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The Glenoid Labral Articular Teardrop Lesion: A Chondrolabral Injury With Distinct Magnetic Resonance Imaging Findings
The Glenoid Labral Articular Teardrop Lesion: A Chondrolabral Injury With Distinct Magnetic Resonance Imaging Findings Evan S. Lederman, M.D., Stephen Flores, M.D., Christopher Stevens, M.D., Damien Richardson, M.D., and Pamela Lund, M.D.
Purpose: Evaluation and description of a pathognomonic lesion identified on magnetic resonance imaging (MRI) of a chondrolabral injury of the glenohumeral joint. Methods: Patients were prospectively identified at the time of MRI by a characteristic teardrop appearance of a pedicled displaced chondrolabral flap in the axillary recess on coronal imaging and retrospectively reviewed. Results: In a sample of 36 patients, there were 30 males (83%), and the average age was 27 years (14-75 years). Twenty-four (67%) were noted to have sustained an instability episode or had findings of instability on physical examination; 19 patients (53%) were playing a sport at the time of injury. The characteristic teardrop lesion measured 3.36 mm (1-9 mm) in the coronal plane, 6.98 mm (2-20 mm) sagittal and 11.78 mm (1-25 mm) longitudinal. The lesion was located in the anterior inferior quadrant of the glenoid. Conclusions: The glenoid labral articular teardrop (GLAT) lesion represents a pathognomonic lesion in the spectrum of chondral labral injury, indicating articular cartilage damage to the glenoid. Level of Evidence: Level IV, therapeutic case series.
See commentary on page 412
T
raumatic injuries to the glenoid, capsule, and labral structures can be classified into chondral, labral, chondrolabral, labroligamentous, and bone lesions. Chondrolabral injuries have previously been described to include glenoid labral articular disruption (GLAD) lesions and variants, glenoid articular rim divot (GARD) lesions, and glenoid labral articular flap (GLAF) lesions as well as other variants.1-5 This case series describes a From the Orthopedic Clinic Association (E.S.L.); and Department of Orthopedic Surgery, University of Arizona College of MedicineePhoenix (E.S.L., D.R.), Phoenix, Arizona; Covenant Medical Center (S.F.), Lubbock, Texas; Tucson Orthopedic Institute (C.S.), Tucson, Arizona; and SimonMed Imaging (P.L.), Phoenix, Arizona, U.S.A. The authors report the following potential conflicts of interest or sources of funding: E.S.L. is a paid consultant for Arthrex; receives payment for lectures including service on speakers bureaus from Arthrex; receives royalties (individual and institutional) from Arthrex; and receives fellowship support on behalf of the institution from Smith & Nephew, Ossur, and Wright Medical. P.L. receives travel expenses from SimonMed Imaging. Full ICMJE author disclosure forms are available for this article online, as supplementary material. Received March 3, 2017; accepted August 2, 2017. Address correspondence to Evan S. Lederman, M.D., The Orthopedic Clinic Association, PC 2222 E Highland Ave, Suite 300, Phoenix, AZ 85016, U.S.A. E-mail: [email protected] Ó 2017 by the Arthroscopy Association of North America 0749-8063/17244/$36.00 https://doi.org/10.1016/j.arthro.2017.08.236
chondrolabral variant that involves a pedicled labral tear with an associated chondral lesion creating a pathognomonic finding on both magnetic resonance imaging (MRI) and at the time of arthroscopy that differentiate it from previously described chondrolabral lesions. The authors describe the glenoid labral articular teardrop (GLAT) lesion and the characteristic MRI appearance that aids in diagnosis of this variant of chondrolabral pathology. The purpose of this study was the evaluation and description of a pathognomonic lesion identified on MRI of a chondrolabral injury of the glenohumeral joint. Our hypothesis was that this chondrolabral injury pattern with pathognomonic MRI findings can aid the clinician in diagnosis.
