Glenoid Labrum: Difference between revisions

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== Description  ==
== Introduction ==
 
[[File:AC ligs.png|thumb|Glenoid Labrum (marked lig.)]]
The glenoid labrum (glenoid ligament) is a fibrocartilaginous rim attached around the margin of the glenoid cavity in the shoulder blade. The shoulder joint is considered a ball and socket joint. However, in bony terms the 'socket' (the glenoid fossa of the scapula) is quite shallow and small, covering at most only a third of the 'ball' (the head of the humerus). The socket is deepened by the glenoid labrum.
The glenoid labrum is a fibrocartilaginous complex that attaches as a rim to the articular [[cartilage]] of the glenoid fossa. Its role is to deepen and increase the surface area of the glenoid (acting as a static stabiliser of the [[Glenohumeral Joint|glenohumeral joint]]); resist anterior and posterior movement and assist with blocking [[Shoulder Dislocation|shoulder dislocation]] and [[Shoulder Subluxation|subluxation]] at the maximal ranges of motion.<ref name=":0">Radiopedia [https://radiopaedia.org/articles/glenoid-labrum Glenoid Labrum] Available:https://radiopaedia.org/articles/glenoid-labrum (accessed 10.1.2023)</ref>
 
The labrum is triangular in section, the base is fixed to the circumference of the cavity, while the free edge is thin and sharp.
 
It is continuous above with the tendon of the long head of the biceps brachii, which gives off two fascicles to blend with the fibrous tissue of the labrum.<ref>https://en.wikipedia.org/wiki/Glenoid_labrum</ref><br>  


The labrum is frequently involved in shoulder pathology by acute trauma (e.g. shoulder dislocation) or more commonly by repeated microtrauma, e.g. shoulder subluxation.<ref name=":1">Clavert P. [https://www.sciencedirect.com/science/article/pii/S1877056814003259 Glenoid labrum pathology.] Orthopaedics & Traumatology: Surgery & Research. 2015 Feb 1;101(1):S19-24.Available:http://www.sciencedirect.com/science/article/pii/S1877056814003259 (accessed 10.1.2023)</ref>
== Structure  ==
== Structure  ==
Glenoid labrum basics<ref name=":0" />:


The glenoid labrum is similar to the meniscus of the knee. It is a fibro-cartilaginous rubbery structure which encircles the glenoid cavity deepening the socket providing static stability to the glenohumeral joint. It acts and looks almost like a washer, sealing the two sides of the joint together.The labrum is described like a clock face with 12 o'clock being at the top (superior), 3 o'clock at the front (anterior), 6 o'clock at the bottom (inferior) and 9 o'clock at the back (posterior). Clinicans may reverse the 3 o'clock and 9 o'clock for left shoulder describing 3 o'clock at the back. This can be confusing, so the European Society of Shoulder &amp; Elbow Surgeons (SECEC) has agreed to keep 3 o'clock at the front for either shoulder.<ref>https://www.shoulderdoc.co.uk/article/1399</ref>
* Made of fibrocartilage, 3 mm thick and 4 mm wide (highly variable).  
 
* The labrum is most commonly triangular or round on cross-section.
The glenoid labrum is approximately 4 mm thick and is round or triangular in cross section.&nbsp;
* Inferior to the equatorial pole of the glenoid, the labrum gradually becomes rounder and smaller in contrast to superiorly , where it is more triangular in shape and larger.
 
