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Description

The glenoid labrum (glenoid ligament) is a fibrocartilaginous rim attached roughly the margin the the glenoid cavity in the shoulder blade. The shoulder share is thought about a ball and also socket joint. However, in bony terms the "socket" (the glenoid fossa that the scapula) is fairly shallow and also small, covering at many only a third of the "ball" (the head the the humerus). The socket is deepened by the glenoid labrum.

The labrum is triangle in section, the basic is fixed to the one of the cavity, while the free edge is thin and sharp.

It is continuous above v the tendon the the lengthy head the the biceps brachii, which gives off 2 fascicles come blend through the fibrous organization of the labrum.

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Structure

The glenoid labrum is similar to the meniscus that the knee. The is a fibro-cartilaginous rubbery structure which encircles the glenoid cavity deepening the socket giving static security to the glenohumeral joint. That acts and looks practically like a washer, sealing the two sides the the share together.The labrum is described like a clock face with 12 o"clock gift at the height (superior), 3 o"clock in ~ the prior (anterior), 6 o"clock in ~ the bottom (inferior) and 9 o"clock in ~ the earlier (posterior). Clinicians might reverse the 3 o"clock and also 9 o"clock for left shoulder explicate 3 o"clock in ~ the back. This deserve to be confusing, for this reason the European culture of Shoulder & Elbow operated doctor (SECEC) has actually agreed to keep 3 o"clock in ~ the front because that either shoulder.<2>

The glenoid labrum is roughly 4 mm thick and also is round or triangular in cross section.

The capsule the the glenohumeral joint attaches to the glenoid labrum. The glenoid labrum is constant with:

superiorly: tendon the the long head of biceps brachiianteriorly:anterior band of the worse glenohumeral ligament

Clinical Relevance

Most instabilities or ache syndromes are linked with injuries or morphologic alters in the glenoid labrum facility or long head that the biceps tendon origin. The an initial anatomic descriptions go earlier to Fick in 1910 and also since then many authors have described the anatomy of this structures. It was Snyder who presented the hatchet SLAP lesions, classifying superior, anterior, posterior labrum changes into 4 grades. It is still unclear whether all of the described and also arthroscopically observed alters are as result of a post-traumatic, gained lesion or even if it is anatomic variations deserve to be present as well. In order to elucidate this problem, 36 cadaver shoulder joints were inspected macroscopically and sectioned because that microscopic evaluation. Here the glenoid could be separated into one superior and also an anterior- remarkable area demonstrating a wide selection of morphologic labral glenoid changes, while the dorsal and also inferior sectors the the glenoid confirmed a fairly uniform anatomy of a firm labrum-glenoid bond. Four species of biceps tendon attachments might be identified comparable to the description given by Vangsness. In addition, a range of anterior-superior alters could it is in found. The sublabral hole as explained by Esch in the clinical setting was uncovered to be a physiologic variant. Precise knowledge of the anatomic morphology the the common glenoid in that variations seems to be crucial to know variants and enable for distinguishing in between physiologic anatomic variants and also pathoanatomic changes in imaging and also the clinical setting.<4>

Anatomic Variants

The key variants occur in Sectors 1 and 2.

Superior Region, or sector 1

This is most likely the area with the most anatomic variants. In young subjects, the labrum adheres strong to the edge of the glenoid cavity, yet with age, a recess develops, return this is no pathological <5>. That is certainly normal as long as there stays joint cartilage approximately the most peripheral insertion of the labral fibers.

Anterosuperior Region, or sector 2

Here again there are countless anatomic variants, an ext or much less related to age. Normally, the labrum is rounded, and also mobile with respect come the sheet of the Glenoid Cavity (Sublabral or Weitbrecht"s Foramen).

