AOSM Extra-articular origin of long head of biceps brachii that is attached to the rotator cuff

INTRODUCTION

Long head of biceps brachii (LHBB) is an anatomical site in which a lot of anatomical variants exist ­ the most common being a third head LHBB. Conversely, an extra­

articular origin of LHBB has rarely been reported [1-5].

The clinical importance or relevance of these variants are yet unclear [1-4]. Thus, without more knowledge of these anatomical variants it is difficult to accurately diagnose lesions of the biceps through magnetic resonance imaging (MRI) [5]. We found and treated a case of an extra­articular origin of the LHBB that was attached firmly to the rotator cuff with laminated tear.

CASE REPORT

A 57­year­old woman presented with spontaneous pain and weakness in the left shoulder 8 months prior to the hospital visit. The symptoms aggravated 3 weeks prior to the visit when she fell on her left hand. Physical examination showed tenderness on the lateral aspect and on the bicipital groove of the shoulder joint. Range of passive motion was normal, whereas, active flexion and

abduction motions were decreased from normal. The patient showed positive scores for the Neer’s impingement test, Hawkin’s impingement test, empty can test, and full can test, and negative scores for the Speed test, Yergason test, and instability test.

Simple X­ray films showed no abnormal findings;

therefore further radiological checks were made through MRI. MRI revealed a 20 × 19 mm sized full thickness rotator cuff tear that crossed from the rotator interval to the infraspinatus tendon including the supraspinatus tendon. The LHBB could be traced along the bicipital groove, but not in the intra­articular area. The origin of the LHBB was absent on the superior labrum (Fig. 1).

The patient was diagnosed with a full thickness rotator cuff tear. During the arthroscopic operation, we found that the gleno­humeral joint com municated into the subacromial space through a large rotator cuff tear. The torn rotator cuff was laminated and the upper tissue of the laminated rotator cuff was retracted more medially than the lower tissue. We found that the LHBB did not originate from the superior labrum but panned out at its end to merge with the inferior aspect of the lower tissue of the torn supraspinatus tendon, which was assumed The long head of biceps brachii contributes to the stability of glenohumeral joints. Its pathologic changes can cause pain in the shoulders independent of or in combination with other structures. Various anatomical variations of the long head of biceps brachii have been reported, but an extra­articular origin of the long head of biceps brachii has rarely been reported. Here, we report a case of an extra­articular origin of the long head of biceps brachii that was firmly attached to the rotator cuff.

Keywords: Shoulder; Long head of biceps brachii; Anatomic variant; Arthroscopy

Extra-articular origin of long head of biceps brachii that is attached to the rotator cuff

Woo-Jin Yi, Jin-Hyoung Son

Department of Orthopaedic Surgery, Seoul Red-Cross Hospital, Seoul, Korea

Copyright © 2014 Korean Arthroscopy Society and Korean Orthopedic Society for Sports Medicine. All rights reserved.

CC This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/

by-nc/3.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received January 16, 2014; Revised February 18, 2014; Accepted February 26, 2014

Correspondence to: Woo-Jin Yi , Department of Orthopaedic Surgery, Seoul Red-Cross Hospital, 9 Saemunan-ro, Jongno-gu, Seoul 110-747, Korea. Tel: +82-2-2002-8390, Fax: +82-2-2002-8398, E-mail: [email protected]

Arthroscopy and Orthopedic Sports Medicine

AOSM

to be the capsule. The attachment of the LHBB to the lower tissue of the torn rotator cuff was so firm that the torn rotator cuff moved together with the LHBB when the

LHBB glided. There was no pathologic abnormality on the superior labrum except for the absence of the origin of LHBB (Figs. 2, 3).

We performed acromioplasty and then tenodesis of the LHBB to the upper end of the bicipital groove. Lastly, we repaired the lower tissue of the rotator cuff on the footprint just lateral to the articular surface, and then repaired the upper tissue on the lateral area of the repaired lower tissue using a double row suture bridge technique.

