Can the contralateral scapula be used as a reliable template to reconstruct the eroded scapula during shoulder arthroplasty?

Hypothesis: The contralateral scapula can be used as a reliable template to determine scapular offset, glenoid inclination, and version of the native scapula in view of reconstructing pathologic scapulae.

Methods: Three-dimensional measurements of scapular offset, inclination, and version were performed using data from a set of 50 bilateral computed tomography scans of full scapulae to determine direct side-to-side differences.

Results: The scapula pairs had a mean bilateral difference of 2 mm in offset, 2° in inclination, and 2° in version. Ninety percent of the scapula pairs showed an offset difference smaller than 3 mm. In 96% and 94% of the scapula pairs, the inclination difference and version difference, respectively, were smaller than 5°. The maximum bilateral difference for offset, inclination, and version was 6 mm, 6°, and 8°, respectively.

Discussion and conclusion: The anatomic parameters of scapular offset, glenoid inclination, and version are quite symmetrical and fall into the currently technically feasible accuracy of shoulder arthroplasty implantation. The healthy scapula can be used as a template to guide the reconstruction of the glenoid during shoulder arthroplasty planning in the case of unilateral advanced arthropathy.