Noise levels during total hip arthroplasty: the silent health hazard.

BACKGROUND: While there is an enormous amount of data on various surgical aspects of total hip arthroplasty (THA), there is only limited literature on the health hazards incurred by the surgical team. Since THA surgery produces noise, exposure over a long period of time may lead to gradual hearing loss which is known as noise-induced hearing loss. METHODS: We investigated the noise levels during THA and compared it with the maximum allowed limits at the workplace in the United Kingdom. In collaboration with specialised audio engineers, we analysed the noise levels during various steps of performing 7 uncemented THA. RESULTS: The results showed that the noise levels were close to the allowed limits for a workplace in the UK. CONCLUSION: Hospitals and staff who work in orthopaedic operating theatres should be aware of this risk and precautions should be put in place.

The evaluation of articular cartilage lesions of the knee with a 3-Tesla magnet.

PURPOSE: This prospective study was performed to investigate whether 3-Tesla magnetic resonance imaging (MRI) provides an accurate assessment of the articular cartilage in clinical practice. METHODS: Forty patients with persistent knee pain and suspected cartilage lesions underwent 3-T MRI shortly before arthroscopy with the following sequences: axial/coronal/sagittal proton density-weighted turbo spin echo with spectral fat suppression, axial/sagittal 3-dimensional T1-weighted gradient echo with selective water excitation, and axial T2-weighted gradient echo (Intera 3.0T; Philips Medical Systems, Best, The Netherlands). Knee cartilage surfaces were divided into 6 regions; lesions detected on MRI were classified into stages I to IV and compared with the arthroscopic grading. RESULTS: For the 240 cartilage surfaces evaluated, the sensitivities, specificities, positive predictive values, and negative predictive values of 3-T MRI were 74%, 95%, 74%, and 95%, respectively, for the detection of grade IV lesions; 63%, 90%, 60%, and 91%, respectively, for grade III lesions; 62%, 90%, 57%, and 92%, respectively, for grade II lesions; and 29%, 95%, 39%, and 92%, respectively, for grade I lesions. CONCLUSIONS: In these preliminary clinical studies 3-T MRI provided convincing visualization of the hyaline cartilage with comparatively good diagnostic values. Nonetheless, it must be pointed out that the positive predictive values were low for all grades of lesions. Thus, when 3-T MRI suggests a cartilage defect, the probability that the arthroscopic finding corresponds exactly to the MRI result is between 39% and 74%. Therefore, the value of arthroscopy for a detailed assessment and grading of a cartilage disorder with regard to definitive planning of a therapeutic procedure cannot be replaced by 3-T MRI. LEVEL OF EVIDENCE: Level I, testing of previously developed diagnostic criteria in a series of consecutive patients with universally applied gold standard.

Pathological cervical fracture after spinal manipulation in a pregnant patient.

OBJECTIVE: To present the rare case of a displaced odontoid fracture after manipulative treatment. CLINICAL FEATURES: A 37-year-old, 15-week pregnant patient was referred with acute neck pain and a diffuse paravertebral swelling that started after cervical manipulation performed by her general medical practitioner 5 days before. Because of pregnancy, a cervical spine radiographic series was not obtained before treatment. Magnetic resonance imaging revealed a displaced odontoid fracture associated with a pathological process in the vertebral body of C2 and a paravertebral hematoma on the left side from C2 to C4. INTERVENTION AND OUTCOME: After initial halo vest immobilization, an anterior-posterior fusion of C1-C2 was performed. The histological analysis showed features of an aneurysmal bone cyst. The patient was discharged and had an undisturbed pregnancy and was without any neurological complications. CONCLUSIONS: Because of the weakening lesion in C2, the spinal manipulation most likely caused the displaced odontoid fracture. Special imaging should be performed, preferably with magnetic resonance imaging, when a patient experiences significant new symptoms after cervical manipulation.

Visualisation of the brace effect on the spinal profile in idiopathic scoliosis.

We studied the brace effect on the spinal profile in idiopathic scoliosis, using a MR procedure visualising the complete scoliotic spine in any vertical plane, while rotating it 180 degrees on the longitudinal axis of the patient. Thirty-eight female patients (mean age, 14.5 years) were included in the study. Inclusion criteria were an idiopathic scoliosis, a Cobb angle greater than 20 degrees , age of 10-17 years and bracing with a Cheneau brace. The brace effect was studied in 38 thoracic curves. The MR examinations were carried out in direct sequences, with and without brace. A reconstruction algorithm allows visualising the whole spine in vertical projections, with rotational steps of 2 degrees , from -90 degrees to 90 degrees , referred to as MR animation. In various vertical MR projections, the changes of the curves were evaluated by measuring the Cobb angle. Additionally, a translation angle of the apical vertebra was determined, representing the lateral deviation of the apical vertebra from a defined midline. Testing the reproducibility of the Cobb angles, the standard deviation of the intra-individual differences was 1.7 degrees and of the inter-individual differences, 2.1 degrees . For the translation angles, the standard deviation of the intra-individual differences was 0.8 degrees and of the inter-individual differences, 0.9 degrees . With brace the mean Cobb angle of the thoracic curves was significantly reduced in the various vertical MR projections. The mean translation angle was also reduced. MR analysis showed that the brace effect is a translation process, straightening the profile of the scoliotic spine in all vertical planes. MR animation allows visualising the brace effect on the spine in scoliosis based on a 3D data set, without additional radiation exposure. It showed the straightening effect of the brace leading to a flattening of the sagittal spinal profile.

FDG-PET findings of vertebral compression fractures in osteoporosis: preliminary results.

The aim of this study was to evaluate FDG-PET findings in patients with osteoporosis or preclinical osteoporosis and acute vertebral compression fractures in order to determine whether FDG-PET has a value for distinction of pathological from osteoporotic vertebral fractures. 17 patients with a spontaneous compression fracture of the spine were evaluated by bone scanning with Tc-99m HDP, positron emission tomography with fluorine-18 deoxyglucose (FDG-PET) and magnetic resonance imaging (MRI). Osteoporosis had been established in all cases by X-ray and osteodensitometry. PET and bone scan images were scored independently from 0 (no pathological uptake) to 4 (definitive pathological uptake) by two blinded nuclear medicine physicians. The results of the blinded scoring were compared to MRI findings which served as gold standard. In 13 out of 17 patients, MRI demonstrated a vertebral fracture generating from osteoporosis. In 12 of these 13 cases, PET scans were scored with 0 or 1 and categorized as true negative. Standard uptake values (SUV) ranged between 1.1 and 2.4. In one of the 13 patients, PET was interpreted false positive with an uptake score of 3 (SUV = 2.9). Of the 17 patients, MRI revealed a pathological fracture caused by spondylodiscitis in three patients and by plasmacytoma in one patient. In these patients, all PET scans were highly positive with a score of 3 and 4 and SUV values between 3.8 to 9.8. The bone scans of all 17 patients were positive with scores of 3 or 4 but a differentiation between osteoporotic and pathological fractures was not possible. Our preliminary results indicate that acute vertebral fractures that originated from osteoporosis or preclinical osteoporosis tend to have no pathologically increased FDG uptake. Since a high FDG uptake is characteristic for malignant and inflammatory processes, use of FDG-PET may have potential value for differentiation between osteoporotic and pathological vertebral fractures.