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The Bone & Joint Journal
Vol. 99-B, Issue 10 | Pages 1381 - 1388
1 Oct 2017
Wong YW Samartzis D Cheung KMC Luk K

Aims

To address the natural history of severe post-tuberculous (TB) kyphosis, with focus upon the long-term neurological outcome, occurrence of restrictive lung disease, and the effect on life expectancy.

Patients and Methods

This is a retrospective clinical review of prospectively collected imaging data based at a single institute. A total of 24 patients of Southern Chinese origin who presented with spinal TB with a mean of 113° of kyphosis (65° to 159°) who fulfilled inclusion criteria were reviewed. Plain radiographs were used to assess the degree of spinal deformity. Myelography, CT and MRI were used when available to assess the integrity of the spinal cord and canal. Patient demographics, age of onset of spinal TB and interventions, types of surgical procedure, intra- and post-operative complications, and neurological status were assessed.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 92 - 92
1 Jul 2014
Wong H Chu P Cheung K Luk K Yeung K
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Summary

A promising approach to stimulate in vivo bone formation by using our newly developed magnesium-based bone substitutes, which can be an alternative to treat the patients with bone loss in addition to the anticatabolic drugs and growth factors.

Introduction

Bone impairment arising from osteoporosis as well as other pathological diseases is a major health problem. Anti-catabolic drugs such as bisphosphonates and other biological agents such as bone morphogenetic proteins and insulin-like growth factor can theoretically apply to stimulate bone formation. However, the formation of more brittle bone and uncontrolled release rate are still a challenge nowadays. Hence, we propose to stimulate bone formation by using a newly developed magnesium-based bone substitute. Indeed, the presence of magnesium ions can stimulate bone growth and healing by enhancing osteoblastic activity. This study aims to investigate the mechanical, in vitro and in vivo properties of this novel bone substitute.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIX | Pages 102 - 102
1 Sep 2012
Kuong E Cheung K Samartzis D Yeung K Luk K
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Despite the myriad new spinal instrumentation systems, scoliosis can rarely be fully corrected, especially when the curves are stiff. A novel superelastic nickel-titanium (nitinol) rod that maximises the ability to slowly correct spinal deformities by utilising the viscoelastic properties of the spine has been developed. This parallel, double-blinded, randomised controlled trial compared the safety and efficacy of these new rods to conventional titanium rods in 23 patients with adolescent idiopathic scoliosis. The superelastic nitinol rods were found to be safe, could gradually correct scoliosis curves, and ultimately resulted in better coronal and sagittal alignments compared to traditional rods.

Despite the myriad new spinal instrumentation systems, scoliosis can rarely be fully corrected, especially when the curves are stiff. A novel superelastic nickel-titanium (nitinol) rod that maximises the ability to slowly correct spinal deformities by utilising the viscoelastic properties of the spine has been developed. This parallel, double-blinded, randomised controlled trial compared the safety and efficacy of these new rods to conventional titanium rods in 23 patients with adolescent idiopathic scoliosis. The superelastic nitinol rods were found to be safe, could gradually correct scoliosis curves, and ultimately resulted in better coronal and sagittal alignments compared to traditional rods.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVII | Pages 11 - 11
1 Jun 2012
Cheung K Samartzis D Yu K Natarajan D Cheung W Wong Y Shen J Luk K Qiu G
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Introduction

With the use of each pedicle screw for surgical correction of adolescent idiopathic scoliosis (AIS), there is an increase in instrumentation-related costs, operative time, risk of neural injury, and overall health-care expenses. As such, alternate level screw strategy (ALSS) has been reported as a potential alternative to contiguous multilevel screw strategy (CMSS). Moreover, studies have shown the importance in accounting for the flexibility of the curve based on the fulcrum bending radiograph when assessing postoperative curve correction. Therefore, this study addressed a radiographic and cost analysis comparing CMSS with ALSS for the treatment of thoracic AIS with titanium screws and rod application.

