Pathology of the Long Head of the Biceps Tendon

Clinical History: A 68 year-old male presents with a 2 month history of pain and limited range of motion. Coronal oblique T2-weighted fat-suppressed (1a,1b), axial proton density-weighted fat-suppressed (1c), and sagittal oblique T2-weighted FSE (1d) images are provided. What are the findings? What is your diagnosis?

 

Findings

 

Diagnosis

Bursal sided insertional partial tear of the anterior supraspinatus tendon, insertional partial tear of the superior-most subscapularis tendon, medial subluxation of the long head of the biceps tendon with moderately severe intra-articular tendinosis. Accessory head of the long biceps tendon arising from the anterior capsule.

Introduction

The long head of the biceps tendon (LHBT) is widely recognized as an important pain generator. As in the test case, LHBT injuries are rarely an isolated injury and are frequently accompanied by significant shoulder pathology. Consequently, a diagnosis of LHBT injury by physical examination is frequently inconclusive or masked by accompanying shoulder injuries. In addition, the detection of LHBT pathology in certain locations may be difficult at shoulder arthroscopy. Failure to adequately address LHBT injuries or instability often results in suboptimal outcomes to conservative therapy or surgery. MRI plays an important role in evaluating the LHBT and in identifying significant LHBT pathology.

Anatomy and Function

The long biceps tendon arises from the supraglenoid tubercle and partly from the superior glenoid labrum (7a). The tendon is intra-articular but extrasynovial, with a surrounding synovial-lined sheath that communicates with the glenohumeral joint and extends into the bicipital groove. As it passes anteriorly and laterally to the bicipital groove, the intra-articular portion of the LHBT is cradled and stabilized by the superior glenohumeral ligament (SGHL) and coracohumeral ligament (CHL), which fuse along the lateral half of the rotator interval with fibers from the subscapularis and supraspinatus to form the biceps pulley (8a). The LHBT undergoes a rather abrupt angulation of 30 to 40 degrees as it passes through the pulley and into the bicipital groove¹. The intra-articular portion of the long biceps tendon has a flattened and slightly larger cross-sectional contour and transitions to a more rounded and smaller cross-section as it passes into the bicipital groove (9a)². The tendon is smallest in caliber as it exits the bicipital groove³. Within the bicipital groove the deeper, sliding surface of the tendon is avascular and composed of fibrocartilage². The LHBT is 5-6 mm in diameter and approximately 10 cm in length with the musculotendinous junction found deep to the pectoralis major tendon⁴. Further distally the long head of the biceps muscle joins with the short head of the biceps muscle to form the biceps muscle belly. Cheng described the arterial supply to LHB tendon as arising from 3 potential sources consisting of branches of the brachial artery entering the tendon at the musculotendinous junction, thoracoacromial artery branches that cross the tendon-bone interface at the glenoid, and a more variable supply via branches of the anterior circumflex humeral artery that travel in a mesotenon to supply the mid-portion of the LHBT⁵. A relatively consistent zone of hypovascularity is seen 1.2 – 3 cm from the tendon origin⁵. The tendon of the long head of the biceps is innervated by a network of sensory and sympathetic fibers that are asymmetrically distributed with a higher concentration of innervating fibers at the tendon origin. This distribution is felt to play a role in the pathogenesis of shoulder pain arising from biceps tendon injury⁶.

 

 

MR Imaging

MRI with or without intra-articular contrast is the preferred imaging modality for evaluating the intra-articular and extra-articular LHBT and the adjacent structures of the shoulder⁷. Evaluation of the LHBT by MRI relies on a variety of sequences performed in the axial, coronal oblique, and sagittal oblique planes with emphasis on certain angles depending on the portion of the tendon being assessed. Imaging of the biceps anchor relies primarily on coronal oblique images. The rotator interval structures including the biceps pulley and traversing long head of the biceps tendon are best evaluated with sagittal oblique images (8a). Axial images are best for evaluating the LHBT at the level of the bicipital groove (9a). In all instances, correlation with orthogonal views provides important confirmatory and complementary information. By distending the rotator interval, MR arthrography allows more detailed evaluation of the biceps pulley and rotator interval structures which are best seen in the sagittal oblique plane (8a). MR arthrography typically depicts a well-defined proximal superior glenohumeral ligament and a distal superior glenohumeral fold that helps to form the biceps pulley (7a,8a). The intervening rotator interval ligamentous structures are less well delineated⁷.

