Modification of elastic stable intramedullary nailing with a 3rd nail in a femoral spiral fracture model – results of biomechanical testing and a prospective clinical study

Table 3 Comparison between stiffness of osteosynthesis with 2C-shaped nails with the 3rd from antero- lateral “3CL” (Titanium Nails, Santech Nord® Company) and 2C-shaped nails with the 3rd from antero- medial “3CM” (Titanium Nails, Santech Nord® Company)

	3C-shaped nails with 3rd from antero-*lateral*“3CL” (n = 8)		3C-shaped nails with 3rd from antero-*medial*“3CM” (n = 8)
	Mean value (SD)		Mean value (SD)	p value
3CL *more* stable than 3CM
Anterior-posterior	1.23 (0.62) N m/mm	>	0.66 (0.32) N m/mm	<0.001
Lateral-medial	0.88 (0.30) N m/mm	>	0.71 (0.23) N m/mm	0.028
Internal rotation	0.21 (0.07) N m/°	>	0.14 (0.03) N m/°	<0.001
Compression 9° (decrease in length)	0.61 (0.43) mm	<	1.54 (1.24) mm	0.004
3CL *less* stable than 3CM
Posterior-anterior	1.03 (0.97) N m/mm	<	2.87 (2.01) N m/mm	0.001
External rotation	0.19 (0.12) Nm/°	<	0.30 (0.13) N m/°	0.003
No statistical significant difference
Compression 0° (decrease in length)	0.03 (0.03) mm	~	0.02 (0.01) mm	n.s
Medial - lateral	1.10 (0.53) N m/mm	~	1.09 (0.47) N m/mm	n.s

The Holm-Bonferroni correction was applied in view of the multiple series of data. Smaller length changes in compression tests reflect a higher stability. Special terms for biomechanical directions corresponding to the most important clinical problems in elastic stable intramedullary nailing of complex fractures: shortening (= compression 9°), recurvation (= anterior-posterior) and varus (= medial-lateral) as the most important clinical problems in elastic stable intramedullary nailing of complex fractures.

ISSN: 1471-2474