Biomechanical Study of the Fixation Strength of Anteromedial Plating for Humeral Shaft Fractures / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Open reduction and internal fixation with plate and screws are the gold standard for the surgical treatment of humeral shaft fractures, this study was to compare the mechanical properties of anteromedial, anterolateral, and posterior plating for humeral shaft fractures.</p><p><b>METHODS</b>A distal third humeral shaft fracture model was constructed using fourth-generation sawbones (#3404, composite bone). A total of 24 sawbones with a distal third humeral shaft fracture was randomly divided into three Groups: A, B, and C (n = 8 in each group) for anteromedial, anterolateral, and posterior plating, respectively. All sawbones were subjected to horizontal torsional fatigue tests, horizontal torsional and axial compressive fatigue tests, four-point bending fatigue tests in anteroposterior (AP) and mediolateral (ML) directions and horizontal torsional destructive tests.</p><p><b>RESULTS</b>In the horizontal torsional fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 6.12°, 6.53°, and 6.81°. In horizontal torsional and axial compressive fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 5.66°, 5.67°, and 6.36°. The mean plate displacement amplitude was 0.05 mm, 0.08 mm, and 0.10 mm. Group A was smaller than Group C (P < 0.05). In AP four-point bending fatigue tests, the mean plate displacement amplitude was 0.16 mm, 0.13 mm, and 0.20 mm. Group B was smaller than Group C (P < 0.05). In ML four-point bending fatigue tests, the mean plate displacement amplitude were 0.16 mm, 0.19 mm, and 0.17 mm. In horizontal torsional destructive tests, the mean torsional rigidity in Groups A, B, and C was 0.82, 0.75, and 0.76 N·m/deg. The yielding torsional angle was 24.50°, 25.70°, and 23.86°. The mean yielding torque was 18.46, 18.05, and 16.83 N·m, respectively.</p><p><b>CONCLUSIONS</b>Anteromedial plating was superior to anterolateral or posterior plating in all mechanical tests except in AP four-point bending fatigue tests compared to the anterolateral plating group. We can suggest that anteromedial plating is a clinically safe and effective way for humeral shaft fractures.</p>

Comparison of proximal femoral nail and dynamic hip screw for treating intertrochanteric fractures / 中国骨伤

<p><b>OBJECTIVE</b>To discuss characters of proximal femoral nail and dynamic hip screw for treating type A1, A2, A3 of intertrochanteric fractures.</p><p><b>METHODS</b>We review 104 patients with intertrochanteic fractures, 33 patients were treated with proximal femoral nail (PFN), including 13 males and 20 females with an average age of 76 years (ranging from 63 to 87 years). 12 cases of type A1; 18 cases of type A2 and 3 cases of type A3; and 71 patients were treated with dynamic hip screw (DHS), including 29 males and 42 females with an average age of 74.5 years (ranging from 61 to 92 years), 32 cases of type A1, 34 cases of type A2 and 5 cases of type A3. Comparision in an average time of operations, the length of incision, blood loss, weight loading time and complications between two groups.</p><p><b>RESULTS</b>An average time of operation was (51.5 +/- 4.4) min in PFN; (68.8 +/- 5.9) min in DHS. The length of incision was (9.6 +/- 0.9) cm in PFN; (15.5 +/- 1.5) cm in DHS. The blood loss was (179.0 +/- 12.9) ml in PFN; (269.3 +/- 40.0) ml in DHS. Varus collapse was none in PFN, 1 case in DHS. The collodiaphyseal angle of 7 cases decreased in DHS. Lateral hip pain caused by proximal screw removal was 6 cases in PEN.</p><p><b>CONCLUSION</b>The therapeutic effect of DHS and PEN was primitively same in treating type A1 of intertrochanteric fracture. Operative injuries of PFN were less than that of DHS and anti-tonia was more stronger which is more suitable for type A2 and A3 of intertrochateric fractures.</p>