 

 

 

 

Variants of LHBT

A wide range of anatomic variations have been reported for the LHBT and proximal biceps. Aberrant intra-articular and extra-articular origins of the LHBT have been described as well as congenital absence. The LHBT has been reported to arise from the rotator cuff and glenohumeral capsule (11a). Bifurcated origins have been described including tendon origins from the supraglenoid tubercle and posterior superior labrum, a bifid tendon originating from the supraglenoid tubercle, and tendon origins from the rotator cable and the scapula without an origin from the superior labrum or glenoid⁸. While variants of biceps origin are common and typically benign, congenital absence of the long head of the biceps has a higher reported association with other congenital abnormalities and shoulder instability. The association with other congenital anomalies is felt to arise because of a fetal insult at around 7 weeks of gestation during biceps differentiation⁹. Congenital absence of the LHBT has been reported in one patient with spina bifida, congenital inguinal hernia, and undescended testicle¹⁰. Other reported abnormalities in patients with congenital absence of the LHBT include VATER syndrome¹¹, congenital limb abnormalities, multidirectional instability, and glenoid dysplasia with posterior instability. Less commonly congenital absence of the LHBT may occur without associated congenital anomalies or shoulder instability¹².

 

Accessory heads of the biceps brachii are common, ranging from 9.1-22.9% depending on the ethnic group, being most common in the Asian population. Supernumerary bicipital heads include additional origins from the articular capsule of the glenohumeral joint (12a), from the tuberosities of the humerus, and from the coracoid process^13,14,15. By MRI an accessory tendon is seen as an additional hypointense structure within the biceps groove that is often flattened and can be misinterpreted as a longitudinal tear of the LHBT without carefully tracing the accessory tendon to its origin (12a)¹⁵.

 

Function

The biceps functions primarily as a flexor and supinator at the elbow. The function of the LHB tendon at the shoulder remains controversial and unclear. Because the biceps muscle spans two joints, the functional contributions of the LHBT at the shoulder are difficult to isolate. Both cadaveric and electromyographic studies suggest a range of functions served by the LHBT. Mainly through cadaveric studies the LHBT has been variably characterized as a depressor of the humeral head, an anterior stabilizer, a posterior stabilizer, a limiter of external rotation, a lifter of the glenoid labrum, and a head compressor of the shoulder. Earlier electromyographic studies have attributed a relatively weak abduction force to the LHB at the shoulder¹⁶, while more recent studies have shown that when elbow and forearm motion are eliminated, there is virtually no activity in the long head of the biceps tendon with motion at the shoulder^17,18. These latter findings suggest a passive role of the LHBT with motion at the shoulder in the absence of loading from forearm or elbow activity¹⁷. A subsequent study by Youm, et al. supports the role of activity at the elbow in loading the LHBT and confirmed earlier cadaveric studies by demonstrating that progressively loading the long head of the biceps tendon centers the humeral head on the glenoid surface and decreases anterior-posterior and superior-inferior translation, while limiting internal and external rotation¹⁹. Additional studies demonstrate an increased role for the LHBT as a glenohumeral joint stabilizer in the presence of rotator cuff tears and in the presence of glenohumeral instability^20,21.

Clinical Findings

Symptoms

Symptoms of LHBT pathology are variable. The usual presentation is pain over the anterior shoulder and the bicipital groove. Often the pain is poorly localized or vague, and the clinical presentation is commonly complicated by other shoulder pathology including rotator cuff injury, impingement, and shoulder instability. Pain may occur at rest or be worse at night, and may radiate into the biceps muscle and distally into the radial aspect of the hand. Overhead activities may exacerbate symptoms. Rarely, the patient may experience a “clunk” with shoulder abduction and rotation with an unstable LHBT². Rupture of the LHBT is usually noticed as an audible pop, often with immediate resolution of previous anterior shoulder pain²².

