Distal biceps tendon injuries are most common in middle-aged men and usually occur in the dominant arm as the result of a forceful eccentric load applied against active elbow flexion and forearm supination. Most injuries involve complete disruption of the tendon insertion, producing an obvious clinical deformity of the biceps muscle. Acute tears are usually accompanied by ecchymosis in the antecubital fossa and proximal volar forearm. Partial tendon injuries are less common but have a high failure rate with nonoperative treatment; therefore, they are often treated surgically. The primary goal of surgery is to maximize the return of elbow and forearm strength and function in contrast to the outcome of nonoperative treatment, which often results in normal range of motion (ROM) and resolution of pain. Injuries treated without surgery result in elbow flexion strength loss of 20% to 30% and forearm supination strength loss of 30% to 50%.

The optimal indication for surgery is acute injuries, defined as less than 4 to 6 weeks, in active patients medically fit for surgery. Delayed surgical repair is more difficult due to fixed retraction of the biceps tendon and shortening of the muscle. However, primary fixation can sometimes be performed in a delayed fashion if tendon and muscle retraction are minimized by attachment of an intact lacertus fibrosis. If a primary repair of a retracted tendon can be performed with the elbow at 90° of flexion, full ROM and good function can be reliably obtained. Delayed reconstruction often requires an interposition tendon graft. Partial distal biceps tendon injuries are treated with surgical repair after failure of conservative treatment for a period of 3 months.

Contraindications for surgery include low-demand patients, chronic tendon ruptures (>6 months) and patients with medical illnesses precluding surgery. Potential noncompliance must be factored into the decision-making process as well.

Distal biceps tendon repair is performed by reattachment of the tendon into the radial tuberosity of the radius. The surgery can be performed either through a single-incision (transverse or longitudinal) anterior approach or a dual-incision anterior and posterior approach. Care should be taken to reattach the tendon to the apex of the radial tuberosity, thus recreating the anatomic insertion and maximizing the supination function of the biceps muscle (Figure 17.1). Fixation of the tendon can be performed in a variety of ways, including the use of sutures through bone tunnels, suture anchors into bone, cortical button fixation, or tenodesis screw fixation into a bone tunnel (Figure 17.2). Current methods of fixation provide ample fixation strength to allow early passive and active ROM of the forearm and elbow. In some cases, the fixation strength rivals or exceeds the native strength of the biceps tendon.

Single-incision repairs are performed between muscular planes without violation of muscle or tendon tissue. Dissection is performed between the flexor/pronator mass and the brachioradialis muscle. Care is taken to protect the lateral antebrachial
cutaneous nerve, which lies adjacent to the cephalic vein superficial to the muscle fascia and the superficial radial nerve, which lies under the leading edge of the brachioradialis muscle. Deep dissection requires identification and control of crossing blood vessels superficial and distal to the biceps sheath. Medial to the biceps sheath are the brachial artery and the median nerve, which must be protected. The inflamed biceps sheath is incised superficially, often revealing the torn biceps tendon resting on the brachialis fascia. When the biceps is retracted, dissection proximal is performed to identify and retrieve the biceps tendon. Digital palpation of the supinated forearm within the biceps sheath allows exposure of the radial tuberosity. Careful placement of retractors around the exposed radial tuberosity aids visualization; however, care is taken not to trap the posterior interosseous nerve, and retraction force should be minimized to prevent compression of the nerve.

Dual-incision repairs require an anterior approach to retrieve the biceps tendon and a posterior approach to expose the radial tuberosity. Once the biceps is retrieved and secured with a running locked suture, a curved hemostat is passed ulnar to the radial tuberosity (with the elbow flexed) and pushed forward through the common extensor tendon on the posterior aspect of the forearm (Figure 17.3). This helps
to localize the posterior skin incision. The extensor tendons/muscle are split around the hemostat until the supinator muscle fibers are seen. Care is taken not to strip muscle tissue from the ulna to prevent heterotopic ossification. The supinator muscle is then split, with the forearm pronated to protect the posterior interosseous nerve and expose the radial tuberosity. The tuberosity is then prepared for tendon fixation, usually bone tunnels with a dual-incision approach.

Dual-incision repairs may lead to slightly increased early postoperative pain and stiffness compared to single-incision repairs. In addition, dual-incision repairs have historically been associated with higher rates of postoperative heterotopic bone formation and radioulnar synostosis, although these complications are much less common when the extensors are split and the ulna is not exposed. Both single- and dual-incision repairs have been associated with postoperative nerve palsies (10%–15% of cases). The most common nerves involved are the lateral antebrachial cutaneous nerve and, less commonly, the posterior interosseous nerve. Single-incision repairs may have a higher chance of nerve injuries given the retraction necessary to gain visualization of the radial tuberosity from the anterior approach.