Anorectal malformation and Hirschsprung's disease: a cross-sectional multicentre comparison of quality of life and bowel function to a healthy population

PURPOSE

Children with anorectal malformation (ARM) and Hirschsprung's disease (HD) often experience bowel symptoms into adulthood, despite definitive surgery. This study evaluates the quality of life (QOL) and bowel functional outcome of children treated for ARM and HD in comparison to healthy controls.

METHODS

Between December 2020 and February 2023, we recruited patients with ARM and HD aged 3-17 years at four tertiary referral centres, who had primary corrective surgery done >12 months prior. Healthy controls were age-matched and sex-matched. All participants completed the Pediatric Quality of Life Inventory Generic Core Scales 4.0, General Well-Being (GWB) Scale 3.0 and Family Impact (FI) Module 2.0 Questionnaires. Bowel Function Score (BFS) Questionnaires were also administered. We also performed subgroup analysis according to age categories. Appropriate statistical analysis was performed with p<0.05 significance. Ethical approval was obtained.

RESULTS

There were 306 participants: 101 ARM, 87 HD, 118 controls. Patients with ARM and HD had significantly worse Core and FI Scores compared with controls overall and in all age categories. In the GWB Scale, only ARM and HD adolescents (13-17 years) had worse scores than controls. ARM and HD had significantly worse BFSs compared with controls overall and in all age categories. There was significant positive correlation between BFS and Core Scores, GWB Scores and FI Scores.

CONCLUSION

Patients with ARM and HD had worse QOL than controls. Lower GWB Scores in adolescents suggests targeted interventions are necessary. Bowel function influences QOL, indicating the need for continuous support into adulthood.

Clinical characteristic and management of haemophilia patients in Malaysia: A single centre experience

INTRODUCTION

Haemophilia is one of the commonest inherited bleeding disorders which may lead to long term disabilities if not treated properly. Our aim of study is to understand the clinical characteristic, treatment and complications of adult haemophilia patients in our centre.

MATERIALS AND METHODS

A retrospective cross-sectional review of all adult haemophilia A (HA) or haemophilia B (HB) patients who received treatment in Hospital Pulau Pinang from January 2021 to December 2022 was conducted. Data was retrieved from patients' medical records.

RESULTS

A total of 75 haemophilia patients (64 HA and 11 HB) were included in this study with median age of 37 years (range 19 70). 42 of them had severe haemophilia (50% of HA, 91% of HB). All HB and 93.8% of severe HA patients were on prophylaxis. Six severe and one mild HA patients developed inhibitor with four of them currently on non-factor prophylaxis. 24 patients (32%) had prior hepatitis C infection and all of them have been successfully treated. The mean annual bleeding rate for severe haemophilia patients were 1.77 (SD ±3.6). Target joints were observed in 9.3% of patients with ankle joint (71.4%) being the most affected joint. More than one quarter (26.7%) of our patients have comorbidities with majority of them having hypertension (17/20), followed by diabetes mellitus (5/20) and ischemic heart disease (5/20).

CONCLUSION

Our study showed that a significant number of adult patients with haemophilia have comorbidities. Apart from optimising factor replacement therapy, future planning should include improvement in screening, risk modification and prevention of cardiovascular disease.

Sphacelation with auto-anastomosis of the intestine: a rare outcome of intussusception in a child—a case report

Background

Intussusception is the telescoping of a proximal segment of the bowel into a distal segment. It can be idiopathic or pathological. Children commonly present with colicky abdominal pain, vomiting, a palpable abdominal mass, and bloody stools. Our case describes the unusual presentation of bowel sphacelation with auto-anastomosis in a child with intussusception and its clinical progression.

Case presentation

A 3-year-old boy with underlying stage IV rhabdomyosarcoma of the left orbit presented with high-grade fever and diarrhea for 1 day. He was treated for neutropenic sepsis in view of low absolute neutrophil count and recent history of chemotherapy. During his admission, he developed abdominal distension, high bilious aspirates, and diarrhea with bloody stools. Abdominal X-ray showed dilated bowel loops. Impression was septic ileus with coagulopathy. He was treated with blood transfusion and bowel rest. On the 6th day of illness, he passed out a tubular structure per rectum which was confirmed to be a segment of gangrenous bowel by histopathological examination. A diagnosis of intussusception with bowel sphacelation was made. He was treated conservatively, and his obstruction was resolved. He was discharged well with no abdominal symptoms during follow-up.

Conclusion

Intussusception is a common cause of small bowel obstruction in children. A high index of suspicion of intussusception should be maintained in children presenting with vomiting and bloody stools complemented by ultrasound to avoid missing this diagnosis. Sphacelation of the intussuscepted bowel with auto-anastomosis is a rare presentation of intussusception with a favorable outcome.

Three-dimensional pharyngeal airway changes in dento-skeletal class II patients after two-jaw orthognathic surgery with segmentation - a pilot study

PURPOSE

To investigate short- and long-term post-surgical three-dimensional changes of pharyngeal airway morphology and hyoid bone position in dento-skeletal class II deformity patients after two-jaw surgery with segmentation.

METHODS

Relations between skeletal movement, hyoid bone position and three-dimensional pharyngeal airway changes were retrospectively analyzed on pre- and post-surgical CBCTs in dento-skeletal class II patients who underwent orthognathic two-jaw surgery with segmentation.

RESULTS

While long-term significant reductions in length (P= 0.003), surface area (P= 0.042) and volume (P= 0.004) were found in the nasopharynx, the highly significant increases in oropharyngeal airway length, surface area, volume and the minimal cross-sectional area (P < 0.05) prevailed only in the short-term. Although a significant antero-superior movement of the hyoid bone was detected both in short- and long-term follow-up CBCTs (P < 0.05), only its superior, but not the anterior movement was found to be associated with an increased lateral width of the oropharyngeal minimal cross-sectional area.

CONCLUSION

Two-jaw orthognathic surgery with segmentations in dento-skeletal class II patients improved oropharyngeal airway parameters significantly in the short-, but not long-term.

Carotid intima media thickness and high sensitivity C-reactive protein as markers of cardiovascular risk in a malaysian population

INTRODUCTION

Carotid intima media thickness (CIMT) being a cost effective and easily performed technique is useful in the detection of subclinical atherosclerosis and has been shown to be a prognosticator of cardiovascular events. The primary objective of this study was to obtain the distribution of CIMT measurements, highly sensitive C reactive protein (hs-CRP) and assessing health awareness and attitudes of the Malaysian population at cardiovascular disease (CVD) risk and not receiving lipid lowering agents. Secondarily the study sought to assess the significance of the relationship between these measurements against various patient characteristics.