Physical Exam

Physical examination is unreliable in the diagnosis of LHBT pathology. With dislocations, pain and tenderness are more medial over the lesser tuberosity. The dislocated tendon may also be palpable. With tendon rupture, distal retraction of the long head of the biceps muscle and tendon result in the characteristic “Popeye” deformity with accompanying ecchymosis, if acute. Provocative tests for LHBT pathology include Yergason’s, Speed’s, uppercut, bear hug, belly press, O’Brien’s, anterior slide, and dynamic labral shear tests. Kibler et al. demonstrated through regression analysis that the combination of Speed’s test and the uppercut test were best at clinically detecting biceps pathology²³. Speed’s test is positive when bicipital groove pain is reproduced with resisted forward flexion of the shoulder with the elbow fully extended, and the forearm fully supinated. A positive upper cut test occurs when the patient experiences pain or a painful pop over the anterior shoulder while trying to perform a boxing uppercut punch against resistance with the elbow flexed to 90 degrees, the forearm supinated, and the patient making a fist²³.

Pathogenesis

Various schemes have been proposed to classify LHBT injuries with no clearly unified classification system. The difficulties in categorizing LHBT injuries arise because more than one type of tendon lesion may be present at the same time and in more than one tendon location, and additional shoulder pathology is common. Furthermore, coexisting shoulder pathology may be related to LHBT pathology or may be incidental²⁴. LHBT injury has been broadly classified into intrinsic tendon degeneration, mechanical causes including instability, and traumatic causes². Other authors have classified biceps lesions based on the underlying pathologic process and the status of the biceps tendon. Despite these different classification schemes, injury of the LHBT is commonly multifactorial²², and a practical approach is to classify LHBT pathology based on location.

Intra-articular LHBT injuries include injuries at the origin of the LHBT or within the rotator interval. SLAP tears can undermine the biceps tendon or extend into the biceps tendon. Injuries of the LHBT at the rotator interval may result from the repetitive mechanical stresses of internal and external impingement. Subluxation and dislocation of the LHBT occur with damage to the biceps pulley, and are most commonly associated with tears of the subscapularis and supraspinatus tendons. All of these factors contribute to tendinosis and tears of the LHBT.

Extra-articular LHBT pathology occurs in the bicipital groove from mechanical insults to the LHBT associated with subluxation, dislocation, and constriction of the bicipital groove and results in tenosynovitis, tendinosis, and LHBT tears.

SLAP tears

SLAP tears have been more fully discussed in a previous Web Clinic. Certain SLAP tears may undermine or extend into the LHBT. Type II lesions consist of superior labral fraying with stripping of the labrum undermining the attached biceps tendon. Type IV SLAP tears consist of a bucket handle tear of the superior labrum with tear extension into the biceps tendon. The more recently described Type X lesion consists of a superior labral tear extending into the SGHL. In addition SLAP tears are also associated with rotator interval lesions and medial biceps pulley lesions^25,26.

Subluxation and Dislocation of the Long Head of the Biceps Tendon

The structures that contribute to intra-articular stability of the long biceps tendon include the glenoid labrum and capsuloligamentous structures of the glenohumeral joint, the structures of the rotator interval including the coracohumeral and superior glenohumeral ligaments, and the supraspinatus and subscapularis tendons. Extra-articular structures that contribute to LHBT stability include the transverse humeral ligament, the pectoralis major muscle and tendon, and the bicipital groove. The role of the transverse humeral ligament, once thought to be a major contributor to stability of the LHBT, has been deemphasized. Instead, increasing focus has been placed on the role of the biceps pulley mechanism in maintaining LHBT stability.