The capsule of the glenohumeral joint attaches to the glenoid labrum. The glenoid labrum is continuous with:
 
superiorly: tendon of the long head of biceps brachii<br>anteriorly:<br>anterior band of the inferior glenohumeral ligament<br>middle glenohumeral ligament (variably)<ref>https://radiopaedia.org/articles/glenoid-labrum</ref>
 
== Clinical relevance  ==
 
Most instabilities or pain syndromes are associated with injuries or morphologic changes in the glenoid labrum complex or long head of the biceps tendon origin. The first anatomic descriptions go back to Fick in 1910 and since then many authors have described the anatomy of these structures. It was Snyder who introduced the term SLAP lesions, classifying superior, anterior, posterior labrum changes into four grades. It is still unclear whether all of the described and arthroscopically observed changes are due to a post-traumatic, acquired lesion or whether anatomic variations can be present as well. In order to elucidate this problem, 36 cadaver shoulder joints were inspected macroscopically and sectioned for microscopic evaluation. Here the glenoid could be divided into an superior and an anterior- superior area demonstrating a wide variety of morphologic labral glenoid changes, while the dorsal and inferior sectors of the glenoid showed a relatively uniform anatomy of a firm labrum-glenoid bond. Four types of biceps tendon attachments could be identified similar to the description given by Vangsness. In addition, a variety of anterior-superior changes could be found. The sublabral hole as described by Esch in the clinical setting was found to be a physiologic variant. Precise knowledge of the anatomic morphology of the normal glenoid in its variations seems to be necessary to understand variants and allow for distinguishing between physiologic anatomic variants and pathoanatomic changes in imaging and the clinical setting.<ref name="Barthel T et al">https://www.ncbi.nlm.nih.gov/pubmed/12883756</ref>
 
== Anatomic Variants<br>  ==
 
The main variants occur in sectors 1 and 2.
 
1. Superior region, or sector 1
 
This is probably the area with the most anatomic variants. In young subjects, the labrum adheres strongly to the edge of the glenoid cavity, but with age, a recess develops, although this is not pathological <ref>http://www.sciencedirect.com/science/article/pii/S0749806305801057</ref>. It is certainly normal as long as there remains joint cartilage up to the most peripheral insertion of the labral fibers.
 
2. Anterosuperior region, or sector 2
 
Here again there are many anatomic variants, more or less related to age. Normally, the labrum is rounded, and mobile with respect to the edge of the glenoid cavity (sublabral or Weitbrecht's foramen).
 
The most frequent variants are: free (13.5%) or no labrum and narrow, “cord-like” middle glenohumeral ligament (MGHL) in continuity with the biceps footplate (Buford complex) (12%) <ref>https://www.scopus.com/record/display.uri?eid=2-s2.0-29644447279&amp;amp;amp;amp;origin=inward&amp;amp;amp;amp;txGid=F68392337D64C9A9DE1B71C5B7CB7B6A.wsnAw8kcdt7IPYLO0V48gA%3a2</ref>.
 
2.3. Biomechanics
 
The labrum has several functions, and 3 in particular:
 
•<br>it increases the contact area between humeral head and scapula, by 2 mm anteroposteriorly and 4.5 mm supero-inferiorly;<br>•<br>it contributes to the “viscoelastic piston” effect, maintaining -32 mmHg intra-articular negative pressure; this is especially effective against traction stress and, to a lesser extent, against shear stress;<br>•<br>it provides insertion for stabilizing structures (capsule and glenohumeral ligaments), as a fibrous “crossroad”. Labrum and ligaments are in synergy in a genuine complex, each structure's contribution varying with the position of the limb: in abduction and external rotation (ABER), the inferior glenohumeral ligament (IGHL) absorbs 51% of the stress, the superior glenohumeral ligament (SGHL) 22% and the MGHL 9% .<ref>http://www.sciencedirect.com/science/article/pii/S1877056814003259</ref>


