Biomechanical study of internal fixation methods for femoral neck fractures based on Pauwels angle

Abstract

Objective: To select the most appropriate internal fixation method based on the Pauwels angle, in order to provide a new concept for clinical accurate treatment of femoral neck fractures (FNFs).Methods: FNFs models of Pauwels 30°; 40°; 50°; 60° were created respectively. For Pauwels ≤ 50°, 1, 2 and 3 Cannulated Compression Screws (CCS) and Porous Tantalum Screws (PTS) were used to fix the fracture for the models. For Pauwels 60°, 3CCS and Medial Buttress Plate (MBP) combined with 1, 2 and 3CCS were used to fix the fracture. Based on the results of the finite element (FE) analysis, the biomechanical properties of each model were compared by analyzing and evaluating the following four parameters: maximal stress of the bone (MBS), maximal stress of the implants (MIS), maximal displacement of bone (MBD), interfragmentary motion (IFM).Results: At Pauwels 30°, the larger parameters were found in 1CCS, which was 94.8 MPa (MBS), 307.7 MPa (MIS), 0.86 mm (MBD) and 0.36 mm (IFM). In 2CCS group, the parameters were 86.1 MPa (MBS), 254.4 MPa (MIS), 0.73 mm (MBD) and 0.27 mm (IFM), which were similar to those of PTS. At Pauwels 40°; 50°, with the increase of the number of used CCS, accordingly, the parameters decreased. Particularly, the MIS (Pauwels 50°) of 1CCS was 1,195.3 MPa, but the other were less than the yield range of the materials. At Pauwels 60°, the MBS of 3CCS group was 128.6 Mpa, which had the risk of failure. In 2CCS + MBP group, the parameters were 124.2 MPa (MBS), 602.5 MPa (MIS), 0.75 mm (MBD) and 0.48 mm (IFM), The model stability was significantly enhanced after adding MBP.Conclusion: Pauwels type Ⅰ (<30°) fractures can reduce the number of CCS, and PTS is an appropriate alternative treatment. For Pauwels type Ⅱ fractures (30°∼50°), the 3CCS fixation method is still recommended. For Pauwels type Ⅲ fractures (>50°), it is recommended to add MBP to the medial femoral neck and combine with 2CCS to establish a satisfactory fracture healing environment.

Comparison of the clinical efficacy of three cannulated screws with parallel distribution and inverted triangular distribution in the treatment of femoral neck fractures in the elderly

“…Since Dr Smith-Petersen, an American physician, invented trifin screws for treating femoral neck fractures in 1931, femoral neck internal fixation surgical devices have been rapidly developed over the decades, and various internal fixation devices such as cannulated screws, DHS, proximal femoral locking plate, percutaneous compression plate, medial buttress plate, and FNS have been invented are used in clinical practice to this day. Among them, the novel FNS has obvious biomechanical advantages and can support the fracture in multi-axial direction, with excellent anti-rotation and anti-shortening properties, with significant clinical efficacy (15)(16)(17)(18)(19). However, in China, limited by unbalanced economic development, cannulated screw internal fixation is still the most important surgical method, especially in the vast Central and Western regions and primary hospitals.…”

“…- ---------------------------------------------------------------------------------- shown that inverted triangular distribution has theoretically strong biomechanical properties and is the 'gold standard' for treatment with three cannulated screws (12,18,20,21). However, it must be emphasized that inverted triangular distribution has numerous shortcomings and limitations as well (15,16,(22)(23)(24).…”

“…At present, to the best of the authors' knowledge there is no clinical report on the treatment of femoral neck fractures in the elderly with three cannulated screws with parallel distribution in China. In biomechanical studies, the biomechanical stability of various femoral neck fixation devices varied due to their own structure and indications (17,18,30,31). At present, the mainstream view is that FNS exhibits good stability (17,18).…”

Recent advances in photoelectrochemical platforms based on porous materials for environmental pollutant detection

“…6B). [140][141][142][143][144][145] Alternatively, the combination of COFs with other materials could enhance their performance in PEC detection platforms by providing more reactive sites for the determination of target environmental contaminants. In a study by Wang et al, a heterostructure was formed between TiO 2 NTAs and F-COFs through a simple hydrothermal method (Fig.…”

Exploring Schatzker IV Tibial Plateau Fracture: Finite Element Analysis Study of Five Internal Fixation Methods

“…The vertical distance from the distal point of the fracture line to the tibial plateau is 40mm. [8] Fig. 1 The steps of finite element analysis…”