Pre-operative Halo-Pelvic Traction for Neurofibromatosis Patients with Severe Proximal Thoracic Spinal Deformity: Indications and Early Treatment Outcome

Introduction:

To report the indications and early treatment outcomes of pre-operative halo-pelvic traction in patients with neurofibromatosis associated with severe proximal thoracic (PT) spinal deformity.

Materials and methods:

We reviewed four patients with neurofibromatosis with severe PT spinal deformity. Case 1, a 16-year-old male presented with severe PT kyphoscoliosis (scoliosis: 89°, kyphosis: 124°) and thoracic myelopathy. Case 2 was a 14-year-old, skeletally immature male who presented with a PT lordoscoliosis (scoliosis: 85°). Case 3, a 13-year-old male, presented with severe PT kyphoscoliosis (scoliosis: 100°, kyphosis: 95°). Case 4, a 35-year-old gentleman, presented with severe PT kyphoscoliosis (scoliosis: 113°, kyphosis: 103°) and thoracic myelopathy. All patients underwent pre-operative halo-pelvic traction. After a period of traction, all patients underwent posterior spinal fusion (PSF) with autologous bone grafts (local and fibula bone grafts) and recombinant human bone morphogenetic protein-2 (rhBMP-2).

Results:

Both patients with thoracic myelopathy regained near normal neurological status after halo-pelvic traction. Following traction, the scoliosis correction rate (CR) ranged from 18.0% to 38.9%, while the kyphosis CR ranged from 14.6% to 37.1%. Following PSF, the scoliosis CR ranged from 24.0% to 58.8%, while the kyphosis CR ranged from 29.1% to 47.4%. The total distraction ranged from 50-70mm. Duration of distraction ranged from 26-95 days. The most common complication encountered during halo-pelvic traction was pin-related e.g. pin tract infection, pin loosening and migration, osteomyelitis, and halo-pelvic strut breakage. No patients had cranial nerve palsies or neurological worsening.

Conclusion:

Pre-operative correction of severe PT spinal deformities could be performed safely and effectively with the halo-pelvic device prior to definitive surgery.

Minimally Invasive versus Conventional Open Surgery for Fixation of Spinal Fracture in Ankylosed Spine

Introduction:

This was a retrospective study aimed to investigate the perioperative outcomes of long construct minimally invasive spinal stabilisation (MISt) using percutaneous pedicle screws (PPS) versus conventional open spinal surgery in the treatment of spinal fracture in ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH).

Material and Methods:

Twenty-one patients with AS and DISH who were surgically treated between 2009 and 2017 were recruited. Outcomes of interest included operative time, intra-operative blood loss, complications, duration of hospital stay and fracture union rate.

Results:

Mean age was 69.2 ± 9.9 years. Seven patients had AS and 14 patients had DISH. 17 patients sustained AO type B3 fracture and 4 patients had type B1 fracture. Spinal trauma among these patients mostly involved thoracic spine (61.9%), followed by lumbar (28.6%) and cervical spine (9.5%). MISt using PPS was performed in 14 patients (66.7%) whereas open surgery in 7 patients (33.3%). Mean number of instrumentation level was 7.9 ± 1.6. Mean operative time in MISt and open group was 179.3 ± 42.3 minutes and 253.6 ± 98.7 minutes, respectively (p=0.028). Mean intra-operative blood loss in MISt and open group was 185.7 ± 86.4ml and 885.7 ± 338.8ml, respectively (p<0.001). Complications and union rate were comparable between both groups.

Conclusion:

MISt using PPS lowers the operative time and reduces intra-operative blood loss in vertebral fractures in ankylosed disorders. However, it does not reduce the perioperative complication rate due to the premorbid status of the patients. There was no significant difference in the union rate between MISt and open surgery.