METHODS

Measurements of CIMT are obtained by ultrasonography of 12 sites within the common carotid artery was recorded for 123 subjects from a single centre tertiary hospital of Malaysia who had two or more CVD risk factors but were not receiving lipid lowering therapy. CVD risk factors and lipid and glucose profiles were analyzed with respect to distribution of CIMT and high-sensitivity Creactive protein (hs-CRP) values.

RESULTS

The mean-max CIMT was 0.916±0.129mm (minimum 0.630mm, maximum 1.28mm) and the mean-mean CIMT was 0.743±0.110mm (minimum 0.482mm, maximum 1.050mm) and mean hs-CRP was 0.191mg/dL (minimum 0.030mg/dL, maximum 5.440mg/dL). Multivariate analyses confirmed a significant association between increasing CIMT and increasing age, total and low density lipoprotein cholesterol while log-transformed hs-CRP levels showed significant association with increasing body mass index, waist circumference, high blood glucose and triglyceride levels. Our patients had good health awareness on CVD.

CONCLUSION

Newly defined CIMT measurements and hs-CRP levels may be useful adjunctive tools to screen for atherosclerosis in the Malaysian population. It may help in refining risk stratification on top of traditional clinical assessment.

Emergency stenting of vertical vein in a neonate with obstructed supracardiac total anomalous pulmonary venous drainage

A late preterm newborn baby presented with respiratory distress and increasing cyanosis within 2 hours of birth. Bedside transthroracic echocardiography showed a critically obstructed vertical vein in a supracardiac total anomalous pulmonary venous drainage (TAPVd). Emergency stenting of the vertical vein was successfully performed at 24 hours of life.

Physical fitness of normal, stunted and overweight children 6-13 years in Oaxaca, Mexico

BACKGROUND/OBJECTIVE

The objective of this study is to compare the growth and physical fitness of normal, stunted and overweight/obese (owt/ob) Oaxaca children 6-13 years.

SUBJECTS/METHODS

This study was a cross-sectional, included 688 school children (grades 1-3, 4-6), aged 6-13 years, from an indigenous rural community (n=361) and colonia popular (n=327) in Oaxaca, southern Mexico.

MEASUREMENTS

Anthropometry-weight, height, sitting height, limb circumferences, skinfolds. Derived-body mass index, sitting height/height ratio, leg and step lengths, limb muscle areas, sum of skinfolds. Physical fitness-sit and reach, sit-ups, distance run, grip strength, standing long jump, 35 yard dash. Physical activity-steps to and from school, household chores, sports participation.

ANALYSIS

Normal-not stunted, not owt/ob; stunted-not owt/ob; and owt/ob-not stunted were compared with multivariate analysis of covariance controlling for age. Two children were stunted and owt/ob, and were excluded.

RESULTS

Age-adjusted means for body size, muscularity, adiposity and grip strength showed a gradient, owt/ob>normal>stunted in both sexes and grade levels (P<0.001). Relative position of stunted and owt/ob children was reversed for strength per unit mass. Stunted and normal children ran a greater distance than owt/ob children (P<0.05). Normal, stunted and owt/ob children did not differ consistently in other fitness items and indicators of activity and inactivity.

CONCLUSION

Size, muscularity, fatness and strength differed significantly, owt/ob>normal>stunted, but owt/ob children had less strength per unit mass and poorer endurance. Normal and stunted children did not differ consistently in fitness. Physical activity and television time did not differ among the three groups.

Controlled field studies on soil aquifer treatment in a constructed coastal sandfill

A controlled artificial recharge experiment was conducted to investigate the effect of soil aquifer treatment during percolation of secondary and tertiary (ultrafiltered) treated wastewater through the shallow vadoze zone of a newly constructed coastal sandfill. The sandfill is a reclaimed land constructed from marine sand dredged from the seabed. To obtain 1-D flow, a stainless steel column was driven to a depth of 2.5 m, penetrating the phreatic surface. Wastewater was percolated through the column under fully-saturated and unsaturated conditions. Infiltration rates, dissolved organic carbon (DOC) and ultra-violet absorption (UVA) were monitored. The wastewaters were recharged at similar infiltration rates of approximately 5.5 m/day and 3.5 m/day under fully-saturated and unsaturated conditions, respectively. In both cases, clogging occurred 40 days after the start of recharge, under saturated conditions. For secondary treated wastewater, DOC concentration (mg/l) reduced by 28% and 13% under unsaturated and saturated conditions, respectively. The corresponding UVA reduction was 19.4% and 14.1%. Similar reductions in DOC were observed for the tertiary treated wastewater; however, the reduction in UVA was higher; 28% and 22% under unsaturated and saturated conditions, respectively. On an mass removal (mg/m(2) DOC) basis, DOC reduction appeared to be more significant under unsaturated conditions. This is attributed to the presence of interstitial oxygen.

Four beams evanescent waves interference lithography for patterning of two dimensional features

This work presents a theoretical study of using the interference of multiple counter-propagating evanescent waves as a lithography technique to print periodic two dimensional features. The formulation of the three dimensional Cartesian space expression of an evanescent wave is presented. In this work, the evanescent wave is generated by the total internal reflection of a plane wave at the interface between a incident dielectric material and a weakly absorbing transmission medium. The influences of polarization, incident angle and the phase shifting of the incident plane waves on the evanescent wave interference are studied. Numerical simulation results suggest that this technique enables fabrication of periodic two dimensional features with resolution less than one third the wavelength of the irradiation source.

Use of fluorescein as a ground water tracer in brackish water aquifers

A drift and pumpback experiment was conducted in a brackish water sandfill. The sandfill was reclaimed from the sea in the eastern part of Singapore and contains sands with low organic and clay/silt contents. The high salinity in the ground water precludes the use of chloride and bromide as tracers in such an environment, and a field experiment was conducted to assess the viability of using fluorescein as a tracer in brackish water aquifers. Nitrate was used as a second tracer to serve as a check. Initial laboratory studies showed that fluorescence was unaffected over the range of electrical conductivity and pH of the ground water. Results from the field experiment show that fluorescein appears to behave conservatively.