Conceptually, the biceps pulley mechanism is composed of fibers from the superior glenohumeral and coracohumeral ligaments with contributions from the subscapularis and supraspinatus tendons. This complex attaches at the lesser and greater tuberosities forming a sling around the LHBT as it enters the bicipital groove and acting as a pulley to buttress the LHBT medially as it undergoes a bend to enter the bicipital groove. The primary medial stabilizers are the medial limbs of the superior glenohumeral and coracohumeral ligaments and the subscapularis tendon. Recent anatomic and histologic studies emphasize the importance of the superior insertion of the subscapularis tendon in preventing medial LHBT instability^27,28. Arai et al demonstrated a tendinous slip that extends superiorly from the insertion of the superior-most intramuscular tendon of the subscapularis which extends deep to the LHBT and inserts into the fovea capitis of the humerus, represented by a somewhat flattened region superior to the lesser tuberosity and deep to the path of the LHBT. This anatomic configuration serves to lengthen the channel of the LHBT superiorly from the intertubercular groove. The SGHL attaches to this tendinous slip and is interposed between the LHBT and the subscapularis tendon and helps to prevent anteromedial displacement of the LHBT²⁷. Because of the close proximity and interdigitation of the structures that contribute to the biceps pulley, stability is affected by nearby tears of the bordering subscapularis and supraspinatus tendons that extend to involve structures of the biceps pulley^29,30.

Not surprisingly, subscapularis tears are most commonly associated with LHBT instability. Direct injuries of the rotator interval and biceps pulley may also be caused by acute trauma, repetitive microtrauma, and degenerative change². Traumatic injury of the rotator interval and biceps pulley mechanism may result from a fall on an outstretched arm in combination with full external or internal rotation, a fall backward on the hand or elbow, or direct anterior impact³¹. Anterosuperior impingement has also been proposed as a mechanism of superior subscapularis and pulley mechanism injury³².

The initial findings of biceps instability are subtle, depicted by only minor displacement or shift of the LHBT within the bicipital groove and may be difficult to demonstrate by imaging or arthroscopy. Subluxation results from more severe displacement of the biceps tendon but with continued contact with the bicipital groove. With dislocation, the long biceps tendon loses all contact with the bicipital groove. Several classifications have been proposed for patterns of biceps instability. Walch described 4 types of biceps dislocations²⁹. Bennett proposed 5 patterns of biceps instability³³, and Habermeyer¹ described 4 types of biceps pulley lesions leading to subluxation and dislocation of the LHBT.

A more recent modification of the Habermeyer system incorporates 6 patterns of tendon instability which can be grouped into the categories of tendon displacement or subluxation, extra-articular dislocation, and intra-articular dislocation²⁴:

 

 

 

 

 

 

 

 

Although the classification of biceps instability provides valuable information regarding pathogenesis, at present this information results in little modification of the clinical decision-making and surgical approach to treating the unstable LHBT. Attempts at repair of the biceps pulley injury have met with limited success, and since there are few surgical options, most of these patients undergo tenodesis or tenotomy of the LHBT and repair of the associated rotator cuff tendon pathology.

MRI findings

Dislocation

The MRI diagnosis of a dislocated long biceps tendon is typically straightforward. Axial MR images demonstrate an empty bicipital groove. The dislocated tendon may be seen anterior to the subscapularis tendon (20a), within an intratendinous tear of the subscapularis tendon (21a), or deep to the subscapularis tendon in an intra-articular location (22a). Sequential axial images help confirm the structure as the LHBT, and utilizing the orthogonal sagittal oblique or coronal oblique views, the descending portion of the displaced LHBT can frequently be identified. A rare presentation of posterior dislocation of the LHBT (23a,24a) may be seen associated with anterior glenohumeral dislocations and with fractures of the greater tuberosity.