Delayed Post-operative Spinal Epidural Haematoma after Posterior Spinal Surgery: Report of Two Cases

Delayed post-operative spinal epidural haematoma (DPSEH) is diagnosed when the onset of symptoms is more than three days from the index surgery. DPSEH is a rare but serious complication of spinal surgery. Missed diagnosis will result in irreversible neurological deficit which may lead to permanent disabilities. We report two cases of DPSEH who presented with worsening neurological deficit four days after the index surgery. Magnetic resonance imaging (MRI) showed the presence of an epidural haematoma compressing the spinal cord. Surgical evacuation of haematoma were performed for both patients. Both patients experienced neurological improvement. Surgeons should have high index of suspicion to identify delayed onset of spinal epidural haematoma (SEH) and timely intervention should be taken to avoid irreversible neurological damage.

The anatomical locations of postoperative pain and their recovery trajectories following Posterior Spinal Fusion (PSF) surgery in Adolescent Idiopathic Scoliosis (AIS) patients

INTRODUCTION

This study looked into the different anatomical locations of pain and their trajectories within the first two weeks after Posterior Spinal Fusion (PSF) surgery for Adolescent Idiopathic Scoliosis (AIS).

METHODS

We prospectively recruited patients with Adolescent Idiopathic Scoliosis (AIS) scheduled for PSF surgery. The anatomical locations of pain were divided into four: (1) surgical wound pain; (2) shoulder pain; (3) neck pain; and (4) low back pain. The anatomical locations of pain were charted using the visual analogue pain score at intervals of 12, 24, 36, 48 hours; and from day-3 to -14. Patient-controlled analgesia (morphine), use of celecoxib capsules, acetaminophen tablets and oxycodone hydrochloride capsule consumption were recorded.

RESULTS

A total of 40 patients were recruited. Patients complained of surgical wound pain score of 6.2±2.1 after surgery. This subsequently reduced to 4.2±2.0 by day-4, and to 2.4±1.3 by day-7. Shoulder pain scores of symptomatic patients peaked to 4.2±2.7 at 24 hours and 36 hours which then reduced to 1.8±1.1 by day-8. Neck pain scores of symptomatic patients reduced from 4.2±1.9 at 12 hours to 1.8±1.1 by day-4. Low back pain scores of symptomatic patients reduced from 5.3±2.3 at 12 hours to 1.8±1.1 by day- 12.

CONCLUSIONS

Despite the presence of different anatomical locations of pain after surgery, surgical wound was the most significant pain and other anatomical locations of pain were generally mild. Surgical wound pain reduced to a tolerable level by day-4 when patients can then be comfortably discharged. This finding provides useful information for clinicians, patients and their caregivers.

The Clinical Effectiveness of School Screening Programme for Idiopathic Scoliosis in Malaysia

Introduction

There is no large population size study on school screening for scoliosis in Malaysia. This study is aimed to determine the prevalence rate and positive predictive value (PPV) of screening programme for adolescent idiopathic scoliosis.

Materials and Methods

A total of 8966 voluntary school students aged 13-15 years old were recruited for scoliosis screening. Screening was done by measuring the angle of trunk rotation (ATR) on forward bending test (FBT) using a scoliometer. ATR of 5 degrees or more was considered positive. Positively screened students had standard radiographs done for measurement of the Cobb angle. Cobb angle of >10° was used to diagnose scoliosis. The percentage of radiological assessment referral, prevalence rate and PPV of scoliosis were then calculated.

Results

Percentage of radiological assessment referral (ATR >5°) was 4.2% (182/4381) for male and 5.0% (228/4585) for female. Only 38.0% of those with ATR >5° presented for further radiological assessment. The adjusted prevalence rate was 2.55% for Cobb angle >10°, 0.59% for >20° and 0.12% for >40°. The PPV is 55.8% for Cobb angle >10°, 12.8% for >20° and 2.6% for > 40°.

Conclusions

This is the largest study of school scoliosis screening in Malaysia. The prevalence rate of scoliosis was 2.55%. The positive predictive value was 55.8%, which is adequate to suggest that the school scoliosis screening programme did play a role in early detection of scoliosis. However, a cost effectiveness analysis will be needed to firmly determine its efficacy.

