CHAPTER 34 Injury of the Flexors of the Elbow: Biceps Tendon Injury

INTRODUCTION

Except for epicondylitis, injury to the muscles or tendons about the elbow, as an isolated event, is rather uncommon.^3,^13,^16,^30,⁷⁰ Distal biceps tendon injury, usually avulsion from the radial tuberosity, is the most common tendinous injury in this region, and the incidence seems to be increasing. Calcific tendinitis has been observed in the biceps tendon, but it is very uncommon.⁵⁸

DISTAL BICEPS TENDON INJURY

The biceps muscle-tendon complex may be injured at the musculotendinous junction by an incontinuity tear of the tendon and by a complete or partial tear or avulsion from the radial tuberosity (Fig. 34-1).

FIGURE 34-1 The biceps mechanism may be rarely torn at the musculotendinous (large arrow) or tendinous (medium arrow) junction; a complex or partial avulsion is the most common injury (small arrow).

MUSCULOTENDINOUS JUNCTION

This is an uncommon injury and one rarely reported.⁶⁸ The mechanism is similar for all biceps injuries—an eccentric load against a contracting biceps muscle. It may have a predilection for persons with encephalopathy, a condition present in many who experience triceps rupture.

Treatment

Because of the delay in diagnosis, or owing to the frequency of underlying disease, our experience with surgical repair and reconstruction has been unpredictable. I have used a Bunnell-type suture repair and more recently augmentation with an Achilles tendon allgoraft has provided improved clinical outcomes. The elbow is protected in a splint for 3 weeks, with slow stretch and return to function over a 3-month period.

TEAR IN CONTINUITY

A tear of the tendon in continuity is very rare. An Achilles tendon allograft from the tuberosity to the muscle has been used as a “stent” for the tendon insufficiency with success. Simple plication of the stretched tendon is less effective.

AVULSION

By far, the most common injury is tendon avulsion, and complete avulsion is much more common than a partial injury. According to McReynolds,⁵⁴ the first known diagnosis of a distal rupture was reported by Starks in 1843.

INCIDENCE

Avulsion of the biceps tendon at its distal insertion was reported in three of 100 patients with biceps tendon rupture who were studied by Gilcreest.²⁵ The European literature suggests that distal avulsion injury accounts for approximately 3% to 10% of all biceps tendon ruptures.³⁵ Only 24 cases were reported in a 43-year period after the original surgical descriptions by Johnson⁴⁰ in 1897 and Acquaviva¹ in 1898. Three hundred and fifty-five surgeons responded to a questionnaire Dobbie circulated in 1941, and only 51 cases were added.²¹ In addition, only three of this group had experience with as many as three cases. By 1956, the world literature contained 152 cases.²⁷ At present, the injury is well known; either the incidence may be increasing or the lesion is recognized more often.^*

More reports in the literature notwithstanding, we have encountered only two instances of involvement in a woman in the English literature.⁵⁴ In addition, more than 80% of the reported cases have involved the right dominant upper extremity, usually in a well-developed man^9,⁶² whose average age is about 50 years^5,^21,⁵⁷ (range 21⁶³ to 70²¹ years).

MECHANISM OF INJURY

In virtually every reported case,^8,^21,⁵⁷ a single traumatic insult, often a force of 40 kg or more against resistance from an elbow in about 90 degrees of flexion, has been implicated. This mechanism, along with abuse of anabolic steroids, accounts for its surprisingly common occurrence in well-conditioned, healthy, but competitive weightlifters. Pre-existing degenerative changes in the tendon predispose to rupture.^18,¹⁹ Acute pain in the antecubital fossa is noted immediately. Rarely, a patient complains of a second episode of acute pain several days later. Such a history suggests the possibility of an initial partial rupture or of secondary failure of the lacertus fibrosus.^11,¹⁴ Occasionally, forearm pain has been reported, but it is considered rather uncommon.

ETIOLOGY

The cause of the injury has been discussed by several authors and is considered in detail by Davis and Yassine.¹⁸ The histologic pathology is that of a degenerative process, a finding consistent with the radiographic changes of spurring sometimes observed at the radial tuberosity (Fig. 34-2).^21,^37,⁶² During pronation and supination, inflammation and subsequent attenuation of the biceps tendon is initiated by irritation from the irregularity of the radial tuberosity (Fig. 34-3) or from chronic cubital bursitis (Fig. 34-4).⁴² Predisposition to this and other tendon injuries has been associated with anabolic steroid use,⁵¹ hyperparathyroidism,^15,⁶³ chronic acidosis,⁵⁹ and systemic diseases such as lupus erythematosus.⁷¹ One study has also implicated a hypovascular zone of tendon near its attachment as a cause or contributing factor to the injury.⁶⁶

FIGURE 34-2 Irregularity of the biceps tuberosity is frequently observed, suggesting that a degenerative process may be implicated, at least in part, in the causation of this condition.

