Glenoid Bone Loss in Shoulder Instability: Superiority of Three-Dimensional Computed Tomography over Two-Dimensional Magnetic Resonance Imaging Using Established Methodology

Background@#Recent literature suggests that three-dimensional magnetic resonance imaging (3D MRI) can replace 3D computed tomography (3D CT) when evaluating glenoid bone loss in patients with shoulder instability. We aimed to examine if 2D MRI in conjunction with a validated predictive formula for assessment of glenoid height is equivalent to the gold standard 3D CT scans for patients with recurrent glenohumeral instability. @*Methods@#Patients with recurrent shoulder instability and available imaging were retrospectively reviewed. Glenoid height on 3D CT and 2D MRI was measured by two blinded raters. Difference and equivalence testing were performed using a paired t-test and two one-sided tests, respectively. The interclass correlation coefficient (ICC) was used to test for interrater reliability, and percent agreement between the measurements of one reviewer was used to assess intrarater reliability. @*Results@#Using an equivalence margin of 1 mm, 3D CT and 2D MRI were found to be different (p = 0.123). The mean glenoid height was significantly different when measured on 2D MRI (39.09 ± 2.93 mm) compared to 3D CT (38.71 ± 2.89 mm) (p = 0.032). The mean glenoid width was significantly different between 3D CT (30.13 ± 2.43 mm) and 2D MRI (27.45 ± 1.72 mm) (p < 0.001). The 3D CT measurements had better interrater agreement (ICC, 0.91) than 2D MRI measurements (ICC, 0.8). intrarater agreement was also higher on CT. @*Conclusions@#Measurements of glenoid height using 3D CT and 2D MRI with subsequent calculation of the glenoid width using a validated methodology were not equivalent, and 3D CT was superior. Based on the validated methods for the measurement of glenoid bone loss on advanced imaging studies, 3D CT study must be preferred over 2D MRI in order to estimate the amount of glenoid bone loss in candidates for shoulder stabilization surgery and to assist in surgical decision-making.

Glenoid Bone Loss in Shoulder Instability: Superiority of Three-Dimensional Computed Tomography over Two-Dimensional Magnetic Resonance Imaging Using Established Methodology

Background@#Recent literature suggests that three-dimensional magnetic resonance imaging (3D MRI) can replace 3D computed tomography (3D CT) when evaluating glenoid bone loss in patients with shoulder instability. We aimed to examine if 2D MRI in conjunction with a validated predictive formula for assessment of glenoid height is equivalent to the gold standard 3D CT scans for patients with recurrent glenohumeral instability. @*Methods@#Patients with recurrent shoulder instability and available imaging were retrospectively reviewed. Glenoid height on 3D CT and 2D MRI was measured by two blinded raters. Difference and equivalence testing were performed using a paired t-test and two one-sided tests, respectively. The interclass correlation coefficient (ICC) was used to test for interrater reliability, and percent agreement between the measurements of one reviewer was used to assess intrarater reliability. @*Results@#Using an equivalence margin of 1 mm, 3D CT and 2D MRI were found to be different (p = 0.123). The mean glenoid height was significantly different when measured on 2D MRI (39.09 ± 2.93 mm) compared to 3D CT (38.71 ± 2.89 mm) (p = 0.032). The mean glenoid width was significantly different between 3D CT (30.13 ± 2.43 mm) and 2D MRI (27.45 ± 1.72 mm) (p < 0.001). The 3D CT measurements had better interrater agreement (ICC, 0.91) than 2D MRI measurements (ICC, 0.8). intrarater agreement was also higher on CT. @*Conclusions@#Measurements of glenoid height using 3D CT and 2D MRI with subsequent calculation of the glenoid width using a validated methodology were not equivalent, and 3D CT was superior. Based on the validated methods for the measurement of glenoid bone loss on advanced imaging studies, 3D CT study must be preferred over 2D MRI in order to estimate the amount of glenoid bone loss in candidates for shoulder stabilization surgery and to assist in surgical decision-making.

Measurement of Clavicle Fracture Shortening Using Computed Tomography and Chest Radiography

BACKGROUND: Nonoperative management of midshaft clavicle fractures has resulted in widely disparate outcomes and there is growing evidence that clavicle shortening poses the risk of unsatisfactory functional outcomes due to shoulder weakness and nonunion. Unfortunately, the literature does not clearly demonstrate the superiority of one particular method for measuring clavicle shortening. The purpose of this study was to compare the accuracy of clavicle shortening measurements based on plain radiographs with those based on computed tomography (CT) reconstructed images of the clavicle. METHODS: A total of 51 patients with midshaft clavicle fractures who underwent both a chest CT scan and standardized anteroposterior chest radiography on the day of admission were included in this study. Both an orthopedic surgeon and a musculoskeletal radiologist measured clavicle shortening for all included patients. We then determined the accuracy and intraclass correlation coefficients for the imaging modalities. Bland-Altman plots were created to analyze agreement between the modalities and a paired t-test was used to determine any significant difference between measurements. RESULTS: For injured clavicles, radiographic measurements significantly overestimated the clavicular length by a mean of 8.2 mm (standard deviation [SD], ± 10.2; confidence interval [CI], 95%) compared to CT-based measurements (p < 0.001). The intraclass correlation was 0.96 for both plain radiograph- and CT-based measurements (p = 0.17). CONCLUSIONS: We found that plain radiograph-based measurements of midshaft clavicle shortening are precise, but inaccurate. When clavicle shortening is considered in the decision to pursue operative management, we do not recommend the use of plain radiograph-based measurements.

Acute Compartment Syndrome after Non-Contact Peroneus Longus Muscle Rupture

This case demonstrates a rare variation in the pattern of injury and the presentation of acute lateral compartment syndrome of the leg. Although uncommon, lateral compartment syndrome of the leg after an ankle inversion leading to peroneus longus muscle rupture has been previously documented. This case was unusual because there was no overt ankle injury and the patient was able to continue physical activity, in spite of a significant rupture of the peroneus longus muscle that was determined later. This case highlights the necessary vigilance clinicians must maintain when assessing non-contact injuries in patients with possible compartment syndrome.