Posterior spinal instrumented fusion for idiopathic scoliosis in patients with multisystemic neurodegenerative disorder: a report of two cases

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke (MELAS) syndrome is a progressive multisystemic neurodegenerative disorder. MELAS syndrome impairs oxidative phosphorylation and predisposes patients to lactic acidosis, particularly under metabolic stress. We report 2 siblings with MELAS-associated idiopathic scoliosis who underwent posterior spinal instrumented fusion with measures taken to minimise anaesthetic and surgical stress, blood loss, and operating time.

Prevalence of Psychiatric Morbidity in Chinese Subjects with Knee Osteoarthritis in a Hong Kong Orthopaedic Clinic

OBJECTIVES

To identify the prevalence and associated factors of psychiatric morbidities and to evaluate the effectiveness of the Hospital Anxiety and Depression Scale (HADS) in screening for psychiatric morbidity in patients with knee osteoarthritis in a local orthopaedic clinic.

METHODS

A cross-sectional study was conducted from October 2013 to June 2014 to examine patients with knee osteoarthritis at a specialist orthopaedic clinic. They were evaluated for psychiatric diagnoses using the Structured Clinical Interview for the DSM-IV Axis I Disorders (SCID-I). Socio-demographic and clinical characteristics were compared between patients with and without psychiatric morbidity. Patients were also assessed using the HADS with accuracy compared with the psychiatric diagnoses made by the SCID-I.

RESULTS

Of the 115 patients, 39% had current psychiatric disorders. Logistic regression analysis revealed that limitation of physical activity, perceived absence of confidant, a history of psychiatric illness, and follow-up in orthopaedic clinic for ≥ 5 years were independent factors associated with psychiatric disorders.

CONCLUSIONS

The prevalence of psychiatric morbidity in patients with knee osteoarthritis was significant. Recognition of independent associated factors can aid in early identification and intervention in patients who are at risk of developing psychiatric morbidity. The HADS is a useful means to screen for psychiatric morbidity in these patients.

Improved Accuracy and Safety of Intracorporeal Transpedicular Bone Grafting - using Contrast Impregnated Bone: A Case Report

A method of transpedicular bone grafting using contrast impregnated bone to improve the visualization of bone graft on the image intensifier is reported. A - 36-year old man who had sustained traumatic burst fracture of T12 vertebra, with Load-Sharing Classification (LSC) score of 8, was treated with posterior short segment fusion from T11 to L1 with transpedicular bone graft of T12 vertebra. We were able to correct the kyphotic end plate angle (EPA) from 19º to 1.4º. Anterior bone graft augmentation was achieved with contrast enhaced transpedicular bone grafts. At six months follow up, CT scan showed good bony integration of the anterior column with EPA of 4.5º and two years later, radiographs showed EPA of 7.6 º.

In-situ hybridization of calcium silicate and hydroxyapatite-gelatin nanocomposites enhances physical property and in vitro osteogenesis

Low mechanical strengths and inadequate bioactive material-tissue interactions of current synthetic materials limit their clinical applications in bone regeneration. Here, we demonstrate gelatin modified siloxane-calcium silicate (GEMOSIL-CS), a nanocomposite made of gelatinous hydroxyapatite with in situ pozzolanic formation of calcium silicate (CS) interacting among gelatin, silica and Calcium Hydroxide (Ca(OH)2). It is shown the formation of CS matrices, which chemically bonds to the gelatinous hydroxyapatite, provided hygroscopic reinforcement mechanism and promoted both in vitro and in vivo osteogenic properties of GEMOSIL-CS. The formation of CS was identified by Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction. The interfacial bindings within nanocomposites were studied by FTIR and thermogravimetric analysis. Both gelatin and CS have been found critical to the structure integrity and mechanical strengths (93 MPa in compressive strength and 58.9 MPa in biaxial strength). The GEMOSIL-CS was biocompatible and osteoconductive as result of type I collagen secretion and mineralized nodule formation from MC3T3 osteoblasts. SEM and TEM indicated the secretion of collagen fibers and mineral particles as the evidence of mineralization in the early stage of osteogenic differentiation. In vivo bone formation capability was performed by implanting GEMOSIL-CS into rat calvarial defects for 12 weeks and the result showed comparable new bone formation between GEMOSIL-CS group (20%) and the control (20.19%). The major advantage of GEMOSIL-CS composites is in situ self-hardening in ambient or aqueous environment at room temperature providing a simple, fast and cheap method to produce porous scaffolds.

