Introduction

Glenolabral articular disruption (GLAD) lesions represent a specific type of traumatic injury involving the glenoid cartilage and labrum. These injuries may manifest as anterior or diffuse shoulder discomfort and, while relatively uncommon, are a critical differential diagnosis in cases of persistent, non-specific shoulder pain following trauma. The severity of glenoid cartilage damage varies widely, ranging from mild fibrillation to complete cartilage loss. This discussion outlines the presentation, diagnostic evaluation, and management strategies for GLAD lesions of the shoulder.

A GLAD lesion is a distinct subset of soft tissue injuries affecting the shoulder. It consists of a superficial tear in the anterior-inferior labrum accompanied by damage to the adjacent glenoid articular cartilage. The labrum is a fibrocartilaginous ring that stabilizes the glenoid fossa. Despite the labral tear in GLAD lesions, the deep fibers remain intact, rendering the labrum stable. Consequently, patients typically report pain rather than instability-related symptoms such as apprehension.

First described by Neviaser in 1993 as part of a limited case series, GLAD lesions are now recognized as a well-defined yet uncommon cause of post-traumatic shoulder pain. The initial findings suggested that these lesions often result from falls involving forced adduction of an abducted and externally rotated shoulder. However, some cases have also been linked to throwing activities. The original reports described GLAD lesions in the context of stable glenohumeral joints, but subsequent observations have noted that these lesions may occasionally accompany subluxations or dislocations. Over time, the term has been more broadly applied to describe various combinations of labral and adjacent cartilage injuries.

Clinical Presentation

The clinical presentation of GLAD lesions is often non-specific, with symptoms such as anterior or generalized shoulder pain during abduction and external rotation of the joint. Historically, these lesions have been associated with stable glenohumeral joints, where patients typically demonstrate a full range of motion without signs of apprehension or subluxation.

Recent studies, however, have documented GLAD lesions in patients with either isolated or recurrent dislocations, indicating that joint stability may not always be a defining characteristic. The non-specific nature of clinical findings makes the diagnosis of GLAD lesions challenging based on physical examination alone, necessitating imaging studies to confirm the condition.

Etiology

GLAD lesions arise from traumatic events affecting the shoulder joint. The classic mechanism, as described in the original series, involves forced adduction of the shoulder from a position of abduction and external rotation, typically during a fall onto an outstretched arm. In this scenario, the humeral head is driven into the glenoid, creating a shearing force that damages the cartilage. The energy from the trauma subsequently causes a superficial tear in the labral fibers, consistent with this injury pattern. Additionally, GLAD lesions have been associated with forceful adduction during throwing activities, which represents a variation in the mechanism of injury.

Advances in imaging technologies, such as MRI, MRI arthrography (MRA), and arthroscopy, have led to increased recognition of GLAD lesions in clinical practice. These diagnostic tools have also expanded the understanding of the mechanisms associated with the injury, with anterior glenohumeral instability now identified as a contributing factor in some cases.

Epidemiology

Although GLAD lesions are a recognized form of glenolabral pathology, reliable epidemiological data on their prevalence remains scarce. Most literature consists of isolated case reports or small series focusing on clinical evaluation and repair techniques, with limited large-scale data analysis. Despite this, GLAD lesions are widely considered to be rare. While glenohumeral labral tears are common, the majority occur in the anterior-inferior region, and isolated inferior labral tears are relatively uncommon.

Estimates indicate that GLAD lesions account for approximately 1.5% to 2.9% of all traumatic labral tears. Demographically, case reports predominantly involve younger males, which aligns with the general patterns observed in traumatic labral injuries. However, no definitive trends regarding age or gender have been established.

Pathophysiology

GLAD lesions involve disruption of the labrum and damage to the underlying glenoid cartilage within the glenohumeral (GH) joint. The GH joint is a synovial ball-and-socket joint formed by the articulation of the humeral head within the glenoid fossa of the scapula. The fossa is covered with articular cartilage and bordered by a fibrocartilaginous rim, the labrum, which increases the depth of the socket and serves as an attachment site for the long head of the biceps tendon and the glenohumeral ligaments.

The anteroinferior glenohumeral ligament and the anteroinferior labrum collectively form the anterior labroligamentous complex. This structure is a key restraint against anterior dislocation and plays a crucial role in maintaining anterior shoulder stability.

GLAD lesions typically result from forceful adduction of the humeral head against the glenoid fossa, often accompanied by a shearing force. This mechanism leads to a superficial tear of the labrum along its anterior-inferior aspect and varying degrees of cartilage damage. The extent of cartilage injury can range from a focal defect to a more extensive flap tear or even the formation of a loose chondral body.

Traditionally, the anterior labroligamentous complex remains intact in GLAD lesions, explaining the stability of the shoulder joint in most cases. However, more recent findings have identified a potential association between GLAD lesions and anterior shoulder instability, challenging the earlier assumption that joint stability is preserved in all instances.