Methods

77 patients with AIS underwent surgery (range 6–15 levels). 35 patients received CMSS, which was characterised as bilateral screw fixation at every level. 42 patients underwent ALSS, which entailed bilateral screw fixation at alternate levels. Titanium rods were used in all cases. Preoperative and postoperative posteroanterior and fulcrum bending radiographic Cobb angles were obtained for all patients. The fulcrum flexibility and the fulcrum bending correction index (FBCI) were assessed. Cost analysis was also done.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXIII | Pages 179 - 179
1 May 2012
Fok A Cheng J Luk K
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The purpose of this study is to investigate the incidence of patients with isolated bundle ACL tear (either isolated posterolateral or anteromedial bundle) during arthroscopy, and its correlation with physical exam. The relevant surgical technique to reconstruct the ligament is discussed.

Between September 2006 and March 2009, patients with ACL injuries who received double- bundle ACL reconstruction were reviewed retrospectively. A specialist fellow performed a physical exam before and after anaesthesia. Intraop status of the ACL tear was assessed with correlation of the physical findings. Patients with isolated bundle tear would receive anatomical reconstruction of the torn bundle with preservation of the intact bundle.

Double-bundle hamstrings reconstruction would be performed to those with complete tear. Medical notes of 159 patients were reviewed. There were 118 patients (74%) with complete ACL tear, 36 (23%) with isolated AM tear, and 5 (3%) with PL tear.

For patients with complete ACL tear, 94% and 100% had positive Lachman, 50% and 87% had positive pivot shift, before and after anaesthesia. For patients with isolated AM tear, 100% had positive Lachman, 36% and 19% had positive pivot shift, before and after anaesthesia.

For patients with isolated PL tear, 100% had positive Lachman, 20% and 80% had positive pivot shift, before and after anaesthesia.

With better understanding of ACL, patients with isolated-bundle tear can preserve their intact bundle during reconstruction. However, in this study we find that physical exam correlates poorly with the arthroscopic findings.

Further imaging (e.g. MRI) may be helpful to differentiate patients from isolated- bundle tear to complete tear.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 238 - 238
1 Nov 2002
Cheung K Zhang J Lu D Wong Y Luk K Leong J
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Introduction: Anterior convex epiphysiodesis and posterior concave distraction has not been previously described in the literature for the treatment of thoracolumbar hemivertebrae. We describe our experience with long-term follow-up.

Method: Six consecutive patients with a mean age of 3.4 years were operated on with this technique. Levels of fusion extended two levels above and below the hemi-vertebra, while the instrumentation span the full length of the curve. Further concave distraction was carried out when there was evidence of loosening of the hooks.

Results: The average follow-up was 10.8 years (range 8 to 14). The mean Cobb angle before surgery was 49°, and at the latest follow-up was 26°. There was a mean 41% improvement in the scoliosis. In 5 of these cases, this correction was achieved immediately after surgery and did not significantly change despite repeated distraction.

Conclusion: The addition of concave distraction provided better correction than convex epiphysiodesis alone. It is technically easier and safer than hemivertebra excision in the correction of such deformities. This method of treatment is recommended for patients with single fully segmented hemivertebrae located at the thoracolumbar junction that has a significant deformity.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 273 - 273
1 Nov 2002
Cheung K Zhang J Lu D Luk K Leong J
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Introduction: Anterior convex epiphysiodesis and posterior concave distraction has not been previously described in the literature for the treatment of thoracolumbar hemivertebrae. We describe our experience with long-term follow-up.

Methods: Six consecutive patients with a mean age of 3.4 years were operated on using this technique. The levels of fusion extended two levels above and below the hemivertebra, while the instrumentation spanned the full length of the curve. Further concave distraction was carried out when there was evidence of loosening of the hooks.

Results: The average follow-up was 10.8 years (range: eight to 14 years). The mean Cobb angle before surgery was 49 degrees, and at the latest follow-up was 26 degrees. There mean improvement in the scoliosis was 41%. In five of these cases, this correction was achieved immediately after surgery and did not significantly change despite repeated distraction.

Conclusions: The addition of concave distraction provided better correction than convex epiphysiodesis alone. This method of treatment is recommended for patients with single fully segmented hemivertebrae located at the thoracolumbar junction associated with a significant deformity. This method is technically easier and safer than excision of the hemivertebra in the correction of such deformities.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 238 - 238
1 Nov 2002
Lu D Luk K Cheung K Wong Y Leong J
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The FBCI has been shown to be a better method for describing scoliosis correction because it takes spinal flexibility into consideration. 1

Objective: To use FBCI prospectively to compare the efficacy of four different posterior instrumentations in the correction of thoracic scoliosis.