 

Subluxation

Subluxation is much more subtle and difficult to demonstrate, not only with MRI and MRI arthrography, but also at arthroscopy. Axial images at the level of the superior bicipital groove are useful in detecting subluxation by demonstrating medial displacement of the LHBT over the lesser tuberosity. Care must be taken to ensure that the MR image being evaluated is the superior-most cut through the lesser tuberosity demonstrating a convex contour. Immediately above the lesser tuberosity the humeral contour becomes more flattened and at this level the normal medial course of the LHBT should not be confused with subluxation. It is in this region however, that very small tears of the superior-most subscapularis tendon insertion may be seen. Small tears of the superior subscapularis may be identified on T2-weighted images as small fluid-containing tendon defects at the medial margin of the biceps pulley offering a clue to potential biceps pulley injury and LHBT instability (25a). Anterior and inferior displacement of the LHBT on sagittal oblique MR arthrogram images (displacement sign) has been proposed to identify early evidence for LHBT instability and tear of the biceps pulley³⁴.

MRI arthrography is better suited for directly visualizing the biceps pulley anatomy and structures of the rotator interval because of the ability to distend and displace the rotator interval structures away from the glenohumeral joint. Interruption and irregularity of the superior glenohumeral ligament, coracohumeral ligament and subtle alterations in the position of the LHBT on sagittal images are helpful in identifying subtle biceps pulley tears (26a). Commonly associated abnormalities include tears of the superior subscapularis tendon which extend to involve the medial limb of the biceps pulley and tears of the anterior supraspinatus which may extend into the lateral aspect of the biceps pulley(27a)³³. MR arthrography may depict contrast extending beyond the confines of the anterior joint capsule or along the footprint of the subscapularis over the lesser tuberosity³⁵.

 

 

 

Tendon Degeneration

Tendon degeneration or tendinosis encompasses a range of histopathologic changes within the tendon that can occur at any level. The LHBT is subjected to traction, pressure, friction, and shearing forces along its intra- and extra-articular course³⁶, and the effects are hastened in the setting of overuse and instability. In addition, tendon quality may be affected by systemic diseases and aging³⁷. Repetitive mechanical stresses associated with anatomic narrowing may be seen distally within the bicipital groove. Impingement beneath the acromion and the coracoacromial arch may occur with flexion, and this process may be accelerated with thinning or absence of the intervening rotator cuff³. Repetitive traction as is seen in overhead sports may account for the proximal tendon degenerative changes seen at the biceps anchor and may represent precursors to SLAP lesions³. Although degenerative changes within the LHBT are most commonly mechanical in origin, a consistently hypovascular zone of the LHB tendon is found 1.2-3 cm from the tendon origin at the margin of 2 vascular territories⁵, which may also contribute to tendon degeneration.

Initially, microscopic tears of the tendon occur, and the healing response results in disorganization of collagen fibers and an increase in ground substance. Eventually, macroscopic changes in the tendon occur with loss of the normal glistening surface. If unchecked, repetitive stresses progress to tendon fibrillation, tendon hypertrophy or attenuation, macroscopic partial tears, and eventual complete rupture (28a). An accompanying tenosynovitis representing peritendinous inflammation may be seen. This is frequently brought about by lesions within the bicipital groove, such as a narrowed bicipital groove or may be seen with younger individuals associated with overuse. Because the LHBT sheath communicates with the glenohumeral joint, fluid surrounding the LHBT in the bicipital groove may reflect tenosynovitis or fluid extension from a glenohumeral joint effusion.

 

On MR, tendon degeneration or tendinosis is diagnosed on the basis of changes in diameter and signal alteration. These signal changes are often subtle and may be mimicked by partial volume averaging and magic-angle artifacts. Tendon thickening, flattening, and a reduced caliber are all reliably associated with tendon degeneration. However, a lack of diameter change does not exclude the presence of tendon degeneration. Tendinosis may result in increased T1, T2, and proton-density weighted signal changes, or the tendon may demonstrate normal signal (29a). Tendon signal alteration is less consistently related to degeneration, likely in part due to magic angle phenomenon and partial volume artifact related to the curved and oblique course of the tendon over the humeral head and into the intertubercular sulcus. Magic angle artifact is most common just before the entrance of the tendon into the intertubercular groove where the tendon and collagen fibers are closest to the magic angle of 55 degrees relative to the main magnetic field. Magic angle artifact typically involves a short segment of the LHBT with well-defined increased signal on short TE images. In contrast,T2-weighted images demonstrate normal signal at the corresponding locations of the tendon³⁸.

