PIMR Chapter 5

<p>BICEPS TENDON AND SUPERIOR LABRAL LESIONS</p><p>The long head of biceps is a tendinous tissue, susceptible to trauma and injury by the nature of its anatomical site and its role in shoulder mechanics. Some debate exists regarding the etiology of biceps injuries, namely, whether they have a primary cause directly associated with the bi- ceps tendon complex or whether they occur secondary to dysfunction elsewhere in the shoulder girdle. Some authors suggest that greater than 90% of patients with a diagnosis of biceps tendonitis actually have a primary di- agnosis of impingement syndrome or scapular instability that is causing secondary involvement of the biceps ten- don.138,139 Studies based on the results of magnetic res- onance imaging and arthroscopic procedures have shed new light on the pathophysiology of the long head of the biceps tendon.138–142</p><p>One of the most significant contributions to under- standing biceps injuries has come as a result of studies that have investigated the superior glenoid labrum. Andrews et al.143 in 1985 described tears in the superior labrum of the glenohumeral joint noting the placement of these tears at the attachment of the biceps tendon (Figure 5-27). In 1990, Snyder et al.144 first described the superolabral anterior to posterior (SLAP) lesion, a le- sion of the superior labrum and adjoining biceps anchor. They categorized SLAP lesions into four types. Type I lesions show degenerative fraying with no detachment of the biceps insertion; type II lesions show detachment of the biceps insertion; type III lesions show a bucket han- dle tear of the superior aspect of the labrum with an in- tact biceps tendon insertion to bone; and type IV lesions show an intrasubstance tear of the biceps tendon with a bucket handle tear of the superior aspect of the labrum.</p><p> Figure 5-27 Labral lesions of the right shoulder. A, Bankart lesion. B, SLAP lesion. (From Magee DJ: Orthopedic physical assessment, ed 6, p 320, Philadelphia, 2014, WB Saunders.)</p><p> Morgan145 further divided type II SLAP lesions into three subtypes, depending on whether the detachment of the labrum involved the anterior aspect of the labrum alone, the posterior aspect, or both.</p><p>In their three-part series, “The Disabled Throwing Shoulder,” Burkhart et al.5,14,146 described the type II SLAP lesion (i.e., involving detachment of the biceps tendon) as the most common pathological entity associ- ated with a “dead arm” syndrome, which they defined as any pathological shoulder condition that deems an ath- lete unable to throw due to pain and subjective unease in the shoulder. In an arthroscopic study done earlier, these same authors observed what they called a dynamic “peel-back phenomenon” in throwers with posterior and combined anteroposterior SLAP lesions.147 They found</p><p>that with the arm in the cocked position of abduction and lateral rotation the peel-back occurred as a result of the effect of the biceps tendon as its vector shifted to a more posterior position in late cocking. The change in angle and the twist of the biceps tendon produced a torsional force to the posterosuperior labrum, causing detachment if the superior labrum was not well anchored to the glenoid. These findings suggested a mechanism of injury for SLAP lesions in throwers that was differ- ent from the mechanism postulated earlier by Andrews et al.143 These researchers had described a deceleration mechanism of labral injuries in throwers, which occurred as the biceps contracted to slow the rapidly extending elbow in the follow-through phase. They believed that this created a high tensile load in the biceps that acted</p><p> 182 Chapter 5 Shoulder Trauma and Hypomobility</p><p>to pull the biceps and superior labrum complex from the bone. Burkhart et al.146 essentially described the oppo- site, an acceleration mechanism of injury; specifically, in late cocking, as the arm began to accelerate forward from an abducted and laterally rotated position, the long head of the biceps and the superior labrum were peeled back rather than pulled from the bone.</p><p>Also of interest in studies of type II SLAP lesions are the clinical factors associated with the primary pathology. Burkhart et al.146 called these factors the “ultimate cul- prits” in dead arm syndrome: (1) a tight posteroinferior capsule, which causes a GIRD and a shift in the glenohu- meral rotation point, (2) the peel-back mechanism pro- duced by the biceps tendon, which leads to a SLAP lesion, (3) hyperexternal (lateral) rotation of the humerus, and (4) scapular protraction. Of the throwers with SLAP le- sions whom they examined, 31% were also found to have rotator cuff tears (38% were full-thickness tears, and 62% were partial-thickness tears).</p><p>As can be seen, the biceps tendon plays an important role in the overall anatomy and function of the shoul- der joint. Most importantly it has a strong relationship to its adjacent tissue, namely the glenoid, glenoid labrum, and rotator cuff. Injury to any one of these structures un- doubtedly affects the integrity of the biceps tendon and the well-being of the entire shoulder girdle.</p><p>Etiology of Biceps Lesions</p><p>Two main etiologic categories have been proposed rel- ative to biceps lesions.148–151 One includes young pa- tients with anomalies of the bicipital groove in whom repetitive trauma is the most important causal factor; the other includes patients in an older age group, where associated degenerative changes in the tendon tend to be the predominant causal factor. In most cases, the cause of biceps pathology is multifactorial and is related, in some manner, to the anatomical location of the tendon. As mentioned, the potential for impingement of the biceps tendon under the coracoacromial arch is great, especially if dysfunction of the rotator cuff and/or scap- ular misalignment are present. The blood supply of the biceps has been shown to be diminished in the long ten- don region, with a “critical zone” similar to that seen in the supraspinatus tendon.152 In abduction, a zone of avascularity exists in the intracapsular portion of the bi- ceps tendon, which is felt to be caused by pressure from the head of the humerus, a phenomenon referred to as wringing-out. Considering these positions, it is easy to see why patients involved in overhead lifting and throw- ing are more susceptible to ruptures, elongations, and dislocations of the biceps tendon. The past several years have produced a proliferation of information about the superior labrum and its relationship to the biceps ten- don.138,140,142–146 As noted earlier, Andrews et al.143 and Snyder et al.144 originally described lesions of the biceps</p><p>and superior labrum, known as SLAP lesions. Two cited causes of SLAP lesions are (1) a FOOSH, which drives the humeral head up onto the labrum and the biceps tendon, and (2) excessive and forceful contraction of the biceps in throwing athletes (e.g., baseball and foot- ball players).