15th Chapter of Surgeons Lecture: Surgeon of the new millennium--surgeon, scientist and scholar

The surgeon of the new millennium has come a long way from his humble beginnings in the Middle Ages as the lowly barber-surgeon. The skills and techniques developed by outstanding surgeons like Astley Cooper of the 19th century have withstood the test of time and have been refined by subsequent generations of surgical masters. The scientific basis of modern surgery was put on a firm footing in the early 19th century through the discovery of anaesthesia and microorganisms as a cause of many diseases and surgical complications. The 20th century brought about rapid progress in medicine, information technology (IT) and the life sciences, and closed with a big bang with the completion of the sequencing of the human genome. For the surgeon of the 21st century to remain relevant, he must embrace the concept of the Total Surgeon. Not doing so will render him irrelevant in the course of time, for having good surgical technique alone is insufficient. He must also lead in scientific endeavours to push the frontiers of the life sciences in attempts to solve the insoluble, and be scholarly in thought, attitude and behaviour. In other words, he must be a Surgeon-Scientist-Scholar.

From genesis to genes

Since the beginning of time, our ancestors have been plagued by illnesses and injuries that are not too different from today's diseases. Evidence from prehistoric times and ancient civilisations have shown man's attempts at trying to understand the nature and treatment of these conditions. It was not till the early 19th century that the scientific basis of modern medicine was firmly established when microorganisms were discovered and found to be the cause of many of these illnesses. The 20th century saw quantum leaps made in the understanding of the function of the human body and the therapeutic measures aimed at restoration of any such malfunction. The end of the last millennium was marked by historic achievements made in the Life Sciences, in particular the completion of the sequencing of the Human Genome--the code of life. The beginning of the 21st century has already seen many breakthroughs in medical sciences, especially in the fields of stem cell technology and gene therapy. The number of known illnesses directly related to genetic defects or abnormalities have increased exponentially. Many of today's scourges can be prevented or more effectively treated. Our ability to utilise this new knowledge to combat the ravages of the ageing process and its associated illnesses--degenerative diseases and cancers offer much hope for the future.

Influence of patellar thickness on results of total knee arthroplasty: does a residual bony patellar thickness of <or=12 mm lead to poorer clinical outcome and increased complication rates?

With patellar thickness averaging 24.0 mm and 21.9 mm in Singapore men and women undergoing total knee arthroplasty, achievement of precut thickness is difficult if the recommended residual bony thickness of 15 mm is maintained. We retrospectively compared the clinical outcome of 56 patellae resurfaced <or=12 mm (mean residual thickness, 10.4 mm) with 56 patellae resurfaced >12 mm (mean residual thickness, 13.7 mm). Both groups were comparable in terms of demographic characteristics, presentation, precut patellar thickness, and operative details (P> .05). Knee scores (P= .627), extensor mechanism function (P= .625), and postoperative range of motion (P= .344) were comparable. Differences in the overall (P= .167) and patellar (P= .061) complication rates as determined by chi-square test on the SPSS 10.0 program were not significant, although there were 4 patella-related complications in group 2. Increased patella-related complications may be associated with an excessive patellar composite of the patellofemoral articulation. A residual patellar thickness of <12 mm did not appear to affect the clinical outcome in this series.

Results of cervical laminoplasty and a comparison between single and double trap-door techniques

Thirty-seven patients were studied for an average of 32.1 months after canal-expansive laminoplasty for the treatment of multiple-level cervical stenosis caused by spondylosis, ossification of posterior longitudinal ligament, prolapsed intervertebral disc, and other conditions. Short-term and medium-term results were recorded clinically, using the scoring system proposed by the Japanese Orthopedic Association. The canal expansion was also recorded with radiological studies. The improvement rate was good to excellent in 58.3% of the patients. Postoperative neurological deterioration occurred in only four patients. Poorer results were observed in female patients and in those in whom surgery was delayed. Surgery within 12 months of onset of symptoms gave good results. Serious complications occurred in only two patients. There were 12 patients who were treated with the single trap-door (unilateral) laminoplasty and 25 patients treated with the double trap-door (sagittal splitting of the spinous processes) laminoplasty; their results were compared. There was no significant difference in neurological outcome between the two methods.

Deep vein thrombosis after total knee replacement

INTRODUCTION

The prevalence of deep vein thrombosis after total knee replacement has been quoted to be between 46% and 84% in the Western literature. The aims of this study were to determine its prevalence in the Singapore population and to assess the need for prophylaxis against deep vein thrombosis.

MATERIALS AND METHODS

We examined data on 100 consecutive patients undergoing total knee replacement at the Adult Reconstructive Service, Department of Orthopaedic Surgery, Singapore General Hospital and assessed the possible risk factors: age, sex, weight, previous surgery, unilateral or bilateral surgery, postoperative rehabilitation, tourniquet and operating time. Functional and knee scores based on the Knee Society Clinical Rating System were also assessed. No prophylaxis was given to these patients. These patients underwent a duplex scan of both lower limbs on the seventh postoperative day. Treatment was instituted only if proximal deep vein thrombosis was detected.

RESULTS

The overall incidence of deep vein thrombosis was 14% with 64.3% of it occurring distally. Deep vein thrombosis was more common in bilateral total knee replacement (22.2%) compared to unilateral total knee replacement (13.2%). Partial thrombosis was present in 71.4% and occurred predominantly in the ipsilateral leg. There was no evidence of propagation. Only 1 patient developed pulmonary embolism and was treated successfully but there was no evidence of deep vein thrombosis on duplex scan in this patient.

CONCLUSION

There was no significant difference in the risk factors between patients who did and those who did not develop deep vein thrombosis.

Results of revision total knee arthroplasty

BACKGROUND/AIM OF STUDY

The results of primary total knee arthroplasties have improved over the years but some still fail, requiring revision. Revision total knee arthroplasty is technically more difficult and has not enjoyed the same success rates as the index operation. The aim of this retrospective study was to review the results of revision total knee arthroplasties carried out at our centre. This is the first study in Singapore on revision total knee arthroplasty.

METHODS

A retrospective study where 17 patients (18 knees) had been followed up since their revision operations were clinically assessed. Based on the Knee Society Clinical Scoring System, they were assigned separate knee and function scores (each having a maximum possible 100).

RESULTS

The mean knee score was 76 (range 35-93), which rates as good. Of the 18 knees, 67% had excellent or good knee scores. By comparison, the mean function score was 56 (range 0-90) which rates as poor and 33% had excellent or good function scores.

CONCLUSION

Revision total knee arthroplasty achieves good and excellent results in spite of technical difficulties often associated with the revision operation. The difference in mean knee and function scores emphasises that many other factors such as physical strength and stamina affect function. Nevertheless, 15 patients were able to walk out of their house and around their neighbourhood for varying distances. This satisfied their expectations and the poor mean function score may reflect different expectations of patients overseas from whence this scoring system originated.

