Biomechanical Testing, Finite Element Analysis and Pilot, Prospective, Randomized, Experimental Clinical Study of Osteosynthesis of Reverse Oblique Peritrochanteric Fractures With PFLP vs Cephalomedullary Nail.

Background Hip fractures are the second most common fractures regardless of age . At the same time, the prevalence of these fractures is increasing, with the total number of admissions for hip fractures in the US is estimated to reach 289,000 by 2030 with an increase to 4.5 million by 2050. In the United Kingdom, although there has been an age-weighted decline in hip fractures of 0.5% per year, it is estimated that their incidence in the United Kingdom will double in the next 25 years. In addition, hip fractures are associated with a high risk of mortality, especially in the elderly, as well as reduced mobility. Their consequences in the elderly are significant due primarily to the increased mortality and secondarily to the negative effects on the health of patients resulting in reduced mobility and influence of their quality of life. In a recent review of 38 studies by Dyer et al, hip fracture survivors had significantly affected mobility, independent functionality, health, quality of life, and higher institutionalization rates compared to their respective age control group without fracture. Even with advances in rehabilitation institutes and new scientific protocols for the optimal treatment of hip fragility fractures, the in-hospital mortality rate was 2.4% and the overall mortality, one year postoperatively, was 18.7% and complete recovery or slight reduction of mobility was achieved in 32.1% of patients. In a recent study by the Swedish Hip Fracture Registry, the first-year mortality rate was about 20% for women and 30% for men in a total population study of 289,603 patients with first hip fracture. during a period of 20 years (1998-2017).

The first mobilization after a hip fracture seems to be beneficial for patients as it is associated with reduced complications due to prolonged bed rest and helps the fracture heal. Consequently, the vast majority of fractures require surgical interventions to allow for fast mobilization and loading of the limb. Various osteosynthesis techniques have been proposed and used which fall into three main categories: a) Dynamic Hip Screw (DHS) extramedullary systems, b) Proximal femoral nail N [PN] PFNA], γ-nail [GN] or other implants) and (c) Dynamic Condylar Screw, Angled blade plates, Proximal Femur Locking Plate (PFLP). The type of osteosynthesis is based on the pattern of the fracture, the characteristics of the patient and the preference of the surgeon In our study we will analyze the lateral oblique (reverse oblique) peritrochanteric fractures that are classified as A31-1,2,3 according to AO and extend on the lateral wall of the proximal femur (Figure 1).

In this fracture category we will compare the anatomical locked plate PERI-LOC◊ 4.5mm Proximal Femur Locking Plate (PFLP) (Smith & Nephew) with cephalomedullary nail [Figure 2]. PFLP is an implant characterized by the ability to place multiple screws in both the head (5) and the femoral diaphysis. It also has an anatomical design, offers immediate reduction of the fracture with the possibility of additional placement of wires while there is a special guide for the transdermal placement of the peripheral screws. In contrast, the cephalic nails, using a transverse screw compressor, allow the linear compression of the descending sections, while providing a high degree of rotational stability.

The common problem with cephalic nails is that they cannot usually align the outwardly displaced central part of the head (Figure 2) and in addition, the posterior slip of the transverse screw is parallel to the fracture line and exacerbates postoperative misalignment. during charging. Biomechanically, however, it is the central part of the nail that resists the sliding forces and holds the further displacement of the fracture. According to the existing literature, there are conflicting data on the stability of PFLP's. Ozkan et al. In a biomechanical study on the stability of PFLPs against intramedullary nails for unstable intertrochanteric fractures (but not reverse oblique ones) they concluded that for subtrochanteric fractures, PFLP's provided greater stability, but the difference was not statistically significant. A retrospective study of the efficacy of PFLP in peritchanteric fractures has shown that it has fewer complications than other methods. At the same time, biomechanical studies suggest that the axial stability of PFLP'S is less than that of intramedullary implants. In studies evaluating the postoperative parameters of peritrochanteric fractures, good results have been reported in terms of anatomical reduction, fracture healing and patient function scores. Nevertheless, it is shown that the intramedullary nails offer greater mechanical stiffness, stabilization and shorter time of onset of porous. It should be noted, however, that a direct comparison of the peri-loc plate with the cephalomedullary nails is not known to have been published in the literature regarding unstable subtrochanteric fractures, while in a study comparing them biomechanically it appears that this material has comparable stability with the TIT (Smith and Nephew) nail.

I. CLINICAL STUDY Purpose of the study The proposed pilot, monocentric, randomized controlled trial is designed to evaluate clinical and radiological parameters as well as quality-of-life indicators in patients with reverse oblique hip fractures (A31-1.3 against AO) undergoing surgery. With the anatomical proximal femur locking plate, against an intermedullary nailing system. Our main assumption is that the plate will provide better radiological and possibly better clinical results compared to the intramedullary nailing system. The biomechanical differences of the two implants will be examined in the biomechanical study.