Selective growth of silver nanoparticle arrays on nanoimprinted sol-gel silica patterns

Selective growth of silver nanoparticles on ~100 nm thick silica patterns produced by nanoimprint method has been successfully demonstrated using either (1) thermo-induced reduction or (2) room temperature electroless deposition (ELD) without removing the ~25 nm thick residual layer left by nanoimprint process. This selectivity was achieved by silane additive, (3-mercaptopropyl)trimethoxysilane (3-MTS), which was added to the silica matrix to control nucleation and growth of silver. The presence of silver nanoparticles was confirmed by EDX and UV-vis spectrum, and the density, distribution, and size of silver particles were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Silica film heat-treated between 400 and 600 °C resulted in silver particles of 100-120 nm diameter with a linear density of 2.63-3.36 μm(-1), while the film treated by room temperature ELD produced silver particles of 67 nm diameter with a linear density of 5.65 μm(-1). The selective growth ratio based on particle density on pattern area versus residual layer is 12.92 and 20.31 for high- and room-temperature processes, respectively, whereas the samples without 3-MTS shows low selective growth ratio of 1.22 and 1.04. These results prove that both approaches are fast and effective, suggesting their potential to produce other type of nanoparticle arrays directly on nanoimprinted patterns.

An Investigation of Siloxane Cross-linked Hydroxyapatite-Gelatin/Copolymer Composites for Potential Orthopedic Applications()

Causes of bone deficiency are numerous, but biomimetic alloplastic grafts provide an alternative to repair tissue naturally. Previously, a hydroxyapatite-gelatin modified siloxane (HAp-Gemosil) composite was prepared by cross-linking (N, N'-bis[(3-trimethoxysilyl)propyl]ethylene diamine (enTMOS) around the HAp-Gel nanocomposite particles, to mimic the natural composition and properties of bone. However, the tensile strength remained too low for many orthopedic applications. It was hypothesized that incorporating a polymer chain into the composite could help improve long range interaction. Furthermore, designing this polymer to interact with the enTMOS siloxane cross-linked matrix would provide improved adhesion between the polymer and the ceramic composite, and improve mechanical properties. To this end, copolymers of L-Lactide (LLA), and a novel alkyne derivatized trimethylene carbonate, propargyl carbonate (PC), were synthesized. Incorporation of PC during copolymerization affects properties of copolymers such as molecular weight, T(g), and % PC incorporation. More importantly, PC monomers bear a synthetic handle, allowing copolymers to undergo post-polymerization functionalization with graft monomers to specifically tailor the properties of the final composite. For our investigation, P(LLA-co-PC) copolymers were functionalized by an azido-silane (AS) via copper catalyzed azide-alkyne cycloaddition (CuAAC) through terminal alkyne on PC monomers. The new functionalized polymer, P(LLA-co-PC)(AS) was blended with HAp-Gemosil, with the azido-silane linking the copolymer to the silsesquioxane matrix within the final composite.These HAp-Gemosil/P(LLA-co-PC)(AS) composites were subjected to mechanical and biological testing, and the results were compared with those from the HAp-Gemosil composites. This study revealed that incorporating a cross-linkable polymer served to increase the flexural strength of the composite by 50%, while maintaining the biocompatibility of HAp-Gemosil ceramics.