== Assessment  ==
== Attachments ==


The ability to predict the presence of a glenoid labral tear by physical examination was compared with that of magnetic resonance imaging (conventional and arthro gram) and confirmed with arthroscopy. There were 37 men and 17 women (average age, 34 years) in the study group. Of this group, 64% were throwing athletes and 61% recalled specific traumatic events. Clinical assessment included history with specific attention to pain with overhead activities, clicking, and instances of shoulder instability. Physical examination included the apprehension, relocation, load and shift, inferior sulcus sign, and crank tests. Shoulder arthroscopy confirmed labral tears in 41 patients (76%). Magnetic resonance imaging produced a sensitivity of 59% and a specificity of 85%. Physical examination yielded a sensitivity of 90% and a specificity of 85%. Physical examination is more accurate in predicting glenoid labral tears than magnetic resonance imaging. In this era of cost con tainment, completing the diagnostic workup in the clinic without expensive ancillary studies allows the patient's care to proceed in the most timely and economic fashion.<ref>http://journals.sagepub.com/doi/abs/10.1177/036354659602400205</ref>  
* Superiorly: tendon of the long head of [[Biceps Brachii|biceps brachii]]<ref name=":0" />
* Anteriorly: superior glenohumeral ligament; middle glenohumeral ligament (variably)<ref name=":0" />
* Inferiorly: inferior glenohumeral ligament consisting of an anterior band, axillary pouch, and a posterior band<ref name=":0" />


The different lesions of the glenoid labrum are described. They may involve the antero-inferior, the posterior or the superior (SLAP lesions) part of the labrum. CT-arthrography is the gold standard imaging modality in this field of shoulder abnormalities.<ref>https://www.ncbi.nlm.nih.gov/pubmed/9810074</ref>
== Clinical Presentation ==
Patients with tears of the glenoid labrum present with an extensive range of non-specific symptoms including:


EPIDEMIOLOGY, CLASSIFICATION, AND RISK FACTORS — The term SLAP ("superior labrum anterior posterior") was initially coined by Snyder and his colleagues while performing a retrospective review of a large sample of shoulder arthroscopies <ref>https://www.uptodate.com/contents/superior-labrum-anterior-posterior-slap-tears/abstract/1</ref>. While the true overall incidence of SLAP tears is unknown, the incidence among patients undergoing arthroscopy is reported to be between 6 and 26 percent <ref>https://www.uptodate.com/contents/superior-labrum-anterior-posterior-slap-tears/abstract/2</ref>. Four types of SLAP injuries were described initially:
* Discomfort/pain<ref name=":1" />, unable to pinpoint<ref name=":2">Sheikh, Y. (2021) ''Glenoid Labral tear: Radiology reference article'', ''Radiopaedia Blog RSS''. Available at: https://radiopaedia.org/articles/glenoid-labral-tear?lang=us (Accessed: 26 July 2023).</ref>.
* Joint weakness<ref name=":2" /> and/or instability<ref name=":1" /><ref name=":2" />
* Clicking<ref name=":2" />


●Type I demonstrated degenerative fraying with intact biceps insertion<br>●Type II, detachment of the biceps insertion<br>●Type III, a bucket-handle tear with intact biceps tendon attachment to bone<br>●Type IV, an intrasubstance tear of the biceps tendon with bucket-handle tear of the superior labrum<br>In a prospective observational study of 544 consecutive shoulder arthroscopies that included 139 SLAP tears, different tear types were associated with particular conditions or activities. Type I tears were associated with increased age, rotator cuff disease, and osteoarthritis; Type II tears were associated with overhead sports; and Type III and IV tears were associated with high-demand occupations . The authors of the study did not define high-demand occupations or speculate why such occupations were associated with Type III or IV lesions, as few such injuries were identified in the study.
== Anatomic Variants  ==


Given these associations, different types of SLAP injuries likely involve different mechanisms of injury. According to a retrospective review of 84 arthroscopically diagnosed labral tears, the most common mechanism involved an inferior traction-type injury either from a fall or a sudden pull when lifting a heavy object<ref>https://www.uptodate.com/contents/superior-labrum-anterior-posterior-slap-tears/abstract/3</ref> . Other common mechanisms included traumatic glenohumeral dislocation or repetitive shoulder abduction and external rotation (eg, throwers and other overhead athletes). A direct blow to the shoulder or a fall onto an outstretched hand may also cause a SLAP tear. A predisposition to sustaining certain types of SLAP injuries may stem from underlying shoulder comorbidities, such as multidirectional instability or chronic degenerative changes.
* Inconsistent cross-sectional shape: blunted, cleaved, notched or flat.<ref name=":0" />
* Medialised posterior labrum<ref name=":0" />
* Anterior capsulolabral insertion variance<ref name=":0" />