The cross-gender performances of Yam Kim-Fei, or the queer factor in postwar Hong Kong Cantonese opera/opera films

This essay is designed as a brief historical examination of the Cantonese female cross-dressing star Yam Kim-Fei, whose hundreds of films and opera performances in the '50s and '60s have made her one of the century's most celebrated transvestite artists. While her craft has often been relegated to studies of gender alone, I assert that the traditions of Chinese operatic transvestism she employs are not merely a relativist historical-artistic mode without political relevance but can be justifiably reclaimed for the purposes of queer interpretation and spectatorship-for indeed their original intent coincides very well with what we call "queer" today.

Muscarinic regulation of basal versus thyrotropin-releasing hormone-induced prolactin secretion in rat anterior pituitary cells. differential roles of nitric oxide and intracellular calcium mobilization

Acetylcholine (ACh), synthesized in the pituitary, can act locally to modulate pituitary function. We used rat primary anterior pituitary (AP) cells to investigate how ACh affects pituitary prolactin (PRL) secretion in the presence or absence of known PRL regulators: thyrotropin-releasing hormone (TRH), 17beta-estradiol (E(2)) and triiodothyronine (T(3)). Cultured AP cells were prepared from ovariectomized rats and pretreated with diluent, 0.6 nM E(2), 10 nM T(3), or E(2) plus T(3) for 5 days, then challenged with various doses of ACh or muscarinic receptor agonists (oxotremorine or carbachol) and TRH (100 nM) for 20 min. Significant ACh (10(-5) M) suppression of both basal and TRH-induced PRL secretion was not evident in diluent-, E(2)- or T(3)-pretreated cells, but observed only in cells pretreated with both E(2) and T(3). Moreover, in E(2) plus T(3)-pretreated cells, oxotremorine and carbachol, like ACh (10(-7)-10(-5) M), suppressed both responses in a dose- related manner. Pertussis toxin (PTX; 100 ng/ml) as well as atropine (a muscarinic receptor antagonist; 1 mM) blocked these effects of cholinomimetics. ACh also inhibited both PRL responses elicited by drugs elevating intracellular cAMP (10 microM forskolin) or Ca(2+) (1 microM Bay K-8644) in a PTX-sensitive manner. ACh inhibition of basal PRL secretion was unaltered by intracellular Ca(2+) mobilization blockers, TMB-8 (100 microM) and thapsigargin (1 microM), but abrogated by the nitric oxide synthase inhibitor (300 microM L-NAME). ACh inhibition of TRH-induced PRL secretion was accentuated by TMB-8 and alleviated by thapsigargin or L-NAME. In summary, muscarinic inhibition of either basal or TRH-induced PRL secretion was augmented by E(2) and T(3), and involved the PTX-sensitive cAMP/Ca(2+) pathways. Furthermore, nitric oxide mediated the basal rather than TRH-induced PRL response to ACh, whereas the intracellular Ca(2+) mobilization concerned the TRH-induced rather than the basal PRL response to ACh. Thus, ACh synthesized in the AP appears to inhibit basal vs. TRH-induced PRL secretion via different mechanisms.

Intrarenal infusion of supernatant from cytokine-activated human mesangial cells may cause glomerular damage

BACKGROUND

The pathogenesis of glomerular damage in glomerulonephritis (GN) is not fully understood. Several studies have suggested that reactive oxygen molecules play a role in renal disease. It is known that, during GN, mesangial cells are activated. In a previous study, we demonstrated that in vitro interleukin (IL)-1 plus IL-6 stimulated cultured human mesangial cell (HMC) activation to release free oxygen radicals.

METHODS

In this study, we measured hydrogen peroxide (H2O2) and superoxide anion (O2-) levels after stimulation by IL-1 plus IL-6 in cultured HMCs. We then infused H2O2 directly into the left renal arteries of Sprague-Dawley rats. We also infused the culture supernatants of HMCs after stimulation by IL-1 plus IL-6 into the left renal arteries of rats. Two hours after stopping the infusion, the kidneys were removed and fixed using Carson's modified Millonig's buffer for electron microscopy.

RESULTS

Both 100 microM H2O2 and supernatants of HMCs stimulated by IL-1 10 U/ml plus IL-6 1,000 U/ml caused similar glomerular damage, including blebbing and sloughing of endothelial cells, and denuded basement membrane in glomeruli. When 100 microM H2O2 or supernatants of cytokine-activated HMCs were infused into renal arteries, they caused hematuria and proteinuria.

CONCLUSIONS

These results suggest that activated HMCs may secrete free radicals and cause glomerular damage.

Use of titanium prosthesis to bridge a vertebral gap in the spine--a preliminary experimental study

Resection of a vertebral body for spine tumour or fracture results in a vertebral gap which has to be bridged by autogenous graft, allograft, bone cement or metal spacer. Recently, there have been several metal spacers in the market. We have designed a titanium vertebral spacer which is extensible by way of a threaded mechanism. Coating with hydroxyapatite enables bone ingrowth onto the surface of the titanium spacer. Biomechanical analysis, using the Instron biaxial electro-servohydraulic testing machine, showed that the segment bridging the spacer was rigid and stiffer than the adjacent vertebral body motion segment. Histological study showed that there was bone growth across the vertebral gap indicating fusion had taken place.

Phosphatidylinositol 4-phosphate synthesis in immunoisolated caveolae-like vesicles and low buoyant density non-caveolar membranes

This study examined phosphatidylinositol 4-phosphate (PtdIns4P) synthesis in caveolae that have been suggested to be discrete signaling microdomains of the plasma membrane and are enriched in the marker protein caveolin. Caveolin-rich light membranes (CLMs) were isolated from A431 cells by detergent-free, discontinuous density-gradient centrifugation method. The CLM fraction was separated from the bulk of the cellular protein and was greatly enriched in PtdIns, PtdIns4P, and phosphatidylinositol 4, 5-bisphosphate (PtdIns(4,5)P2) and an adenosine-sensitive type II PtdIns 4-kinase activity. Preparation of CLMs by an OptiPrep-based cell fractionation procedure confirmed the co-localization of PtdIns 4-kinase and caveolin. Electron microscopy confirmed that an anti-caveolin antiserum immunopurified vesicles from CLMs that were within the size range described for caveolae in other systems. Co-immunoprecipitated PtdIns 4-kinase activity could utilize endogenous PtdIns, present within the caveolae-like vesicles, to produce PtdIns4P. The addition of recombinant phosphatidylinositol transfer protein increased PtdIns 4-kinase activity both in immunoisolated caveolae and CLMs. However, less than 1% of the total cellular PtdIns and PtdIns 4-kinase activity was present in caveolae-like vesicles, indicating that non-caveolar light membrane rafts are the main site for cellular PtdIns4P production.