 

Severe hypertrophy of the intra-articular portion of the LHBT, most often accompanying a rotator cuff tear, may result in entrapment of the tendon within the joint because the tendon diameter is too large to slide freely through the intertubercular sulcus leading to a loss of passive elevation of the humerus and bicipital groove tenderness. This condition has been coined the hourglass biceps (30a). At arthroscopy, the hypertrophied tendon can be seen to buckle in the joint with forward elevation of the arm with the elbow extended³⁹.

 

Tenosynovitis typically demonstrates a fluid distended tendon sheath that is out of proportion to the amount of fluid in the glenohumeral joint and is best depicted on axial proton density or T2-weighted sequences.

Tendon Tears

The normal LHBT can withstand a high tensile force of 667 to 890 newtons^40,41. Consequently, rupture of a healthy biceps tendon is extremely rare. Instead, partial and complete tears of the LHBT are usually associated with underlying tendon pathology such as tendon degeneration. Additional shoulder pathologies that contribute to weakening of the tendon include external and internal impingement syndromes, rotator cuff tears, SLAP tears, and tendon instability.

Partial and complete tears of the LHBT typically occur along a hypovascular segment of the LHBT found 1.2-3 cm from the tendon origin extending from the intra-articular portion of the tendon at the mid humeral head level into the superior portion of the intertubercular sulcus⁵. A subset of patients has been identified that present with shoulder pain and an often isolated subtle partial tear of the LHBT just proximal to the bicipital groove. This particular LHBT injury has been named the “groove entry lesion”⁴². Because of magic angle artifact prevalent at this portion of the LHBT, these injuries are most reliably depicted on T2-weighted, long TE sequences. Complete rupture of the LHBT is most common in males aged 50 and older⁴³ and most commonly occurs in the bicipital groove or just proximal to the goove²⁴. LHBT injuries account for 96% of all biceps brachii injuries including the distal tendon at the elbow and the short head⁴³. A complete rupture of the LHBT is commonly accompanied by a “Popeye” deformity, a characteristic bulge over the anterior lateral aspect of the proximal arm that results from distal retraction of the LHB tendon and muscle. Frequently complete rupture may relieve pain associated with pre-existing tendinosis or a partial LHBT tear. Because of frequent pre-existing LHBT pathology, complete rupture may occur from relatively minor trauma.

Failure of the biceps tendon in young patients is rare. Complete failure of the biceps at the biceps anchor has been reported in weightlifters⁴⁴. Rupture at the LHBT musculotendinous junction has also been seen in weightlifters and correlated with anabolic steroid use²⁴. Transection of the long and short head muscle bellies has been reported in military parachutists resulting from forced abduction of the arm against a static line⁴⁵. A dramatic presentation of displacement of the proximal biceps muscle has been reported in wakeboarders when a slackened towrope suddenly becomes taut while being gripped with flexed elbows. The sudden force ruptures the proximal heads of the biceps muscle and the extreme recoil displaces the proximally torn muscle distally into the volar subcutaneous soft tissues of the forearm beyond the attached distal biceps tendon^41,46. This phenomenon was described as “slingshot displacement of the biceps brachii muscle”. Biceps muscle resection may be necessary in these injuries because of delayed presentation and associated devascularization and denervation of the displaced muscle^41,46.

