Glenoid and Coracoid Morphology are Ideally Matched for the Congruent-Arc Latarjet

Abstract

BackgroundThe Congruent-Arc Latarjet is modification of the Latarjet open bony stabilisation for shoulder instability. It involves rotation of the coracoid so the curved under-surface lies congruent with the glenoid. The aim of this study was to define the relationship between the concave under surface of the coracoid and the glenoid.Methods An initial study of 210 cadaveric scapulae was performed followed by a study measuring the same curves using 3D CT reconstruction on 20 scapulae from living patients. ResultsCadveric measurement revealed the glenoid's surface had a median radius of curvature of 30 mm and the coracoid had a median radius of curvature of 25 mm. The CT measurements revealed similar radii of curvature with the glenoid measuring 23.9 mm and the coracoid measuring 25.4 mm (p = 0.2488). ConclusionThe curvature of the glenoid in the cadaveric specimens was slightly larger than the corresponding coracoid curvature. In life this difference may be minimised by articular cartilage, labrum and the attachment of capsule. The CT study revealed similar curves, although in contrast to the cadaveric specimens the coracoid curvature was slightly larger. Overall the curvature of the under surface of the coracoid is similar to the glenoid, which supports this modification of the Latarjet procedure.

Reconstruction of a Bony Bankart Lesion

“…Although previous studies have defined the radii of curvature of the glenoid, inferior coracoid, and lateral distal tibia, [8][9][10]15,24 this is, to our knowledge, the first study to directly compare both autograft and osteochondral allograft sites in the same setting as well as to determine the radius of curvature of several novel potential graft sites.…”

“…Reports of the radius of curvature of the glenoid, coracoid, and distal tibia found in the literature closely correlate with our findings. Gooding et al 10 examined the relationship between the glenoid and the undersurface of the coracoid in 210 cadaveric specimens using Mose circle measurements and in 20 living persons using 3-dimensional (3D) computed tomography (CT) radiographic measurements. Their study found that the radius of curvature of the inferior coracoid was 5 mm less than the glenoid (25 vs 30 mm) in the cadaveric measurements but was 1.4 mm larger than the glenoid (25.3 vs 23.9 mm) in 3D CT radiographic measurements.…”

“…Measurements were made with Mose circles, a standard geometric tool found on most goniometers to determine an object's radius of curvature (Figure 1). 10 One standard 8-inch…”

“…6,[24][25][26][30][31][32] Several studies have addressed the anatomic shape of the glenoid, humeral head, and other potential donor sites for their compatibility. [8][9][10]15,24 These studies separately report similar congruity of the glenoid with either the lateral distal tibia or the undersurface of the coracoid process. 9,10,24 However, we are unaware of a comparison of the conformity of multiple autograft or potential osteochondral allograft sites to the glenoid in a single study.…”

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

“…This was essentially done to establish the precise role of a congruent arc Latarjet technique and its efficacy in an Indian population. 5,18…”