Methods From December 2010 to September 2015, a total of 9,895 patients were referred for shoulder MRI to a board-certified musculoskeletal radiologist. No patients or studies were excluded. The characteristic appearance of the GLAT lesion was identified by the authors, and studies were collected prospectively and retrospectively reviewed. Studies were performed on high-field, 1.5- or 3-tesla MRI systems: GE Horizon 1.5-tesla or Signa 3T (GE Medical Systems, Milwaukee, WI) and Siemens Verio (Siemens AG, Munich, Germany). Standard shoulder MRI or MRI arthrography
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 34, No 2 (February), 2018: pp 407-411
407
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E. S. LEDERMAN ET AL.
Table 1. Demographic Data (N ¼ 36) Characteristic Age, years, mean (range) Male MRI arthrogram Instability episode Previous ipsilateral injury Sport injury Football Basketball Soccer Ballet Skiing Softball Baseball
Mean (Range) or n (%) 27 (14-75) 30 (83) 17 (47) 24 (67) 2 (6) 19 (53) 11 3 1 1 1 1 1
MRI, magnetic resonance imaging.
sequences including fast spin-echo axial, coronal, and sagittal proton density fat saturated, coronal T2-weighted fat saturated for standard MRI studies. Axial and coronal T-1 fat-saturated sequences were added for MRI arthrography studies. Dedicated shoulder coils were used for all imaging procedures. The lesion is described as a chondral elliptically shaped fragment, acutely angled, with a thin stalk at the apex attached to the inferior glenoid articular surface. The lesion was clearly seen on coronal images displaced into the axillary pouch. The displaced fragment into the axillary pouch appeared as a teardrop on imaging. MRI findings characteristic of a GLAT lesion were evaluated for size of the lesion in the axial, coronal, and sagittal planes; location of the lesion with respect to the glenohumeral joint clockface; the presence of a pedicle flap; and any associated
injuries, including Hill-Sachs lesions, additional labral pathology, and the presence of any loose bodies. A second musculoskeletal radiologist independently reviewed all images. A retrospective chart review was then performed to evaluate the mechanism of injury, including sport played at time of injury (if any), history of a frank dislocation, previous history of ipsilateral shoulder injury or surgery, and any physical examination findings of instability. When available, arthroscopic findings were correlated with MRI findings to further describe the chondrolabral injury.
Results We identified 36 patients with GLAT lesions. Of the 36 patients, there were 30 males (83%), with an average age of 27 years (14-75 years); 24 (67%) were noted to have sustained an instability episode or had findings of instability on physical examination; 19 patients (53%) were playing a sport at the time of injury. Two (6%) reported to have previously sustained an ipsilateral shoulder injury that required an operative procedure (Table 1). All patients exhibited the characteristic teardrop lesion on coronal MRI localized to the glenohumeral recess (Figs 1-4). The displaced fragment dimensions are listed in Table 2. A corresponding glenoid defect donor site was inconsistently identified on MRI. Seventeen (47%) had lesions identified by MRI arthrogram and 19 (53%) by standard MRI. The location of the lesion is summarized in Figure 5. This teardrop lesion was visualized arthroscopically (9 patients) to be a variably sized chondral fragment located in
Fig 1. GLAT MRI. (A) Coronal T1-weighted fat-saturated MRI arthrogram image of a right shoulder shows low-signal elliptical teardrop chondral fragment displaced into inferior glenohumeral recess (arrow) with narrow apex attached to the inferior margin glenoid articular cartilage by a thin pedicle (arrowhead). Coronal and longitudinal GLAT measurements are shown. (B, C) Sagittal and axial T1-weighted fat-saturated MRI arthrogram image show GLAT in inferior recess with sagittal/anteroposterior measurement. (GLAT, glenoid labral articular teardrop; MRI, magnetic resonance imaging.)
