A gentleman in his 40’s presented with pain in the anterior aspect of the left upper arm and anterior left elbow. He recalled an event 3 months earlier when he was lifting a heavy item and noticed a sharp pain in the anterior elbow that had not settled with time. He worked in a manual job and it was impacting on his ability to do this and was  therefore referred for further imaging by his GP.

On examination, there was no obvious deformity. There was full passive range of the elbow with no pain. There was no visible effusion. He had reasonable power, which was painful although slightly weaker than his asymptomatic side. It was possible to palpate the biceps tendon with elbow in full extension, although this was tender.

On ultrasound, the images to the right were encountered. It is difficult to always correlate the very distal insertion on short axis and longitudinal view as this is a challenging tendon to interrogate. There was a distinct difference in the echotexture of the distal tendon in comparison to the asymptomatic side.

Differential diagnosis:

• Complete rupture of the biceps tendon
• Partial thickness tear of the biceps tendon

Final diagnosis: Ultrasound appearances suggestive of a partial tear of the distal biceps tendon, with loss of the normal echotexture in the deeper aspects of the tendon measuring L1.63cmx 0.60cm.

Further imaging was advised and the diagnosis was confirmed later on MRI with similar measurements to the longitudinal view on ultrasound.

Discussion

Distal biceps tears tend to occur in middle aged men and are usually related to trauma.

Tears of the distal insertion of the biceps are less common than the proximal tears of the long head of biceps (Lobo et al, 2013). Clinically, complete ruptures of the distal biceps insertion are easily diagnosed, with significant loss of power, palpable defect in the antecubital fossa  and noticeable functional difficulties. Partial thickness tears are more challenging to highlight clinically (Miller & Adler, 2000), with a varied presentation and diffuse pain reporting. MRI has been shown to be reliable for evaluating the distal biceps, however, ultrasound is increasingly  used as it is more accessible, cheaper and can be used dynamically (Lobo et al, 2013). There is however a lack of research comparing reports and surgical findings.

Ultrasound has been shown to differentiate between complete and partial tear with 95% sensitivity , 71% specificity and 91% accuracy. It is however a challenging structure to visualise and difficult to correlate short axis images with long axis views.

References

Belli, P., Costantini, M., Mirk,P., Leone, A., Pastore, G., Marano. (2001) Sonographic Diagnosis of Distal Biceps tendon rupture: A Prospective Study of 25 Cases., Journal of Ultrasound in Medicine, 20, 587-595.

Da Gama Lobo, L., Fessel, D.P., Miller, B.S., Kelly, A., Young Lee,J., Brandon, C., Jacobson, J (2013) The Role of Sonography in Differentiating Full Versus Partial Distal Biceps Tendon Tears: Correlation with Surgical Findings, American Journal of Roentgenology, 200, 158-162.

Kosuge, D. & Nairn, D (2011) Focus on: Rupture of the distal tendon of the Biceps Brachii, The Journal of bone and joint surgery (Br).

Miller, T. & Adler, R. (2000) Sonography of tears of the distal biceps tendon, American Journal of Roentgenology, 175, 1081-1086.

Smith, J., Finnoff, J., O’Driscoll, & Lai, J. (2010) Sonographic evaluation of the distal biceps tendon using a medial approach: The pronator window.