos device. We obtained the normal range of Korean adults, and used as a standard value for judgment of mechanical instability. We analyzed the sensitivity, specificity, positive and negative prediction value of ankle stress radiograph. Results: On ankle stress radiograph, normal range of talar tilt angle and anterior talar translation was below $8.3^{\circ}$, below 7.6mm. Talar tilt angle on varus stress radiograph showed 57% of sensitivity, 97% of specificity, 89% of positive and 86% of negative prediction value. Anterior talar translation on anterior drawer stress radiograph showed 69% of sensitivity, 97% of specificity, 91% of positive and 90% of negative prediction value. Conclusion: Ankle stress radiograph had a good specificity, positive and negative prediction value for the evaluation of mechanical instability. However it underestimated the mechanical instability of ankle joint. It must be remembered that normal stress radiograph does not exclude ankle instability.

• Journal of Korean Neurosurgical Society
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• v.48 no.1
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• pp.37-45
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• 2010

Objective : Craniovertebral junction (CVJ) consists of the occipital bone that surrounds the foramen magnum, the atlas and the axis vertebrae. The mortality and morbidity is high for irreducible CVJ lesion with cervico-medullary compression. In a clinical retrospective study, the authors reviewed clinical and radiographic results of occipitocervical fusion using a various methods in 32 patients with CVJ instability. Methods : Thirty-two CVJ lesions (18 male and 14 female) were treated in our department for 12 years. Instability resulted from trauma (14 cases), rheumatoid arthritis (8 cases), assimilation of atlas (4 cases), tumor (2 cases), basilar invagination (2 cases) and miscellaneous (2 cases). Thirty-two patients were internally fixed with 7 anterior and posterior decompression with occipitocervical fusion, 15 posterior decompression and occipitocervical fusion with wire-rod, 5 C1-2 transarticular screw fixation, and 5 C1 lateral mass-C2 transpedicular screw. Outcome (mean follow-up period, 38 months) was based on clinical and radiographic review. The clinical outcome was assessed by Japanese Orthopedic Association (JOA) score. Results : Nine neurologically intact patients remained same after surgery. Among 23 patients with cervical myelopathy, clinical improvement was noted in 18 cases (78.3%). One patient died 2 months after the surgery because of pneumonia and sepsis. Fusion was achieved in 27 patients (93%) at last follow-up. No patient developed evidence of new, recurrent, or progressive instability. Conclusion : The authors conclude that early occipitocervical fusion to be recommended in case of reducible CVJ lesion and the appropriate decompression and occipitocervical fusion are recommended in case of irreducible craniovertebral junction lesion.

• Science of Emotion and Sensibility
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• v.5 no.4
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• pp.45-49
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• 2002

Recently, virtual environment systems are used in various application fields such as industry, medicine, and training and education. However, the negative effect, cybersickness including nausea, visual fatigue, and disorientation, could be happened while using VR systems. It prevents VR system from spreading much more. To control the cybersickness, first of all, the objective measurement method should be established. As one of alternative methods, the postural instability could be a measure of cybersickness. In this study, 45 participants' postural sway before and after experiencing a H driving simulator was measured by using a force platform. Especially, we examined if two factors, motion and feedback, could affect on the postural instability The results showed the postural instability slightly increased after experiencing the VR driving simulator. For the factors, the providing of motion synchronized to visual display showed statistical significant decrease in postural sway along lateral side. To check the effectiveness of postural instability as a cybersickness measure, further studies are needed.

• Clinics in Shoulder and Elbow
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• v.5 no.2
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• pp.118-123
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• 2002

Purpose: The purpose was to identify the effectiveness of beach-chair position in the arthroscopic Bankart repair over conventional lateral decubitus position with distal traction. Materials & Methods: 36 arthroscopic Bankart repair through July 2000 to July 2001 was done under beach chair position. All cases were shoulder instability. Male patients were 6 and female were 4 with average age of 25 years. Arthroscopic suture anchor was used in 24 cases and average number was 3. Results: Interscalene block was tried in 29 patients and 1 case was changed to general anesthesia. Arthroscopic examination to identify Bankart lesion and associated pathology was done without difficulty Bankart lesions were easily reduced to anatomic position and placed suture anchor and hooking approprately. After the arthroscopic examination,3 cases were converted to open procedure without any positional change. Conclusion: Under interscalene block, the preparation was more simple and the patient could watch arthroscopic procedure with confidence. There was no hindrance in arthroscopic examination and arthroscopic repair could be dont: in more anatomic position. It can be easily changed to open repair if it needed

• International Journal of Fluid Machinery and Systems
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• v.3 no.3
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• pp.235-244
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• 2010

Recent studies on the moment whirl due to leakage flow in the back shroud clearance of hydro-turbine runners or centrifugal pump impellers are summarized. First, destabilizing effect of leakage flow is discussed for lateral vibrations using simplified models. Then it is extended to the case of whirling motion of an overhung rotor and the criterion for the instability is obtained. The fluid moment caused by a leakage clearance flow between a rotating disk and a stationary casing was obtained by model tests under whirling and precession motion of the disk. It is shown that the whirl moment always destabilizes the whirl motion of the overhung rotor while the precession moment destabilizes the precession only when the precession speed is less than half the rotor speed. Then vibration analyses considering both whirl and precession are made by using the hydrodynamic moments determined by the model tests. For larger overhung rotors, the whirl moment is more important and cause whirl instability at all rotor speed. On the other hand, for smaller overhung rotors, the precession moment is more important and cancels the destabilizing effect of the whirl moment.

