Disorders of the Proximal Biceps Tendon

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CHAPTER 17 Disorders of the Proximal Biceps Tendon

Pathology affecting the tendon of the long head of the biceps brachii (LHB) has long been recognized, but enthusiasm for its treatment has varied considerably. The explanation for this may be a lack of understanding of the anatomy, mechanics, and possible pathologies of the intra-articular portion of the tendon, but also the continued debate and uncertainty about its true function in the shoulder.

ANATOMY

The LHB arises from the glenoid labrum and supraglenoid tubercle. It is an intra-articular but extrasynovial structure that is essentially static within the joint, sliding passively on the humeral head during elevation or rotation.¹ The tendon is approximately 9 cm long and 5 to 6 mm in diameter, and the articular portion is flatter and a little larger than the groove portion.

The location of the LHB just anterior to the supraspinatus tendon makes it susceptible to subacromial impingement. In addition, under load, the LHB often bears on the medial aspect of the groove, with the lesser tuberosity and soft tissues acting as a pulley (Fig. 17-1). This renders the tendon highly vulnerable to mechanical attrition and, if the soft tissue restraints of the biceps pulley become incompetent, subluxation.³

FIGURE 17-1 The bicipital groove lies anterior to the axis of the glenohumeral joint, resulting in an oblique line of pull (A), which causes the LHB to bear on the medial side of the groove, predisposing to attrition and subluxation of the tendon (B).

The contributions of the superior glenohumeral ligament and coracohumeral ligament to the biceps pulley mechanism are critical to the stability of the tendon. The transverse humeral ligament is not a significant stabilizer at the entry of the groove, and doubt has been expressed about its existence as a distinct entity, because it may be a continuation of the insertion of the subscapularis.⁴ Posteriorly, the leading edge of the supraspinatus is the primary restraint, although the anterior location of the groove and anterior vector of the pull of the tendon make this less important in most functional positions.

The function of the LHB at the shoulder is still a matter of debate. Some authors have considered it a purely vestigial structure with no true function at the glenohumeral joint, viewing it as the appendix of the shoulder. It functions as a weak abductor of the shoulder, but only when the arm is in external rotation, a position that is rarely used in activities of daily living.⁴^,⁵ It has also been proposed as a depressor of the humeral head and, although some cadaver, biomechanical, and radiologic studies have supported this,⁶^,⁷ electromyographic studies,⁸^,⁹ clinical observation, and the long-term results of tenotomy in the presence of a rotator cuff tear¹⁰ appear to negate this role. The primary function of the biceps is at the elbow, where it acts as a flexor and supinator.

There has been recent interest in the role of the LHB in glenohumeral stability, especially following the description of superior labrum anteroposterior (SLAP) lesions,⁶^,¹¹^–¹³ and mostly in the context of the throwing athlete.¹⁴^,¹⁵ Anterior instability leads to increased activity in the muscle on electromyography, indicating the possible role of the biceps as a secondary glenohumeral stabilizer. However, the magnitude of this function is likely to be small.

PATHOANATOMY

Tenosynovitis, tendinosis, delamination, prerupture, and rupture probably represent the natural history of progressive degeneration of the biceps. The LHB is subject to tenosynovitis because of its anatomy, with a synovial sheath and constrained path in the bicipital groove.¹⁶^–¹⁸ Arthroscopic evaluation shows fluid, adhesions, and increased vascularity around the tendon, but this must not be confused with the normal vascular pattern on the superficial surface of the tendon within the groove. Early tendinosis may be difficult to visualize arthroscopically, and may be best visualized using magnetic resonance imaging (MRI) or ultrasound imaging. Often, the tendon appears macroscopically normal, although there may be some increase in diameter. As the condition progresses, fibrillation, splits, and hypertrophy or attentuation occur, and may be described as delamination or prerupture.

Most degenerative changes in the LHB are associated with pathology of the rotator cuff, as highlighted by Neer.¹⁹ The relative importance of these structures in producing symptoms is still uncertain and will probably continue to be as long as our understanding of the mechanism of pain generation in disease of the rotator cuff remains incomplete.