According to some researchers, the "peel-back" mechanism accounts for Type II labral injuries <ref>https://www.uptodate.com/contents/superior-labrum-anterior-posterior-slap-tears/abstract/4</ref>. In this mechanism, excessive stress on the biceps tendon attachment when the shoulder is placed in abduction and maximal external rotation leads to separation and tearing of the superior posterior labrum from the glenoid. Overhead throwing athletes (eg, baseball pitchers, cricket bowlers) and laborers who swing tools overhead frequently assume this position.  
== Biomechanics ==
The labrum's most important functions include<ref name=":1" />:
# Increasing the contact area between [[Humerus|humeral]] head and [[scapula]].
# Helping in the provision of the “viscoelastic piston” effect. This is particularly effective against traction traction stress.
# Providing insertion for stabilising structures, as a fibrous “crossroad”.  


During repetitive overhead motions that involve abduction to 90 degrees and maximal external rotation, increases in external rotation range can be seen over time. Often, this increase is associated with a loss of internal rotation, a pattern termed glenohumeral internal rotation deficit (GIRD) <ref>https://www.uptodate.com/contents/superior-labrum-anterior-posterior-slap-tears/abstract/5</ref>. While it remains unclear how GIRD develops, it can lead to tightening of the posterior capsule, which in turn changes the translational mechanics of the humeral head within the glenoid. These changes can lead to internal impingement and posterior labral injury.<ref>https://www.uptodate.com/contents/superior-labrum-anterior-posterior-slap-tears</ref>
== Accuracy of Assessment ==


== Treatment ==
The ability to predict the presence of a glenoid labral tear by physical examination was compared with that of magnetic resonance imaging (conventional and arthro gram) and confirmed with arthroscopy. The main points of study include<ref>Liu SH, Henry MH, Nuccion S, Shapiro MS, Dorey F. [https://journals.sagepub.com/doi/abs/10.1177/036354659602400205 Diagnosis of glenoid labral tears: a comparison between magnetic resonance imaging and clinical examinations.] The American journal of sports medicine. 1996 Mar;24(2):149-54 </ref>:


Postoperative treatment and results — It typically requires six months and often as long as 12 months to return to throwing after surgical repair of a SLAP lesion. Healing must not be rushed. The patient should work through the appropriate stages of rehabilitation gradually and clinicians must guard against the patient progressing prematurely. Given the complexity and importance of post-operative rehabilitation, patients are best served by participating in a rehabilitation program under the supervision of a knowledgeable physical therapist, athletic trainer, or comparable clinician.
* 37 men and 17 women (average age, 34 years) in the study group, 64% were throwing athletes and 61% recalled specific traumatic events.
* Clinical assessment included history with specific attention to pain with overhead activities, clicking, and instances of shoulder instability.  
* Physical examination included the [[Apprehension Test|apprehension]], relocation, [[Load and Shift|load and shift]], [[Inferior Sulcus Test|inferior sulcus sign]], and [[Crank Test|crank tests]].
* Shoulder arthroscopy confirmed labral tears in 41 patients (76%).  
* Magnetic resonance imaging produced a sensitivity of 59% and a specificity of 85%.
* Physical examination yielded a sensitivity of 90% and a specificity of 85%.  


