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Dive into the research topics where J. C. Y. Leong is active.

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Featured researches published by J. C. Y. Leong.


Journal of Bone and Joint Surgery, American Volume | 1993

Changes in residual volume relative to vital capacity and total lung capacity after arthrodesis of the spine in patients who have adolescent idiopathic scoliosis.

S. S. Upadhyay; E. K. W. Ho; W. M. S. Gunawardene; J. C. Y. Leong; L. C. S. Hsu

We evaluated pulmonary functions before correction and again after a mean follow-up of three years in thirty-five patients who had adolescent idiopathic scoliosis. The mean age (and standard deviation) at the time of correction was 13.7 +/- 1.8 years, and at the time of follow-up it was 17.1 +/- 2.5 years. The findings in the patients were compared with those in matched normal control subjects. With the exception of forced vital capacity, all of the determinations of absolute pulmonary volume increased postoperatively, but the increases were not all proportional. When the preoperative and follow-up determinations were expressed as percentages of the predicted pulmonary volumes (on the basis of age) to eliminate any effects of the difference in age, there was no change in total lung capacity, but vital capacity and forced vital capacity were significantly reduced. In addition, there was a significant increase in residual volume. Of the mean increase in total lung capacity after correction of the scoliosis, 82 per cent was due to an increase in residual volume and 18 per cent, to an increase in vital capacity. However, in control subjects age-matched at the time of follow-up, the increase in vital capacity contributed 69 per cent of the mean increase in total lung capacity, a very marked difference from the findings in the patients who had scoliosis. In addition, two pulmonary-volume ratios--residual volume to vital capacity and residual volume to total lung capacity--increased in a highly significant fashion (Mann-Whitney test, p < 0.001) after arthrodesis of the spine.(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of Bone and Joint Surgery-british Volume | 2001

Talectomy in patients with recurrent deformity in club foot: A long-term follow-up study

J. Legaspi; Y. H. Li; W. Chow; J. C. Y. Leong

We reviewed 24 feet in 15 patients who had undergone talectomy for recurrent equinovarus deformity; 21 were associated with arthrogryposis multiplex congenita, two with myelomeningocele and one with idiopathic congenital talipes equinovarus. The mean follow-up was 20 years. Good results were achieved in eight feet (33%) in which further surgery was not needed and walking was painless; a fair result was obtained in ten feet (42%) in which further surgery for recurrence of a hindfoot deformity had been necessary but walking was painless; the remaining six feet (25%) were poor, with pain on walking. All patients wore normal shoes and could walk independently, except one who was wheelchair-bound because of other joint problems. Recurrent deformity, the development of tibiocalcaneal arthritis and spontaneous fusion of the tibia to the calcaneum were all seen in these patients.


Journal of Bone and Joint Surgery-british Volume | 2001

Talectomy in patients with recurrent deformity in club foot

J. Legaspi; Y. H. Li; W. Chow; J. C. Y. Leong

We reviewed 24 feet in 15 patients who had undergone talectomy for recurrent equinovarus deformity; 21 were associated with arthrogryposis multiplex congenita, two with myelomeningocele and one with idiopathic congenital talipes equinovarus. The mean follow-up was 20 years. Good results were achieved in eight feet (33%) in which further surgery was not needed and walking was painless; a fair result was obtained in ten feet (42%) in which further surgery for recurrence of a hindfoot deformity had been necessary but walking was painless; the remaining six feet (25%) were poor, with pain on walking. All patients wore normal shoes and could walk independently, except one who was wheelchair-bound because of other joint problems. Recurrent deformity, the development of tibiocalcaneal arthritis and spontaneous fusion of the tibia to the calcaneum were all seen in these patients.


Journal of Pediatric Orthopaedics | 2000

Chiari Osteotomy and Shelf Augmentation in the Treatment of Hip Dysplasia

H. C. Fong; W. Lu; Y. H. Li; J. C. Y. Leong

The clinical and radiographic results of Chiari osteotomy and shelf augmentation for acetabular dysplasia in 30 hips were reported. The average age at operation was 17 years for Chiari osteotomy and 13.8 years for shelf augmentation. The mean follow-up was 7.1 years for Chiari osteotomy and 4.1 years for shelf augmentation. Of the 14 Chiari osteotomies, 12 had good results by Tonnis clinical grading and 2 had poor results. There were significant improvements in the radiographic parameters measured (p < 0.01). They included center-edge angle of Wiberg, the acetabular angle of Sharp, the percentage of femoral head coverage, and the “c/b” ratio. For the 16 shelf augmentations, there were 8 good, 2 fair, and 6 poor results. The radiographic parameters measured were also all significantly improved (p < 0.01). The final Severin grading of the hips were improved by both Chiari osteotomy and shelf augmentation.


Journal of Pediatric Orthopaedics | 2002

Twenty-year follow-up of hip problems in arthrogryposis multiplex congenita.

Peter W. P. Yau; W. Chow; Y. H. Li; J. C. Y. Leong

Nineteen patients with arthrogryposis (38 hips) with significant hip problems were reviewed (13 dislocations, 9 subluxations, 16 contractures). The average follow-up was 20 years, with 15 patients reaching skeletal maturity. All patients had minimal or no pain. Thirteen of the 19 patients were community walkers. The dislocation group in general had more stiffness of the hip joint than the subluxation and the contracture groups. However, the long-term functional results were comparable among these three groups. Closed treatment always failed in treating dislocation of hips in arthrogryposis. Open reduction was successful in stabilizing the hip, but the hips were usually stiffer. However, after 20 years of follow-up, the function of the openly reduced hips was comparable with others.


