Effect of Preoperative MRI Coracoid Dimensions on Postoperative Outcomes of Latarjet Treatment for Anterior Shoulder Instability

Abstract

Background: Preoperative coracoid dimensions may affect the size of the bone graft transferred to the glenoid rim and thus the postoperative outcomes of Latarjet coracoid transfer.

Purpose: To determine the effect of coracoid length and width as measured on preoperative magnetic resonance imaging (MRI) on outcomes after Latarjet treatment of anterior shoulder instability.

Study design: Cohort study; Level of evidence, 3.

Methods: Included were patients who underwent primary Latarjet surgery between 2009 and 2019 and had preoperative MRI scans and minimum 2-year postoperative outcomes. Longitudinal coracoid length was measured on axial MRI sequences as the distance from the coracoclavicular ligament insertion to the distal tip. Comparisons were made between shorter and longer coracoids and between narrower and wider coracoids. The outcomes of interest were recurrent instability, reoperation, complications, return to sport (RTS), and American Shoulder and Elbow Surgeons (ASES) score. Independent-samples t test, Mann-Whitney test, chi-square test, and Fisher exact test were used to compare outcomes between groups, and univariate correlation coefficients were calculated to evaluate the relationships between demographics and coracoid dimensions.

Results: Overall, 56 patients were included (mean age, 28.4 years). The mean ± SD coracoid length was 21.6 ± 2.4 mm and width 10.0 ± 1.0 mm. Relative to patients with a longer coracoid (≥22 mm; n = 26), patients with a shorter coracoid (<22 mm; n = 30) had similar rates of recurrent instability (shorter vs longer; 6.7% vs 3.8%), complications (10.0% vs 15.4%), reoperation (3.3% vs 7.7%), and RTS (76.5% vs 58.8%) and similar postoperative ASES scores (85.0 vs 81.6) (P ≥ .05 for all). Likewise, relative to patients with a wider coracoid (≥10 mm; n = 27), patients with a narrower coracoid (<10 mm; n = 29) had similar prevalences of recurrent instability (narrower vs wider; 6.9% vs 3.7%), complications (17.2% vs 7.4%), reoperation (3.5% vs 7.4%), and RTS (66.7% vs 68.4%) and similar postoperative ASES scores (87.1 vs 80.0) (P ≥ .05 for all).

Conclusion: Patients undergoing Latarjet coracoid transfer had similar postoperative outcomes regardless of preoperative coracoid dimensions. These findings should be confirmed in a larger cohort before further clinical recommendations are made.

Keywords: Latarjet; MRI; coracoid; instability; shoulder.

Figure 1.

Identification of the coracoclavicular ligament on an axial T2 fat-saturated magnetic resonance imaging slice. The coracoclavicular ligament is the T2 hypointense structure (arrow) seen inserting on the medial margin of the coracoid base.

Figure 2.

Demonstration of coracoid width measurements. (A) First, on the coronal oblique T1-weighted sequence, the coracoclavicular ligaments were identified (between the red arrows), outlined by fat, including the more lateral trapezoid ligament and medial conoid ligament. (B) Using scout localizers, the insertion of the coracoclavicular ligaments on the fluid-sensitive axial sequence was identified (red arrow). A line was drawn from this point to the anterior margin of the glenoid (yellow dotted line) denoting the width of the coracoid base. Coracoid width measurements were then collected at 3 locations: 5 mm anteriorly from the coracoid base, midpoint, and 5 mm posteriorly from the coracoid tip (white dotted lines). A straight line from the midpoint of the base to the tip (yellow solid line) was drawn to approximate coracoid length.

Figure 3.

Scatterplot showing the coracoid dimensions of the 56 patients who underwent a Latarjet procedure. No relationship was observed between coracoid length and width (R = 0.16). Green line, coracoid width group cutoff (10 mm); blue line, coracoid length group cutoff (22 mm); black dotted line, trendline.

Figure 4.

Difference between female and male patients in mean preoperative coracoid length and width as measured on magnetic resonance imaging. ×, mean; line, median; box, interquartile range; error bars, 95% CI; circle, outlier.