</p><p>Relevant Anatomy</p><p>The long head of the biceps tendon originates from the su- perior glenoid labrum and the supraglenoid tubercle and travels obliquely within the shoulder joint, turning sharply inferiorly to exit the joint underneath the transverse hu- meral ligament within the bicipital groove. Interestingly, the biceps tendon does not slide in the groove; rather, the humerus moves on a fixed, passive biceps tendon during shoulder motions. The groove can move along the tendon as much as 4 cm (1.5 inches). The origin of the biceps tendon reportedly varies, not only in the type of insertion (single, bifurcated, or trifurcated) but also in the specific anatomical location where it inserts.148,153,154 Vangsness et al.148 dissected 105 cadaveric shoulders to study the biceps tendon origin and its relationship to the labrum and the supratubercular groove. They classified their findings into four insertion types. Type I insertions occurred in 22% of the subjects and showed a labral at- tachment that was entirely posterior with no contribution to the anterior labrum. In type II insertions the labral contribution was primarily posterior with a small anterior band present. Type III insertions had equal contributions to the anterior and posterior labrum and were found in 37% of the cadavers. Type IV insertions occurred in 8% of the cadavers and consisted mainly of an anterior labral attachment. A different study138 noted the biceps tendon originating from the supraglenoid tubercle 20% to 30% of the time, from the posterosuperior portion of the gle- noid labrum 48% to 70% of the time, and from both the supraglenoid tubercle and the glenoid labrum 25% to 28% of the time. It is clear to see from these studies why the biceps tendon and superior labrum are commonly injured together.</p><p>The biceps tendon is surrounded by a synovial sheath, which ends at the distal end of the bicipital groove, mak- ing the tendon an intra-articular but extrasynovial struc- ture. As the long head of the biceps tendon moves from its origin on the superior glenoid labrum and supragle- noid tubercle to its muscle insertion, it is stabilized in po- sition by the supraspinatus and subscapularis tendons and the capsuloligamentous tissues. The triangular-shaped area between the supraspinatus and the subscapularis tendons is referred to as the rotator interval. It contains the coracohumeral and the superior glenohumeral liga- ments and has on its medial side the coracoid process. Histoanatomical studies have found that both the su- perior glenohumeral ligament and the coracohumeral ligament are important structures in the stabilization</p><p> of the biceps tendon in its groove, and lesions associ-</p><p>ated with any of the components of the rotator interval</p><p>leave the biceps tendon and the rotator cuff vulnerable to injury.141,152,155</p><p>Function of the Biceps</p><p>The biceps extends from the scapula to the forearm and as a result plays an important role in function of the shoulder and elbow. Basmajian and Latif150 characterized the action of biceps as flexion of the elbow when the forearm is in the neutral or supinated position. The muscle is also described as having an important role in decelerating the rapidly moving arm during activities such as forceful overhand throwing. The exact function of the biceps at the shoulder is not well understood. Most references regard it as a weak flexor,140,153,155 but its proposed role as a humeral head depressor remains controversial.152,154,155 One study, which used simulated muscle forces on a biomechanical cadaver model, showed that the biceps tendon force restrained superior humeral translation. A key factor in this study was that this oc- curred in the presence of a large rotator cuff tear.141 A similar study demonstrated that the biceps assisted gleno- humeral anterior stability through increased resistance to torsional forces. Other studies have disputed biceps role as a shoulder stabilizer, finding only a small amount of muscle activity during shoulder motion.140,155–157 Despite the debate, the relationship between the long head of biceps and the function and stability of the glenohumeral joint is an important clinical feature, which must always be considered in the management of patients with a shoulder dysfunction.</p><p>Classification of Biceps Lesions</p><p>Historically, lesions involving the biceps tendon have been categorized as being either a tendonitis or instability. Tendonitis can be further divided into primary tendon- itis, which occurs as a result of pathology of the tendon sheath, or secondary tendonitis, which occurs secondary to an underlying injury that causes subsequent biceps ir- ritation and injury. Many believe that the pathology seen in the biceps is directly related to its intimate relationship with the rotator cuff because they both pass under the coracoacromial arch and are therefore susceptible to im- pingement. “Isolated” ruptures of the long head of the biceps tendon are reportedly uncommon. Neer believed that most ruptures of the long head of the biceps tendon were associated with supraspinatus tears.158,159 One study documented isolated biceps tendon ruptures in as many as 25% of patients,145 but this incidence has not been re- produced in subsequent studies.</p><p>Slatis and Aalto160 developed a three-part classification for biceps lesions. A type A lesion is referred to as im- pingement tendonitis because it occurs secondary to an impingement syndrome and rotator cuff disease. The de- fective cuff exposes the biceps to a rigid coracoacromial</p><p>Chapter 5 Shoulder Trauma and Hypomobility 183</p><p>arch, resulting in tendonitis. This is the most common cause of biceps tendonitis. Type B lesions describe a sub- luxation of the biceps tendon. All subluxations and disloca- tions of the biceps tendon are included in this category. Lesions of the coracohumeral ligament allow the biceps tendon gradually to displace medially; the slipping of the tendon into and out of its groove leads to inflammation and fraying. A type C lesion is called attrition tendonitis. These are primary lesions of the biceps tendon that occur inside the canal, resulting in inflammation and eventual degeneration of the biceps tendon. Often spurring and fraying are evident with this type of tendonitis.