The most constant variants are:

Free (13.5%) or no labrum

Biomechanics

The labrum has actually several functions, and 3 in particular:

Increases the call area between humeral head and also scapula, by 2 mm Antero-posteriorly and 4.5 mm Supero-inferiorly;Contributes come the “Viscoelastic Piston” effect, maintaining -32 mmHg intra-articular negative pressure; this is especially effective versus traction anxiety and, to a lesser extent, against shear stress;

Assessment

The capacity to predict the existence of a glenoid labral tear by physical examination was compared with the of magnetic resonance imaging (conventional and also arthro gram) and confirmed v arthroscopy. There to be 37 men and 17 females (average age, 34 years) in the research group. That this group, 64% to be throwing athletes and 61% recalled details traumatic events. Clinical evaluate included background with specific attention to pain v overhead activities, clicking, and instances of shoulder instability. Physical examination consisted of the apprehension, relocation, load and shift, inferior sulcus sign, and also crank tests. Shoulder arthroscopy shown labral tears in 41 patient (76%). Magnetic resonance imaging produced a sensitivity of 59% and a specificity that 85%. Physical examination gave in a sensitivity the 90% and also a specificity the 85%. Physical examination is much more accurate in predicting glenoid labral tears 보다 magnetic resonance imaging. In this era of cost con tainment, completing the diagnostic workup in the clinic without expensive ancillary studies permits the patient"s treatment to proceed in the many timely and also economic fashion.<8>

The various lesions of the glenoid labrum space described. They may involve the antero-inferior, the posterior or the premium (SLAP lesions) part of the labrum. CT-arthrography is the gold typical imaging modality in this ar of shoulder abnormalities.<9>

Epidemiology

The hatchet SLAP ("superior labrum anterior posterior") was at first coined by Snyder and his colleagues while performing a retrospective testimonial of a huge sample the shoulder arthroscopies <10>. While the true as whole incidence the SLAP tears is unknown, the incidence amongst patients undergoing arthroscopy is reported to be between 6 and also 26 percent <11>.

Classification

Four species of SLAP injuries were explained initially:

Type i demonstrated degenerative fraying with undamaged biceps insertionType II, offhanded of the biceps insertionType III, a bucket-handle tear with intact biceps tendon attachments to boneType IV, one intrasubstance tear that the biceps tendon v bucket-handle tear that the exceptional labrum

Risk Factors

In a prospective observational study of 544 continuous shoulder arthroscopies that included 139 SLAP tears, different tear species were linked with details conditions or activities. Type I tears were connected with boosted age, rotator cuff disease, and also osteoarthritis; type II tears were connected with overhead sports; and type III and also IV tears were connected with high-demand occupations . The writer of the examine did not define high-demand occupations or speculate why together occupations were connected with form III or IV lesions, as few such injuries were figured out in the study.

Mechanisms of Injury

Given this associations, different types of SLAP injuries likely involve various mechanisms that injury. Follow to a retrospective review of 84 arthroscopically diagnosed labral tears, the most common mechanism involved an worse traction-type injury one of two people from a autumn or a suddenly pull when lifting a heavy object<12> . Other usual mechanisms had traumatic glenohumeral dislocation or repetitive shoulder abduction and also external rotation (eg, throwers and other overhead athletes). A direct blow come the shoulder or a autumn onto an outstretched hand may also cause a SLAP tear. A predisposition to maintain certain varieties of SLAP injuries might stem from basic shoulder comorbidities, such as multidirectional instability or chronic degenerative changes.

According to some researchers, the "peel-back" system accounts for form II labral injuries <13>. In this mechanism, excessive stress on the biceps tendon attachment when the shoulder is inserted in abduction and maximal external rotation leader to separation and also tearing the the premium posterior labrum from the glenoid. Overhead throw athletes (eg, baseball pitchers, cricket bowlers) and laborers who swing devices overhead commonly assume this position.

