Abstract

Background: Shoulder prosthesis should accurately mimic the proximal shoulder and glenoid anatomy to recreate the shoulder biomechanics. There may be a mismatch in the sizes of the Indian native bone and the currently available western shoulder prosthesis, since the bony morphology of Indians may be different from that of the western counterpart. Purpose: To measure the average humeral head diameter and glenoid length and width, so that a proper implant selection may be done based on the knowledge of average Indian bony morphology. Methods: Twenty shoulders in ten fresh cadavers were dissected to expose the humeral head and glenoid articular surface. The humeral head diameter was measured with the help of a digital vernier caliper in two planes: Supero-inferior diameter (D1) and antero-posterior diameter (D2). The glenoid length (l) and width (w) were measured with the help of a vernier caliper. Results: The average humeral head diameter (D1) ± S.D. in the Supero-inferior plane was 45±3.4 mm (range 40- 50.6mm) and antero-posterior (D2) plane was 42.7±2.2 mm (range 40-46mm) with a mean difference of 2.2 mm. The average length of the glenoid (l) was 35.4±1.3 mm (range 32-37mm) and width of the glenoid (w) was 25.3±2.1 mm (range 21-28mm). The shape of the humeral head was more ellipsoidal at diameters above 45 mm. Conclusion. We can conclude that the humeral head diameters and glenoid length and width in Indian population are smaller than the western counterparts. The ellipsoidal shape of the humeral heads becomes more marked at diameters above 45mm.

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