GLENOID LABRAL ARTICULAR TEARDROP (GLAT) LESION
409
Fig 2. (A) Coronal T1-weighted fat-saturated MRI arthrogram image of a right shoulder reveals characteristic elliptical GLAT fragment inferior recess with pedicle attachment to the inferior glenoid margin. The fragment has linear signal void consistent with small osseous component medially. (B) Sagittal image from the same study shows contrast within the glenoid chondral or osteochondral donor site. (GLAT, glenoid labral articular teardrop; MRI, magnetic resonance imaging.)
the inferior glenohumeral recess, at the 5- to 7-o’clock position rotated on a thin pedicle, which remained attached to the donor site. The arthroscopic findings correlated with the MRI findings. At the time of surgery, 1 lesion required simple debridement, 8 lesions required a Bankart repair, and in 4 cases the repaired labrum was advanced into and covered the articular defect. Associated injuries included Hill-Sachs lesions (71%), anterior labroligamentous periosteal sleeve avulsion injuries (16%), labral tears (16%), osseous Bankart lesions (13%), and additional loose bodies (10%).
Discussion The authors describe the GLAT lesion as another pattern of injury along the spectrum of chondrolabral injury. This
teardrop fragment is a displaced chondral fragment rotated on a thin pedicle, or a displaced flap-type injury. In our series of 36 teardrop lesions, 67% of those were found in patients thought to have instability whereas 33% were identified in individuals with no history or physical examination findings of instability. The history of injury was taken from chart review and may underreport the association with direct instability events. The characteristic displaced chondral fragment into the glenohumeral recess as visualized on coronal MRI is pathognomonic for significant chondral injury and should be recognized, as the glenoid donor sites were inconsistently identified on MRI. Chondrolabral injuries can be challenging entities for treating physicians to diagnose clinically.6,7 The incidence of chondral injuries in the setting of instability has been
Fig 3. MRI and arthroscopy of 29-year-old man with recent anterior dislocation of his right shoulder. (A) Coronal T1-weighted fatsaturated MR arthrogram image shows GLAT inferior recess (arrow) attached to the glenoid margin with adjacent nondisplaced inferior articular cartilage flap (arrowhead). (B) Arthroscopic image confirms elliptical GLAT fragment with narrow apex and pedicle attached to the glenoid articular cartilage. (GLAT, glenoid labral articular teardrop; MRI, magnetic resonance imaging.)
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E. S. LEDERMAN ET AL.
Fig 4. (A) Arthroscopic appearance of a left shoulder with a chondrolabral teardrop lesion in the axillary pouch from the posterior viewing portal in a lateral decubitus position. (B, C) View from anterosuperior and posterior portal after reduction of the fragment. This was an osteochondral fragment. (D) Fragment excised. (E, F) Arthroscopic repair with partial advancement into glenoid defect.
reported to be 36% in instability cases and increases to 46% in instability cases with associated labral tears.8 Neviaser first described the GLAD lesion to include a superficial anterior inferior labral tear, an articular defect, and no associated findings of instability by history, physical examination, or at the time of surgery.3 He hypothesized that the mechanism for this injury included forced shoulder adduction from and abducted and externally rotated position. Sanders et al.4 further correlated Neviaser’s GLAD findings in a large series review of MRI arthrograms and identified 6 patients with the characteristic superficial labral tear with adjacent chondral injury and again noted that none exhibited findings of anterior instability. He also reported that although 2 patients had oval osteochondral defects, 4 patients were noted to have chondral flap-type injuries, with 3 having large 12- to 15-mm chondral tears with a flap beginning in the central portion of the anteroinferior glenoid cartilage and extending beneath the glenoid labrum. These lesions are likely similar to those in the current study but the images in their study did not reveal the displaced fragment in the axillary recess. Page et al.2 similarly reported on a chondral flap injury pattern in their description of the GLAF duallesion complex. The GLAF lesion was reported to be
associated with anterior instability and involved an avulsion of the anteroinferior glenoid labrum in conjunction with a flap tear of the adjacent articular cartilage. The chondral component was described as a large undermined region with full-thickness chondral separation of the glenoid articular surface with extension up to the bare spot and measuring 15 18 mm. Galano et al.1 described a GLAD variant in 2 cases of instability. One case involved a labral tear with a displaced, unstable osteochondral flap of the anteroinferior glenoid. The second case included findings of a labral tear with chondral flap lesion beginning at the bare area and extending to the inferior glenoid edge. The authors proposed that the mechanism of the lesion is related to the relocation effect of tearing of the labrum leaving a pedicle and avulsing the attached Table 2. Dimensions of the Displaced Chondral Labral Fragment
Coronal Sagittal Height
Average (mm) 3.36 6.98 11.78
Range (mm) 1-9 2-20 1-25
Standard Deviation (mm) 1.69 4.16 4.53
GLENOID LABRAL ARTICULAR TEARDROP (GLAT) LESION
Fig 5. Location of the teardrop lesion. The clock-face position represents the location of the pedicle.