Isolated metal-backed patellar component revision following total knee arthroplasty

BACKGROUND

Twenty-two consecutive revisions for failed metal-backed patellar components following total knee arthroplasty in 17 patients were retrospectively reviewed. All had similar total condylar knee prosthesis inserted with retention of the posterior cruciate ligament and resurfacing of the patella with a metal-backed component. There were 3 male and 14 female patients.

RESULTS

The mean time to failure of the patellar component was 60 months (range 26 to 93 months). The majority of patients presented with metallic crepitus (86.4%) and knee pain (72.7%). At surgery, full thickness polyethylene wear exposing the metal-backing was present in 81.8% with surface damage of the femoral components present in 40.9%. All 22 cases underwent successful isolated patellar component revision with all polyethylene patellar components.

CONCLUSION

Resurfacing of the patella in total knee arthroplasty with metal-backed patellar components carries a significant risk of early failure and the use of these components is no longer practised at our institution.

Evidence for the involvement of protein kinase C in the inhibition of prolactin gene expression by transforming growth factor-beta2

We investigated the mechanisms by which transforming growth factor (TGF)-beta2 inhibited prolactin mRNA expression in GH3 rat pituitary tumor cells. Maximal inhibition was observed with cells exposed to 5 ng/ml TGF-beta2 for 24 hr. Continuous presence of the hormone during the entire period was not necessary because exposure of cells to TGF-beta2 for 20 min was sufficient to trigger the same extent of prolactin mRNA inhibition at 24 hr as with its persistent presence. The action of TGF-beta2 could be abolished by cycloheximide or EGTA, suggesting the requirement of a newly synthesized protein and extracellular Ca2+. The response of prolactin mRNA to TGF-beta2 was inhibited by preincubation of cells with phorbol-12-myristate-13-acetate, which down-regulated protein kinase C (PKC). The activities of both the cytosolic and membrane PKC were significantly reduced at 20 min after TGF-beta2 addition, and inhibition continued to 24 hr, the last time point analyzed. However, the ratio of cytosolic to membrane PKC was not altered by TGF-beta2. Inhibition of PKC did not require the sustained presence of TGF-beta2. In vitro kinase assays of the immunoprecipitated PKC demonstrated that the activities of alpha, epsilon, mu, and zeta isozymes were significantly decreased in the TGF-beta2-treated cells, whereas that of PKClambda was not affected. Western blotting did not reveal any change in PKCepsilon steady state protein levels, suggesting TGF-beta2 inhibits PKC activity through a post-translational mechanism. Our results support that inhibition of PKC activity is an early event mediating TGF-beta2-inhibited prolactin mRNA expression in GH3 cells.

Differential effect of age on transforming growth factor-beta 1 inhibition of prolactin gene expression versus secretion in rat anterior pituitary cells

Transforming growth factor-beta 1 (TGF-beta 1) synthesized in the pituitary may act as an autocrine/paracrine regulator of lactotrope function. We examined the effects of TGF-beta 1 on PRL messenger RNA (mRNA), PRL synthesis, and PRL secretion in cultured anterior pituitary (AP) cells from rats at different ages. APs excised from ovariectomized female Sprague-Dawley rats, either young(2-3 months old; average serum PRL: 9 ng/ml), middle-aged (11-12 months old; average serum PRL: 133 ng/ml), or old (24 months old; average serum PRL: 159 ng/ml), were dispersed and cultured for 5 days. Then, cells were washed and challenged with increasing doses of TGF-beta 1 (0-100 ng/ml) for 1-48 h in serum-free medium. Northern blot analysis showed an increase in basal PRL mRNA levels, and a decrease in responsiveness to TGF-beta 1 with age. TGF-beta 1 suppressed PRL mRNA in a dose- and time-dependent manner in cells from young rats. Maximum inhibition was observed at 0.5-1 ng/ml of TGF-beta 1. At 0.5 ng/ml TGF-beta 1, significant reduction in PRL mRNA was detected at 6 h, and maximum inhibition was observed at 12-48 h post TGF-beta 1 incubation. Cells from middle-aged rats were less responsive to TGF-beta 1, whereas cells from old rats did not seem to respond under our experimental conditions. In addition to its effect on PRL mRNA in young AP cells, TGF-beta 1 dose dependently inhibited the rate of PRL synthesis, as indicated by reduced [35S]methionine incorporation into immunoprecipitated PRL. Responsiveness of PRL synthesis to TGF-beta 1 inhibition also decreased with age; however, significant inhibition by TGF-beta 1 on PRL synthesis could still be observed in old AP cells. Analysis by RIA demonstrated that young AP cells produced lower levels (15 micrograms/10(6) cells.24 h) of PRL in culture medium than old AP cells (32 micrograms/10(6) cells.24 h). TGF-beta 1 decreased medium PRL levels in old AP cells as efficaciously as in young AP cells. Significant reduction in medium PRL secreted by young AP cells was observed at 3 h when changes in both PRL mRNA and PRL synthesis were not evident. Taken together, our data suggest that TGF-beta 1 affects PRL production at multiple levels. Moreover, its inhibition on PRL synthesis and mRNA expression, but not on PRL secretion, is age-related. Thus, TGF-beta 1 may play an important role in regulating lactotrope function during aging.

Popliteal artery pseudoaneurysm caused by an osteochondroma--a traditional medicine massage sequelae

We report an unusual case of a popliteal aneurysm complicating a distal femoral osteochondroma caused by the repeated massages of a traditional medicine practitioner (sinseh). Management was by excision of the exostosis and reconstruction of the damaged arterial segment by a reversed long saphenous vein graft. We advice against massage over an osteochondroma on the distal medial aspect of the femur and suggest prophylactic removal of such lesions because of this potential complication.

Factors affecting healing of below knee amputation

Between January and December 1992, 54 diabetic patients with 60 below knee amputations performed in the Department of Orthopaedic Surgery O, Singapore General Hospital were available for evaluation. The average follow-up period was 16.3 months with a range of 13 to 24 months. Five patients had stump necrosis and above knee amputation was performed. Eight patients had partial stump necrosis and required debridement with or without secondary procedures. The other patients had uneventful stump healing which was defined as healing of the stump wound without complications and remained intact for at least 6 months after surgery. Absence of popliteal pulse, presence of central cardiovascular disease and absence of intraoperative skin flap bleeding were found to be associated with higher incidence of stump necrosis.