The post-operative rehabilitation program is typically divided into three stages:
Conclusion: Physical examination is more accurate in predicting glenoid labral tears than magnetic resonance imaging. In this era of cost containment, completing the diagnostic workup in the clinic without expensive additional studies allows the patient's care to proceed in the most timely and economic fashion.
== Location of Injuries ==
[[File:Shoulder dislocation, anteroposterior after reduction, with Bankart and Hill-Sachs lesions, with labels.jpeg|thumb|Bankart lesion, a glenoid labrum injury]]
Labral injuries are named according to their location:


●Phase 1 – Maximal protection phase (approximately six weeks duration)<br>●Phase 2 – Moderate protection phase (approximately six weeks duration)<br>●Phase 3 – Minimum protection phase (approximately 14 weeks duration)<br>The maximal protection phase begins the day after surgery until around six weeks. During this phase the primary goal is to protect the surgical repair from re-injury and to minimize pain and inflammation. The patient is typically in a sling for the full six weeks; avoiding any motion that loads the biceps tendon is critical. The patient begins to perform passive and active assisted range of motion (ROM) exercises during this phase but these are limited. Protected motion begins with passive motion below 90 degrees of shoulder flexion and abduction, and progresses gradually after the first two weeks. Limited active motion is introduced gradually. Toward the end of this stage, the patient begins to perform some basic isometric strength exercises.
* Superior labrum: [[SLAP Lesion|SLAP]] lesions are the most common and includes 8 types of SLAP tears. Less frequently, Andrew's lesion can occur<ref name=":1" />.
* Anterior labral tear: This is very rare and is a pure anterior tear associated with a medial glenohumeral ligament tear<ref name=":1" />.
* Posterior labrum: Less frequent when compared to anterior tears. It is caused by Walch’s internal impingement in the stable shoulder. There are various contributing factors including anterior capsule insufficiency, humeral retroversion or posteroinferior capsule contracture<ref name=":1" />.
* Anteroinferior labrum: Typically found in shoulders with acute or chronic anterior instability. Injury types include: [[Bankart lesion]]; Perthes lesion; glenolabral articular disruption lesion (GLAD); anterior labroligamentous periosteal sleeve avulsion lesion (ALPSA). Bankart lesions are the most common type of injury in the unstable shoulder<ref name=":1" />.
* Posteroinferior labrum: These injuries are found in the rare cases of posterior instability. Injuries include reverse Bankart lesion; and Kim's lesion (superficial tears between the posterior glenoid labrum and glenoid articular cartilage without labral detachment)<ref name=":1" />. Other lesions include posterior GLAD and posterior labrocapsular periosteal sleeve avulsion lesion (POLPSA).
* Circumferential labral lesion


The moderate protection phase begins at approximately week seven and continues through week 12. During this phase, one major goal is to regain full active range of motion. Around week 10, active loading of the biceps tendon can begin. If full ROM is not obtained with the basic program, additional focused stretching and mobilization exercises may be required. Increasing levels of resistance are used for scapular and rotator cuff exercises. Exercises for developing core strength are performed during this phase.
== Treatment and prognosis ==
'''Painful tears:'''


The minimum protection phase begins at approximately week 13 and continues through week 26. During this phase, the patient may gradually resume throwing or overhead occupational activities until full function is restored. Throwing from a mound may begin around 24 to 28 weeks after surgery in most cases. It is critical that full shoulder mobility is achieved. Full strength and motion of the scapular stabilizers and rotator cuff muscles should be achieved before full activity is resumed. To prevent reinjury, it is important that a pitcher’s throwing mechanics be assessed and any problems resolved, and that appropriate guidelines regarding the type and number of pitches thrown be followed .
SLAP: There is debate between tenodesis of the long head of biceps brachii tendon versus suturing the labral tear. In flap or bucket-handle tears, treatment can be as simple as a resection of the bucket-handle followed by a check of the biceps footplate insertion stability. Tenodesis is probably the most effective and final option<ref name=":1" />. The French Arthroscopy Society suggests that suturing can be done in athletic, under 20 years old persons and that for the rest, biceps tenodesis and tenotomy should be done<ref name=":1" />.


For the patient who follows up with a primary care or sports medicine physician, failure to progress through the phases in a reasonable time frame (approximately three months for phases 1 or 2 and six months for phase 3) merits consultation with the orthopedic surgeon who completed the repair. Similarly, if the patient develops unexpected pain or dysfunction during the post-operative rehabilitation, the patient should return to their orthopedic surgeon for evaluation. The surgeon should have the final say about whether the patient is ready to resume full activity.
Walch’s internal impingement: Rehabilitation by a physiotherapist is the first-line of treatment. Should conservative management fail, the old successful surgery option is Lévigne glenoidplasty<ref name=":1" />.