</p><p>Biceps lesions have also been classified according to their anatomical location, specifically, at their origin, in the rotator interval, or in association with rotator cuff tears.138 As noted earlier, the third category has spurred considerable study regarding the intimate relationship be- tween the rotator cuff and the biceps tendon complex.</p><p>Clinical Presentation of Biceps Lesions</p><p>Patients with biceps tendon injuries typically present with pain in the proximal anterior area of the shoulder directly over the biceps tendon, with occasional radiation of pain down into the muscle belly. Similar to rotator cuff im- pingement syndromes, the pain can also be described at the deltoid insertion. It is unusual for biceps-related pain to radiate into the neck or distally beyond the el- bow joint. Night pain is sometimes reported with biceps lesions. However, this likely can be explained by overall problems associated with trying to sleep with a painful shoulder. Most shoulder conditions are worse at night for a number of reasons. A compressive load may be present (e.g., lying on the affected shoulder) or in some instances traction may be applied to the shoulder (e.g., arm hanging over the bed); either of these results in pain. Positioning to avoid pain is difficult; however, most pa- tients find that, with the use of many pillows, lying on the contralateral side with the affected arm in neutral, resting on the pillows, is among the most comfortable positions. Many patients with a painful shoulder report that their best rest is achieved in a semireclined position, such as in a recliner, with the arm resting on a pillow in the shoulder resting position.</p><p>Patients with a biceps injury usually describe an insidi- ous onset of their symptoms; however, the pattern of pain can be linked to repetitive types of activities. Acute trauma may be part of the original injury that predisposed the bi- ceps tendon to subsequent rupture or dislocation. Patients with bicipital tendonitis tend to be young or middle aged, with a pain pattern that is less at rest and more intense with activity. This is especially true with overhead activi- ties in daily living, work, and/or sports. Rotation of the humerus at or above the horizontal level brings the tuber- osities, bicipital groove, biceps tendon, and rotator cuff in direct contact with the anterior acromion and the cora- coacromial ligament. Biceps instability is most commonly</p><p>184 Chapter 5 Shoulder Trauma and Hypomobility</p><p>associated with the throwing athlete, where in certain po- sitions of overhead rotation, the motion is accompanied by a palpable snap and pain. Pain is felt locally at the anterior aspect of the shoulder and is aggravated by elevating the arm to around 90°. If the biceps tendon ruptures, there is associated acute pain and sometimes an audible pop in the shoulder, followed in a few days by a notable change in the contour of the arm, with ecchymosis that often tracks downward to the distal muscle belly.</p><p>Numerous special tests have been described that can assist in the diagnosis of biceps conditions; however, their findings should be interpreted in combination with other clinical tests because the sensitivity and specificity of these tests have been reported to be only moderate (see Volume 1 of this series, Orthopedic Physical Assessment, Chapter 5). Most biceps lesions present with tenderness on palpation in the bicipital groove, which often disappears as the lesser tuberosity and groove rotate medially under the short head of the biceps and coracoid process. This is different from the tenderness noted with subdeltoid bursitis and impingement syndromes, which has a more diffuse pat- tern that does not change with arm rotation. According to Burkhead et al.,153 this “tenderness in motion” sign is among the most specific for differentiating biceps lesions. ROM may be slightly restricted and painful into full ab- duction and medial and lateral rotation, usually as a result of pain rather than capsular constriction. Resisted isomet- ric testing reveals a painful weakness with forward flexion of the shoulder.</p><p>Treatment of Biceps Injuries</p><p>As is almost universally true of all injuries, the most ef- fective form of treatment of a biceps injury is prevention. As noted, the biceps is often part of the domino effect that occurs as a result of other primary shoulder patholo- gies. Therefore prevention of injury and overuse in these regions of the shoulder (e.g., rotator cuff) conceivably could prevent injuries to the biceps tendon. Individuals involved in manual labor with either repetitive overhead work or heavy lifting, as well as individuals participating in sports that demand overhand motions, are particularly at risk for biceps injury and should be educated on how to monitor and prevent injuries in this region. Developing a balanced shoulder musculature that includes a strong, healthy rotator cuff and scapular muscle region can help prevent the vicious cycle of impingement tendonitis, irri- tation, and muscle weakness that leads to altered kinemat- ics, instability, and further impingement of tissue, such as the long head of the biceps.</p><p>Once the biceps tendon has been injured, the first step in proper management is a thorough examination of the anterior shoulder, structures of the shoulder girdle, and, if appropriate, kinetic chain. Failure either to identify as- sociated lesions (e.g., those affecting the glenoid labrum and rotator cuff) or to note contributing factors (e.g., poorly stabilized scapula, hypomobile cervical and/or</p><p>thoracic spine, or altered muscle recruitment patterning) may lead the clinician to direct the sole treatment to the affected biceps tendon rather than addressing the true cause of the shoulder injury. Depending on the specific nature and severity of the biceps injury, treatment can range from managing an early, acute inflammatory situ- ation locally at the tendon to treating the biceps tendon by retraining the scapular stabilizing muscles and rota- tor cuff to properly position the glenohumeral joint and therefore reduce impingement on the long head of the biceps anteriorly. Whichever is the case, the message is always the same: the clinician must make sure that treat- ment encompasses not only the affected tissue but also the causal tissue.