The yeast and mammalian isoforms of phosphatidylinositol transfer protein can all restore phospholipase C-mediated inositol lipid signaling in cytosol-depleted RBL-2H3 and HL-60 cells

The mammalian phosphatidylinositol transfer proteins (PITP) and the yeast Saccharomyces cerevisiae PITP (SEC14p) that show no sequence homology both catalyze exchange of phosphatidylinositol (PI) between membranes compartments in vitro. In HL-60 cells where the cytosolic proteins are depleted by permeabilization, exogenously added PITPalpha is required to restore G protein-mediated phospholipase Cbeta (PLCbeta) signaling. Recently, a second mammalian PITPbeta form has been described that shows 77% identity to rat PITPalpha. We have examined the ability of the two mammalian PITPs and SEC14p to restore PLC-mediated signaling in cytosol-depleted HL-60 and RBL-2H3 cells. Both PITPalpha and PITPbeta isoforms as well as SEC14p restore G protein-mediated PLCbeta signaling with a similar potency. In RBL-2H3 cells, crosslinking of the IgE receptor by antigen stimulates inositol lipid hydrolysis by tyrosine phosphorylation of PLCgamma1. Permeabilization of RBL cells leads to loss of PLCgamma1 as well as PITP into the extracellular medium and this coincides with loss of antigen-stimulated lipid hydrolysis. Both PLCgamma1 and PITP were required to restore inositol lipid signaling. We conclude that (i) because the PI binding/transfer activities of PITP/SEC14p is the common feature shared by all three transfer proteins, it must be the relevant activity that determines their abilities to restore inositol lipid-mediated signaling and (ii) PITP is a general requirement for inositol lipid hydrolysis regardless of how and which isoform of PLC is activated by the appropriate agonist.

ARF and PITP restore GTP gamma S-stimulated protein secretion from cytosol-depleted HL60 cells by promoting PIP2 synthesis

BACKGROUND

In many cell types, including neutrophils and HL60 cells, there is an absolute requirement for a GTP-dependent step to elicit Ca(2+)-regulated secretion. Neutrophils and HL60 cells secrete lysosomal enzymes from azurophilic granules; this secretion is inhibited by 1% ethanol, indicating that phosphatidate (PA) produced by phospholipase D (PLD) activity may be involved. PLD can use primary alcohols in preference to water during the hydrolytic step, generating the corresponding phosphatidylalcohol instead of PA, its normal product. As ARF (ADP-ribosylation factor) proteins regulate PLD activity and are implicated in constitutive vesicular traffic, we have investigated whether ARF is also required for GTP-dependent secretion in HL60 cells.

RESULTS

We have used a cell-permeabilization protocol that allows HL60 cells to become refractory to stimulation with GTP gamma S plus 10 microM Ca2+ with regard to secretion and PLD activity. Permeabilization with streptolysin O for 10 minutes permitted the loss of freely diffusable cytosolic proteins, including ARF proteins. Fractions derived from brain cytosol, enriched in ARF proteins, restored secretory function and PLD activity. The major contaminating protein present in these ARF-enriched fractions was identified as phosphatidylinositol transfer protein (PITP). Unexpectedly, PITP was also found to restore GTP gamma S-dependent secretion. Restoration of secretory function was characterized using recombinant proteins, rARF1 and rPITP alpha and rPITP beta. The rARF1 protein restored both secretory function and PLD activity, whereas PITP only restored secretory function. However, both ARF and PITP were capable of stimulating phosphatidylinositol bis phosphate (PIP2) synthesis.

CONCLUSIONS

ARF and PITP restore secretory function in cytosol-depleted cells when stimulated with GTP gamma S plus Ca2+. We have previously shown that PITP participates in the synthesis of PIP2. In comparison, ARF1 activates PLD, producing PA, which is a known activator of phosphatidylinositol-4-phosphate 5 kinase, the enzyme responsible for PIP2 synthesis. We propose that ARF and PITP both restore exocytosis by a common mechanism-promoting PIP2 synthesis.

Comparison of various interpositional materials in the prevention of transphyseal bone bridge formation

Various interpositional materials, except muscle, have been used to prevent transphyseal bone bridge formation after resection of the damaged physeal plate. In this animal model, muscle was used as an interpositional material, and its effectiveness was compared with that of 3 known materials (fat, physeal allograft, and iliac apophyseal autograft). Five experiments were done on the distal femoral physis of 40 skeletally immature 3-month-old New Zealand white rabbits. The rabbits were divided into 5 groups, each containing 8 rabbits. A standard defect was created in the lateral distal physis of the left femur in all the rabbits. In Group A, there was no interpositional material. Vastus lateralis muscle, groin fat, physeal allograft, and iliac apophyseal autograft were inserted into the femoral defect in Groups B, C, D, and E, respectively. The right femur served as a sham control for the animals. The animals were sacrificed at 12 weeks after surgery. The results of limb length discrepancy and angular deformity of the groups with interpositional material were compared with those of Group A (experimental control). Muscle, fat, and iliac apophyseal autografts had less severe limb length discrepancy and angular deformity. These differences were statistically significant, whereas the differences between allograft and experimental control were statistically insignificant.

Arthroscopic treatment of osteochondral lesion of the talus

A retrospective study of the arthroscopic treatment of osteochondral lesions of the talus in 25 patients was conducted. The follow-up period ranged from 1 to 4 years with an average of 2 years. Of the 25 patients, 20 could recall a history of injury. The diagnosis could be made by standard anteroposterior and lateral X-rays in 22 out of 25 patients. The standard anteromedial and anterolateral portals were usually sufficient. Patients with stage I and II lesions did well uniformly. In the 16 patients with stage III and IV lesions, good results were obtained in 12 and fair in 4. Morbidity was minimal.

Comparing staple fixation to buttress plate fixation in high tibial osteotomy

A retrospective study was made between July 1988 and March 1992, of 171 patients (223 knees) who had high tibial osteotomy at the Singapore General Hospital. Seventy-four cases (97 knees) had buttress plate fixation and 97 cases (126 knees) had staple fixation. The mean postoperative Hospital for Special Surgery Knee Score was 87.0 for the buttress plate group and 87.4 for the staple group. The difference was statistically not significant (P > 0.05). The hospitalisation stay was shorter in the staple fixation group as compared to the buttress plate group (P < 0.05). However, the mean rehabilitation time was shorter in the buttress plate group as compared to the staple fixation group (P < 0.05). The incidence of wound infection was higher among those fixed with buttress plate (9 cases) as compared to those fixed with staple (1 case). The difference was statistically significant (P < 0.05). Buttress plate fixation did not seem to eliminate the risk of non-union of the osteotomy (4 out of 126 osteotomies compared to 3 out of 97 in the staple group), neither did it prevent recurrence of varus deformity (2 out of 126 osteotomies). Overall it would appear that buttress plating did not have any significant advantage over staple fixation for high tibial osteotomy.