A systematic review of studies of the management of Type 2 SLAP tears (506 patients included) found that 83 percent of patients reported good-to-excellent results following operative repair . However, only 73 percent of patients returned to their prior level of function, while only 63 percent of overhead throwing athletes returned to their previous level of play. Should primary repair fail, biceps tenodesis often relieves pain. About 40 percent of patients report an excellent outcome with this surgery, while approximately 4 percent experience significant complications . Common long-term disabilities after a failed surgical repair include pain and instability with overhead or abducted and externally rotated shoulder positions. It is unclear whether SLAP tears increase the risk for glenohumeral osteoarthritis.<ref>https://www.uptodate.com/contents/superior-labrum-anterior-posterior-slap-tears</ref>
'''Cases of instability:'''


== See also ==
Anterior instability: In summary, arthroscopy is performed to reinsert the detached anterior labrum and capsule and to treat any associated lesions. When bone-blocks are done, resection of the anterior labral tear will be done<ref name=":1" />.


== Recent Related Research (from Pubmed)  ==
Posterior instability: Reliability of arthroscopic posterior stabilisation is improving and includes suturing the labrum onto the posterior edge of the glenoid cavity<ref name=":1" />.
<div class="researchbox"><rss>LINK HERE|charset=UTF-8|short|max=10</rss></div><div class="researchbox">http://bmjopensem.bmj.com/content/2/1/e000209</div><div class="researchbox"></div><div class="researchbox"></div><div class="researchbox"></div><div class="researchbox"></div><div class="researchbox"><ref>https://www.google.co.in/url?sa=t&amp;amp;amp;amp;amp;rct=j&amp;amp;amp;amp;amp;q=&amp;amp;amp;amp;amp;esrc=s&amp;amp;amp;amp;amp;source=web&amp;amp;amp;amp;amp;cd=15&amp;amp;amp;amp;amp;cad=rja&amp;amp;amp;amp;amp;uact=8&amp;amp;amp;amp;amp;ved=0ahUKEwiWxdi4rsnTAhWIvo8KHZ4YCzw4ChAWCDgwBA&amp;amp;amp;amp;amp;url=http%3A%2F%2Fbmjopensem.bmj.com%2Fcontent%2F2%2F1%2Fe000209&amp;amp;amp;amp;amp;usg=AFQjCNEZEuZbcs2W0kNsE41MC0GmrcuP-A</ref></div><div class="researchbox"></div><div class="researchbox"><ref>https://www.google.co.in/url?sa=t&amp;amp;amp;amp;amp;rct=j&amp;amp;amp;amp;amp;q=&amp;amp;amp;amp;amp;esrc=s&amp;amp;amp;amp;amp;source=web&amp;amp;amp;amp;amp;cd=11&amp;amp;amp;amp;amp;cad=rja&amp;amp;amp;amp;amp;uact=8&amp;amp;amp;amp;amp;ved=0ahUKEwiWxdi4rsnTAhWIvo8KHZ4YCzw4ChAWCCAwAA&amp;amp;amp;amp;amp;url=https%3A%2F%2Fwww.hindawi.com%2Fjournals%2Faorth%2F2013%2F125960%2F&amp;amp;amp;amp;amp;usg=AFQjCNFvsPzgF0lSEGFymewl_7_Wr-_sVg</ref></div><div class="researchbox"></div><div class="researchbox"><ref>https://www.google.co.in/url?sa=t&amp;amp;amp;amp;amp;rct=j&amp;amp;amp;amp;amp;q=&amp;amp;amp;amp;amp;esrc=s&amp;amp;amp;amp;amp;source=web&amp;amp;amp;amp;amp;cd=17&amp;amp;amp;amp;amp;cad=rja&amp;amp;amp;amp;amp;uact=8&amp;amp;amp;amp;amp;ved=0ahUKEwiWxdi4rsnTAhWIvo8KHZ4YCzw4ChAWCEMwBg&amp;amp;amp;amp;amp;url=http%3A%2F%2Femedicine.medscape.com%2Farticle%2F92512-overview&amp;amp;amp;amp;amp;usg=AFQjCNGPKr4rkJuaP20iSvzycYUY4sLFig</ref></div>