FIGURE 34-3 Illustration of the pathophysiology of distal biceps rupture. Hypertrophic changes at the radial tuberosity cause irritation of the tendon, predisposing it to degenerative changes and rupture during pronation and supination.

(Redrawn from Davis, W. M., and Yassine, Z.: An etiologic factor in the tear of the distal tendon of the biceps brachii. J. Bone Joint Surg. 38A:1368, 1956.)

FIGURE 34-4 Cubital bursitis may occur in association with degeneration of the distal biceps insertion. BT, biceps tendon.

(Redrawn from Karanjia, N. D., and Stiles, P. J.: Cubital bursitis. J. Bone Joint Surg. 70B:832, 1988.)

More recent studies of the “footprint” and function of the biceps tendon insertion have revealed additional insight into the insertion pattern (Fig. 34-5). The portion oriented more distally is along the line of the short head tendon; the long head portion inserts further from the axis of rotation (see Fig. 34-5).²²

FIGURE 34-5 The “footprint” of the tuberosity reveals the short head tendon inserts more distally (arrows); the long head portion more “ulnarly” from the axial rotation axis. The bursa lies more radially.

PRESENTATION

Subjective Complaints

The common symptom of distal biceps tendon rupture is a sudden, sharp, tearing-type pain, followed by discomfort in the antecubital fossa or in the lower anterior aspect of the brachium. The intense pain usually subsides in several hours, but a dull ache persists for weeks. Immediately after the injury, activity is possible but difficult. If surgical repair is not performed, chronic pain with activity is common.³⁸ Flexion weakness of about 15 percent inevitably develops but over time some flexion strength returns.⁴⁶ Loss of supination strength has been reported as the source of variable dysfunction but has been measured as averaging 40 percent,⁵⁷ and diminution of grip strength also has been recognized.^2,^46,⁵⁷

Objective Complaints

Ecchymosis is variably present in the antecubital fossa,^21,⁶¹ and occasionally over the proximal ulnar aspect of the elbow joint.⁸ Extensive bleeding is uncommon but is seen occasionally (Fig. 34-6). With elbow flexion, the muscle contracts proximally and a visible, palpable defect of the distal biceps muscle is obvious (Fig. 34-7). If the contour is relatively normal, the lacertus fibrosus may be intact or the lesion may be a partial tear. With time, stretch of the lacertus fibrosus¹⁴ may occur. Assessment of strength alteration is essential to substantiate the diagnosis. Local tenderness is present in the antecubital fossa. The defect may be palpable; if it is not and if symptoms are otherwise consistent with the diagnosis, a partial rupture may have occurred. With partial rupture, an intense peritendinosis or bursitis may develop and crepitus or grinding is noted with forearm rotation.¹¹ Motion is not altered, except possibly as a result of pain at the extremes of flexion, extension, and supination. Flexion weakness usually is detectable by routine clinical examination. The loss of strength may be profound,²¹ especially on supination immediately after injury. Loss of grip strength is variable in degree but does occur with most injuries.

FIGURE 34-6 A, The forearm ecchymosis is variable and only rarely is extensive.

FIGURE 34-7 Proximal retraction of the biceps muscle is the consistent and obvious finding and should allow the diagnosis to be readily made.

Imaging of the Distal Biceps Tendon

Plain x-ray study is usually normal; however, spurring of the bicipital tuberosity is sometimes seen as being suggestive of a chronic tendon enesiopathy. Magnetic resonance imaging is commonly used to make or to confirm the diagnosis,⁴⁷ especially when the lacertus fibrosus is intact and the typical retraction deformity is not present or when trying to differentiate complete tears from partial tears. The treatment of complete tears without retraction or partial tears can benefit from precise delineation of the extent of the pathology. Guiffre and Moss²⁶ have described the Flexion Abduction Supination (FABS) view. With the elbow flexed and forearm supinated, the radial tuberosity is directed medially and the distal biceps tendon is almost a direct line from the tuberosity to the muscle belly (Fig. 34-8), allowing a longitudinal view to include the muscle belly, tendon, and the difficult-to-assess bicipital tuberosity insertion (Fig. 34-9). Because the tendon is assessed longitudinally and is at full length and partially unravelled, the differentiation of partial from complete tears is made easier (Fig. 34-10). In addition, the elbow is near the center of the magnet and, thus, fat suppression is optimal, enhancing visualization of small amounts of fluid. Continuing technical advances allow visual reconstruction and enhancements (see Fig. 34-10B).