Spontaneous rupture of the LHB is usually secondary to progression of a chronic partial tear, and may happen during a movement of daily living or a minor injury. Rupture usually occurs in the presence of a cuff tear.¹⁹ The classic Popeye sign of a ruptured LHB is unmistakable, but not all rupture, or tenotomies produce this deformity.¹⁰^,²⁰ Dislocated tendons often become encased in fibrous tissue or adherent to the subscapularis before rupture, and hypertrophic tendons may become fixed within the bicipital groove, resulting in an autotenodesis. Dislocation itself may, by shortening the course of the tendon, produce a low-rising muscle belly, which we call a false Popeye sign (Fig. 17-2).

FIGURE 17-2 CT arthrogram, axial view, demonstrating the LHB (arrow) dislocated in the substance of the subscapularis (A), with resulting loss of contour of the muscle belly in the left arm, or false Popeye sign (B).

Mechanical incarceration of the tendon within the joint has been described as an hourglass biceps,²¹ which is often seen in association with advanced disease of the rotator cuff. The intra-articular portion becomes hypertrophic and is unable to slide into the bicipital groove, resulting in buckling of the tendon on elevation of the shoulder, with painful entrapment of the tendon between the humeral head and glenoid and a mechanical block to terminal elevation. The hypertrophic tendon may also dilate the entry to the groove and lead to subluxation.

Failure of the biceps sling leads to subluxation and eventually dislocation in the presence of a rotator cuff tear. Although the difference may be subtle, it is important to distinguish subluxation from dislocation. A subluxation is defined as a partial and/or transient loss of contact between the tendon and its groove. A dislocation is the complete and permanent loss of contact between the tendon and the groove. Dislocations of the LHB can be classified into intra-articular, intratendinous, and extra-articular subtypes, depending on its position relative to the subscapularis. In cases of subluxation and dislocation, the subscapularis is almost always torn and, most often, the supraspinatus is also torn.³ Instability of the LHB is almost always medial, but lateral instability has been described, mainly in a traumatic context in association with anterior dislocation and/or fracture of the greater tuberosity,²²^,²³ but also in association with supraspinatus tears (see Fig. 17-2B).²⁴

Isolated pathology of the LHB is uncommon and found mostly in younger athletes, especially in throwers, gymnasts, swimmers, and participants in contact sports and martial arts. The LHB is subject to large forces of acceleration and deceleration of the arm as well as torsion and shear stresses, especially when coupled with tension during forced flexion of the elbow or forearm supination. Tenosynovitis, tears, instability of the tendon, and rupture may all occur in the athlete. Prevention of rupture is paramount, as even mild loss of power in elbow flexion or supination will be poorly tolerated, particularly in patients who place high demands on the biceps, such as overhead athletes or manual laborers.

HISTORY AND PHYSICAL EXAMINATION

Biceps pathology is rarely encountered in isolation, so the history and physical examination should also focus on commonly related pathologies, such as rotator cuff tears and instability. Pain related to pathology of the biceps tendon is located mainly at the anterior part of the shoulder, often at the bicipital groove. Pain may also be localized to the superior angle of the scapula on a referred basis. Pain at rest, night pain, and pain on glenohumeral rotation are common. The pain often radiates down the arm and muscle belly, and occasionally reaches the radial aspect of the hand, but lacks a precise distribution. Patients may also describe paresthesias in this distribution. Although the clunk of a subluxating and unstable biceps tendon is classic when the shoulder is rotated, especially in abduction, this clinical sign is uncommon as dislocations are usually irreducible.

Spontaneous rupture of the tendon is often accompanied by retraction of the tendon and the classic Popeye deformity. With subluxation or dislocation of the tendon, the muscle belly can have the attenuated appearance of a false Popeye sign (see Fig. 17-1). A side to side comparison palpating the bicipital groove is often useful, and is felt most easily in 10 degrees of internal rotation.²⁵ In dislocations of the LHB, the tenderness is more medial on the lesser tuberosity, and the tendon can sometimes be rolled under the fingers. We also find the Speed test (palm-up test) useful for diagnosing biceps pathology.

