Limited magnetic resonance imaging (MRI) and the occult hip fracture.

INTRODUCTION: Diagnosis of hip fracture is normally readily made from clinical evaluation and plain radiographs. Occasionally, clinical suspicion of fracture is not confirmed on plain X-rays. MATERIALS AND METHOD: Between January 2001 and March 2002, 422 patients were admitted to our department for post-traumatic hip pain. The diagnosis of hip fracture was unequivocally made in 365 patients (86%). Fifty-seven (14%) patients had a negative or equivocal radiograph. RESULTS: Limited magnetic resonance imaging (MRI) of the hip in this group of 57 patients confirmed that 8 (14%) sustained a femoral neck fracture, while 5 (9%) had an intertrochanteric fracture. In 19 patients (33%), some other pathology was found, mainly stable fractures of the femoral trochanters and pubic rami. Overall, 32 scans (56%) were positive and 25 (44%) were negative. Limited MRI detected patients with undisplaced hip fractures and identified them as candidates for surgery. CONCLUSION: The use of MRI in this specific and 'limited' way provides orthopaedic surgeons with a rapid, accurate and cost-effective diagnostic tool in this clinical scenario. Definitive diagnosis allows the correct management plan to be implemented early. We recommend that patients, who have significant hip pain following injury but indeterminate plain radiographs, undergo a limited MRI scan as a matter of routine.

To establish the normal bone mineral density reference database for the Singapore male.

INTRODUCTION: The objective of this study was to establish the normal bone mineral density (BMD) reference curve for the Asian Singapore male. MATERIALS AND METHODS: Three hundred and eighty-three male subjects were enrolled; comprising of 309 Chinese, 44 Malays and 30 Indians resident in Singapore. Bone mineral density was measured at the lumbar spine and left hip using a Hologic QDR 4500 Elite dual-energy X-ray absorptiometry (DXA) scanner. RESULTS: The mean peak BMD for the average lumbar spine and the neck of femur was 1.006 g/cm2 and 0.97 g/cm2, respectively. The mean peak BMD was taken at the 20 to 24 years age group at both the hip and spine based on data distribution for the various age groups. The BMD corresponding to -2.5 standard deviations from the peak adult value was 0.719 g/cm2 for the average lumbar spine and 0.655 g/cm2 for the neck of femur. CONCLUSION: This Asian male BMD reference database, which is 10% and 5% lower than corresponding values from the Caucasian reference database, allows for more accurate diagnosis of osteoporosis in Asian males.

The Ottawa Ankle Rules in Asia: validating a clinical decision rule for requesting X-rays in twisting ankle and foot injuries.

This was a study to determine if the Ottawa Ankle Rules (OAR) for requesting x-ray studies in twisting ankle and foot injuries are applicable in our Asian population. Four hundred ninety-four consecutive eligible patients presenting to the emergency department with twisting injuries about the ankle were examined by emergency physicians for clinical criteria requiring ankle and foot x-ray studies according to the OAR. Four hundred eighty-eight of these patients underwent x-ray studies that were interpreted by a radiologist. The sensitivity and specificity of the OAR for predicting the presence of fracture were calculated to be 0.9 and 0.34, respectively. When the rules were modified to cast a wider screening net, sensitivity improved to 0.99. We conclude that the OAR are not applicable to our population because of inadequate sensitivity, but when modified become acceptable and can reduce the number of x-ray studies requested by 28%.

Overview of imaging in rheumatologic diseases.

The role of radiology in rheumatologic diseases has for many years been confined to conventional radiography alone. The advances in medicine placed great demands on earlier and more accurate evaluation of these diseases. Conventional radiographs have been used as diagnostic aids and radiographic features and measurements are well established. However, the newer technologies, such as ultrasound, computed tomography and magnetic resonance imaging (MRI) have recently influenced accuracy of diagnosis and allowed for earlier detection and a more comprehensive evaluation of the results of therapy. One leading example is the significant role MRI plays in the early detection of avascular necrosis, especially of the hips. The clinical benefits of the newer modalities in radiology are being increasingly recognised and its full potential realised by both rheumatologists and radiologists.

The role of preoperative cervical spine X-rays in rheumatoid arthritis.

The cervical spine is frequently involved in rheumatoid arthritis and yet there exists no consensus on the need to screen for cervical spine subluxations preoperatively. We reviewed retrospectively 77 patients who underwent 132 operations under general or regional anaesthesia over a 44-month period. We found that while the majority of patients had received preoperative X-ray screening for cervical spine instability, a third of the X-ray examinations done had been inadequate. Many anaesthetists did not repeat cervical spine X-rays if there were previously performed views available. We showed that a complete X-ray examination of the cervical spine should include flexion and extension stress views in addition to frontal views of the odontoid and entire cervical spine. Anterior atlantoaxial subluxation was the most common subluxation encountered in our study population. The detection of cervical spine instability was found to significantly affect anaesthetic management, favouring techniques that avoided unprotected manipulations of the neck under anaesthesia.

Tendon xanthoma in familial hypercholesterolemia--a clinical and ultrasonographic study.

Familial hypercholesterolemia is a common autosomal dominant condition characterised by increased low density lipoprotein cholesterol, tendon xanthomas and premature atherosclerosis. Ultrasonography is the diagnostic tool of choice for the detection of tendon xanthomas in the Achilles tendon, demonstrated by the presence of hypoechoeic nodules or an increase in the antero-posterior diameter. It can also be used in screening and clinical follow-up of patients with familial hypercholesterolemia.

Diagnosis of deep venous thrombosis: accuracy of colour doppler ultrasound compared with venography.

Doppler ultrasound is becoming increasingly accepted as an accurate, non-invasive means of imaging in suspected deep venous thrombosis (DVT). Several studies done abroad have reported (combined) sensitivity of 95% and specificity of 98%. Locally, however, we have still been relying primarily on venography to diagnose lower limb DVT. We performed a prospective study to assess the accuracy of ultrasound compared to venography, in the local context. Forty-one limbs were studied by ultrasound within 24 hours of a venogram examination. We assessed grey-scale appearance, compressibility, presence or absence of flow, and flow characteristics. Seventeen venograms were positive for DVT, and ultrasound was positive in all seventeen cases. There were two false positive ultrasound examinations. Two cases of small localised thrombi in the superficial femoral vein only were accurately detected by ultrasound. One case of isolated calf thrombosis was also successfully diagnosed. Overall, sensitivity and specificity for detection of lower limb DVT was 100% and 91.7% respectively. Overall accuracy was 95.1%.