FIGURE 34-8 The biceps tendon view consists of the patient lying prone, the elbow flexed over the head, and the forearm supinated.

FIGURE 34-9 The view described earlier nicely demonstrates the length of the biceps tendon as well as the musculotendinous junction (bottom arrow) and its insertion into the tuberosity (top arrow).

(Courtesy of Dr. Mark Collins.)

FIGURE 34-10 A, Magnetic resonance imaging scan of the arm shown in Fig. 34-1, 4 days after the injury. This study was useful for demonstrating distal avulsion with retraction of the tendon and absence of tendon in the cubital fossa. B, Visual reconstruction.

Surgical Findings

If the biceps tendon is explored early, local hemorrhage is present in the antecubital space but usually is not extensive. The tendon may have recoiled into the muscle or may lie loosely curled in the antecubital fossa. Invariably, the separation is clean and from the radial tuberosity,^8,^21,^46,^52,^57,⁶¹ with a bulbous stump of degenerative tendon. This supports our histologic studies and the hypothesis that the underlying lesion is degeneration at the site of attachment.^14,¹⁸ After several months, typically the tendon has retracted into the substance of the biceps muscle and cannot be retrieved to be reattached. However, this response as well as the status of the lacertus fibrosus is variable.

TREATMENT

Acute Disruption

Reliance on the older literature is unwise. Nonoperative management has been reported to provide satisfactoryresults ³⁷; however, the functional superiority of surgical treatment is obvious when the results of cases treated with and without surgical intervention are reviewed.⁵⁷ The recent literature offers overwhelming documentation of the excellent results of early repair.^2,^6,^50,⁶⁰ Although tendon strains will heal, true partial rupture does not and chronic pain necessitates surgical repair.

Surgical Repair

Reattachment to the radius by any one of several techniques ^5,^9,^24,^59,⁶⁹ is clearly the treatment of choice. The difficulty of performing the anterior exposure needed to avoid radial nerve injury has inspired the development of a second incision that is placed over the dorsal aspect of the forearm.¹² Curiously, this technique appears first to have been employed in 1937 by Plummer to reattach the biceps tendon to the proximal ulna.²¹ It is paramount to understand that the two-incision Boyd-Anderson technique originally described has been modified at the Mayo Clinic to reduce the likelihood of the development of ectopic bone between the radius and ulna. This point is explained later.

Because of concern over the development of ectopic bone associated with the two-incision technique, and with the advent of suture anchors, the anterior exposure using these anchors is gaining popularity. If the procedure is performed promptly, the tract of the biceps tendon is still present and is easily identified. Later (more than 2 weeks after injury), the tract may be obliterated, making the exposure more difficult ³⁶ and complications more frequent.⁴⁴

SURGICAL TECHNIQUE

Two-Incision Technique (Mayo)

This technique has been described in detail elsewhere.⁵⁶ With the patient in the supine position, a tourniquet is applied to the arm and the extremity is prepared, draped, and placed on an elbow table. A limited 3-cm transverse incision is made in the cubital crease (Fig. 34-11). The brachium is grasped and milked distally to deliver the biceps tendon. In the majority of cases, the tendon is readily retrieved with this maneuver. The tendon is inspected and invariably is found to be cleanly avulsed from the radial tuberosity. The distal 5 to 7 mm of degenerative tendon is resected, and two No. 5 nonabsorbable Bunnell or whipstitch (Krackow) sutures are placed in the torn tendon for a distance of at least 3 cm (see Fig. 34-11). The tuberosity is palpated with the indexfingers, and a blunt, curved hemostat is carefully inserted into the space previously occupied by the biceps tendon. The instrument slips past the tuberosity and is advanced below so its tip may be palpated on the dorsal aspect of the proximal forearm (see Fig. 34-11). A second incision is made over the instrument. The tuberosity is exposed by a muscle-splitting incision, with the forearm maximally pronated.