Objective: To explore the efficacy of shoulder arthroplasty for comminuted proximal humeral fracture and measure anatomical specimens to determine the proximal humeral data for placing a shoulder prosthesis and designing a new prothesis.
Methods: A total of 68 Chinese adult cadaveric humeri were selected. The parameters of humeral breadth of proximal epiphysis, across diameter of humeral head, vertical diameter of humeral head, retroverion angle, maximal interval of humeral head-tuberosity and humeral head-shaft angle were measured and analyzed with SPSS 10 program.
Results: The data were as follows: Across diameter of humeral head: left (40.7 ± 1.9) mm, right (40.5 ± 1.4) mm; Vertical diameter of humeral head: left (44.5 ± 1.3) mm, right (43.4 ± 1.5) mm; Retroversion angle: left (26.6 ± 1.4)°, right (26.8 ± 1.6)°; Max interval of humeral head-tuberosity: left (6.6 ± 1.1) mm, right (6.8 ± 1.0) mm; Head-shaft angle: left (134.3 ± 3.5)°, right (135.6 ± 1.5)°; Superior breadth: left (47.2 ± 1.3) mm, right (46.9 ± 1.5) mm.
Conclusion: Ideally the fitting prosthesis' diameter is 40 - 45 mm with a retroversion angle of approximately 30°. And the prosthesis should be higher than the greater tubercle by 6-8 mm.