Patients with a dislocation of the LHB may present with a very typical clinical picture. Dislocation is often traumatic and almost always associated with a tear of the upper subscapularis. The patient presents with a loss of active elevation above 90 degrees, and it is common to find a limitation of active and passive external rotation with extra-articular and intratendinous dislocations because the dislocated biceps tendon tethers the inferior part of the subscapularis. The clinical sign of a hypertrophied and entrapped hourglass biceps is loss of the terminal 10 to 20 degrees of active and passive elevation without loss of rotation. This represents true mechanical locking of the shoulder, and should not be confused with a frozen shoulder.²¹

DIAGNOSTIC IMAGING

Radiographic examination should include a standard roentgenographic series (anteroposterior views in neutral, internal, and external rotation, axillary view, and supraspinatus outlet view), to rule in or out any associated abnormalities. We also find contrast studies (computed tomography [CT] arthrography, magnetic resonance [MR] arthrography) very useful to help diagnose pathology of the biceps tendon. With disruption of the medial sling, the LHB is frequently found to ride over the lesser tuberosity in a subluxated position, with a flattened appearance. With complete disruption of the sling, contrast material may escape from the biceps sheath and help outline the LHB in its dislocated position (see Fig. 17-2A).

INDICATIONS AND CONTERAINDICATIONS

Indications for tenodesis of the biceps (whether open or arthroscopic) include pain associated with significant tenosynovitis, prerupture of the tendon, subluxation, and dislocation. This procedure can be effectively used in three clinical situations: (1) in association with arthroscopic or miniopen rotator cuff repairs; (2) in cases of isolated pathology of the biceps tendon with an intact cuff, especially in a young athlete, presenting as tendinitis, subluxation, prerupture, or type 4 SLAP lesion with large extension into the biceps anchor; or (3) in cases of massive and irreparable cuff tears with a pathologic biceps tendon, especially in an older but active muscular patient. In this last situation, tenodesis of the LHB may be a preferable alternative to simple tenotomy, avoiding distal retraction and bulging of the muscle at the elbow (a potential source of painful cramping while working) and slight decrease in supination strength.

Whereas an isolated biceps tenotomy or tenodesis is indicated for patients with painful loss of elevation, it is contraindicated for patients with a true pseudoparalytic shoulder caused by a massive rotator cuff tear, which persists despite rehabilitation. Such patients are better served by a reverse shoulder arthroplasty. Similarly, the presence of glenohumeral osteoarthritis or humeral head necrosis (Hamada stage 4 or 5) is also a contraindication for isolated treatment of the biceps in favor of reverse arthroplasty.

Although we prefer to use an interference screw when performing LHB tenodesis, in cases in which the subscapularis requires concomitant repair, we tend to use suture anchors. Double-loaded anchors placed in the bicipital groove are used both to tenodese the LHB and repair the subscapularis. The anchors do not provide the same strength of fixation as a single interference screw, but they take up less space and allow us to treat both the LHB and subscapularis with multiple points of fixation.

Finally, a very thin, fragile LHB may be the technical limit of open or arthroscopic tenodesis. In this case, the procedure can easily be converted to a simple tenotomy. A simple tenotomy is also favored for low-demand older patients.

TREATMENT OPTIONS

Conservative Treatment

Tenosynovitis may respond to rest, physiotherapy, and analgesia. Injections of steroid and local anesthetic have diagnostic and therapeutic roles, but many conditions of the LHB are mechanical and, when symptomatic, require surgical intervention. Evidence in favor of conservative management for lesions of the LHB is limited and almost always includes other causes of shoulder symptoms.

