Distal Biceps Tendon Rupture
In 1941, Dobbie was the first to report the results of surgical reattachment of the distal biceps tendon. He recommended routine tenodesis of the biceps to the brachialis because of the risks associated with anatomic repair from the surrounding neurovascular structures within the antecubital fossa. Improved surgical technique and a better understanding of the anatomy and biomechanics of the distal biceps tendon subsequently changed this sentiment. Many orthopaedic surgeons now advocate early anatomic surgical repair of the distal biceps tendon in young, active patients.
Controversies continue to exist regarding the optimal treatment of distal biceps tendon ruptures. Many of these controversies focus on patient selection, timing of surgery, approach to the radial tuberosity, and tendon fixation techniques. The first half of this chapter reviews the relevant pathoanatomy, workup, and treatment of patients with distal biceps tendon ruptures. The second half of the chapter focuses on triceps tendon rupture and repair.
The estimated incidence of distal biceps tendon ruptures is 1.2 per 100,000 population per year. Distal ruptures account for only 3% of biceps brachii tendon injuries. The injury is most commonly seen between the fourth and sixth decades of life, with an average age of approximately 50 years (range, 18 to 72 years). Several patient factors have been associated with distal biceps tendon ruptures, with the most significant factor being male predominance. Of more than 300 reported cases in the literature, all accounts of complete rupture except for one have occurred in men. Eighty-six percent of distal biceps tendon ruptures occur in the dominant extremity, and they typically occur in highly active persons. Poisson regression analysis of tobacco use yields a 7.5 times increased risk of distal biceps tendon rupture among persons who smoke. Middle-aged men who use nicotine and anabolic steroids have a higher incidence of nonsimultaneous bilateral injuries.
The biceps brachii muscle is contained in the anterior compartment of the arm and is composed of two heads. The long head originates from the supraglenoid tubercle within the shoulder joint, and the short head originates from the coracoid process. The two heads converge at the level of the deltoid tuberosity. The distal tendon gives rise to the lacertus fibrosus (bicipital aponeurosis) before passing deep through the antecubital fossa and inserting onto the radial tuberosity. Anatomic investigation of the distal tendon reveals two distinct attachment sites. The tendon of the short head attaches more distally on the tuberosity and biomechanically acts as a flexor. The tendon of the long head inserts further away from the central axis and acts as a strong supinator. The lacertus fibrosis spreads out in an ulnar direction and blends into the forearm fascia, ultimately inserting onto the subcutaneous border of the ulna ( Fig. 66-1 ). This aponeurosis may provide stability to the distal tendon.
Innervation of the biceps brachii comes from the musculocutaneous nerve, a branch of the lateral cord of the brachial plexus. It penetrates the biceps muscle an average of 134 mm distal to the acromion and travels between the biceps and the brachialis before it penetrates the deep fascia of the arm and becomes the lateral antebrachial cutaneous nerve, which supplies sensation to the volar-lateral aspect of the forearm.
The biceps brachii is surrounded by and in close proximity to many vital neurovascular structures. The brachial artery, brachial vein, and the median nerve lie just medial to the biceps tendon and directly underneath the lacertus fibrosis. The brachial artery bifurcates into the radial and ulnar arteries at the level of the radial head. The radial recurrent artery arises from the radial artery and crosses laterally across the antecubital fossa within the usual anterior surgical field ( Fig. 66-2 ). Lateral to the biceps tendon, the radial nerve enters the proximal forearm between the brachialis and the brachioradialis. The radial nerve divides into the deep and superficial branch anterior to the lateral humeral condyle.
In contrast to the dual insertion of the proximal biceps tendon, the distal counterpart has a single insertion that may correspond to greater morbidity when ruptured. The biceps muscle provides both power and endurance for forearm supination and assists the brachialis in elbow flexion. The extent to which the biceps brachii contributes to elbow flexion correlates with the position of the forearm, with increasing contribution as the forearm is supinated. Furthermore, the biceps is able to exert maximum supination strength with the elbow at 90 degrees of flexion.
