Diagnostic ultrasound imaging for lateral epicondylalgia: a case-control study.
BACKGROUND
Lateral epicondylalgia (LE) is clinically diagnosed as pain over the lateral elbow that is provoked by gripping. Usually, LE responds well to conservative intervention; however, those who fail such treatment require further evaluation, including musculoskeletal ultrasound. Previous studies of musculoskeletal ultrasound have methodological flaws, such as lack of assessor blinding and failure to control for participant age, sex, and arm dominance. The purpose of this study was to assess the diagnostic use of blinded ultrasound imaging in people with clinically diagnosed LE compared with that in a control group matched for age, sex, and arm dominance.


METHODS
Participants (30 with LE and 30 controls) underwent clinical examination as the criterion standard test. Unilateral LE was defined as pain over the lateral epicondyle, which was provoked by palpation, resisted wrist and finger extension, and gripping. Controls without symptoms were matched for age, sex, and arm dominance. Ultrasound investigations were performed by two sonographers using a standardized protocol. Grayscale images were assessed for signs of tendon pathology and rated on a four-point ordinal scale. Power Doppler was used to assess neovascularity and rated on a five-point ordinal scale.


RESULTS
The combination of grayscale and power Doppler imaging revealed an overall sensitivity of 90% and specificity of 47%. The positive and negative likelihood ratios for combined grayscale and power Doppler imaging were 1.69 and 0.21, respectively.


CONCLUSIONS
Although ultrasound imaging helps confirm the absence of LE, when findings are negative for tendinopathic changes, the high prevalence of tendinopathic changes in pain-free controls challenges the specificity of the measure. The validity of ultrasound imaging to confirm tendon pathology in clinically diagnosed LE requires further study with strong methodology.
University of Queensland, National Health and Medical Research Council Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, Brisbane, Queensland, AUSTRALIA.
Luke James
LJ
Heales
Nathan
N
Broadhurst
Rebecca
R
Mellor
Paul William
PW
Hodges
Bill
B
Vicenzino
D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D012680:Sensitivity and Specificity; D013716:Tennis Elbow / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D055815:Young Adult