3D MRI PD-SPACE-COR Predicting Safety Margin for Coracoid Transfer

The maximum bone length available for coracoid process transfer varies among individuals, while no preoperative guideline has been developed for predicting the safety margin (SM) in Latarjet shoulder reconstruction. The aim of the study was to evaluate the 3D MRI proton density (PD)-weighted sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) sequence in preoperatively predicting SM for coracoid transfer.

The post-multiplanar reconstructed images were obtained from 24 volunteers (17 males, seven females) to determine the clarity and sensitivity of the PD-SPACE-COR and PD-SPACE-FS-COR protocols. Furthermore, the distance from the coracoid tip to the lateral edge of the attachment of trapezoid ligament (TL) was measured. To evaluate the accuracy of 3D MRI prediction, a cadaveric cohort has been launched in 32 shoulders (nine males, seven females). The distance between the tip of coracoid process and the outmost edge of TL footprint, namely, the SM, was measured.

A better sensitivity was found in PD-SPACE-COR in detecting coracoclavicular ligaments (CCLs), including TL and conoid ligament (CL), compared to PD-SPACE-FS-COR by ranking, McNemar test (P = 0.001), and kappa coefficients (κ = 0.51, P = 0.43). The SM determined by the PD-SPACE-COR protocol was 24.28 ± 2.17 mm while that by cadaveric morphometry was 25.53 ± 2.84 mm. No difference was found between measurements (P = 0.78).

This research provides new insights for preoperatively geometrical planning coracoid transfer by 3D MRI PD-SPACE-COR, which motivates personalized medicine in orthopedics.