History and Physical

In cases of shoulder trauma, a comprehensive and targeted history, followed by a detailed physical examination including neurovascular assessment and specific tests, is essential during the initial evaluation. However, clinical history and examination findings for GLAD lesions are often vague, making it challenging to confirm their presence based solely on suspicion. These injuries typically occur in younger male patients following high-energy trauma, often with a distinct onset of pain, which may be localized anteriorly or present more diffusely after the event. GLAD lesions are frequently associated with falls onto an outstretched arm, where an adduction force impacts an abducted and externally rotated shoulder.

The arm’s position at the time of injury and the direction of impact can provide clues to the presence of a GLAD lesion. In some cases, these injuries are linked to persistent pain following a traumatic instability episode, such as subluxation or dislocation.

During physical examination, pain may be provoked by abduction and external rotation of the shoulder, while forced adduction might elicit a “popping” sensation. Patients often report deep-seated anterior joint pain. These findings are typically observed in the context of a stable shoulder joint, as the anterior labroligamentous complex usually remains intact, with damage confined to the superficial labral fibers. However, more recent studies have identified an association between GLAD lesions and anterior shoulder instability, challenging the notion of shoulder stability in all cases.

Due to the non-specific nature of clinical findings, imaging is essential for confirming the diagnosis of GLAD lesions.

Evaluation

Imaging is the cornerstone of diagnosing GLAD lesions and should be conducted promptly when clinical suspicion arises. These lesions can be challenging to detect using non-contrast MRI or CT arthrography. However, advances in imaging technology, particularly with the newer 3T MRI scanners, have improved detection rates even without contrast. Nevertheless, MR arthrography (MRA) remains the gold standard for identifying and characterizing GLAD lesions.

The defining feature of a GLAD lesion is a superficial tear of the anterior-inferior labrum accompanied by an associated cartilage defect in the glenoid. The cartilage damage may vary in severity, ranging from a superficial defect to a trans-chondral lesion exposing the underlying subchondral bone. On MRA, these features are clearly visualized as contrast material tracks through the labral tear and into the cartilage defect or beneath a damaged articular flap.

For optimal accuracy and sensitivity in detecting anterior labral tears, it is recommended that the imaging be performed with the shoulder positioned in abduction and external rotation, provided patient mobility permits. This positioning significantly enhances diagnostic precision for anterior-inferior labral pathology. However, such positioning protocols may vary across imaging units and often depend on the clinical suspicion prior to the scan.

Treatment and Management (Rewritten)

Management of GLAD lesions involves both operative and non-operative approaches, and the choice of treatment should be tailored to each case. Factors such as the patient’s expectations, time since injury, symptom severity, functional demands, and response to initial treatment all play a role in determining the best course of action. While epidemiological data on GLAD lesions is limited, the condition typically affects younger patients who sustain high-energy traumatic or sports-related injuries.

In younger, active individuals, the likelihood of success with non-operative treatment remains uncertain due to the limited understanding of the condition. A trial of non-operative management, including time, analgesia, and physical therapy, may be beneficial for some patients. However, surgical intervention may be necessary to address the glenoid articular surface and labral injury, particularly for patients who do not respond to conservative measures or experience significant pain that hinders rehabilitation.

In older patients, clinicians should exercise caution when diagnosing GLAD lesions, as cartilage and labral degeneration are common with age. Even when a traumatic event is suspected, a non-invasive approach is typically favored, focusing on pain control and functional optimization through analgesia and physiotherapy.

Surgical Intervention

Arthroscopic surgery is the established approach for treating GLAD lesions, addressing both labral and chondral pathologies. Labral surgery may involve debridement of unstable fibers or stabilization of significant partial tears. For chondral defects, treatment includes debridement of loose cartilage material, and in cases of exposed glenoid bone, microfracture techniques may be employed to promote healing.

The surgical procedure is often determined by the size and severity of the chondral defect or the combination of labral and cartilage injuries. In some cases, a full-thickness glenoid cartilage defect may be managed by debriding the damaged cartilage and advancing the labrum over the defect to provide coverage. If the defect is extensive and cannot be fully addressed, the articular surface may be debrided while leaving the labrum intact. The decision-making process is highly individualized, reflecting the complexity of the injury and the goals of treatment.

Differential Diagnosis

The nonspecific presentation of GLAD lesions, coupled with their occurrence in both stable and unstable shoulder injuries, necessitates consideration of a broad differential diagnosis. This should include other traumatic glenolabral pathologies that result in anterior or generalized shoulder pain. Potential differential diagnoses include:

• Traumatic Labral Tears: Partial or complete tearing of the labrum and associated ligaments from the glenoid, most commonly involving the anterior-inferior labrum, as seen in Bankart lesions.
• Bony Bankart Lesions: Anterior-inferior instability injuries associated with fractures of the glenoid rim.
• Perthes Lesion: A labral complex injury in which the labrum remains attached to the glenoid via an intact periosteal sleeve.

• Anterior Ligamentous Periosteal Sleeve Avulsion (ALPSA): A labral injury where the labrum becomes medially displaced along the glenoid neck, while still attached to the periosteum.