For anterior and posterior instability, prognosis depends on associated (especially cartilage) lesions<ref name=":1" />.
== References  ==
== References  ==


<references />  
<references />  


[[Category:Anatomy]] [[Category:Ligaments]]
[[Category:Anatomy]]  
[[Category:Shoulder - Anatomy]]
[[Category:Shoulder - Anatomy]]
[[Category:Ligaments]]
[[Category:Shoulder - Ligaments]]
[[Category:Shoulder]]

Latest revision as of 15:32, 26 July 2023

Original Editor - Priyanka Chugh

Top Contributors - Priyanka Chugh, Kim Jackson, Lucinda hampton, Wendy Snyders, Naomi O'Reilly, Wanda van Niekerk and 127.0.0.1

Introduction[edit | edit source]

Glenoid Labrum (marked lig.)

The glenoid labrum is a fibrocartilaginous complex that attaches as a rim to the articular cartilage of the glenoid fossa. Its role is to deepen and increase the surface area of the glenoid (acting as a static stabiliser of the glenohumeral joint); resist anterior and posterior movement and assist with blocking shoulder dislocation and subluxation at the maximal ranges of motion.[1]

The labrum is frequently involved in shoulder pathology by acute trauma (e.g. shoulder dislocation) or more commonly by repeated microtrauma, e.g. shoulder subluxation.[2]

Structure[edit | edit source]

Glenoid labrum basics[1]:

  • Made of fibrocartilage, 3 mm thick and 4 mm wide (highly variable).
  • The labrum is most commonly triangular or round on cross-section.
  • Inferior to the equatorial pole of the glenoid, the labrum gradually becomes rounder and smaller in contrast to superiorly , where it is more triangular in shape and larger.

Attachments[edit | edit source]

  • Superiorly: tendon of the long head of biceps brachii[1]
  • Anteriorly: superior glenohumeral ligament; middle glenohumeral ligament (variably)[1]
  • Inferiorly: inferior glenohumeral ligament consisting of an anterior band, axillary pouch, and a posterior band[1]

Clinical Presentation[edit | edit source]

Patients with tears of the glenoid labrum present with an extensive range of non-specific symptoms including:

  • Discomfort/pain[2], unable to pinpoint[3].
  • Joint weakness[3] and/or instability[2][3]
  • Clicking[3]

Anatomic Variants[edit | edit source]

  • Inconsistent cross-sectional shape: blunted, cleaved, notched or flat.[1]
  • Medialised posterior labrum[1]
  • Anterior capsulolabral insertion variance[1]

Biomechanics[edit | edit source]

The labrum's most important functions include[2]:

  1. Increasing the contact area between humeral head and scapula.
  2. Helping in the provision of the “viscoelastic piston” effect. This is particularly effective against traction traction stress.
  3. Providing insertion for stabilising structures, as a fibrous “crossroad”.

Accuracy of Assessment[edit | edit source]

The ability to predict the presence of a glenoid labral tear by physical examination was compared with that of magnetic resonance imaging (conventional and arthro gram) and confirmed with arthroscopy. The main points of study include[4]:

  • 37 men and 17 women (average age, 34 years) in the study group, 64% were throwing athletes and 61% recalled specific traumatic events.
  • Clinical assessment included history with specific attention to pain with overhead activities, clicking, and instances of shoulder instability.
  • Physical examination included the apprehension, relocation, load and shift, inferior sulcus sign, and crank tests.
  • Shoulder arthroscopy confirmed labral tears in 41 patients (76%).
  • Magnetic resonance imaging produced a sensitivity of 59% and a specificity of 85%.
  • Physical examination yielded a sensitivity of 90% and a specificity of 85%.