DISCUSSION

The LHBB has many kinds of anatomical variants, but the attachment between LHBB and the rotator cuff is not commonly encountered in daily practice. Normally, the LHBB originates from the posterior part of the superior labrum and the supraglenoid tubercle. From its origin, it travels to the intra­articular space over the humeral head, passes out of the joint capsule, and runs down along the bicipital groove.

Fig. 2. (A) The arthroscopic view from the posterior portal shows the upper tissue (arrows) and the lower tissue (arrowheads) of laminated rotator cuff tear that is firmly attached to the long head of biceps brachii (LHBB). (B) When the LHBB is pushed down, the panning out of the LHBB is clearly seen. The lateral margin of the lower tissue of the rotator cuff (arrowheads) can be distinguished from the LHBB.

Fig. 3. The arthroscopic view from posterior portal shows the non­

intra­articular origin of the long head of biceps brachii on the superior labrum (arrow). SSc, subscapularis tendon; G, glenoid surface.

Fig. 1. (A) A oblique coronal view of a pre­

operative magnetic resonance imaging (MRI) shows a full thickness rotator cuff tear (black arrow). And an absence of the long head of biceps brachii (LHBB) in the intra­articular space and in the superior labrum (white arrow). (B) Another oblique coronal view of a preoperative MRI shows a normal intact LHBB (arrowheads) in the bicipital groove.

Functionally, the LHBB contributes to the stability of shoulder joints. Clinically, the pathologic changes in LHBB may cause pain with or without collateral patho­

logic changes in other structures. Further, during an arthroscopic operation, understanding the anatomical structure and anatomic variants of LHBB may aid surgeons to distinguish between an actual pathology and a rare anatomical property. Thus, the need for a set of standards to differentiate between pathologic changes and anatomic variants of the LHBBs is very important [4,6,7].

Although some investigators suggest that LHBB does not have any specific function in shoulder joints, it is generally accepted that LHBB contributes to the stability of the glenohumeral joint by pushing down the humeral head and placing it on the glenoid surface [4,6,8,9]. In fact, many investigators emphasize the correlation between LHBB and anterior instability. Based on the studies that anterior instabilities are commonly found in the patients with LHBB variants, and other studies that electrical activities of the LHBs on electromyography tests are increased in the pitchers with anterior instabilities.

Numerous anatomic variants of LHBBs have been previously reported. Two seminal studies have syste­

matically classified intra­articular variants of LHBBs by reviewing many cases. Dierickx et al. [1] classified variants of the intra­articular LHBBs into 4 major families and into 12 subgroups by analyzing 3,000 arthroscopic findings from retrospective reviews. Kanatli et al. [7] classified variants of intra­articular LHBBs into 7 types by analyzing 671 arthroscopic findings.

But with regard to our case, the classification of Kanatli et al. [7] suggests only one type, the complete synovial tunnel, for the cases that LHBBs are not observed in the

intra­articular spaces. Therefore, it doesn’t include absence of the LHBB or the extra­articular origin from joint capsule or rotator cuff as in our case. The classification of Dierickx et al. [1] does not differentiate the extra­articular origin of LHBB, originating from the joint capsule or rotator cuff, from the complete synovial tunnel, which is described by Kanatli et al. [7] and reported by Hammond and Bryant [10].

The characteristic of synovila tunnel making distinction from our case is that a pristine LHBB of the intra­articular space is completely encased by a a synovial envelope, and thus it is not the true BARC (biceps adhesion to the rotator cuff) complex. So taking this distinction into con­

sideration, we reviewed the cases where the LHBBs did not originate from the superior labrums or supraglenoid tubercles and were not observed in the intra­articular spaces, and then classified them using the classification of Dierickx et al. [1]. In order to exclude complete synovial tunnel, we included only the cases in which the firm attachments of LHBB to the rotator cuffs were identified.

