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Clinical Application of the "Glenoid Track" Concept for Defining Humeral Head Engagement in Anterior Shoulder Instability: A Preliminary Report.

Metzger PD, Barlow B, Leonardelli D, Peace W, Solomon DJ, Provencher MT - Orthop J Sports Med (2013)

Bottom Line: The "glenoid track" concept was developed to biomechanically quantify the effects of a combined glenoid and humeral head bony defects on instability.The 2 groups were then compared with clinical evidence of engagement on examination under anesthesia (EUA) using video arthroscopy, number of dislocations, length of instability, and patient age.In addition, younger age and a greater number of recurrences were predictive of engagement.

View Article: PubMed Central - PubMed

Affiliation: US Naval Hospital Okinawa, Okinawa, Japan.

ABSTRACT

Background: The optimal treatment of Hill-Sachs injuries is difficult to determine and is potentiated by the finding that a Hill-Sachs injury becomes more important in the setting of glenoid bone loss, making engagement of the humeral head on the glenoid inherently easier. The "glenoid track" concept was developed to biomechanically quantify the effects of a combined glenoid and humeral head bony defects on instability.

Purpose: To clinically evaluate humeral head engagement on the glenoid by utilizing glenoid track measurements of both humeral head and glenoid bone loss.

Study design: Retrospective cohort.

Methods: A total of 205 patients with recurrent anterior shoulder instability were evaluated, and of these, 140 patients (68%; 9 females [6%] and 131 males [94%]) with a Hill-Sachs lesion and a mean age of 27.6 years (range, 15-47 years; standard error of mean [SEM], 0.59) were included in the final magnetic resonance angiogram [MRA]) analysis. Bipolar bone loss measures of glenoid bone loss (sagittal oblique MRA) and multiple size measures of the Hill-Sachs injury (coronal, axial, and sagittal MRA) were recorded. Based on the extent of the bipolar lesion, patients were classified with glenoid track as either outside and engaging of the glenoid on the humeral head (OUT-E) or inside and nonengaging (IN-NE). The 2 groups were then compared with clinical evidence of engagement on examination under anesthesia (EUA) using video arthroscopy, number of dislocations, length of instability, and patient age.

Results: The mean glenoid bone loss was 7.6% (range, 0%-29%; SEM, 1.20%), and 31 of 140 (22%) patients demonstrated clinical engagement on EUA. Radiographically, 19 (13.4%) patients were determined to be OUT-E, while 121 (86.6%) were IN-NE and not expected to engage. Of those 19 patients with suggested radiographic engagement (OUT-E), 16 (84.5%) had clinical evidence of engagement versus only 12.4% that clinically engaged (15/121) without radiographic evidence of engagement (IN-NE) (P < .001). Younger age and a greater number of recurrence events were jointly predictive of a patient being classified as OUT-E (11.8 vs 6.4 dislocations; P = .015).

Conclusion: This study demonstrates that glenohumeral engagement was well predicted based on preoperative glenoid and humeral head bone loss measurements using the glenoid track method. In addition, younger age and a greater number of recurrences were predictive of engagement. The glenoid track concept may be important to fully assess the overall risk for engagement prior to surgery and may help guide surgical decision making such as bony augmentation procedures.

No MeSH data available.


Related in: MedlinePlus

(A) The glenoid track is calculated as 84% of the actual glenoid width measured on the sagittal oblique magnetic resonance (MR) image. A best-fit circle is placed on the glenoid to calculate the expected width prior to bone loss. Therefore, both percentage of bone loss and glenoid track can be determined. In this case, the actual glenoid width is 24 mm, with 4 mm of bone loss (17% bone loss). The glenoid track is 84% of 24 mm, or 20.1 mm. (B) The distance from the rotator cuff footprint to the medial margin of the Hill-Sachs lesion is measured on the coronal MR. In this case, it is 23.1 mm. Since the Hill-Sachs width to the footprint (23.1 mm) is greater than the glenoid track measurement (20.1 mm), it is considered outside the glenoid track and at high risk for engaging.
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fig2-2325967113496213: (A) The glenoid track is calculated as 84% of the actual glenoid width measured on the sagittal oblique magnetic resonance (MR) image. A best-fit circle is placed on the glenoid to calculate the expected width prior to bone loss. Therefore, both percentage of bone loss and glenoid track can be determined. In this case, the actual glenoid width is 24 mm, with 4 mm of bone loss (17% bone loss). The glenoid track is 84% of 24 mm, or 20.1 mm. (B) The distance from the rotator cuff footprint to the medial margin of the Hill-Sachs lesion is measured on the coronal MR. In this case, it is 23.1 mm. Since the Hill-Sachs width to the footprint (23.1 mm) is greater than the glenoid track measurement (20.1 mm), it is considered outside the glenoid track and at high risk for engaging.

Mentions: In the current study, the original glenoid track model was modified to quantify it based on MR images of patients. The glenoid width was measured based on the technique described by Huysmans et al,13 the bare spot was identified on a sagittal oblique MR image, and the glenoid width was measured using this central reference point. Then, to determine the expected glenoid width, a best-fit circle was placed on the inferior third of the glenoid centered on the bare spot and the diameter of the circle was measured to calculate the expected width prior to bone loss (Figure 2).12 Therefore, both percentage of glenoid bone loss and glenoid track were determined from these measurements. The glenoid track was calculated as 84% of the actual glenoid width, which was the expected glenoid width minus any bone loss.32


Clinical Application of the "Glenoid Track" Concept for Defining Humeral Head Engagement in Anterior Shoulder Instability: A Preliminary Report.