Conclusion: Physical examination is more accurate in predicting glenoid labral tears than magnetic resonance imaging. In this era of cost containment, completing the diagnostic workup in the clinic without expensive additional studies allows the patient's care to proceed in the most timely and economic fashion.

Location of Injuries[edit | edit source]

Bankart lesion, a glenoid labrum injury

Labral injuries are named according to their location:

  • Superior labrum: SLAP lesions are the most common and includes 8 types of SLAP tears. Less frequently, Andrew's lesion can occur[2].
  • Anterior labral tear: This is very rare and is a pure anterior tear associated with a medial glenohumeral ligament tear[2].
  • Posterior labrum: Less frequent when compared to anterior tears. It is caused by Walch’s internal impingement in the stable shoulder. There are various contributing factors including anterior capsule insufficiency, humeral retroversion or posteroinferior capsule contracture[2].
  • Anteroinferior labrum: Typically found in shoulders with acute or chronic anterior instability. Injury types include: Bankart lesion; Perthes lesion; glenolabral articular disruption lesion (GLAD); anterior labroligamentous periosteal sleeve avulsion lesion (ALPSA). Bankart lesions are the most common type of injury in the unstable shoulder[2].
  • Posteroinferior labrum: These injuries are found in the rare cases of posterior instability. Injuries include reverse Bankart lesion; and Kim's lesion (superficial tears between the posterior glenoid labrum and glenoid articular cartilage without labral detachment)[2]. Other lesions include posterior GLAD and posterior labrocapsular periosteal sleeve avulsion lesion (POLPSA).
  • Circumferential labral lesion

Treatment and prognosis[edit | edit source]

Painful tears:

SLAP: There is debate between tenodesis of the long head of biceps brachii tendon versus suturing the labral tear. In flap or bucket-handle tears, treatment can be as simple as a resection of the bucket-handle followed by a check of the biceps footplate insertion stability. Tenodesis is probably the most effective and final option[2]. The French Arthroscopy Society suggests that suturing can be done in athletic, under 20 years old persons and that for the rest, biceps tenodesis and tenotomy should be done[2].

Walch’s internal impingement: Rehabilitation by a physiotherapist is the first-line of treatment. Should conservative management fail, the old successful surgery option is Lévigne glenoidplasty[2].

Cases of instability:

Anterior instability: In summary, arthroscopy is performed to reinsert the detached anterior labrum and capsule and to treat any associated lesions. When bone-blocks are done, resection of the anterior labral tear will be done[2].

Posterior instability: Reliability of arthroscopic posterior stabilisation is improving and includes suturing the labrum onto the posterior edge of the glenoid cavity[2].

For anterior and posterior instability, prognosis depends on associated (especially cartilage) lesions[2].

References[edit | edit source]

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Radiopedia Glenoid Labrum Available:https://radiopaedia.org/articles/glenoid-labrum (accessed 10.1.2023)
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 Clavert P. Glenoid labrum pathology. Orthopaedics & Traumatology: Surgery & Research. 2015 Feb 1;101(1):S19-24.Available:http://www.sciencedirect.com/science/article/pii/S1877056814003259 (accessed 10.1.2023)
  3. ↑ 3.0 3.1 3.2 3.3 Sheikh, Y. (2021) Glenoid Labral tear: Radiology reference article, Radiopaedia Blog RSS. Available at: https://radiopaedia.org/articles/glenoid-labral-tear?lang=us (Accessed: 26 July 2023).
  4. ↑ Liu SH, Henry MH, Nuccion S, Shapiro MS, Dorey F. Diagnosis of glenoid labral tears: a comparison between magnetic resonance imaging and clinical examinations. The American journal of sports medicine. 1996 Mar;24(2):149-54
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