chondral surface similar to the osteochondral fracture mechanism of a patellar dislocation/relocation injury.9 With further evaluation and awareness of this injury pattern, the mechanism will likely become more clear. Currently, no consensus exists with regard to the operative treatment of these chondrolabral injuries. Operative management currently includes labral and chondral debridement, labral and/or chondral repair, labral advancement into the defect, and microfracture of significant chondral lesions.1-3 Current management of smaller, displaced, chondrolabral fragments typically follows the thought of previously described management techniques for patellar osteochondral fractures. This involves fragment excision or debridement, and labral repair or advancement into the defect. For larger-sized fragments, attempts at fixation may be attempted to secure the defect and re-create the normal anatomy. Numerous studies have described common patterns of chondrolabral injury. It is likely that the previously described lesions including the GLAD, GLAF, and now GLAT lesions represent a spectrum of chondrolabral injury associated with glenohumeral impaction, subluxation, and dislocation. Chondral lesions are concerning injuries with the potential to progress to significant glenohumeral arthrosis. These injuries are furthermore a challenge to identify on advanced imaging, which is why the pathognomonic imaging finding of the GLAT lesion should be carefully considered by the treating physician for proper identification, diagnosis, and potential surgical planning in the management of chondrolabral injuries. Additional research is needed to recommend appropriate management of these lesions.
411
Limitations This is a retrospective review at one imaging center, and all lesions were identified by one specialty trained radiologist. The study group consisted of all shoulder MRI patients and not patients who had an MRI study ordered after injury. Most of the MRI studies were ordered by a primary care physician, and detailed information was inconsistent. Another limitation of this study was that arthroscopic evaluation was only available for 9 patients. In these cases, the MRI was ordered by the treating orthopaedic surgeon and information regarding the surgical findings was available. Information was not available for the other 27 patients with respect to surgical treatment.
Conclusions The GLAT lesion represents a pathognomonic lesion in the spectrum of chondral labral injury indicating articular cartilage damage to the glenoid.
References 1. Galano GJ, Weisenthal BM, Altchek DW. Articular shear of the anterior-inferior quadrant of the glenoid: A glenolabral articular disruption lesion variant. Am J Orthop (Belle Mead, NJ) 2013;42:41-43. 2. Page R, Bhatia DN. Arthroscopic repair of a chondrolabral lesion associated with anterior glenohumeral dislocation. Knee Surg Sports Traumatol Arthrosc 2010;18:1748-1751. 3. Neviaser TJ. The GLAD lesion: Another cause of anterior shoulder pain. Arthroscopy 1993;9:22-23. 4. Sanders TG, Tirman PF, Linares R, Feller JF, Richardson R. The glenolabral articular disruption lesion: MR arthrography with arthroscopic correlation. AJR Am J Roentgenol 1999;172:171-175. 5. Amrami KK, Sperling JW, Bartholmai BJ, Sundaram M. Radiologic case study. Glenolabral articular disruption (GLAD) lesion. Orthopedics 2002;25:29, 95-96. 6. Beltran J, Rosenberg ZS, Chandnani VP, Cuomo F, Beltran S, Rokito A. Glenohumeral instability: Evaluation with MR arthrography. Radiographics 1997;17:657-673. 7. Singh RB, Hunter JC, Smith KL. MRI of shoulder instability: State of the art. Curr Probl Diagn Radiol 2003;32:127-134. 8. O’Brien J, Grebenyuk J, Leith J, Forster BB. Frequency of glenoid chondral lesions on MR arthrography in patients with anterior shoulder instability. Eur J Radiol 2012;81:3461-3465. 9. Rorabeck CH, Bobechko WP. Acute dislocation of the patella with osteochondral fracture: A review of eighteen cases. J Bone Joint Surg Br 1976;58:237-240.
