Anthropometric and Radiologic Measurements of Coracoid Dimensions and Clinical Implications in an Indian Population

Abstract

Background: Recurrent shoulder dislocation and anterior instability are most commonly attributed to pathology of the capsulolabral complex with the presence of bony loss at the humeral and glenoid surfaces. Unassessed bone loss has been a cause of failure of primary soft tissue procedures or recurrence of symptoms, despite adequate address of soft tissue pathology. Purpose: To study the anthropometric and radiologic dimensions of the coracoid in relation to glenoid bone loss, its adequacy in filling glenoid defects in an Indian population, and whether the choice of surgical technique (congruent arc vs classical) and graft positioning alters the surgical results. This study also intended to establish whether computed tomography measurements correlate with actual anthropometric measurements. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 64 participants with 108 healthy shoulders were included in this study. Additionally, 100 skeletally mature bone specimens of the scapula were measured to assess glenoid diameter as well as coracoid width and length in 2 perpendicular planes with a humeral subtraction 3-dimensional en face glenoid view. Results: Specimen and participant measurements proved that the congruent arc technique was able to fill up to 50% more glenoid bone loss than the classical technique in an Indian population (mean ± SD, 13.45 ± 6.97 vs 7.96 ± 4.89 mm, respectively), with computed tomography being the best and most accurate modality to study it. The mean difference in the bone block length restoration of the glenoid bony arc was 5.41 ± 2.08 mm. Radii of curvature were congruent in populations of the Indian subcontinent. Conclusion: The congruent arc technique can be performed in an Indian population but with caution and careful presurgical assessment of bone loss. However, adequate coracoid dimension to accommodate the implant for fixation without failure must be ensured, as anthropometry suggests the existence of a subset of the population in whom the graft may have compromised width for accommodating standard implants for fixation.