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Glenolabral articular disruption (GLAD) lesions are a form of traumatic combined glenoid cartilage and labral injury that may present with anterior or global shoulder discomfort. They occur relatively infrequently but are an important differential diagnosis in managing persistent non-specific shoulder pain following trauma. The extent and type of underlying damage to the glenoid cartilage vary; it can be anything from more minor fibrillation to complete cartilage loss. This activity covers the presentation, examination, diagnosis, and management of GLAD lesions of the shoulder. Objectives: Describe the typical history and clinical exam findings of a GLAD lesion. Explain the recognized pathognomonic features of a GLAD lesion on MR Arthrography and at arthroscopy. Review the pathogenesis of the GLAD lesion following a typical mechanism of injury. Summarize the typical treatment options for GLAD lesions. Access free multiple choice questions on this topic.

A glenolabral articular disruption (GLAD) lesion is a specific subtype of a soft tissue shoulder injury (see Image. Magnetic Resonance Angiography, Axial GLAD Lesion). It involves a combination of a superficial tear to the anterior-inferior labrum and damage to the adjacent articular cartilage on the glenoid. The labrum is the fibrocartilaginous ring surrounding the glenoid fossa. The GLAD superficial labral tear pattern, with the deep fibers still intact, means that the labrum is not grossly unstable. Therefore, pain rather than frank instability symptoms should be present. The extent and type of underlying damage to the glenoid cartilage vary; it can be anything from more minor fibrillation to complete cartilage loss. Since Neviaser first reported it as a limited series in 1993, it is now recognized as an uncommon but well-established cause of shoulder pain following trauma. The original observations indicated that the mechanism usually involves a fall with forced adduction of the abducted, externally rotated shoulder, but 2 cases were related to throwing activities.[1] There may also be a subluxation or dislocation injury associated with it.[2] Since Neviaser reported the original series, it is apparent that the term may sometimes be used more loosely to describe any combined labral pathology and an adjacent articular cartilage lesion. Clinical examination findings may be non-specific, including anteriorly sited or generalized shoulder pain during abduction and external rotation of the joint. Historically, GLAD lesions have been associated with a stable glenohumeral joint. As such, patients would reportedly display a full range of movement on examination without evidence of apprehension or subluxation.[1] More recently, however, several reports have described GLAD lesions in the context of either isolated or recurrent dislocations. Thus, the joint's stability is not necessarily regarded as a distinguishing examination finding.[2] The indistinct findings on examination make a clinical diagnosis of the lesion challenging, and imaging is required to confirm its presence.

GLAD lesions occur as a result of trauma to the shoulder joint. The classic pattern from the original series involves forced shoulder adduction from a position of abduction and external rotation. Typically, this occurred in the context of a fall onto the outstretched arm. The humeral head being forced into the glenoid and then continuing to move with a shear forc,e damaging the cartilage, with the energy of the injury finally tearing the superficial labral fibers, would fit with that mechanism.[3] However, the injury has also been linked to forceful adduction from throwing, clearly a slightly different mechanism.[1] In modern practice, the use of magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA), and arthroscopy to evaluate shoulder injuries has increased recognition of these injuries. As such, the associated injury mechanisms have expanded, and anterior glenohumeral instability is now recognized as a distinct injury mechanism.[2][4][5]

Despite their status as a described glenolabral pathology, the epidemiological data on GLAD lesions are poor. The literature has primarily cited sporadic case reports or small series detailing clinical evaluation and repair techniques rather than reporting more extensive data analyses.[2] The consensus is that GLAD lesions are rare. Glenohumeral labral tears are common; most are anterior-inferior, and isolated inferior tears are less common.[6] GLAD lesions have been estimated to occur in 1.5% to 2.9% of cases of traumatic labral tears.[4] Demographically, case reports generally involve younger males, in keeping with general traumatic labral pathology, although no specific age or gender trends have been reported.

