Modified dynamic hip screw loaded with autologous bone graft for treating Pauwels type-3 vertical femoral neck fractures

Femoral neck fractures represent a relatively uncommon injury in the non-elderly population often resulting from high-energy trauma. Clinical outcome in these patients can be improved by optimizing surgical procedures and selecting appropriate fixation methods. The aim of this study was to develop a numerical fracture model to investigate the influence of critical mechanical factors on the stability of fixation methods for femoral neck fractures. The mechanical stability of fracture fixation was assessed through employing finite element models and simulating progressive consolidation of the fracture for a vertical femoral neck fracture (i.e. Pauwels type III in which the angle between the fracture line and the horizontal plane is greater than 70°). Mechanical performance was compared among three different fixation methods (cannulated screws, dynamic hip screw with de-rotational screw, and proximal femoral locking plate). Axial femoral head displacement varied from 2.3 mm for cannulated screws to 1.12 mm for proximal femoral locking plate, although dynamic hip screw with de-rotational screw indicated a value of 0.94 mm. Considering a consolidated fracture and full weight-bearing load case, average displacements of fracture fragments were obtained of about 1.5, 3 and 70 µm for dynamic hip screw with de-rotational screw, proximal femoral locking plate and cannulated screws methods, respectively. In terms of interfragmentary movements at the fracture site, outcomes of this study demonstrated that, in agreement with our previous experimental research, the dynamic hip screw with de-rotational screw implant is a more effective choice than cannulated screws and proximal femoral locking plate techniques for vertical femoral neck fractures in young patients. Thus, one may conclude that the use of dynamic hip screw with de-rotational screw, particularly during the early stages of bone healing, could provide suitable mechanical environments that facilitate direct bone formation and shorter healing times.

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Cemented acetabular component with femoral neck autograft for acetabular reconstruction in Crowe type III dislocated hips

The Bone & Joint Journal ◽

10.1302/0301-620x.103b2.bjj-2020-1214.r1 ◽

2021 ◽

Vol 103-B (2) ◽

pp. 299-304

Author(s):

Eiji Goto ◽

Hirotsugu Umeda ◽

Makoto Otsubo ◽

Tadashi Teranishi

Keyword(s):

Femoral Neck ◽

Bone Graft ◽

Acetabular Component ◽

Surgical Techniques ◽

Autologous Bone Graft ◽

Anatomical Reconstruction ◽

Type Iii ◽

Acetabular Bone Defect ◽

Autologous Bone

Aims Various surgical techniques have been described for total hip arthroplasty (THA) in patients with Crowe type III dislocated hips, who have a large acetabular bone defect. The aim of this study was to evaluate the long-term clinical results of patients in whom anatomical reconstruction of the acetabulum was performed using a cemented acetabular component and autologous bone graft from the femoral neck. Methods A total of 22 patients with Crowe type III dislocated hips underwent 28 THAs using bone graft from the femoral neck between 1979 and 2000. A Charnley cemented acetabular component was placed at the level of the true acetabulum after preparation with bone grafting. All patients were female with a mean age at the time of surgery of 54 years (35 to 68). A total of 18 patients (21 THAs) were followed for a mean of 27.2 years (20 to 33) after the operation. Results Radiographs immediately after surgery showed a mean vertical distance from the centre of the hip to the teardrop line of 21.5 mm (SD 3.3; 14.5 to 30.7) and a mean cover of the acetabular component by bone graft of 46% (SD 6%; 32% to 60%). All bone grafts united without collapse, and only three acetabular components loosened. The rate of survival of the acetabular component with mechanical loosening or revision as the endpoint was 86.4% at 25 years after surgery. Conclusion The technique of using autologous bone graft from the femoral neck and placing a cemented acetabular component in the true acetabulum can provide good long-term outcomes in patients with Crowe type III dislocated hips. Cite this article: Bone Joint J 2021;103-B(2):299–304.

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