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238                    11. ANALYSIS OF THE BIOMECHANICAL BEHAVIOR OF INTRAMEDULLARY NAILING


                      S, Mises                            S, Mises
                      (Avg: 75%)                          (Avg: 75%)
                         217.07                              23.23
                         199.00                              21.32
                         180.94                              19.40
                         162.87                              17.49
                         144.80                              15.58
                         126.74                              13.66
                         108.67                              11.75
                          90.60                              9.84
                          72.54                               7.92
                          54.47                               6.01
                          36.40                               4.10
                          18.34                               2.18
                          0.27                                0.27
                     (A)                                 (B)
           FIG. 11.30  Von Mises stress maps in the screws, proximal fracture (gap size 3mm): (A) upper screw; (B) lower screws.




                     S, Mises                              S, Mises
                      (Avg: 75%)                            (Avg: 75%)
                         57.19                                 55.10
                         52.53                                 50.54
                         47.87                                 45.98
                         43.21                                 41.42
                         38.56                                 36.86
                         33.90                                 32.30
                         29.24                                 27.74
                         24.58                                 23.18
                         19.92                                 18.62
                         15.26                                 14.05
                         10.60                                 9.49
                         5.94                                  4.93
                         1.28                                  0.37
                    (A)                                   (B)
           FIG. 11.31  Von Mises stress maps in the screws, distal fracture (gap size 3mm): (A) upper screw; (B) lower screws.

                         TABLE 11.5  Time Consolidation for the Clinical Follow-Up (Months)
                         Study                Comminution grade             Mean time of the consolidation

                         A                    Noncomminutes                 4.1
                                              1                             4.9
                                              2                             6.2
                                              4                             7.1
                         B                    Noncomminutes                 4.8
                                              1                             5.2
                                              2                             5.2


           • Among the studied combinations of distal screws, the one with two distal screws medial-lateral provided the best
              results in terms of stability at the fracture site and global movement at the top of the nail along the three fracture gap
              sizes. This tendency is because the locking effect is maximized when the distance between the distal screws is
              increased. This parameter is limited by the proximity to the fracture site and the distance to the femoral condyles.
              In conclusion, an anterograde locked nail is particularly useful in the treatment of a wide range of supracondylar
           fractures with proximal extension into the femoral diaphysis, which confirms that this technique is nowadays the ref-
           erence surgical treatment for this kind of fracture.



           Acknowledgments

           This research has been partially financed by the Fundacion Mutua Madrileña (Research Projects: AP162632016) and by the Government of Spain:
           Ministry of Economy and Competitiveness (Research Project: DPI2016-77745-R).



                                                       I. BIOMECHANICS
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