A Cochrane ²⁶ review has looked at 26 trials of physiotherapy for shoulder conditions, and concluded that there was some evidence for mobilization and exercise in rotator cuff disorders, but no trials looked specifically at pathology of the LHB. It also concluded that there was no evidence to support the therapeutic use of ultrasound or laser for this group of conditions.²⁶ Intra-articular injections can relieve bicipital symptoms, but they may be ineffective if adhesions or synovitis restrict the dispersal of the injection into the bicipital groove. In our opinion, injections into the bicipital groove should be placed under ultrasound guidance to improve accuracy, and are particularly valuable when a subacromial injection has been ineffective in the presence of an intact rotator cuff.

Arthroscopic Treatment

The principle of arthroscopic biceps tenodesis is simple. After biceps tenotomy, the tendon is exteriorized and doubled on a suture. The biceps tendon is then pulled into a humeral socket and fixed using a bioabsorbable interference screw.

Although the lateral decubitus position can be used, we prefer to perform this technique with the patient in the beach chair position without traction because of the ability to change the position of the arm and forearm intraoperatively. This allows dynamic arthroscopic examination of the biceps and pulley system, as well as making the tenodesis easier. The shoulder should be placed in approximately 30 degrees of flexion, 30 degrees of internal rotation, and 30 degrees of abduction (arthrodesis position), allowing the anterior part of the subacromial bursa to be adequately filled with saline to have a clear view of the superior part of the bicipital groove. When using the beach chair position, a classic U-shaped knee support is used, with a Mayo stand to place the shoulder in the desired position. The elbow can be extended and flexed to 90 degrees. Alternatively, a limb positioner such as the SPIDER (Tenet Medical Engineering, Calgary, Alberta, Canada) may be used. We perform the procedure under general anesthesia and/or interscalene block.

Bony landmarks are drawn on the shoulder to identify the acromion, coracoid process, and coracoacromial ligament. The procedure requires three arthroscopic portals—the classic posterior portal is created over the soft spot and two anterior portals (anteromedial and anterolateral) are created 1.5 cm on each side of the bicipital groove, 3 cm distal to the anterior corner of the acromion (Fig. 17-3A). A pump is helpful to obtain distention of the joint and the bursa but it is important to maintain low pump pressure (30 mm Hg or lower) during the procedure to prevent excessive soft tissue distension. The surgical technique is comprised of six steps, as follows.

FIGURE 17-3 Bony landmarks—posterior, anteromedial, and anterolateral portals—are drawn on the skin of the patient’s right shoulder in the modified beach chair position. In the extra-articular portion of the procedure, the anteromedial portal is the working portal (A) and the anterolateral portal is the viewing portal (B).

Step 1: Glenohumeral Exploration and Tenotomy of the Long Head of the Biceps

The 30-degree arthroscope is inserted through the posterior portal and a diagnostic arthroscopy of the glenohumeral joint is performed. An anteromedial portal is established using an inside-out technique, passing the trocar through the rotator interval lateral to the coracoid process, 1 cm distal to it, and just above the subscapularis tendon. An 8-mm cannula is then inserted. Biceps pathology is often in the intertubercular groove portion and it is important to draw this part of the LHB into the joint with a probe. Dynamic examination of the biceps is then performed, first with the hourglass test, in which the shoulder is elevated in the scapular plane in neutral rotation with the elbow extended (Fig. 17-4A). In a positive hourglass test, the hypertrophic tendon fails to slide in the bicipital groove and buckles in the articulation, limiting elevation (see Fig. 17-4B).²¹ The swinging test is then performed, in which the adducted shoulder is rotated internally and externally to look for instability of the LHB. Medial subluxation in external rotation indicates a partial- or full-thickness tear of the subscapularis tendon, whereas lateral subluxation in external rotation indicates a tear of the supraspinatus, which may be a PASTA (partial articular-sided supraspinatus tendon avulsion) lesion or a full-thickness tear.²⁷

FIGURE 17-4 A, The hourglass test is performed by elevating the arm in the plane of the scapula while observing the LHB at the entrance to the bicipital groove. B, In a positive test, the LHB fails to slide in the groove and becomes trapped in the joint.