Morrey et al. performed a biomechanical study of 10 patients to evaluate the differences between conservative management and operative reattachment of distal biceps tendon ruptures. Immediate surgical fixation of the tendon to its insertion ultimately restored normal elbow flexion and forearm supination strength. In the group treated conservatively, an average loss of 40% supination strength and 30% flexion strength occurred. In a similar study, Baker and Bierwagen found an 86% decrease in supination endurance in patients treated conservatively.
Classification of distal biceps tendon ruptures is based on chronicity, degree of tear (partial vs. complete), and extent of retraction. The Ramsey classification uses these three characteristics to help guide treatment by predicting the ability to reattach the distal biceps tendon to the radial tuberosity ( Box 66-1 ).
The mechanism of injury is nearly always a forceful, eccentric contraction of the biceps muscle. Examples of this mechanism include a preacher curl performed with excessive weight by a weight lifter and forcible extension of the elbow during an attempted tackle by a football player. The most common description and localization of initial pain is an abrupt, intense tearing sensation in the antecubital fossa. A palpable or audible “pop” is frequently recounted. Patients may report sudden and persistent weakness, especially with forearm supination and elbow flexion. As days pass and the swelling diminishes, the patient may notice a cosmetic deformity of the arm as the biceps retracts proximally. Many patients report the slow migration of skin discoloration from the elbow region toward the wrist over time.
Inspection of the elbow will often reveal deformity and proximal retraction of the biceps (termed a “Popeye muscle”), swelling, and ecchymosis within the antecubital fossa and medial aspect of the forearm ( Fig. 66-3 ). Palpation elicits tenderness in the antecubital fossa and a defect of the tendon compared with the contralateral arm. In patients with an intact lacertus fibrosis, deformity may be less pronounced. Marked weakness in resisted forearm supination compared with the contralateral side is universally observed in complete ruptures.
Other physical examination tests specific for distal biceps tendon ruptures include the hook test and the biceps squeeze test. The hook test was originally described by O’Driscoll et al. and is performed by first placing the patient’s arm at 90 degrees of flexion. Next, the examiner attempts to hook the lateral edge of the biceps tendon with the index finger by pulling from a lateral to medial direction within the antecubital fossa. A positive test elicits an intact cordlike distal biceps tendon. The test is reported to have 100% sensitivity and between 85% and 92% specificity. The biceps squeeze test is similar to the Thompson test for Achilles tendon ruptures. The examiner squeezes the biceps brachii muscle, and in patients with an intact distal tendon, the forearm should supinate.
A standard elbow radiographic trauma series (i.e., anteroposterior, lateral, and oblique views) should be obtained to evaluate for other causes of anterior elbow pain. Generally no osseous abnormalities are evident, but anterior soft tissue swelling may be appreciated. In rare cases an avulsion fracture of the radial tuberosity may occur and should be visible on radiographs.
Magnetic resonance imaging (MRI) is an excellent modality for assessment of the integrity of the distal biceps tendon, but it is not always necessary to make or confirm the diagnosis. MRI is valuable for differentiating complete from partial tears in equivocal cases, such as in obese patients and persons with an intact lacertus fibrosis.
Nonoperative treatment consists of a brief period of immobilization, analgesia, and physical therapy. The goals of physical therapy are range of motion restoration with gradual elbow flexion and forearm supination strengthening. Patients who elect nonoperative treatment must be counseled on the risk of chronic activity-related pain and loss of supination strength and endurance. Patients also must be made aware that outcomes after delayed repair (>4 weeks) are inferior to those obtained with acute repair and may require tendon grafting or be deemed irreparable.
Certain factors must be taken into consideration prior to distal biceps tendon reattachment. These factors include time from injury to repair, anatomic versus nonanatomic repair, exposure of the radial tuberosity (one incision vs. two incisions), and tendon fixation methods. Because no single surgical plan is definitely superior, operative treatment must be tailored to the individual patient and the proficiency of the surgeon.