Biceps Tendon and Superior Labral Lesions

The long head of the biceps tendon is prone to injury due to its anatomical location and role in shoulder mechanics. There is ongoing debate about whether biceps injuries are primarily caused by issues within the biceps tendon complex or secondary dysfunctions in the shoulder girdle, with some arguing that over 90% of biceps tendonitis cases stem from underlying conditions such as impingement syndrome.

Significant contributions to the understanding of biceps injuries have come from studies of the superior glenoid labrum. SLAP lesions (superolabral anterior to posterior) were categorized by Snyder et al. in 1990 into four types: Type I (fraying without detachment), Type II (detachment of the biceps insertion), Type III (bucket handle tear with intact insertion), and Type IV (intrasubstance tear with bucket handle tear).

Burkhart et al. identified the type II SLAP lesion as common in athletes with “dead arm” syndrome, indicating a painful inability to throw, prompted by mechanisms like the peel-back phenomenon and tight posterior capsule leading to inferior rotation shifts. The biceps tendon plays a critical role in shoulder anatomy and function, particularly in relation to the glenoid, labrum, and rotator cuff.

SUMMARY

Biceps lesions can occur due to repetitive trauma in younger patients or degenerative changes in older patients. Risk factors include biceps tendon impingement and reduced blood supply, often leading to ruptures or elongations, particularly in overhead athletes.

The biceps tendon has various anatomical origins; it is tied closely to the labrum, making injuries common in conjunction. Its function includes forearm flexion and aiding in decelerating arm movements during throwing activities. Classification of biceps lesions generally includes tendonitis (primary or secondary) and instability.

Patients with biceps injuries typically experience pain in the proximal shoulder, with symptoms worsening during activity. Diagnosis may involve special tests to identify tenderness in the bicipital groove. Treatment emphasizes prevention through education on injury risks and aims at addressing not just the biceps but the associated shoulder structures to ensure comprehensive recovery.</p>