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| ==Introduction==
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| The indications for imaging the elbow in the setting of acute elbow pain do not appear to have been assessed formally. A MEDLINE search of all English language articles using the search terms “elbow” and “pain” for the period 1966 to early 1998 failed to detect any articles addressing the utility, sensitivity or specificity of any investigations in the setting of acute elbow pain.
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| The cardinal role of medical imaging of the elbow will be for the detection of fractures or of rare, exotic, or occult conditions, particular those of bone, such as osteomyelitis, tumours, ostenecrosis, and osteochondritis. In the course of a responsible and systematic history and examination, the routes to medical imaging are limited.
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| A history of injury raises the possibility of fracture. The grounds for suspecting a fracture of the elbow have not been formally assessed, but from first principles, reasonable grounds would be:
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| * significant force applied to the elbow,
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| * immediate loss of function,
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| * bony swelling or marked soft tissue swelling, and
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| * bony tenderness.
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| In the presence of one or more of these features, a plain X-ray would be indicated.
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| Bony swelling or bone tenderness raises the possibility of intra-osseous pathology, and should be an indication for plain X-ray, and bone scan subsequently if plain radiographs are not diagnostic.
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| Any risk factor for osteoporosis or pathological fracture should be an indication for plain X-ray.
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| Conditions such as osteonecrosis or osteochondritis may exhibit no clinical signs, other than perhaps reproduction of pain upon compression the joint, or upon pronation/supination. However, there is no justification for ordering medical imaging as a screening test for these rare conditions in any or every patient with elbow pain. These conditions should be considered upon, and only upon, finding no signs of any other condition. Plain X-rays should suffice in the first instance.
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| If stressing the elbow in varus or valgus produces abnormal movement, radiography is indicated to determine the degree and cause of hypermobility.
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| Imaging is not indicated in any other condition of the elbow.
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| The commonest source of acute musculoskeletal elbow pain is lateral epicondylitis. This is a purely clinical diagnosis. It therefore follows that the criterion standard for the study of any diagnostic test is the clinical examination. Those studies that have considered the imaging of lateral epicondylitis have compared the modality of interest to used the clinical diagnosis, and therefore cannot be demonstrated to have any benefit over the clinical assessment. Even a test displaying a 100% sensitivity and 100% specificity would be no better than the clinical diagnosis. The role of investigations in the setting of suspected lateral epicondylitis is therefore the study of the phenomena surrounding the diagnosis itself rather than adding anything to the diagnostic process.
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| The findings on Magnetic Resonance Imaging (MRI) scans of seven patients with chronic - rather than acute - lateral epicondylitis has been reported 1. The authors noted increased signal on STIR sequences (sensitive to water content and suppressive of fat signal) in the anconeus muscle on the symptomatic side compared to the other (control) side in the same patient. The significance of this is not known. The study patients had had their symptoms from 2 months to 10 years, so are not strictly acute, and there is no evidence that these findings made any difference to their management.
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| Thermographic abnormalities were noted by Binder et al 2, who found that 53 of 56 patients with clinical lateral epicondylitis had a hot focus over the affected elbows compared with 3 of 120 age and sex matched controls. An Australian study has considered both infrared thermography and isotopic bone scanning in twenty six patients with tennis elbow 3. The diagnosis was again made clinically, on the basis of point tenderness over the lateral epicondyle and pain on resisted wrist extension. Nine patients had bilateral symptoms. Hot foci were observed over the affected lateral epicondyle on thermography in all but one symptomatic elbow. Abnormal increased uptake in radioisotope tracer was found in 20 of the 35 affected elbows.
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| MEDLINE searches using the terms “Biceps” and “Tendonitis”, “Triceps” and “Tendonitis” and “Medial Epicondylitis” failed to reveal any studies considering imaging in these diagnoses.
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| ==Recommendations==
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| The use of medical imaging in the assessment of acute elbow pain should be guided by history and clinical signs.
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| Plain x-rays are indicated
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| when there is a history of trauma consistent with the possibility of fracture or dislocation;
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| in the face of bone tenderness in patients in whom no other diagnosis is apparent, in order to screen for intra-osseous pathology;
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| in patients in whom compression of the joint reproduces their pain, in order to screen for intra-articular pathology;
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| in the face of risk factors for osteoporosis and pathological fractures;
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| in the presence of abnormal movements of the elbow.
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| For lesions such as lateral epicondylitis, medial epicondylitis and biceps and triceps tendonitis, there is no indication for imaging studies as these remain purely clinical diagnoses.
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| ==References== | | ==References== |
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| 1. Coel M, Yamada CY, Ko J. MR imaging of patients with lateral epicondylitis of the elbow (tennis elbow): importance of increased signal of the anconeus muscle. AJR 1993; 161:1019-1021.
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| 2. Binder A, Parr G, Page Thomas P, Hazleman BL. A clinical and thermographic study of lateral epicondylitis. Br J Rheumatol 1983; 22:77-81.
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| 3. Thomas D, Siahamis G, Marion M, Boyle C. Computerised infrared thermography and isotopic bone scanning in tennis elbow. Ann Rheum Dis 1992; 51:103-107.
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| [[Category:Elbow & Forearm]] | | [[Category:Elbow & Forearm]] |