Purpose: Evaluation and description of a pathognomonic lesion identified on magnetic resonance imaging (MRI) of a chondrolabral injury of the glenohumeral joint. Methods: Patients were prospectively identified at the time of MRI by a characteristic teardrop appearance of a pedicled displaced chondrolabral flap in the axillary recess on coronal imaging and retrospectively reviewed. Results: In a sample of 36 patients, there were 30 males (83%), and the average age was 27 years (14-75 years). Twenty-four (67%) were noted to have sustained an instability episode or had findings of instability on physical examination; 19 patients (53%) were playing a sport at the time of injury. The characteristic teardrop lesion measured 3.36 mm (1-9 mm) in the coronal plane, 6.98 mm (2-20 mm) sagittal and 11.78 mm (1-25 mm) longitudinal. The lesion was located in the anterior inferior quadrant of the glenoid. Conclusions: The glenoid labral articular teardrop (GLAT) lesion represents a pathognomonic lesion in the spectrum of chondral labral injury, indicating articular cartilage damage to the glenoid. Level of Evidence: Level IV, therapeutic case series.
See commentary on page 412
T
raumatic injuries to the glenoid, capsule, and labral structures can be classified into chondral, labral, chondrolabral, labroligamentous, and bone lesions. Chondrolabral injuries have previously been described to include glenoid labral articular disruption (GLAD) lesions and variants, glenoid articular rim divot (GARD) lesions, and glenoid labral articular flap (GLAF) lesions as well as other variants.1-5 This case series describes a From the Orthopedic Clinic Association (E.S.L.); and Department of Orthopedic Surgery, University of Arizona College of MedicineePhoenix (E.S.L., D.R.), Phoenix, Arizona; Covenant Medical Center (S.F.), Lubbock, Texas; Tucson Orthopedic Institute (C.S.), Tucson, Arizona; and SimonMed Imaging (P.L.), Phoenix, Arizona, U.S.A. The authors report the following potential conflicts of interest or sources of funding: E.S.L. is a paid consultant for Arthrex; receives payment for lectures including service on speakers bureaus from Arthrex; receives royalties (individual and institutional) from Arthrex; and receives fellowship support on behalf of the institution from Smith & Nephew, Ossur, and Wright Medical. P.L. receives travel expenses from SimonMed Imaging. Full ICMJE author disclosure forms are available for this article online, as supplementary material. Received March 3, 2017; accepted August 2, 2017. Address correspondence to Evan S. Lederman, M.D., The Orthopedic Clinic Association, PC 2222 E Highland Ave, Suite 300, Phoenix, AZ 85016, U.S.A. E-mail: [email protected] Ó 2017 by the Arthroscopy Association of North America 0749-8063/17244/$36.00 https://doi.org/10.1016/j.arthro.2017.08.236
chondrolabral variant that involves a pedicled labral tear with an associated chondral lesion creating a pathognomonic finding on both magnetic resonance imaging (MRI) and at the time of arthroscopy that differentiate it from previously described chondrolabral lesions. The authors describe the glenoid labral articular teardrop (GLAT) lesion and the characteristic MRI appearance that aids in diagnosis of this variant of chondrolabral pathology. The purpose of this study was the evaluation and description of a pathognomonic lesion identified on MRI of a chondrolabral injury of the glenohumeral joint. Our hypothesis was that this chondrolabral injury pattern with pathognomonic MRI findings can aid the clinician in diagnosis.