GLAD lesions disrupt the labrum and the underlying glenoid cartilage within the glenohumeral joint. The glenohumeral joint itself is formed by the articulation of the humeral head within the glenoid fossa of the scapula, a synovial ball-and-socket joint. The fossa is lined by articular cartilage and surrounded at its margin by a fibrocartilaginous rim: the labrum.[7] The labrum provides additional depth to the fossa and an anchoring point for both the long head of the biceps tendon and the glenohumeral ligaments.[8] The anteroinferior glenohumeral ligament and anteroinferior labrum together form the anterior labroligamentous complex. This provides an important restraint against anterior dislocation and is considered the most essential soft-tissue structure in maintaining anterior shoulder stability.[3] GLAD lesions typically arise when the humeral head impacts the glenoid fossa due to forceful adduction. There may also be a shear force. This causes a superficial tear to the labrum along its anterior-inferior aspect and a variable degree of underlying cartilage damage. This may include a focal cartilage defect, a more substantial flap tear, or even a loose chondral body.[8] Classically, the integrity of the anterior labroligamentous complex is preserved, which explains why the shoulder joint remains stable in these cases.[3] However, the literature now recognizes the association between GLAD lesions and anterior shoulder instability.[2][4][5][9][10][11][12]

As in any shoulder trauma presentation, a thorough and targeted history, followed by examination including neurovascular assessment and special tests, should be performed on initial review. Often, clinical history and examination findings are vague, and isolating the presence of a GLAD based on clinical suspicion alone is difficult.[1] However, these are typically higher-energy injuries in younger male patients with what should be a clear onset of pain, potentially anteriorly, though perhaps more diffusely, after that event. GLAD lesions may result from a fall onto an outstretched arm and classically involve an adduction force on an abducted, externally rotated shoulder.[1] Therefore, the position of the arm at injury and the direction of impact may provide some indication that a GLAD lesion may be present. However, it may simply be that pain persists following a traumatic instability episode, including a subluxation or dislocation. On examination, pain may be elicited on abduction and external rotation, while forced adduction may produce a ‘popping’ sensation. The patient may localize to deep-seated anterior joint pain. Typically, the above findings are observed in the context of a stable shoulder joint, as the anterior labroligamentous complex remains intact (only the superficial labral fibers are damaged). In more recent studies, however, an association between GLAD lesions and anterior shoulder instability has also been recognized.[11][13][14] In any case, the non-specific nature of the clinical characteristics makes evaluation with imaging essential for diagnosis.

Imaging evaluation is the hallmark of diagnosing the GLAD lesion and should be performed early when clinical suspicion is raised. Lesions may be more difficult to detect on non-contrast MRI or computed tomography arthrography, but newer 3T MRI scanners may improve the detection rate without contrast.[1] MR Arthrography (MRA) is the recognized gold standard for detecting or defining the GLAD lesion.[3][8][15] The pathognomonic finding of the GLAD lesion is a superficial tear to the anterior-inferior labrum with an associated underlying glenoid cartilage defect. The cartilage defect may range from superficial to a transchondral defect exposing subchondral bone. This is demonstrated well on MRA, as contrast is observed tracking the labral tear and filling into the chondral defect or tracks under a damaged articular flap. It is described that the scan should ideally be performed with the shoulder in abduction and external rotation, as this significantly enhances both accuracy and sensitivity in detecting anterior labral tears of the shoulder.[8] This positioning is not necessarily standard for investigating the more common anterior-inferior labral tears and is likely influenced by individual unit protocols and the index of suspicion pre-imaging.

Both operative and non-operative care have been described and should be considered on a case-by-case basis. Preferences for either option depend on individual factors, including expectations, time since the injury, symptom severity, functional demands, and response to treatment to date.[16] Although we recognize that the GLAD lesion epidemiological data is limited, realistically, this injury concerns a younger demographic of patients with a higher energy sporting or traumatic injury pattern. In the typical younger, active patient, we need to recognize that we do not know enough about this condition to predict how likely a trial of non-operative treatment be successful. Time, analgesia, and physical therapy may treat a proportion of patients. However, operative intervention is an option to improve the glenoid articular surface and labral injury. It becomes especially relevant if patients do not improve with a trial of non-operative management or have too much pain to engage with that adequately.[4] It is known that there is an increase in incidental findings on the imaging of older patients, and clinicians should be more cautious of making this diagnosis in such patients; cartilage and labral degeneration are common with increasing age, and even if there is a traumatic event at the onset the emphasis would be a non-invasive approach with analgesia and physiotherapy - controlling pain and optimizing function. An established arthroscopic approach includes treating labral and chondral pathology. The labral surgery may be a debridement of any unstable labral fibers, though any substantive partial tear might be suitable for stabilization. The chondral defect debridement removes loose chondral material and may involve the microfracture of any exposed glenoid bone. The definitive procedure often depends on the size of the chondral defect encountered or, indeed, the combination of labral and chondral injury. Sometimes, a full-thickness glenoid cartilage defect may be debrided, and the labrum may be advanced over it to cover the defect. If the defect is too large, only the articular surface is debrided, and the labrum is left in situ.[4][16]