If a tenodesis is planned, the LHB is transfixed with a spinal needle intra-articularly at its entrance into the groove to avoid its retraction (Fig. 17-5A). The tendon is then detached from its glenoid insertion using a scalpel or punch, or electrocautery (see Fig. 17-5B). If a simple tenotomy is planned, it is not necessary to place a needle and the tendon is allowed to retract out of the joint. An hourglass biceps tendon may not slide out of the joint with extension of the elbow and shoulder. In such cases of autotenodesis, we simply resect the intraarticular portion of the LHB.

FIGURE 17-5 A, Arthroscopic view from the posterior glenohumeral portal of a right shoulder after the LHB is transfixed with a needle at the entrance to the bicipital groove. It is tenotomized near its origin on the glenoid. B, With the arthroscope placed in the anterior subdeltoid space via the anterolateral portal, the bicipital groove is identified and opened with electrocautery.

Step 2: Identification and Opening of the Bicipital Groove

The anterolateral portal is now created. It is located 3 cm from the anterior border of the acromion and 3 cm from the anteromedial portal to allow triangulation (see Fig. 17-3A). The arthroscope is now placed in the anterolateral portal. The anteromedial cannula is removed from the joint and reoriented into the anterior subdeltoid space. At this point, the anteromedial portal is the working portal and the anterolateral portal is the viewing portal (see Fig. 17-3B). A blunt trocar is used via the anteromedial cannula to palpate the soft spot corresponding to the bicipital groove, which is found between the hard surfaces of the lesser and greater tuberosities. The trocar can be used to push the “cobwebs” of fibrous tissue off the transverse ligament gently, without disrupting the adjacent vessels, and to feel the roll of the LHB in the groove. Visualization of the white fibers of the transverse ligament and of the ascending lateral vessels also help locate the groove.

The bursa anterior to the bicipital groove is resected with a motorized shaver or the Mitek VAPR radiofrequency device (DePuy Mitek, Raynham, Mass). Anterior bursectomy is essential for visualization and is continued until the bicipital groove and overlying transverse ligament are clearly seen. It is also possible to use the spinal needle as a landmark, but we avoid doing so because there is a tendency to bleed when the dissection is carried superiorly into the vascular anterosuperior bursa. The transverse ligament is now opened in a longitudinal fashion, using a hook-tipped electrocautery or VAPR device (see Fig. 17-5B). Once the groove is open, the LHB is probed and a careful synovectomy is performed using the shaver. Now the biceps tendon is lifted out of the groove to free possible adhesions. Location of the groove is much easier when there is a large cuff tear, with the biceps being uncovered when it enters the superior part of the groove.

Step 3: Biceps Exteriorization and Preparation

The spinal needle is removed and the elbow is slowly extended. As the proximal cut end of the LHB comes into view, it is grasped (Fig. 17-6A) and exteriorized through the anteromedial portal. Two atraumatic vascular clamps are used to grasp it progressively more distally to exteriorize as much tendon as possible. About 4 to 5 cm of tendon should be exteriorized, which is facilitated by flexion of the elbow. A single clamp is then used to keep the tendon outside for preparation (see Fig. 17-6B). Any remaining synovium is removed and, if necessary, the tendon is trimmed in the line of its fibers so that the diameter of the doubled tendon will be 8 mm.

FIGURE 17-6 A, The LHB is grasped via the anteromedial portal and exteriorized. B, Vascular clamps are used to exteriorize as much tendon as possible.

The tendon is now doubled over a no. 2 Ethibond suture (Ethicon, Somerville, NJ) and a no. 1 polydiaxonone (PDS) suture (Ethicon). The end of the tendon is whip-stitched using a running baseball stitch with no. 1 absorbable polyglactin 910 (Vicryl) suture (Ethicon). The tendon should be doubled and sewn to its anterior face for a length of about 2 cm, where a mark is made with ink (Fig. 17-7A). The PDS suture is then tied at the end of the loop, with one end as long as possible and the other cut short. The PDS suture will later be used to guide the interference screw and screwdriver into the humeral socket. The no. 2 Ethibond suture is left passing through the doubled tendon loop unsecured; it will later be used to pull the tendon into the socket and subsequently removed after the tendon is fixed.