Methods From December 2010 to September 2015, a total of 9,895 patients were referred for shoulder MRI to a board-certified musculoskeletal radiologist. No patients or studies were excluded. The characteristic appearance of the GLAT lesion was identified by the authors, and studies were collected prospectively and retrospectively reviewed. Studies were performed on high-field, 1.5- or 3-tesla MRI systems: GE Horizon 1.5-tesla or Signa 3T (GE Medical Systems, Milwaukee, WI) and Siemens Verio (Siemens AG, Munich, Germany). Standard shoulder MRI or MRI arthrography
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 34, No 2 (February), 2018: pp 407-411
407
408
E. S. LEDERMAN ET AL.
Table 1. Demographic Data (N ¼ 36) Characteristic Age, years, mean (range) Male MRI arthrogram Instability episode Previous ipsilateral injury Sport injury Football Basketball Soccer Ballet Skiing Softball Baseball
Mean (Range) or n (%) 27 (14-75) 30 (83) 17 (47) 24 (67) 2 (6) 19 (53) 11 3 1 1 1 1 1
MRI, magnetic resonance imaging.
sequences including fast spin-echo axial, coronal, and sagittal proton density fat saturated, coronal T2-weighted fat saturated for standard MRI studies. Axial and coronal T-1 fat-saturated sequences were added for MRI arthrography studies. Dedicated shoulder coils were used for all imaging procedures. The lesion is described as a chondral elliptically shaped fragment, acutely angled, with a thin stalk at the apex attached to the inferior glenoid articular surface. The lesion was clearly seen on coronal images displaced into the axillary pouch. The displaced fragment into the axillary pouch appeared as a teardrop on imaging. MRI findings characteristic of a GLAT lesion were evaluated for size of the lesion in the axial, coronal, and sagittal planes; location of the lesion with respect to the glenohumeral joint clockface; the presence of a pedicle flap; and any associated
injuries, including Hill-Sachs lesions, additional labral pathology, and the presence of any loose bodies. A second musculoskeletal radiologist independently reviewed all images. A retrospective chart review was then performed to evaluate the mechanism of injury, including sport played at time of injury (if any), history of a frank dislocation, previous history of ipsilateral shoulder injury or surgery, and any physical examination findings of instability. When available, arthroscopic findings were correlated with MRI findings to further describe the chondrolabral injury.
Results We identified 36 patients with GLAT lesions. Of the 36 patients, there were 30 males (83%), with an average age of 27 years (14-75 years); 24 (67%) were noted to have sustained an instability episode or had findings of instability on physical examination; 19 patients (53%) were playing a sport at the time of injury. Two (6%) reported to have previously sustained an ipsilateral shoulder injury that required an operative procedure (Table 1). All patients exhibited the characteristic teardrop lesion on coronal MRI localized to the glenohumeral recess (Figs 1-4). The displaced fragment dimensions are listed in Table 2. A corresponding glenoid defect donor site was inconsistently identified on MRI. Seventeen (47%) had lesions identified by MRI arthrogram and 19 (53%) by standard MRI. The location of the lesion is summarized in Figure 5. This teardrop lesion was visualized arthroscopically (9 patients) to be a variably sized chondral fragment located in
Fig 1. GLAT MRI. (A) Coronal T1-weighted fat-saturated MRI arthrogram image of a right shoulder shows low-signal elliptical teardrop chondral fragment displaced into inferior glenohumeral recess (arrow) with narrow apex attached to the inferior margin glenoid articular cartilage by a thin pedicle (arrowhead). Coronal and longitudinal GLAT measurements are shown. (B, C) Sagittal and axial T1-weighted fat-saturated MRI arthrogram image show GLAT in inferior recess with sagittal/anteroposterior measurement. (GLAT, glenoid labral articular teardrop; MRI, magnetic resonance imaging.)
GLENOID LABRAL ARTICULAR TEARDROP (GLAT) LESION
409
Fig 2. (A) Coronal T1-weighted fat-saturated MRI arthrogram image of a right shoulder reveals characteristic elliptical GLAT fragment inferior recess with pedicle attachment to the inferior glenoid margin. The fragment has linear signal void consistent with small osseous component medially. (B) Sagittal image from the same study shows contrast within the glenoid chondral or osteochondral donor site. (GLAT, glenoid labral articular teardrop; MRI, magnetic resonance imaging.)
the inferior glenohumeral recess, at the 5- to 7-o’clock position rotated on a thin pedicle, which remained attached to the donor site. The arthroscopic findings correlated with the MRI findings. At the time of surgery, 1 lesion required simple debridement, 8 lesions required a Bankart repair, and in 4 cases the repaired labrum was advanced into and covered the articular defect. Associated injuries included Hill-Sachs lesions (71%), anterior labroligamentous periosteal sleeve avulsion injuries (16%), labral tears (16%), osseous Bankart lesions (13%), and additional loose bodies (10%).