During recurring overhead motions that show off abduction to 90 degrees and also maximal external rotation, increases in outside rotation variety can be viewed over time. Often, this increase is connected with a ns of inner rotation, a sample termed glenohumeral internal rotation deficit (GIRD) <14>. When it remains unclear exactly how GIRD develops, it deserve to lead come tightening of the posterior capsule, i m sorry in turn transforms the translational mechanics of the humeral head in ~ the glenoid. These alters can lead to inner impingement and also posterior labral injury.<15>

Treatment

Postoperative Treatment and Results

Typically requires six months and also often as long as 12 month to return to throwing ~ surgical repair of a SLAP lesion. Healing should not be rushed. The patient should work through the proper stages that rehabilitation gradually and also clinicians need to guard versus the patient proceeding prematurely. Given the complexity and also importance the post-operative rehabilitation, patient are finest served by participating in a rehabilitation routine under the supervision of a knowledgeable physics therapist, athletic trainer, or similar clinician.

The post-operative rehabilitation regime is frequently divided into three stages:

Phase 1 Maximal protection phase (approximately six weeks duration)Phase 2 Moderate defense phase (approximately six weeks duration)Phase 3 Minimum defense phase (approximately 14 main duration)Phase 1 Maximal defense Phase

The maximal defense phase starts the job after surgical procedure until approximately six weeks. During this step the major goal is to protect the surgical fix from re-injury and also to minimize pain and also inflammation. The patient is typically in a sling for the complete six weeks; avoiding any motion that tons the biceps tendon is critical. The patient starts to perform passive and active assisted range of activity (ROM) exercises throughout this phase however these are limited. Safeguarded motion starts with passive motion listed below 90 degrees of shoulder flexion and abduction, and progresses slowly after the first two weeks. Minimal active activity is presented gradually. Toward the end of this stage, the patient begins to do some basic isometric toughness exercises.

Phase 2 Moderate defense Phase

The moderate defense phase starts at about week seven and also continues through week 12. During this phase, one major goal is come regain full active variety of motion. Roughly week 10, energetic loading the the biceps tendon can begin. If full ROM is not acquired with the simple program, extr focused stretching and also mobilization exercises may be required. Raising levels the resistance are offered for scapular and also rotator cuff exercises. Exercises for emerging core strength space performed throughout this phase.

Phase 3 Minimum security Phase

The minimum protection phase starts at about week 13 and also continues with week 26. Throughout this phase, the patient may progressively resume throwing or overhead occupational activities until full role is restored. Throwing indigenous a mound may begin around 24 to 28 main after surgical procedure in most cases. It is vital that complete shoulder mobility is achieved. Complete strength and motion the the scapular stabilizers and rotator cuff muscles need to be completed before full task is resumed. To stop reinjury, the is essential that a pitcher’s cram mechanics it is in assessed and also any troubles resolved, and that proper guidelines regarding the kind and variety of pitches thrown be adhered to .

For the patience who complies with up with a primary treatment or sports medicine physician, failure to progress through the phases in a reasonable time frame (approximately three months because that phases 1 or 2 and six months because that phase 3) merits consultation v the orthopedic surgeon who completed the repair. Similarly, if the patient creates unexpected ache or dysfunction during the post-operative rehabilitation, the patient need to return to your orthopedic surgeon because that evaluation. The operated doctor should have actually the final say around whether the patience is prepared to resume complete activity.

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A systematic review of researches of the management of type 2 SLAP tears (506 patient included) discovered that 83 percent of patients reported good-to-excellent results adhering to operative repair . However, just 73 percent that patients returned to their prior level the function, while only 63 percent the overhead throw athletes went back to their vault level the play. Should main repair fail, biceps tenodesis regularly relieves pain. About 40 percent of patient report wonderful outcome v this surgery, while around 4 percent experience far-ranging complications . Typical long-term disabilities ~ a failed surgical repair encompass pain and instability through overhead or abducted and also externally rotated shoulder positions. That is unclear even if it is SLAP tears boost the hazard for glenohumeral osteoarthritis.<16>