Direct scaffolding of biomimetic hydroxyapatite-gelatin nanocomposites using aminosilane cross-linker for bone regeneration

Hydroxyapatite-gelatin modified siloxane (GEMOSIL) nanocomposite was developed by coating, kneading and hardening processes to provide formable scaffolding for alloplastic graft applications. The present study aims to characterize scaffolding formability and mechanical properties of GEMOSIL, and to test the in vitro and in vivo biocompatibility of GEMOSIL. Buffer Solution initiated formable paste followed by the sol-gel reaction led to a final hardened composite. Results showed the adequate coating of aminosilane, 11-19 wt%, affected the cohesiveness of the powders and the final compressive strength (69 MPa) of the composite. TGA and TEM results showed the effective aminosilane coating that preserves hydroxyapatite-gelatin nanocrystals from damage. Both GEMOSIL with and without titania increased the mineralization of preosteoblasts in vitro. Only did titania additives revealed good in vivo bone formation in rat calvarium defects. The scaffolding formability, due to cohesive bonding among GEMOSIL particles, could be further refined to fulfill the complicated scaffold processes.

The efficacy and safety of intramuscular injections of methylcobalamin in patients with chronic nonspecific low back pain: a randomised controlled trial

INTRODUCTION

Chronic, nonspecific low back pain is a difficult ailment to treat and poses an economic burden in terms of medical expenses and productivity loss. The aim of this study was to determine the efficacy and safety of intramuscular metylcobalamin in the treatment of chronic nonspecific low back pain.

METHODS

This was a double-blinded, randomised, controlled experimental study. 60 patients were assigned to either the methylcobalamin group or the placebo group. The former received intramuscular injections of 500 mcg parenteral methylcobalamin in 1 ml solution three times a week for two weeks, and the placebo group received 1 ml normal saline. Patients were assessed with Oswestry Disability Index questionnaire Version 2.0 and Visual Analogue Scale pain score. They were scored before commencement of the injections and at two months interval.

RESULTS

Of the 60 patients, 27 received the placebo injections and 33 were given methylcobalamin injections. A total of 58 patients were available for review at two months (placebo: n is 26; methylcobalamin: n is 32). There was a significant improvement in the Oswestry Disability Index and Visual Analogue Scale pain scores in the methylcobalamin group as compared with the placebo group (p-value less than 0.05). Only minor adverse reactions such as pain and haematoma at the injection sites were reported by some patients.

CONCLUSION

Intramuscular methylcobalamin is both an effective and safe method of treatment for patients with nonspecific low back pain, both singly or in combination with other forms of treatment.

Spontaneous deposition of gold nanoparticle nanocomposite on polymer surfaces through sol-gel chemistry

A aminosilica nanocomposite layer containing a monolayer of gold nanoparticles (d = 18-22 nm) with a well-defined spacing was spontaneously deposited on an unmodified polystyrene surface via a sol-gel reaction when the reduction reaction was carried out under 1:8 molar ratio (gold(III):aminosilane). The amount of aminosilica and spacing between gold nanoparticles were found to be a function of the aminosilane:water molar ratio, which contributes to the plasmonic property of the films with its absorption wavelength ranging between 701 and 548 nm. Furthermore, the nanocomposite film that consists of a monolayer of nanoparticles in aminosilica has also been deposited on the surface of polystyrene beads. This core-shell structure was found capable of storing electrostatic charges and forming a well-separated 2D array.

Aminosilane as an effective binder for hydroxyapatite-gelatin nanocomposites

Aminosilane has been explored as an alternative chemical linker to facilitate the binding and solidification of hydroxyapatite-gelatin nanocomposite at room temperature, which was synthesized using co-precipitation method in the presence of gelatin. This aminosilane treatment was found effective at low concentration (~25 μL/mL) and the solidification and dehydration of hydroxyapatite-gelatin slurry completes within hours depending on the amount of aminosilane. The resulting sample exhibits compressive strength of 133 MPa, about 40% higher than glutaraldehyde treated samples, and shows good biocompatibility based on cell adhesion, proliferation, alkaline phosphate synthesis, and mineralization studies.