Regulation of topoisomerase II expression during the VM-26 induced differentiation of IW32 murine erythroleukemia cells

The effect of VM-26, a topoisomerase II targeting drug, on IW32 murine erythroleukemia cells was investigated. The VM-26 induced IW32 cells to differentiate at a non-toxic but cytostatic concentration (0.01 microgram/ml). More than 40% of the cells were induced to synthesize hemoglobin, and cells were arrested in G2/M phase of the cell cycle. Levels of beta-globin mRNA also increased significantly. Cells became committed to erythroid maturation after 16 h of continuous drug exposure. Replacement with fresh VM-26 after 48 h of drug treatment further increased the hemoglobin containing cells to greater than 80%. Unlike other drug induced erythroleukemia cell differentiation, c-myc mRNA expression was not affected by VM-26. Inhibition of topoisomerase II activity was observed during the first 12 h of VM-26 treatment; however, elevated enzyme activity was found thereafter. Northern blot analysis showed significant increase in the expression of topoisomerase IIalpha mRNA at 12 and 24 h after VM-26 addition. These findings indicate that VM-26 inhibited the activity of topoisomerase II and promoted the committed differentiation of IW32 cells along the erythroid pathway. In addition, a parallel increase in mRNA and activity levels of topoisomerase II in differentiated cells suggests that regulation of the enzyme expression occurred in the VM-26 induced erythroid maturation.

Tarsometatarsal (Lisfranc's) injuries--results of open reduction and internal fixation

Injuries of the tarsometatarsal (Lisfranc's) joint are uncommon and are potentially associated with chronic disability. The aim of our study was to review retrospectively the results of open reduction with Kirschner wire internal fixation of tarsometatarsal injuries. In this study, 12 patients with Lisfranc's injuries treated between January 1986 and March 1993 were reviewed at an average of 36 months after the injuries. Majority of the patients suffered from type B injuries (Hardcastle's classification, 1982). There were 9 closed and 3 open injuries. All were high energy injuries sustained in motor vehicle accidents, fall from a height or crush force. All were treated with open reduction and internal fixation with Kirschner wires. Anatomical reduction was achieved and maintained. There was no postoperative redisplacement. During follow-up, most patients developed radiological evidence of post-traumatic osteoarthritic changes. However, majority of the patients were pain-free or had very little foot pain, and were able to return to their previous occupation. Our study showed that open reduction with Kirschner wire internal fixation offered satisfactory anatomical and functional results.

Vascular assessment in the neuropathic diabetic foot

Diabetic foot infections, a common source of morbidity and mortality, often have been related to vasculopathy and neuropathy in its etiopathogenesis, especially in the elderly person with diabetes. However, blood flow in the neuropathic diabetic foot has not been evaluated extensively, and there is evidence of abnormal blood flow patterns in the neuropathic diabetic foot unrelated to ischemia. The authors studied young persons with diabetes, with varying degrees of neuropathy, to assess the extent of vasculopathy in their lower limbs. Twelve young persons with insulin-dependent (Type I) diabetes (mean age, 36.1 +/- 1.975 years) and peripheral neuropathy, all of whom had previous surgery for diabetic foot infections, were identified. Confirmatory evidence of neuropathy was made using electromyographic studies and clinical tests that showed severe peripheral neuropathy. The results of vascular assessment of both lower limbs did not reveal any change in the pulse wave velocities from the popliteal to the digital vessels of the big toe as compared with correspondingly matched controls. There also was no significant stenosis in any of the vessels studied as far as the level of the dorsalis pedis and posterior tibial vessels. The normal triphasic pattern of arterial blood flow was lost. A monophasic pattern was present in all patients with prolonged diastolic flow at the level of the dorsalis pedis and posterior tibial arteries and distally. The pulsatility index was 3.14 +/- 0.81 as compared with 9.85 +/- 4.2. Mean toe pressures in the patient with diabetes was 64.17 +/- 20.87 mm Hg as compared with 98.23 +/- 10.12 mm Hg in controls. A linear correlation of decreasing toe pressures with increasing severity of neuropathy was seen (R = 0.7). The data suggest that changes exist in the blood flow patterns in young patients with diabetes and neuropathy, even in the absence of lower limb ischemia.

Congenital perforations of the triangular fibrocartilage of the wrist

A cadaveric study of the triangular fibrocartilage of the wrist in the foetus and infant revealed a high incidence of congenital perforation. In the second half of the study, wrist arthrography in foetal and infant cadavers with crown-rump length of more than 20 cm followed by dissection of the wrist joints showed good correlation between the two. In 60 cadavers there were 11 with bilateral perforations and five had unilateral perforation. This gave a total of 27 perforations in 120 wrist joints studied.

Surgical treatment of symptomatic accessory navicular

The accessory navicular is a known cause of foot pain. When symptomatic and conservative measures have failed, surgical intervention may be required. Simple excision of the ossicle or the Kidner procedure with transplantation of tibialis posterior tendon to the undersurface of the navicular bone may be done. Eighteen patients with symptomatic accessory navicular were reviewed at the Singapore General Hospital, Department of Orthopaedic Surgery 'O' Unit. All 18 patients had foot pain and restriction of activities. Thirteen noticed a prominence on the medial side of the affected foot and 7 had difficulty with shoe fitting. Nine underwent simple excision of the ossicle while the other 9 had the Kidner procedure done. The average follow-up period was 3.1 years. Both the simple excision and the Kidner procedure were equally successful in relieving symptoms in 15 out of the 18 cases. The Kidner procedure did not confer any particular advantage over simple excision.

Effect of growth hormone on bone marrow grafts in fracture healing--an experimental study in rabbits

The lack of effectiveness of growth hormone in stimulating the healing of fresh fractures has been attributed to the presence of insufficient precursor osteogenic cells at the fracture site for the growth hormone to exert its influence. We tested the effect of growth hormone on healing in a rabbit non-union model after injection of autogenous marrow cells into the fracture gap. Two millilitres of bone marrow were injected percutaneously into 1 cm diaphyseal defects of rabbit radii. The test group was given subcutaneous human recombinant growth hormone at 0.3 IU/kg/day in divided doses for 2 weeks, while the control group received subcutaneous saline injections. Biomechanical, radiological and callus calcium content assessments were carried out at 4 and 7 weeks. There was significantly increased tensile strength and callus calcium concentration in the group given growth hormone both at 4 and 7 weeks but there was no significant difference in stiffness or in callus volume in the 2 groups. These data suggest that growth hormone can enhance the osteogenic potential of bone marrow as a graft in the treatment of fracture non-union.

