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

	2C-shaped nails “2C“ (n = 8)		3C-shaped nails with 3rd from antero-*medial*“3CM” (n = 8)
	Mean value (SD)		Mean value (SD)	p value
No statistical significant difference
Anterior-posterior	0.78 (0.29) N m/mm	~	0.66 (0.32) N m/mm	n.s.
Posterior-anterior	1.78 (1.31) N m/mm	~	2.87 (2.01) N m/mm	n.s.
Lateral-medial	0.86 (0.33) N m/mm	~	0.71 (0.23) N m/mm	n.s.
Medial-lateral	1.10 (0.40) N m/mm	~	1.09 (0.47) N m/mm	n.s.
External rotation	0.32 (0.18) N m/°	~	0.30 (0.13) N m/°	n.s.
Internal rotation	0.14 (0.04) N m/°	~	0.14 (0.03) N m/°	n.s.
Compression 0° (decrease in length)	0.02 (0.03) mm	~	0.02 (0.01) mm	n.s.
Compression 9° (decrease in length)	2.18 (2.37) mm	~	1.54 (1.24) mm	n.s.

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