Method: 123 idiopathic scoliosis patients with thoracic curves were surgically treated prospectively using 4 different posterior instrumentations: TSRH (n=35); ISOLA (n=33); CD-Horizon (CD-H: n=32); and Moss-Miami (MM: n=23). All the operations were performed by the same team of surgeons using standard techniques. The curve was measured using the Cobb’s method on the pre-operative PA standing, fulcrum bending and 1-week post-operative PA standing radiographs. The conventional correction rate and the FBCI were calculated. One-way ANOVA and independent sample t-test were used for statistical analysis.

Results: (1) There were no significant differences between any of the 4 instrumentations when assessed using the FBCI, however, the correction rate was better in CD-H than in ISOLA and TSRH (Table 1). (2) Higher FBCIs were observed in the stiff curve group (fulcrum flexibility £ 50%) compared with those in the flexible group (fulcrum flexibility > 50%), while the correction rates were lower in the former than in the latter (Table 2).

Discussion: Better correction rate obtained in the CD-H group was attributed to the more flexible curves rather than the instrumentation itself. In the flexible curve group, the instrumentations have been able to take up all the flexibility revealed by the fulcrum-bending radiograph. Although the correction rate was less in the stiff curve group, the FBCI showed that the deformity correction was actually more than that indicated by the fulcrum bending radiographs. One possible explanation of this phenomenon may be that the fulcrum-bending radiograph is less effective in eliciting all the flexibility in the stiff curves.

Conclusion: All 4 instrumentations were EQUALLY effective in correction of thoracic scoliosis when the curve flexibility was taken into consideration.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_III | Pages 239 - 239
1 Nov 2002
Lu D Luk K Wong C Cheung K Wong Y Leong J
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In scoliosis, it is well known that lateral deformity is coupled with vertebral axial rotation. Coupled motion in the sagittal plane, however, has not been investigated.

Objective: To investigate the behavior of the sagittal alignment changes when coronal deformity was corrected in idiopathic thoracic scoliosis.

Method: 36 idiopathic scoliosis patients with thoracic curves were examined before surgery. Coronal deformity was corrected using the Fulcrum Bending technique1, and biplane radiographs were taken to monitor the correction of the deformity, as well as the coupled sagittal alignment changes. Sagittal alignment was measured from T4/T5 to T12 using Cobb’s method. Difference of less or equal to 3 degrees between two measurements was treated as no change. Results were compared with those measured from standing lateral radiographs prior to and at 1 week after surgery (Posterior correction and fusion with ISOLA: n=15; CD-Horizon: n=8; Moss-Miami: n=11, USS: n=2). Pearson correlation was used for statistical analysis.

Results: (A) When scoliosis was corrected under fulcrum bending, the coupled changes in the thoracic kyphosis were decreased if it was greater than 20 degrees (n= 18), increased if less than 20 degrees (n= 2), and kept no change if it was around 20 degrees (n= 16). These changes were not related to the amount of deformity or flexibility in the coronal plane (Table I). (B) There was strong relationship between the sagittal alignment measured on the pre-operative fulcrum bending and postoperative lateral radiographs (P< 0.01). However, the final sagittal alignment was neither correlated with the magnitude or flexibility of the coronal deformity, nor the instrumentation applied (P> 0.05)

Discussion: A coupling exists between the coronal lateral deformity and the sagittal alignment in thoracic scoliosis. It seems that the sagittal alignment in a scoliotic spine tends to “normalize” with correction of the deformity: a “hyper-kyphotic” spine tends to reduce, and a “hypo-kyphotic” one tends to increase the kyphosis. Post-operative sagittal alignment seems to be decided by the coupling motion and the amount of curvature of the pre-bent rod, as neither the nature (degree or flexibility or curve pattern) of the coronal deformity nor the choice of instrumentation were related to the post-operative sagittal alignment.


