There is usually a history of sudden and sharp extension load to an elbow flexed at 90° with the biceps in a contracted state. This is followed by sharp pain, typically in the antecubital fossa, but sometimes felt in the posterolateral elbow. These may be associated with an audible “pop” [1]. Partial tears tend to be more painful than complete tears and patients tend to remain symptomatic or progress despite non-surgical treatment [17, 18].

Those with distal biceps tendonitis/tendinosis or bicipitoradial bursitis often present with deep-seated anterior elbow pain, generally exacerbated by repetitive use. The condition is atraumatic but patients often relate their symptoms to a vague inciting event. Uncommonly for distal biceps pathology, these patients tend to be female often with co-morbidities that predispose to tendon degeneration such as diabetes, renal disease and immunosuppressive therapy.

An unrepaired rupture leads to a deficit of 27 % in supination and 47 % loss of supination endurance when compared with the normal contralateral arm. Flexion strength and endurance are decreased by 21 % [2]. Freeman et al. (2009) found a mean 25 % reduction in supination strength but only a statistically non-significant 7 % loss of flexion when compared with the normal contralateral arm.

In any tear, there may be ecchymosis over the antecubital fossa, palpable gap in biceps tendon and/or tenderness on palpation over the radial tuberosity. Weakness of supination against resistance tends to be more marked than flexion as brachialis compensates for weakness of flexion.

The signs of partial tears are subtle and diagnosis is difficult owing to unreliable clinical examination. There may be crepitus or grinding on passive rotation of the forearm [4] and weakness of resisted supination. A direct tuberosity compression test has been described where the examiner palpates the lateral aspect of the fully supinated radium 2.5 cm distal to the radiocapitellar joint. The patient is then asked to rotate the forearm. If this elicits more pain than the normal contralateral side, the test is considered positive [11].

Several clinical tests to aid in the diagnosis of complete rupture have been described [28], described the hook sign (Table 13.1), where the patient is asked to actively supinate and flex the elbow to 90°. The examiner then hooks their finger under the distal biceps tendon from the lateral aspect of the elbow. In the case of a complete distal biceps tendon rupture, the hook test is thought to be the most useful test in making the diagnosis, as the examiner is unable to satisfactorily hook their finger under the tendon. However, it can be unclear when the biceps tendon sheath remains attached distally despite retraction of the tendon or when a pseudotendon develops to bridge the gap in a chronic tear. The hook test is also unclear in partial or single head ruptures. In Table 13.2, the features of the hook test have been correlated with pathologies in which they might appear.

A new ultrasound technique involving a medial approach through the pronator window has been adopted to diagnose distal biceps tears. This technique has resulted in more complete visualisation of the ulnarly facing radial tuberosity and distal biceps insertion [30] but remains less reliable than magnetic resonance imaging (MRI).

MRI has been shown to depict the level and nature of the tear (Table 13.2). A FABS view (flexed, abducted and supinated views) has been described to allow a longitudinal view of the tendon to be obtained in one slice [6], allowing easier recognition of pathology. However, MRI has a sensitivity of 59 % for partial ruptures and cannot distinguish between those that require repair and those that do not [19].

Endoscopy can provide both diagnostic and therapeutic implications in distal biceps pathology and has become the gold standard for diagnosis in our practice. It is particularly useful in assessing and diagnosing suspected partial or complete tears, extent of the tear and quality of residual tendon to allow for repairs in the acute setting. In chronic cases, endoscopy allows for identification and debridement of the pseudotendon and any scar tissue that extends to the footprint on the radial tuberosity and facilitates retrieval of chronically retracted tendons.

However, endoscopy is relatively contraindicated in patients with pre-existing abnormal anatomy, such as from previous injury or surgery at the elbow and antecubital fossa. Additionally, endoscopic repairs should only be attempted after a considerable number of open repairs have been performed and familiarity with diagnostic endoscopy has been developed.

Distal biceps pathology can be classified according to degree (partial or complete), temporally (acute or chronic) or anatomically into the three zones described above. Most injuries occur in zone 3 (tendon-bone interface). In this chapter, tendon pathology at zone three has been graded on a scale from 0 to 4 (Table 13.2). Each grade has distinct clinical, radiological and operative findings. The hook test, as described above, should be interpreted carefully in certain grades.

The two-incision technique of distal biceps tenodesis was initially described by Boyd and Anderson [3] and modified by Morrey, leading to lower rates of heterotopic ossification and synostosis.

Anteriorly, a 3–4 cm transverse incision over the antecubital fossa is made and tendon is secured using a grasping stitch. The forearm is then fully supinated and a blunt artery forceps is passed through the dorsolateral aspect of the forearm, along the medial border of the radius, until it visibly tents the skin. At this point, it is crucial that the tip of the forceps passes along the radius only and does not breach the periosteum of the ulna to minimise the risk of radioulnar synostosis. An incision is then made on the dorsolateral aspect of the forearm over the tip of the forceps and blunt dissection is performed down to the radius.