Journal of Bone and Joint Surgery-british Volume | 1993

Split tibialis posterior transfer for equinovarus deformity in cerebral palsy. Long-term results of a new surgical procedure

M. J. Saji; S. S. Upadhyay; L. C. S. Hsu; J. C. Y. Leong

We report the results of a new surgical procedure for spastic equinovarus deformity due to cerebral palsy. This is the transfer of the anterior half of the split tibialis posterior to the dorsum of the foot through the interosseous membrane. We performed the operation on 23 feet in 18 children. All patients were assessed before operation and at follow-up at a mean of 8.4 years postoperatively. Using the criteria of Kling et al (1985), excellent results were obtained in 14 feet, good results in eight, and a poor result in only one.


European Spine Journal | 1995

Evaluation of deformities and pulmonary function in adolescent idiopathic right thoracic scoliosis.

S. S. Upadhyay; A. B. Mullaji; K. D. K. Luk; J. C. Y. Leong

SummarySeventy patients with adolescent idiopathic right thoracic scoliosis had full assessment of their pulmonary function using a computerised pulmonary function system. Their mean age at evaluation was 13.8 years. The following measurements were obtained from anteroposterior and lateral standing and antero-posterior supine bending radiographs: lateral curvature, vertebral rotation, kyphosis, maximum sterno-vertebral distance and apical rib-vertebral angles. Using the above measurements, the flexibility of curve, vertebral rotation and rib-vertebral angle asymmetry were calculated. Patients were classified into three groups on the basis of their predicted vital capacity, to determine whether radiological features of deformity can help identify patients with compromised pulmonary function. The mean Cobb angle and vertebral rotation for the 70 patients were 50° (range 35–100°) and 22° (range 1–44°) respectively. The mean flexibility of curve and vertebral rotation were 52% and 49% respectively. Mean thoracic kyphosis was 25%, ranging from -7 to 55%. Of the patients with Cobb angle less than 90%, 71% had vital capacity less than 80% of predicted values, and of these, 18% had marked compromise of vital capacity (less than 60% of predicted values). Mean values of Cobb angle, vertebral rotational flexibility, kyphosis, rib-vertebral angle asymmetry (in standing as well as supine bending radiographs) differed significantly between patients with more than 80% of predicted vital capacity and those with 60% or less of predicted values. Radiological features indicative of better pulmonary function were: rotational flexibility exceeding 55%, rib-vertebral angle asymmetry (standing) less than 25% and kyphosis greater than 15%. Two deformity parameters—that give a better prediction of pulmonary function than the widely used Cobb angle, vertebral rotational flexibility and rib-vertebral angle asymmetry—were identified in this study.


Journal of Pediatric Orthopaedics | 1995

The c/b ratio in the radiological monitoring of the hip joint in congenital dislocation of the hip.

Y. H. Li; M. Hafeez; R. J. H. Emery; J. C. Y. Leong

We report a method of monitoring hip joint development for congenital dislocation of the hip in children. The c/b ratio was measured on serial radiographs of 41 hips in 38 patients. The measurement was compared to c/b ratio obtained from normal hips. It was used to detect concentric reduction or its loss by migration of the femoral head during growth. The age at diagnosis ranged from 8 months to 10 years 6 months. The normal c/b ratio was found to change little with age. Deviation of the c/b ratio from normal in congenital dislocation of the hip resulted in a poor outcome and identified cases requiring further surgical intervention. This measurement of c/b ratio is simple and accurate, using easily determined points. The graphic display promotes critical analysis of situation and allows selection of cases at risk for treatment.


Journal of Bone and Joint Surgery-british Volume | 2000

The Sofield-Millar operation in osteogenesis imperfecta

Y. H. Li; W. Chow; J. C. Y. Leong

We have reviewed the results of the Sofield-Millar operation on 58 long bones in ten patients. If more than three osteotomies were undertaken the time to union of the bone was significantly prolonged (p < 0.001) with significant thinning of the bone (p < 0.02). We have used a modified technique in order to minimise surgical trauma and devascularisation of the bone. The rod is introduced under the control of an image-intensifier. Small surgical exposures are made only at the sites of corrective wedge osteotomies. The number of osteotomies is kept to the minimum.


Injury-international Journal of The Care of The Injured | 1995

Fractured lateral epicondyle associated with lateral elbow instability

Y. H. Li; J. C. Y. Leong

A Jo-year-old housewife fell on her outstretched hand causing pain and swelling of the left elbow. Initial X-ray revealed no obvious fracture (Figure I). She was treated non-operatively. No manipulation was performed. Subsequently she noticed a varus deformity of the left elbow. It was 6 months later that she was seen by us. On examination, a varus deformity of the left elbow was noticed (FigmreZ). X-rays showed slight opening up of the radio-capitular space (Figure,?). On varus stress, there was marked lateral laxity with an avulsed fragment of the lateral epicondyle (Figure 4).

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Y. H. Li

Boston Children's Hospital

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W. Chow

Boston Children's Hospital

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S. S. Upadhyay

Boston Children's Hospital

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M. J. Saji

Boston Children's Hospital

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J. Legaspi

Boston Children's Hospital

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L. C. S. Hsu

Boston Children's Hospital

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A. B. Mullaji

Boston Children's Hospital

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E. K. W. Ho

Boston Children's Hospital

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G. A. Day

Boston Children's Hospital

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K. D. K. Luk

Boston Children's Hospital

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