The Journal of Bone & Joint Surgery British Volume
Vol. 76-B, Issue 6 | Pages 870 - 876
1 Nov 1994
Mullaji A Upadhyay S Luk K Leong J

We studied 29 girls and one boy with adolescent idiopathic scoliosis who were at Risser grade 0 at the time of posterior spinal fusion and were followed until maturity (mean 7.8 years). We used serial radiographs to measure the ratio of disc to vertebral height in the fused segments and to detect differential anterior spinal growth and assess its effect on scoliosis, vertebral rotation, kyphosis, and rib-vertebral-angle difference (RVAD). From one year after surgery to the latest review, the percentage anterior disc height decreased by nearly one-half and the percentage posterior disc height by nearly one-third in the fused segments (p < 0.001). There was a 4 degree increase in mean Cobb angle (p < 0.001), 11 patients (37%) having an increase of between 6 degrees and 10 degrees. There was a significant increase in mean apical rotation by 2 degrees (p = 0.003), and four patients (13%) had an increase of between 6 degrees and 16 degrees. There was little change in kyphosis. There was an increase in mean RVAD by 4 degrees (p = 0.003), seven patients (23%) showing a reduction by 1 degree to 7 degrees, and 11 (37%) increases of between 6 degrees and 16 degrees. Spinal growth occurs after posterior fusion in adolescents who are skeletally immature, as a result of continued anterior vertebral growth. There is some progression of scoliosis, vertebral rotation, and RVAD, but little change in kyphosis. The increase in deformity is not enough to warrant the use of combined anterior and posterior fusion. The findings are relevant to the management of progressive curves, the timing and extent of surgery, and the prognosis for progression of deformity in this group of patients.


The Journal of Bone & Joint Surgery British Volume
Vol. 72-B, Issue 4 | Pages 675 - 678
1 Jul 1990
Pun W Chow S Luk K Cheng C Hsu L Leong J

Of 37 consecutive patients suffering from tuberculosis of the lumbosacral spine, 26 were reviewed after an average follow-up of 20 years. Those presenting at under 10 years of age usually had a discharging sinus or a pointing abscess and a visible kyphosis. In older patients, low back pain was the predominant presenting symptom. Neurological involvement was uncommon. Both operative and conservative treatment had resulted in fusion but all patients treated conservatively ended up with a kyphosis associated with trunk shortening. They had a higher incidence of back pain and more complications in pregnancy. Anterior debridement and fusion with a strut graft can reduce the incidence and size of kyphosis, but is technically demanding. Treatment remains difficult and requires individual consideration.


The Journal of Bone & Joint Surgery British Volume
Vol. 70-B, Issue 5 | Pages 846 - 847
1 Nov 1988
Freedman L Luk K Leong J


The Journal of Bone & Joint Surgery British Volume
Vol. 70-B, Issue 1 | Pages 135 - 139
1 Jan 1988
Chow S So Y Pun W Luk K Leong J

Crushing of the radial side of the hand results in a wide spectrum of injuries varying from contusion of muscles to total loss. The main problem concerns the function of the thumb. The results of such injuries in 161 hands were reviewed. Those with mild injuries treated conservatively or by debridement alone had good results. When skin flaps were required for wound coverage, the results were still satisfactory. However, when bones and joints were injured, the results were poor. In certain patients opponensplasty through scarred tissue proved to be a good procedure to improve the function of the thumb.


The Journal of Bone & Joint Surgery British Volume
Vol. 69-B, Issue 1 | Pages 97 - 99
1 Jan 1987
Luk K Pun W

We report a case in which compartment syndrome and tourniquet paralysis occurred simultaneously. This is a previously unreported combination which presents a diagnostic problem. We recommend that electrophysiological studies and continuous monitoring of compartment pressures should be used to minimise morbidity in high-risk cases.


The Journal of Bone & Joint Surgery British Volume
Vol. 68-B, Issue 2 | Pages 197 - 200
1 Mar 1986
Luk K Ho H Leong J

The development of the iliolumbar ligament and its anatomy and histology were studied in cadavers from the newborn to the ninth decade. The structure was entirely muscular in the newborn and became ligamentous only from the second decade, being formed by metaplasia from fibres of the quadratus lumborum muscle. By the third decade, the definitive ligament was well formed; degenerative changes were noted in older specimens. The iliolumbar ligament may have an important role in maintaining lumbosacral stability in patients with lumbar disc degeneration, degenerative spondylolisthesis and pelvic obliquity secondary to neuromuscular scoliosis.