Discussion The authors describe the GLAT lesion as another pattern of injury along the spectrum of chondrolabral injury. This
teardrop fragment is a displaced chondral fragment rotated on a thin pedicle, or a displaced flap-type injury. In our series of 36 teardrop lesions, 67% of those were found in patients thought to have instability whereas 33% were identified in individuals with no history or physical examination findings of instability. The history of injury was taken from chart review and may underreport the association with direct instability events. The characteristic displaced chondral fragment into the glenohumeral recess as visualized on coronal MRI is pathognomonic for significant chondral injury and should be recognized, as the glenoid donor sites were inconsistently identified on MRI. Chondrolabral injuries can be challenging entities for treating physicians to diagnose clinically.6,7 The incidence of chondral injuries in the setting of instability has been
Fig 3. MRI and arthroscopy of 29-year-old man with recent anterior dislocation of his right shoulder. (A) Coronal T1-weighted fatsaturated MR arthrogram image shows GLAT inferior recess (arrow) attached to the glenoid margin with adjacent nondisplaced inferior articular cartilage flap (arrowhead). (B) Arthroscopic image confirms elliptical GLAT fragment with narrow apex and pedicle attached to the glenoid articular cartilage. (GLAT, glenoid labral articular teardrop; MRI, magnetic resonance imaging.)
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E. S. LEDERMAN ET AL.
Fig 4. (A) Arthroscopic appearance of a left shoulder with a chondrolabral teardrop lesion in the axillary pouch from the posterior viewing portal in a lateral decubitus position. (B, C) View from anterosuperior and posterior portal after reduction of the fragment. This was an osteochondral fragment. (D) Fragment excised. (E, F) Arthroscopic repair with partial advancement into glenoid defect.
reported to be 36% in instability cases and increases to 46% in instability cases with associated labral tears.8 Neviaser first described the GLAD lesion to include a superficial anterior inferior labral tear, an articular defect, and no associated findings of instability by history, physical examination, or at the time of surgery.3 He hypothesized that the mechanism for this injury included forced shoulder adduction from and abducted and externally rotated position. Sanders et al.4 further correlated Neviaser’s GLAD findings in a large series review of MRI arthrograms and identified 6 patients with the characteristic superficial labral tear with adjacent chondral injury and again noted that none exhibited findings of anterior instability. He also reported that although 2 patients had oval osteochondral defects, 4 patients were noted to have chondral flap-type injuries, with 3 having large 12- to 15-mm chondral tears with a flap beginning in the central portion of the anteroinferior glenoid cartilage and extending beneath the glenoid labrum. These lesions are likely similar to those in the current study but the images in their study did not reveal the displaced fragment in the axillary recess. Page et al.2 similarly reported on a chondral flap injury pattern in their description of the GLAF duallesion complex. The GLAF lesion was reported to be
associated with anterior instability and involved an avulsion of the anteroinferior glenoid labrum in conjunction with a flap tear of the adjacent articular cartilage. The chondral component was described as a large undermined region with full-thickness chondral separation of the glenoid articular surface with extension up to the bare spot and measuring 15 18 mm. Galano et al.1 described a GLAD variant in 2 cases of instability. One case involved a labral tear with a displaced, unstable osteochondral flap of the anteroinferior glenoid. The second case included findings of a labral tear with chondral flap lesion beginning at the bare area and extending to the inferior glenoid edge. The authors proposed that the mechanism of the lesion is related to the relocation effect of tearing of the labrum leaving a pedicle and avulsing the attached Table 2. Dimensions of the Displaced Chondral Labral Fragment
Coronal Sagittal Height
Average (mm) 3.36 6.98 11.78
Range (mm) 1-9 2-20 1-25
Standard Deviation (mm) 1.69 4.16 4.53
GLENOID LABRAL ARTICULAR TEARDROP (GLAT) LESION
Fig 5. Location of the teardrop lesion. The clock-face position represents the location of the pedicle.