Identification of cervical neoplasia using a simulation of human vision

OBJECTIVE

To determine whether a computer simulation of human vision could detect and discriminate cervical cancer precursors and cancer from normal epithelium.

METHODS

The Georgia Tech Vision (GTV) system was trained to recognize normal and abnormal cervical features. GTV then assessed a new series of images to determine whether it could detect and diagnose cervical neoplasia without any a priori information about the images.

RESULTS

After training on one set and testing on another set of images, GTV demonstrated 100% sensitivity and 98% specificity to detect cervical intraepithelial neoplasia 3 (CIN3). GTV also had 88% sensitivity and 93% specificity to detect cervical cancer following training on one set and testing on another set of digitized cervical colposcopic images.

CONCLUSION

This study demonstrated that GTV can detect CIN3 and cancer from digitized cervical colposcopic images. Furthermore, GTV could discriminate cervical cancer precursors and cancer from normal cervical epithelium, including immature metaplasia.

Chronic recurrent multifocal osteomyelitis of the first metatarsal bone: a case report

We report a case of chronic recurrent multifocal osteomyelitis in a 9-year-old girl. She presented with a 9-month history of gradually worsening pain and swelling in her left foot. Non-steroidal anti-inflammatory drugs were prescribed but the symptoms persisted. She underwent curettage through a small oval corticotomy window on the first metatarsal bone. The pain and swelling improved promptly and she was able to walk without pain 2 weeks later. Curettage enabled rapid symptomatic relief and induced remission, with little risk of complications.

Is the femoral neck geometry adequate for placement of the proximal femoral nail in the Malaysian population? A review of 100 cases

Issues that had been encountered during proximal femoral fracture fixation using proximal femoral nail include (i) the adequacy of the femoral neck width in the local population and (ii) the potential difficulty encountered during fixation in certain prefixed angles as determined by the implant. This was a retrospective, descriptive study evaluating the anterior-posterior pelvic radiographs of 100 consecutive patients, from January to August 2007, managed at University Malaya Medical Centre, Kuala Lumpur. The femoral neck width in the population studied was adequate for placement of femoral neck screw and anti-rotation pin or hip pin using the proximal femoral nail implant. (mean = 34.0 +/- 3.7 mm, min = 24.6 mm). There was no significant difference between the working area using an implant angled at 130 degrees or 135 degrees (P = 0.91). Both femoral neck width and neck shaft angle of the Malaysian population studied were not a factor influencing the placement of femoral neck lag screws and anti-rotation pin.

Association of tri-nucleotide (CAG and GGC) repeat polymorphism of androgen receptor gene in Taiwanese women with refractory or remission rheumatoid arthritis

We investigated the relationship between CAG and GGC repeat polymorphism of the androgen receptor (AR) gene and rheumatoid arthritis (RA) in female patients with different disease subtypes. This case-control study enrolled 215 women in three groups: RA patients refractory to standardized therapy (n = 51); RA patients at complete remission phase (n = 60); and healthy controls (n = 104). CAG and GGC repeat lengths were determined by automated fluorescence-based DNA fragment-sizing method. Demographic data, allele lengths, allele distribution, and zygosity status of CAG/GGC repeats were assessed for the three groups. Refractory RA patients tend to have a significantly younger onset age of RA and more elevated erythrocyte sedimentation rates than do remission RA patients. Mean and median values of CAG and GGC repeat lengths are similar in both RA and control patients. However, RA patients harboring any long CAG alleles with more than 23 repeats had an increased risk of a refractory course, whereas differences in risk were not observed between these patients and RA subtypes harboring any long GGC alleles with more than 16 repeats. In addition, the homozygous frequency of CAG but not GGC alleles was lower in refractory RA than in remission RA patients or in controls (p = 0.042). Neither CAG nor GGC repeat lengths had a significant relationship with rheumatoid factor reactivity. Our observations indicate that short CAG repeats of the AR gene with higher transactivation activity may have protective effects against refractory course of RA development and that homozygous frequency of CAG alleles may be involved in the disease remission subtype. In contrast, lack of association of GGC polymorphism and RA was also observed. Together, these data imply that CAG but not GGC alleles in the AR polymorphism may play an important role in modulating the disease pattern of RA among Taiwanese women.