• Journal of Korean Foot and Ankle Society
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• v.8 no.2
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• pp.204-207
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• 2004

An unstable second metatarsophalangeal joint may produce pain in the forefoot. Plication of stretched lateral ligament and capsule and transfer of the extensor digitorum brevis under the transverse intermetatarsal ligament performed as the primary procedure to stabilize this painful joint. But the pain was not subsided and the proximal phalanx was resubluxated. So, we osteotomized the second metatarsal to restore a normal alignment of the second toe. Then the symptom was subsided. We report a case of painful instability of the metatarsophalangeal joint of the second toe.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.185-190
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• 1995

In recent years, many researcher have been interested in the stability of a thin beam. Among them, Pai and Nayfeh[1] had investigated the nonplanar motion of the cantilever beam under lateral base excitation and chaotic motion, but this study is associated with internal resonance, i.e. one to one resonance. Also Cusumano[2] had made an experiment on a thin beam, called Elastica, under bending loads. In this experiment, he had shown that there exists out-of-plane motion, involving the bending and the torsional mode. Pak et al.[3] verified the validity of Cusumano's experimental works theoretically and defined the existence of Non-Local Mode(NLM), which is came out due to the instability of torsional mode and the corresponding aspect of motions by using the Normal Modes. Lee[4] studied on a thin beam under bending loads and investigated the routes to chaos by using forcing amplitude as a control parameter. In this paper, we are interested in the motion of a thin beam under torsional loads. Here the form of force based on the natural forcing function is used. Consequently, it is found that small torsional loads result in instability and in case that the forcing amplitude is increasing gradually, the motion appears in the form of dynamic double potential well, finally leads to complex motion. This phenomenon is investigated through the poincare map and time response. We also check that Harmonic Balance Method(H.B.M.) is a suitable tool to calculate the bifurcated modes.

• Journal of Veterinary Clinics
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• v.36 no.3
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• pp.166-168
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• 2019

A 22-month-old female mongrel dog weighing 4.8 kg was referred with chief complaint of bite wounds and lameness. The patient showed non-weight bearing lameness on left hindlimb and lateral instability of intertarsal joint. On radiograph, proximal intertarsal luxation between calcaneus and fourth tarsal bone was diagnosed. To imitate the long collateral and calcaneoquartal ligament, bone tunnels were drilled in the distal calcaneus and proximal fifth metatarsal bone. The figure-eight suture was placed with 0.5 mm cerclage wire through the predrilled holes. At 2 weeks after surgery, the lameness of hindlimb was still present. However, the patient had weight bearing lameness for 4 weeks after operation and was able to walk and run without lameness at 5 weeks after surgery. This case report explains the successful correction of intertarsal luxation with a single figure of eight wire suture in case of luxation to the intertarsal joint.

• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.163-170
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• 2024

Objective: The purpose of this study was to compare the muscle activity of the vastus lateralis, vastus medialis, rectus femoris, and gluteus medius muscles according to the medial/lateral bias of the knee during lunge exercise. Design: Crossed-control group study Methods: This study recruited 20 healthy men and women in their 20s who were capable of lunge exercise and had no musculoskeletal or neurological abnormalities. All three postures were performed three times each during lunge exercise. In each posture, surface electromyography (EMG) equipment was used to measure muscle activity of the vastus lateralis, vastus medialis, rectus femoris, and gluteus medius during lunge exercise. Results: As a result of comparing lower extremity muscle activity in normal, medial and lateral knee-deviation postures according to lunge exercise, the muscle activity of the vastus medialis was 107.09±13.90% in the normal posture, 79.24±5.26% in the medial- deviation posture and 125.73±14.30% in the lateral- deviation posture, which was a statistically significant difference (p<0.05). However, In the case of the vastus lateralis, rectus femoris and gluteus medius there was no statistically significant difference in muscle activity in the medial and lateral deviation positions(p>0.05). Conclusions: As a result, it was found that the muscle activity of the vastus medialis during lunge exercise significantly increased in the lateral deviation posture compared to the normal and medial deviation postures. In the case of the vastus lateralis, rectus femoris and gluteus medius there was no significant difference in muscle activity for medial and lateral knee deviation.

• Journal of Korean Neurosurgical Society
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• v.30 no.1
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• pp.114-117
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• 2001

Generally, the posterolateral approach had been recommended in case of extraforaminal disc herniation or lateral stenosis but it has been speculated that this procedure may be feasible to posterolateral disc herniation at the high lumbar levels of the L1-L2 interspace. Topographically, a posterolateral approach should be able to access anteromedial side of the spinal canal without the risk of the bony instability and damage to the neural structures. During the past one year period, three patients with high lumbar discs at the L1-L2 level were treated by the modified posterolateral approach. This article describeds the details of this approach with pertinent literature review.