The vague presenting features of GLAD lesions and their association with both unstable and stable shoulder injuries mean that a broad differential diagnosis should be considered. This should include any traumatic glenolabral pathology causing either anterior or global shoulder discomfort. Such lesions may consist of: Common traumatic labral tears, tearing of the labrum and associated ligaments partially or completely off the glenoid, most commonly the anterior-inferior labrum (Bankart lesions) [17] Anterior-Inferior instability lesions that include a glenoid rim fracture - bony Bankart lesions [17] Perthes lesion: a labral complex injury, but the labrum is still attached to the glenoid via a periosteal sleeve [18] Anterior ligamentous periosteal sleeve avulsion: another labral injury, but it displaces medially on the glenoid neck [18] Humeral avulsion of the glenohumeral ligament: the anterior-inferior glenohumeral ligament is avulsed from the humeral rather than labral attachment [19]

Due to their relative infrequency, data on the prognosis of GLAD lesions are scarce, so it isn't easy to be confident on this topic. When the lesion was originally reported in 1993, all 5 cases returned to full functional activities with a full range of movement postoperatively.[1] Other case reports also support this outcome, suggesting excellent results following operative treatment of GLAD lesions when assessed by both pain and function.[4][5] A more rigorous level of outcome assessment is still required to support these clinical opinions, and, hopefully, increased knowledge enables better-informed care decision-making.

As mentioned, research suggests that GLAD lesions may be associated with episodes of anterior shoulder instability. One study, for example, found that GLAD lesions were associated with higher failure rates in arthroscopic Bankart repair.[20] Another study demonstrated a correlation between GLAD lesions and reduced glenohumeral stability in a cohort of cadaveric shoulders, suggesting that the lesion may represent a biomechanical risk factor in shoulder instability. One hypothesis is that the GLAD lesion reduces the depth of the normal joint concavity, already limited, and therefore compromises concavity-compression and hence stability within the glenoid fossa.[21] It has also been postulated that patients may be at risk of osteoarthritis (OA) following a GLAD injury. This hypothesis is based on trends observed following labral repair in hip surgery and knee meniscectomy, as well as on the analogous anatomy and physiology among these 3 joints.[22][23]

At the time of diagnosis, it can be helpful to explain the pathoanatomy of the GLAD lesion using models and diagrams. Under specialist supervision, good patient engagement helps their rehabilitation and recovery progress.

The evolution of imaging techniques has revolutionized the clinician’s ability to diagnose specific glenolabral pathology, including GLAD lesions. Consequently, several different glenolabral pathologies have been identified, each of which may be associated with persistent post-traumatic shoulder pain. Gleno-labral injuries often have a similar clinical presentation, and differences among recognized subtypes can be subtle. Imaging also has some limitations and does not guarantee the identification of all such lesions. Even for shoulder experts, the diagnosis and management of persistent post-traumatic shoulder pain can pose clinical challenges.[3] Optimal patient care is supported by an interprofessional team that includes clinicians (MDs, DOs, NPs, or PAs), relevant specialists such as orthopedists and radiologists, and nursing staff and physical therapists. If the patient initially reports to their family clinician, prompt orthopedic referral and consultation by a shoulder specialist is paramount and should be encouraged if undiagnosed significant shoulder pain has persisted after injury. Nursing staff, particularly specialized orthopedic nurses, can assist in patient evaluation and referral. Nurses can also assist during surgery, post-operative care, and follow-up in cases where surgery is necessary. If a GLAD lesion or one of the alternative traumatic subtypes of injury patterns is suspected, the involvement of a musculoskeletal radiologist to facilitate an appropriate imaging modality, likely MR arthrography, is equally important.[8] Once diagnosed and treated, a specialist physiotherapist should supervise the recovery period, whether or not a surgical approach is adopted. This interprofessional paradigm, with open communication among team members, offers the best chance for patients to recover as much shoulder function as can be expected.