Prophylactic antibiotics in orthopaedic surgery: guidelines and practice

The national clinical practice guideline has recommended that prophylactic antibiotic be given in orthopaedic surgery involving joint replacements and internal fixation of fractures. The aim of this study is to assess the current antibiotics prophylaxis practice in a state level hospital. One hundred and three patients (68 males, 35 females; mean age 41.6 +/- 22.2 years) undergoing internal fixation for closed fractures and joint replacement surgery were included in this prospective study. The choice of pre and post-operative antibiotics, their dosages and duration of administration were recorded. The pre-operative antibiotics were only deemed to have been given if it was documented in the case notes and in the case of post-operative antibiotics if it was signed on the drug chart. Eighty eight percent were given pre-operative prophylactic antibiotics and 92% were given post-operative antibiotics. For patients undergoing internal fixation of fractures, the most commonly used antibiotic for both pre and post-op is intravenous cefuroxime. For joint replacement surgery, the most commonly used antibiotic is intravenous cefoperazone. The duration or number of doses of post-operative antibiotics was highly variable. It was not stated in 56% of the post-operative instructions. Post-operative antibiotic was ordered for 48 hours or longer in 10%. In conclusion, prophylactic antibiotics appear to be widely practised. The first line antibiotics as recommended by the present guideline were not given in any of the patients. Second generation followed by third generation cephalosporins are the most popular antibiotics, with a trend towards using third generation cephalosporins in arthroplasty patients. Single dose prophylaxis was rarely practised.

Microbial contamination of femoral head allografts

OBJECTIVE

To study the incidence of microbial contamination at the bone bank of the United Christian Hospital. DESIGN. Retrospective study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

A total of 151 patients (33 men and 118 women) who underwent hip arthroplasty surgery and from whom femoral head allografts were retrieved between January 1994 and March 2000; and 81 patients in whom allografts were implanted.

MAIN OUTCOME MEASURES

Bone biopsies were taken from the femoral head and used to detect any microbial contamination that might have occurred during removal and after storage. The rates of infection among recipients and donors were also assessed.

RESULTS

Of the 151 allografts, 94 non-contaminated allografts were implanted by the end of the study. Fourteen (9.3%) heads showed positive culture results after retrieval and were discarded. Four (4.3%) of the 94 stored allografts that were implanted tested positive for microbial growth, but the recipients of these allografts did not develop any clinical infection. Three (3.2%) had wound infections after implantation of the stored allografts although the grafts had previously been tested negative for any microbial contamination.

CONCLUSION

Our centre has a low allograft contamination rate. The wound infection rate among recipients was also low. The culture of a bone biopsy sample is a reliable method to detect contamination of bone grafts. However, the contamination rate among stored allografts should prompt orthopaedics departments to review allograft handling procedures, so as to minimise the chance of contamination.

Emergency department D-dimer testing

Since the early 1980s, much attention has been paid to the development of a biochemical marker for venous thromboembolism. D-dimers are derivatives of fibrinolysis and recently have been touted as a means of screening for thromboemoblism. We review the physiologic, pathologic, and chemical bases for this new test, and outline the specific D-dimer assays currently available. We conclude with a discussion of the clinical utility of D-dimer in the evaluation of patients with venous thromboembolism.

Hepatoatrial anastomosis and tricuspid valve replacement in Budd-Chiari syndrome 8

The rare complication of tricuspid valve stenosis due to displacement of a peritoneovenous shunt catheter developed in a patient with Budd-Chiari syndrome. Surgical management included shunt removal and tricuspid valve replacement combined with hepatoatrial anastomosis. The tricuspid valve was replaced with a bioprosthesis, and liver resection opened the stenotic confluence of the hepatic veins. The right atrium was sutured to the liver capsule, thereby restoring physiologic hepatic venous blood flow.