Partial tendon tears are depicted by an abrupt, often severe reduction in tendon caliber and irregularity of the tendon contour. Intratendinous increased T2 signal may be seen within partial tears (31a). Intrasubstance delamination tears appear as longitudinally oriented intratendinous increased signal on fluid-sensitive sequences. Complete tears of the biceps are indicated by absence of tendon within the bicipital groove (32a). Careful inspection of the images confirms that the tendon is not dislocated. With acute ruptures edema tracks distally ventral to the proximal humerus. The retracted irregular long biceps tendon is frequently identified in this region outlined by T2 hyperintense signal

 

Arthroscopy

Visualization of the subscapularis tendon and its footprint on the lesser tuberosity is best performed through a posterior viewing portal. Abduction and internal rotation of the arm allows visualization of the subscapularis insertion and footprint⁴⁷. The 70 degree arthroscope allows improved visualization of the bicipital groove and subscapularis insertion. Nevertheless, a persistent blind spot for the arthroscopist is the LHBT within the bicipital groove. 3-5 cm of the LHBT can be pulled into the joint and inspected during arthroscopy, allowing only partial visualization of the tendon in the groove⁴⁸. Lesions within the distal bicipital groove and beyond will not be seen. MRI allows preoperative assessment of the LHBT within and distal to the bicipital groove.

Treatment

Initial management of patients with symptoms attributed to the LHBT begin with nonoperative therapies including modification of activity, nonsteroidal anti-inflammatory medication, and physical therapy focused on any coexisting underlying shoulder pathology. Steroid injections into the glenohumeral joint or directly into the bicipital tendon sheath at the bicipital groove may be utilized.

For patients presenting with a cosmetic deformity from LHBT rupture, biceps muscle spasm is common initially with resolution of pain and spasm after 6-8 weeks, with little residual dysfunction of the LHBT^49,50. However more recent studies suggest that the nonoperative treatment of LHBT rupture may not be completely benign, especially in younger patients. Long term follow-up in these patients revealed decreased elbow flexion strength of 8-29% and a decrease in forearm supination strength of 21-23% with continued complaints of pain or disability^51,52.

Surgical treatment is necessary for patients with LHBT pathology that remain symptomatic after nonoperative therapeutic measures. Repair of concomitant impingement, rotator cuff tears, and labral pathology is performed in conjunction with a tenodesis or tenotomy of the LHBT. The indications for tenodesis or tenotomy for biceps tendon injuries include partial tears of the long head of the biceps tendon affecting greater than 25-50% of the tendon diameter, longitudinal tears affecting tendon gliding in the bicipital groove, medial subluxation of the tendon, disruption of the biceps sling, and pain associated with subscapularis tears, massive rotator cuff tears, shoulder arthroplasty, and some SLAP tears⁴⁹.

Evidenced-based studies are limited in the current literature in regards to the efficacy of tenotomy versus tenodesis of the LHBT. In general, tenotomy is recommended for older patients who are more sedentary, patients with obese arms, or patients unconcerned with cosmesis. Tenodesis is recommended for young (<40 year-old) physically active patients with thin arms or for those with concern for cosmesis. Tenotomy can be performed arthroscopically by transecting the LHBT at the superior labrum or supraglenoid tubercle, allowing the tendon to retract distally and out of the glenohumeral joint and into the bicipital groove. In the setting of an hourglass tendon, the intra-articular portion of the tendon is resected to allow distal retraction.

Further debate has centered on the proper location and method of performing a tenodesis. Tenodesis may be performed arthroscopically or as an open procedure depending on the site of fixation. Reattachment sites include fixation to the lesser tuberosity, coracoid, and bicipital groove, transverse humeral ligament, short head of the biceps, and pectoralis major tendon. Fixation may be provided by interference screws, suture anchors, or soft tissue suture fixation.

Conclusion

Pathology of the long head of the biceps (LHB) tendon is a frequent cause of pain. While injuries of the long biceps tendon can be the result of a single traumatic event, they most often occur due to repetitive microtrauma and degeneration. Damage of the supporting biceps pulley mechanism leads to LHBT instability and is most closely associated with subscapularis tendon tears. Because the detection of LHBT pathology is frequently nonspecific by physical examination and may be difficult to identify with shoulder arthroscopy, LHBT injuries may be overlooked during arthroscopic repairs of rotator cuff and labral tears, leading to poor outcomes and necessitating additional surgery. MRI offers the best imaging option for detecting the varied manifestations of biceps tendon pathology and helps to evaluate the adjacent frequently injured shoulder structures.

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