FIGURE 17-7 The tendon is doubled and sewn to its anterior face for a length of about 2 cm, where a mark is made with ink, A, The PDS suture is tied and later used to guide the interference screw. The Ethibond suture is left unsecured, and will later be used to pull the tendon into the socket. B, The tendon is then moved aside as the bicipital groove is prepared.

The diameter of the double tendon is measured using the same type of graft sizer used in anterior cruciate ligament (ACL) reconstruction. The size of the double tendon determines the drill diameter needed to drill the humeral socket and should be 7 or 8 mm. The prepared tendon is then kept outside the wound and held by an assistant or clamped to the drapes. The rest of the procedure is performed with the arthroscope in the anterolateral (viewing) portal and the instruments inserted through the anteromedial (working) portal (see Fig. 17-7B).

Step 4: Drilling the Humeral Socket

The bicipital groove is débrided of all fibrous tissue with the shaver or the VAPR, exposing the groove from its entrance into the joint superiorly to the “three sisters”—the transversely oriented vessels that cross the groove at the level of the inferior edge of the subscapularis tendon. Care must be taken not to disrupt the three sisters or the vessels that ascend just medially and laterally to the groove to avoid bleeding. Socket placement is now planned and assessed with a probe. Optimal placement is approximately 10 mm below the superior limit of the groove to prevent any anterosuperior impingement with the acromial arch. In practice, this is roughly halfway between the top of the groove and the three sisters.

The location of the humeral socket is initially penetrated with a sharp-tipped awl to prevent skiving of the guide pin when drilling. A guidewire is then placed in the pilot hole and oriented strictly perpendicular to the humerus and parallel to the lateral border of the acromion (Fig. 17-8). The guidewire is drilled until it engages the posterior cortex of the humerus. The humeral guide pin is overdrilled with a cannulated reamer the same size as the doubled tendon (7 or 8 mm), to a depth of 25 mm, and the reamer and guide pin are removed. The shaver, VAPR, and an arthroscopic burr are used via the anteromedial portal to chamfer smooth the edges of the socket entrance and remove bone debris and tissues that may block or abrade the tendon (Fig. 17-9A). Most attention is paid to the inferior part of the humeral socket, where the tendon will enter.

FIGURE 17-8 A, The guidewire is placed in the bicipital groove approximately 1 cm below the entrance to the joint. B, The socket is then drilled perpendicular to the humerus and parallel to the acromion.

FIGURE 17-9 A, The socket should be smooth and free of soft tissue that may impede the passage of the tendon. B, The reamer is inserted in the socket in a reversed orientation to center the Beath pin.

Step 5: Passing the Transhumeral Pin

A Beath pin pull-through technique is used for tendon placement. This pin has an eyelet on its trailing end and serves as a suture passer. The Beath pin is placed through the anteromedial cannula into the humeral socket. To centralize the pin, we place the reamer in the socket in a reversed orientation, removing it once the pin has been advanced (see Fig. 17-9B). The direction of the transhumeral Beath pin is important; it should be strictly perpendicular to the humerus and parallel to the lateral border of the acromion. The pin is drilled until it exits the skin, which will be approximately 2 cm inferior and 2 cm medial to the posterolateral border of the acromion, avoiding the axillary nerve (Fig. 17-10A).²⁸^,²⁹ Both ends of the Ethibond suture are threaded through the eyelet of the Beath pin, and the pin and sutures are pulled through the humerus. The PDS suture is not passed posteriorly, because it will later be used to guide the screw into the socket. The tendon is checked for twists and, if necessary, reoriented with a probe or grasper. The Ethibond suture is used to pull the doubled loop of biceps tendon into the humeral socket. The ink mark at the base of the doubled portion of the tendon should pass just inside the socket (see Fig. 17-10B).