Injury chronicity is the most important factor for the surgeon to consider. Early diagnosis allows for easier reattachment of the biceps tendon to the radial tuberosity regardless of the integrity of the lacertus fibrosis. In this regard, primary reattachment is reliable if it is accomplished within 4 weeks of the injury. An intact lacertus fibrosis may minimize tendon retraction and increase the window for reattachment beyond 4 weeks. Concurrent rupture of the lacertus fibrosis will lead to proximal retraction of the tendon and formation of scar tissue with attachment to the adjacent brachialis muscle. Delayed surgery often necessitates extensive scar dissection to liberate the coiled tendon and regain critical length for primary reattachment.
Primary repair may not be possible in persons with chronic injuries, and tendon autograft/allograft reconstruction may be offered to these patients as an alternative to nonoperative care. The most commonly used autografts are semitendinosus and fascia lata, whereas the standard allograft is the Achilles tendon. Delayed reconstruction with use of a tendon graft historically has a less predictable outcome than early anatomic repair of the native tendon. Improvements in strength and endurance are possible, but delayed reconstruction should probably be reserved for patients with significant disability.
Nonanatomic repair or distal biceps tenodesis to the brachialis muscle was first proposed in an effort to decrease complications associated with anatomic reattachment. Several studies have evaluated the efficacy of nonanatomic repair and have found excellent return of flexion strength but, predictably, little or no improvement in forearm supination strength. With modern anatomic reattachment techniques, the complication rate has decreased and nonanatomic repair has largely fallen from favor. One exception is a patient with a chronic, irreparable tear who has a chief complaint of activity-related pain and cramping rather than weakness and loss of endurance.
Exposure of the radial tuberosity via a one-incision or two-incision technique is the subject of considerable debate. The discussion focuses on the ability to anatomically reattach the biceps tendon to the footprint of the radial tuberosity and the complications associated with each approach. Originally, the surgery was performed using a one-incision technique to expose the radial tuberosity through the antecubital fossa. Because of a relatively high rate of nerve injury, Boyd and Anderson developed a two-incision technique to expose the footprint through an additional posterolateral approach. Attachment of the biceps tendon through the posterolateral approach permits a more anatomic reconstruction to the radial tuberosity and requires less extensive anterior exposure, theoretically decreasing the risk of iatrogenic nerve injury. Critics of this two-incision approach point to the unique risk of radioulnar synostosis. Failla et al. responded to this drawback by reporting a case series of four patients with radioulnar synostosis who were treated with a modification of the Boyd and Anderson procedure involving a muscle-splitting approach between the common extensor mass and the supinator. This modification allows exposure of the radial tuberosity without violating the ulnar periosteum and decreases the risk of radioulnar synostosis. A subsequent study revealed that the rate of radioulnar synostosis increases if the posterolateral incision is made over the subcutaneous border of the ulna rather than over the common extensors.
Four fixation techniques are presently being used to reattach the distal biceps tendon to the radial tuberosity: transosseous tunnels, suture anchors, interference screws, and cortical fixation buttons (or a combination thereof). Several biomechanical studies have compared fixation strength and stiffness between the different fixation techniques. In general, all fixation methods provide adequate fixation strength compared with the intact tendon, with the highest load to failure achieved using cortical fixation buttons ( Table 66-1 ).
|Study||LOAD TO FAILURE (N)|
|Intact Tendon||Transosseous Tunnel||Suture Anchor||Interference Screw||Cortical Fixation Button|
|Berlet et al.||307 (±142)||220 (±54)|
|Lemos et al.||203||263|
|Idler et al.||204 (±76)||125 (±23)||178 (±54)|
|Greenberg et al.||177||584|
|Mazzocca et al.||310||381||232||440|
Acute operative fixation of the distal biceps should be offered to all healthy patients who require strength and endurance with elbow flexion and forearm supination. Nonoperative treatment of complete ruptures will yield between a 12% to 40% loss of supination strength, up to 86% loss of supination endurance, and consistently decreased Disabilities of the Arm, Shoulder and Hand (DASH) and European Society of Surgery of the Shoulder and Elbow scores. Conversely, early anatomic reconstruction of the distal biceps can completely restore elbow flexion and supination strength and endurance and demonstrates higher clinical and functional outcomes. Nonoperative management should be reserved for elderly or sedentary patients or persons with considerable medical comorbidities that preclude surgical intervention.