• Humeral Avulsion of the Glenohumeral Ligament (HAGL) or Bony HAGL: Injuries where the anterior-inferior glenohumeral ligament is avulsed from its humeral attachment rather than the labral attachment.

These conditions should be considered during clinical evaluation and imaging, as they share overlapping features with GLAD lesions but may require different management strategies.

Prognosis

Due to the rarity of GLAD lesions, data on their prognosis remains limited, making definitive conclusions challenging. When the lesion was first described in 1993, all five reported cases achieved a full return to functional activities with a complete range of motion following surgical intervention.

Subsequent case reports have supported these findings, indicating excellent outcomes with operative treatment, particularly when evaluating improvements in both pain relief and functional capacity. However, a higher level of rigorous outcome assessment is needed to validate these clinical observations. As understanding of the condition grows, more comprehensive data will likely enable better-informed treatment decisions and prognosis predictions.

Complications

Research suggests that GLAD lesions may be associated with anterior shoulder instability. For instance, one study found that the presence of a GLAD lesion was linked to higher rates of failure in arthroscopic Bankart repairs. Another investigation using cadaveric shoulder models demonstrated a correlation between GLAD lesions and reduced glenohumeral stability, proposing that these lesions may represent a biomechanical risk factor for shoulder instability.

One proposed mechanism for this instability is the reduction in the normal depth of the joint concavity caused by a GLAD lesion. This diminished concavity compromises the concavity-compression mechanism, which is critical for maintaining stability within the glenoid fossa.

Additionally, there is speculation that GLAD lesions may predispose patients to osteoarthritis (OA) over time. This hypothesis draws parallels with trends observed in other joints, such as the hip following labral repair and the knee following meniscectomy. The analogous anatomy and biomechanics of these joints support the possibility that GLAD lesions could similarly increase the risk of degenerative changes in the shoulder. Further research is needed to clarify these potential long-term complications.

Postoperative and Rehabilitation Care

Postoperative care for GLAD lesions focuses on physiotherapy to restore and optimize shoulder function, with guidance from a specialist physiotherapist. The rehabilitation protocol varies depending on the specific surgical intervention, whether it involves labral repair, debridement, microfracture, or a combination of these procedures. For labral repair cases, rehabilitation generally follows a standard pathway similar to that of arthroscopic instability repair.

A typical rehabilitation program includes:

• Initial Phase (0–4 Weeks): Use of a sling for four weeks to protect the repair, accompanied by elbow, wrist, and hand exercises to maintain mobility. Shoulder pendulum movements are encouraged during this phase to prevent stiffness.
• Progressive Phase (4–8 Weeks): Gradual introduction of gentle active shoulder movements, progressing to a full active range of motion. Rotational movements, stretching, and light controlled strengthening exercises are incorporated as tolerated.
• Strengthening Phase (8+ Weeks): Focus shifts to more intensive strength conditioning, progressively increasing resistance and intensity based on the patient’s functional capacity and recovery milestones.

For athletes, return to sport typically follows a staged approach:

• Non-contact activities: At approximately five months post-surgery.
• Contact sports: At six months post-surgery.

These timelines serve as general guides and are contingent upon the patient achieving key functional recovery milestones throughout the rehabilitation process. Close monitoring and individualized adjustments ensure optimal outcomes.

Deterrence and Patient Education (Rewritten)

Educating patients about the pathoanatomy of a GLAD lesion using visual aids, such as anatomical models or diagrams, can help them better understand their condition. Clear explanations and engagement in the rehabilitation process, under specialist supervision, are essential for encouraging active participation and promoting recovery.

Enhancing Healthcare Team Outcomes (Rewritten)

Advancements in imaging technology have significantly improved the ability of clinicians to diagnose specific glenolabral pathologies, including GLAD lesions. However, the clinical presentations of these injuries are often similar, with subtle distinctions between subtypes. While imaging modalities, particularly MR arthrography, are invaluable, they have limitations and may not always identify all lesions. Diagnosing and managing persistent post-traumatic shoulder pain remains a clinical challenge, even for experienced shoulder specialists.

Optimal management of GLAD lesions involves an interprofessional healthcare team comprising clinicians (MDs, DOs, NPs, or PAs), specialists (orthopedists and radiologists), nurses, and physical therapists. For patients presenting with persistent undiagnosed shoulder pain after trauma, timely referral to an orthopedic specialist is crucial.

• Nursing staff, especially orthopedic nurses, play a critical role in patient evaluation, referrals, and assistance during surgery and postoperative care.
• Musculoskeletal radiologists are vital for selecting appropriate imaging techniques, such as MR arthrography, to confirm the diagnosis.
• Specialist physiotherapists oversee rehabilitation and recovery, whether surgical or conservative management is chosen.

Effective communication and coordination within this interprofessional team ensure the best possible outcomes. Collaborative care fosters accurate diagnosis, appropriate treatment, and successful recovery, enabling patients to regain as much shoulder function as possible.