Table 1.

Preoperative patient data

Institution	Male	Female	Average age (years)	Left fractures	Right fractures
Shanghai Punan Hospital	1	3	72.5 (range, 63–78)	2	2
Shanghai General Hospital	9	20	78.9 (range, 64–91)	13	16
Shanghai Seventh People's Hospital	3	16	69.9 (range, 64–85)	12	7
Total	13 (25%)	39 (75%)	75.1 (range, 63–91)	27	25