Objective To investigate the biomechanical properties and clinical outcomes of four-screw configuration used for internal fixation of Pauwels type Ⅲ femoral neck fractures.Methods A three-dimensional finite element model (FEM) of Pauwels type Ⅲ femoral neck fracture was established and analyzed in three fixation groups (Group 1, an inverted triad of screws; Group 2, four-screw configuration with one transverse screw and three parallel inverted triangle screws; Group 3, hybrid fixation of one dynamic hip screw and one de-rotation screw).Simulated load with one leg standing was applied and then the stress and displacement of the model were calculated to compare the biomechanical stability of different fixation strategies.Retrospective clinical analysis of 31 cases with Pauwels type Ⅲ femoral neck fractures using four-screw fixation was conducted.Results Biomechanically, finite element analysis showed that the strongest construct for stabilizing a Pauwels type Ⅲ femoral neck fracture was Group 3, followed in descending order by Group 2 and Group 1, and the screw displacement in descending order was Group 3, Group 2, and Group 1.Clinically, 31 patients with Pauwels type Ⅲ femoral neck fractures were treated with four-screw configuration; 24 patients (77.4%) were followed up for 24 months and over (24-62 months).None of the cases was nonunion and the mean union time was 16.3 weeks (12-24 weeks).Three cases (12.5%) had necrosis of femoral head.The mean Harris score of hip function was 80±8.5 points, and the excellent-and-good rate was 83.3%.Conclusion The four-screw configuration with one transverse screw and three parallel inverted triangle screws can be used to fix Pauwels type Ⅲ femoral neck fracture.Further studies with larger sample size and longer follow-up are required to assess its clinical efficacy.
RAO Zhitao
,
ZHANG Yingqi
,
CHEN Lei
,
WANG Jiaqi
,
WANG Shuqing
. Finite element study and clinical efficacy analysis on Pauwels type Ⅲ femoral neck fractures fixed with four screws[J]. Surgical Research and New Technique, 2018
, 7(2)
: 83
-88
.
DOI: 10.3969/j.issn.2095-378X.2018.02.002
[1] Kemker B, Magone K, Owen J, et al.A sliding hip screw augmented with 2 screws is biomechanically similar to an inverted triad of cannulated screws in repair of a Pauwels type-Ⅲ fracture[J].Injury, 2017, 48(8):1743-17438.
[2] Shen M, Wang C, Chen H, et al.An update on the Pauwels classification[J].J Orthop Surg Res, 2016, 11(1):161.
[3] Enocson A, Lapidus LJ.The vertical hip fracture-a treatment challenge.A cohort study with an up to 9 year follow-up of 137 consecutive hips treated with sliding hip screw and antirotation screw[J].BMC Musculoskelet Disord, 2012, 13(1):171.
[4] Liporace F, Gaines R, Collinge C, et al.Results of internal fixation of Pauwels type-3 vertical femoral neck fractures[J].J Bone Joint Surg Am, 2008, 90(8):1654-1659.
[5] Kuan FC, Yeh ML, Hong CK, et al.Augmentation by cerclage wire improves fixation of vertical shear femoral neck fractures-A biomechanical analysis[J].Injury, 2016, 47(10):2081-2086.
[6] Slobogean GP, Sprague SA, Scott T, et al.Management of young femoral neck fractures:is there a consensus?[J].Injury, 2015, 46(3):435-440.
[7] 张长青,王清和,邱国良,等.股骨头、干三维互动复位技术治疗难复位性股骨颈骨折[J].中华创伤杂志, 2014,30(3):217-220.
[8] 梅炯.股骨颈骨折内固定手术的研究历程与展望[J].中国骨与关节杂志, 2015, 4(2):82-85.
[9] Stoffel K, Zderic I, Gras F, et al.Biomechanical evaluation of the femoral neck system in unstable pauwels Ⅲ femoral neck fractures: A comparison with the dynamic hip screw and cannulated screws[J].J Orthop Trauma, 2017, 31(3):131-137.
[10] Aminian A, Gao F, Fedoriw WW, et al.Vertically oriented femoral neck fractures:mechanical analysis of four fixation techniques[J].J Orthop Trauma, 2007, 21(8):544-548.
[11] Gumustas SA, Tosun HB, Agir I, et al.Influence of number and orientation of screws on stability in the internal fixation of unstable femoral neck fractures[J].Acta Orthop Traumatol Turc, 2014,48(6):673-678.
[12] Linde F, Andersen E, Hvass I, et al.Avascular femoral head necrosis following fracture fixation[J].Injury, 1986,17(3):159-163.
[13] Zhang YL, Chen S, Ai ZS, et al.Osteonecrosis of the femoral head,nonunion and potential risk factors in Pauwels grade-3 femoral neck fractures:A retrospective cohort study[J].Medicine (Baltimore), 2016, 95(24):e3706.
[14] Zlowodzki M, Brink O, Switzer J, et al.The effect of shortening and varus collapse of the femoral neck on function after fixation of intracapsular fracture of the hip: a multi-centre cohort study[J].J Bone Joint Surg Br, 2008,90(11):1487-1494.
[15] Boraiah S, Paul O, Hammoud S, et al.Predictable healing of femoral neck fractures treated with intraoperative compression and length-stable implants[J].J Trauma, 2010,69(1):142-147.