Infection in diabetic patients with ankle fractures

Between January 1992 to June 1993, 93 ankle fractures underwent surgical treatment, of which, 10 patients were diabetic and 83 were non-diabetic. Infection occurred in 5 patients and all belonged to the diabetic group. The average follow-up period of the infected cases was 16.2 months. Wound infection occurred in 4 patients treated with open reduction and internal fixation. An infected pressure sore developed in the other patient treated initially in a below-knee cast for which arthrodesis of the ankle was performed. Infection was resistant to treatment in 2 patients and they ended up with below-knee amputation. Infection resolved in 3 patients with treatment. Of these, 1 developed neuropathic ankle joint and the other 2 achieved fracture union.

Failed back surgery syndrome: differentiating epidural fibrosis and recurrent disc prolapse with Gd-DTPA enhanced MRI

The failed back surgery syndrome (FBSS) is a difficult diagnostic problem. Two of the more common causes of FBSS are epidural fibrosis and recurrent disc prolapse. Forty-five gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) enhanced magnetic resonance (MR) scans were performed on 43 patients to evaluate the effectiveness in differentiating recurrent disc prolapse from epidural fibrosis. Operative findings were available in 11 patients and they confirmed the pre-operative radiological diagnosis of recurrent disc prolapse in 6, epidural fibrosis in 4 and facet joint hypertrophy in 1 patient. Although the number of surgically verified cases is small, our initial experience of 100% diagnostic accuracy reflects the tremendous potential of this investigative tool. Separating epidural fibrosis from recurrent disc prolapse is crucial as patients with the former are expected to benefit from further surgery. Patients with epidural fibrosis, on the other hand, generally do not gain relief from another operation.

Long-term results of free vascularized fibular graft. A clinical and radiographic evaluation

Seven patients who had free vascularized fibular grafts for bone defects > 6 cm (mean, 16.6 cm) were studied retrospectively. There were 5 cases of tumor, 1 pseudoarthrosis, and 1 chronic osteomyelitis. The average followup period was 9.2 years (range, 5.2-11.3 years). Of the 5 patients with grafts to the lower limb, 1 showed a 30% reduction in bone width as seen on anteroposterior radiographs, whereas 4 patients had increases ranging from 44% to 100% (average, 66%). There were 4 graft stress fractures, of which 1 developed eventual shortening of 2.5 cm. One graft had pseudoarthrosis involving the proximal graft-host junction that required secondary procedures with autogenous cancellous bone grafting, with eventual limb-length shortening of 5 cm. All other graft-recipient junctions healed primarily. The Functional Evaluation Score ranged from 60% to 100% of normal function (mean, 85%). Three patients were able to return to sports participation. Mild weakness of the extensor hallucis longus in the donor limb was observed in 5 patients. Two patients had mild loss of plantar flexion, and 4 had limitation of dorsiflexion affecting the ankle of the donor limb.

Social aspects in patients following proximal femoral fractures

Between January 1989 and December 1990, a study was conducted on the social aspects of 123 patients admitted to the Singapore General Hospital, Department of Orthopaedic O, with proximal femoral fractures. Twenty-three patients passed away, leaving 100 patients for review at 2 years post-fracture. Of the 20 social functions evaluated, less than 60% improvement was observed in 6 lower limb dependent activities. Before fracture, 82 patients were independent and 83 were ambulating without aids. After fracture, improvement occurred progressively and reached a plateau at 1 year with 62 (75.6%) patients independent and 41 (49.4%) patients ambulating normally. All the patients stayed in their own home before fracture and 90 (90%) patients returned to their home after their discharge. Of the 59 patients who were unable to ambulate without aids, 21 had visual problems, 9 had cerebrovascular accident and 8 had both problems.

Reactivation of rheumatoid arthritis in knees following total knee replacement

Between May 1985 and December 1990, 20 patients with rheumatoid arthritis had 34 total knee replacements performed. The mean follow-up period was 4.1 years and the range was 2.3 to 7.8 years. Five knees with total knee replacements (74.7%) in 4 patients were affected by activation of the rheumatoid process at an average postoperative interval of 28.6 months while the other 29 knees with total knee replacements (85.3%) remained in remission. Factors that appeared to have an influence on post total knee replacement rheumatoid activation included the activity of the disease preoperatively, and whether synovectomy was undertaken at surgery. Whether patella replacement was undertaken appeared not to have influenced postoperative reactivation of the disease. Using the Hospital for Special Surgery Knee score, total knee replacement in our cases gave excellent results. The complications included one knee with dislocation of the patella and another with infection.

Torsional performance of canine femoral osteotomy union

This study allows the establishment of a protocol for standardizing the technical methodology of canine surgery for mechanical testing. Twenty mongrels were divided into 4 groups of 5 dogs each. All dogs had one femur selected as the test bone and the contralateral as paired control. The test femur was osteotomized and plated. The dogs were sacrificed at 7, 10, 13 and 16 weeks according to their group designation to determine healing of the osteotomy. Both test and control femora were tested to fracture in torsion using a computerized torsion machine. Various mechanical parameters were studied with the age of osteotomy union. The study found that all bones sustained spiral fractures through the osteotomy site. The maximum torque capacity and stiffness increased with age of union. There is an apparent biphasic pattern in the remodelling process. Up till the 13th week there was a decline in the polar moment of inertia and a rise in the torsional stress with an increase in strength. We postulate that this was due to a reduction of the outer diameter of the external bridging callus. After the 13th week, there was a reversal in the process and the outer diameter of the callus increased. The findings provide a baseline reference for future studies involving osteotomy healing as is necessary in bone allograft reconstruction and bone transport.

De Quervain's tenosynovitis and ganglion over first dorsal extensor retinacular compartment

Between 1988 to 1991, 80 cases of de Quervain's disease were managed at the Department of Orthopaedic Surgery, Singapore General Hospital. Six of them had an associated ganglion over the first dorsal retinacular compartment. Five out of 6 cases had intracompartment injections of hydrocortisone and lignocaine but the treatment was not effective in relieving the pain of de Quervain's tenosynovitis. All 6 cases had excision of the ganglion and decompression of the first extensor compartment. All the lumps were found arising from the dorsal aspect of the retinaculum and no intracompartment extension of the ganglion was found.