According to our literature review, 5 cases of ADH­

CO (completely attached to the supraspinatus, but not attached to the labrum) were reported [1-5], and in these, 2 cases were identified as having a firm attachment to the rotator cuff [1,4]. The other 2 cases were excluded because there was no clear evidence of a firm attachment to the rotator cuff and therefore, possibilities of complete synovial tunnel existed [2,5]. Whereas in the last case, the LHBB were tapered and merged to the rotator interval [3].

Our case is quite similar to the ADH­CO case reported by Dierickx et al. [1], except for the laminated appearance of the rotator cuff tear. The above two cases can be thought to be caused by the secondary adhesion of LHBB to the

Fig. 4. (A) The oblique coronal view of magnetic resonance imaging of the non­

symptomatic right shoulder shows a non­labral origin (white arrow) and non­

intra­articular origin of the long head of biceps brachii (LHBB). (B) The extra­

articular portion of the LHBB of the non­

symptomatic right shoulder is identified.

An intact rotator cuff (arrowheads) can be seen.

rotator cuff after both are torn. However, the likelihood of this seems to be low in our case for three reasons.

First, the remaining portion of LHBB appears completely normal without any inflammatory changes or adhesion to other tissues. Second, the LHBB pans out at its end and smoothly merges with the joint capsule and rotator cuff (Fig. 2B). Lastly, the MRI of the non­symptomatic contralateral shoulder of the same patient also shows absence of an intra­articular portion of the LHBB but an intact rotator cuff (Fig. 4).

In laminated rotator cuff tears, the lower tissues are usually retracted more medially than the upper tissues, but in our case, the lower tissue was unusually retracted less medially than the upper tissue. This unusual retraction of the lower tissue may have come under constrain by the tension from strong attachment with the LHBB.

During embryonic development, the LHBB is formed from the mesoderm of the arm bud at around the 7th or 8th week [6]. In the past, the LHBB was thought to first develop in the extra­articular, extra­capsular space and then migrate into the intra­articular space. But now the site of development and occurrence of the transmigration is under dispute [1,7]. Audenaert et al. [11] proposed that the LHBB develops between the fibrous capsule and synovial layer, and the staged migration occurs into intra­articular position. Egea et al. [3] and Parikh et al. [9]

proposed that this migration may be interrupted, and this may explain the variations in LHBB. But histological findings by Yeh et al. [12] in their case showed that the tendon fibers dispersed and mixed with the connective tissue of the superior joint capsule after it merged with the capsule, and they stated that the incomplete differentiation of the LHBB and the rotator cuff can explain these variants, a hypothesis to which Gaskin et al.

[5] agreed.

Although the variations of LHBBs have been thought to have no relations with pathology, a lot of opinions have been suggested that the possibility of the shoulder instability increases when accompanied with the variation of LHBB [2,3,5]. The relation with the rotator cuff tear was also suggested [1,3,7]. Dierickx et al. [1] believe that the rotator cuff tears can be induced by a complete adherence or a solid fusion between the rotator cuff and the LHBB. Egea et al. [3] suggested a correlation between a rotator cuff tear and an absence of the LHBB in the intra­

articular space. In agreement to these previous findings, our case of abnormal LHBB was also accompanied with a full thickness rotator cuff tear. We believe the rotator cuff tear may have been caused by the stress on the rotator cuff insertion during biceps contraction because of its firm attachment to the biceps tendons. But further investigation is required to prove this assumption.

As variants of intra­articular LHBBs are difficult to diagnose accurately with MRI or other examinations, it is easy to misinterpret them as pathologic changes.

Therefore, increasing the knowledge and awareness of the variants of LHBBs is a way to improve the rate of accurate interpretations at preoperative examinations. This will help avoid unnecessary operations and decrease the possibility of treatment failures. In an effort to contribute to this, we report a case of an extra­articular origin of a LHBB firmly attached to the rotator cuff that has a laminated tear.

CONFLICT OF INTEREST

No potential conflict of interest relevant to this article was reported.

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