Metzger PD, Barlow B, Leonardelli D, Peace W, Solomon DJ, Provencher MT - Orthop J Sports Med (2013)

(A) The glenoid track is calculated as 84% of the actual glenoid width measured on the sagittal oblique magnetic resonance (MR) image. A best-fit circle is placed on the glenoid to calculate the expected width prior to bone loss. Therefore, both percentage of bone loss and glenoid track can be determined. In this case, the actual glenoid width is 24 mm, with 4 mm of bone loss (17% bone loss). The glenoid track is 84% of 24 mm, or 20.1 mm. (B) The distance from the rotator cuff footprint to the medial margin of the Hill-Sachs lesion is measured on the coronal MR. In this case, it is 23.1 mm. Since the Hill-Sachs width to the footprint (23.1 mm) is greater than the glenoid track measurement (20.1 mm), it is considered outside the glenoid track and at high risk for engaging.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4555484&req=5

fig2-2325967113496213: (A) The glenoid track is calculated as 84% of the actual glenoid width measured on the sagittal oblique magnetic resonance (MR) image. A best-fit circle is placed on the glenoid to calculate the expected width prior to bone loss. Therefore, both percentage of bone loss and glenoid track can be determined. In this case, the actual glenoid width is 24 mm, with 4 mm of bone loss (17% bone loss). The glenoid track is 84% of 24 mm, or 20.1 mm. (B) The distance from the rotator cuff footprint to the medial margin of the Hill-Sachs lesion is measured on the coronal MR. In this case, it is 23.1 mm. Since the Hill-Sachs width to the footprint (23.1 mm) is greater than the glenoid track measurement (20.1 mm), it is considered outside the glenoid track and at high risk for engaging.
Mentions: In the current study, the original glenoid track model was modified to quantify it based on MR images of patients. The glenoid width was measured based on the technique described by Huysmans et al,13 the bare spot was identified on a sagittal oblique MR image, and the glenoid width was measured using this central reference point. Then, to determine the expected glenoid width, a best-fit circle was placed on the inferior third of the glenoid centered on the bare spot and the diameter of the circle was measured to calculate the expected width prior to bone loss (Figure 2).12 Therefore, both percentage of glenoid bone loss and glenoid track were determined from these measurements. The glenoid track was calculated as 84% of the actual glenoid width, which was the expected glenoid width minus any bone loss.32

Bottom Line: The "glenoid track" concept was developed to biomechanically quantify the effects of a combined glenoid and humeral head bony defects on instability.The 2 groups were then compared with clinical evidence of engagement on examination under anesthesia (EUA) using video arthroscopy, number of dislocations, length of instability, and patient age.In addition, younger age and a greater number of recurrences were predictive of engagement.

View Article: PubMed Central - PubMed

Affiliation: US Naval Hospital Okinawa, Okinawa, Japan.

ABSTRACT

Background: The optimal treatment of Hill-Sachs injuries is difficult to determine and is potentiated by the finding that a Hill-Sachs injury becomes more important in the setting of glenoid bone loss, making engagement of the humeral head on the glenoid inherently easier. The "glenoid track" concept was developed to biomechanically quantify the effects of a combined glenoid and humeral head bony defects on instability.

Purpose: To clinically evaluate humeral head engagement on the glenoid by utilizing glenoid track measurements of both humeral head and glenoid bone loss.

Study design: Retrospective cohort.

Methods: A total of 205 patients with recurrent anterior shoulder instability were evaluated, and of these, 140 patients (68%; 9 females [6%] and 131 males [94%]) with a Hill-Sachs lesion and a mean age of 27.6 years (range, 15-47 years; standard error of mean [SEM], 0.59) were included in the final magnetic resonance angiogram [MRA]) analysis. Bipolar bone loss measures of glenoid bone loss (sagittal oblique MRA) and multiple size measures of the Hill-Sachs injury (coronal, axial, and sagittal MRA) were recorded. Based on the extent of the bipolar lesion, patients were classified with glenoid track as either outside and engaging of the glenoid on the humeral head (OUT-E) or inside and nonengaging (IN-NE). The 2 groups were then compared with clinical evidence of engagement on examination under anesthesia (EUA) using video arthroscopy, number of dislocations, length of instability, and patient age.

Results: The mean glenoid bone loss was 7.6% (range, 0%-29%; SEM, 1.20%), and 31 of 140 (22%) patients demonstrated clinical engagement on EUA. Radiographically, 19 (13.4%) patients were determined to be OUT-E, while 121 (86.6%) were IN-NE and not expected to engage. Of those 19 patients with suggested radiographic engagement (OUT-E), 16 (84.5%) had clinical evidence of engagement versus only 12.4% that clinically engaged (15/121) without radiographic evidence of engagement (IN-NE) (P < .001). Younger age and a greater number of recurrence events were jointly predictive of a patient being classified as OUT-E (11.8 vs 6.4 dislocations; P = .015).

Conclusion: This study demonstrates that glenohumeral engagement was well predicted based on preoperative glenoid and humeral head bone loss measurements using the glenoid track method. In addition, younger age and a greater number of recurrences were predictive of engagement. The glenoid track concept may be important to fully assess the overall risk for engagement prior to surgery and may help guide surgical decision making such as bony augmentation procedures.

No MeSH data available.


Related in: MedlinePlus