chondral surface similar to the osteochondral fracture mechanism of a patellar dislocation/relocation injury.9 With further evaluation and awareness of this injury pattern, the mechanism will likely become more clear. Currently, no consensus exists with regard to the operative treatment of these chondrolabral injuries. Operative management currently includes labral and chondral debridement, labral and/or chondral repair, labral advancement into the defect, and microfracture of significant chondral lesions.1-3 Current management of smaller, displaced, chondrolabral fragments typically follows the thought of previously described management techniques for patellar osteochondral fractures. This involves fragment excision or debridement, and labral repair or advancement into the defect. For larger-sized fragments, attempts at fixation may be attempted to secure the defect and re-create the normal anatomy. Numerous studies have described common patterns of chondrolabral injury. It is likely that the previously described lesions including the GLAD, GLAF, and now GLAT lesions represent a spectrum of chondrolabral injury associated with glenohumeral impaction, subluxation, and dislocation. Chondral lesions are concerning injuries with the potential to progress to significant glenohumeral arthrosis. These injuries are furthermore a challenge to identify on advanced imaging, which is why the pathognomonic imaging finding of the GLAT lesion should be carefully considered by the treating physician for proper identification, diagnosis, and potential surgical planning in the management of chondrolabral injuries. Additional research is needed to recommend appropriate management of these lesions.
411
Limitations This is a retrospective review at one imaging center, and all lesions were identified by one specialty trained radiologist. The study group consisted of all shoulder MRI patients and not patients who had an MRI study ordered after injury. Most of the MRI studies were ordered by a primary care physician, and detailed information was inconsistent. Another limitation of this study was that arthroscopic evaluation was only available for 9 patients. In these cases, the MRI was ordered by the treating orthopaedic surgeon and information regarding the surgical findings was available. Information was not available for the other 27 patients with respect to surgical treatment.
Conclusions The GLAT lesion represents a pathognomonic lesion in the spectrum of chondral labral injury indicating articular cartilage damage to the glenoid.
References 1. Galano GJ, Weisenthal BM, Altchek DW. Articular shear of the anterior-inferior quadrant of the glenoid: A glenolabral articular disruption lesion variant. Am J Orthop (Belle Mead, NJ) 2013;42:41-43. 2. Page R, Bhatia DN. Arthroscopic repair of a chondrolabral lesion associated with anterior glenohumeral dislocation. Knee Surg Sports Traumatol Arthrosc 2010;18:1748-1751. 3. Neviaser TJ. The GLAD lesion: Another cause of anterior shoulder pain. Arthroscopy 1993;9:22-23. 4. Sanders TG, Tirman PF, Linares R, Feller JF, Richardson R. The glenolabral articular disruption lesion: MR arthrography with arthroscopic correlation. AJR Am J Roentgenol 1999;172:171-175. 5. Amrami KK, Sperling JW, Bartholmai BJ, Sundaram M. Radiologic case study. Glenolabral articular disruption (GLAD) lesion. Orthopedics 2002;25:29, 95-96. 6. Beltran J, Rosenberg ZS, Chandnani VP, Cuomo F, Beltran S, Rokito A. Glenohumeral instability: Evaluation with MR arthrography. Radiographics 1997;17:657-673. 7. Singh RB, Hunter JC, Smith KL. MRI of shoulder instability: State of the art. Curr Probl Diagn Radiol 2003;32:127-134. 8. O’Brien J, Grebenyuk J, Leith J, Forster BB. Frequency of glenoid chondral lesions on MR arthrography in patients with anterior shoulder instability. Eur J Radiol 2012;81:3461-3465. 9. Rorabeck CH, Bobechko WP. Acute dislocation of the patella with osteochondral fracture: A review of eighteen cases. J Bone Joint Surg Br 1976;58:237-240.