**4. Clinical and experimental studies for optimal stabilization of trochanteric fractures: the gliding nail**

The high incidence of osteoporosis in the elderly population and the high mechanical load on the proximal femur make the trochanteric region a common fracture site.

Due to the different types of fracture patterns, each with its own characteristics, a universally applicable implant is very difficult to set. The fixation strength for a pertrochanteric fracture is determined by different variables such as bone quality, bone fragment geometry, fracture reduction, implant design, and implant placement [12].

Numerous studies show that the implant used, as well as its placement, is very important for a successful outcome [13–15].

Depending on the implant position, the types of implants used can be extramedullary or intramedullary.

The dynamic hip screw (DHS) and the blade plate are commonly used implants in pertrochanteric fractures. Due to the longer length of the lever arm, they are subjected to a higher bending stress, making the risk of fatigue fractures or cutout higher than intramedullary implants (**Figure 5**). Moreover, the placement of such an implant requires large incisions with soft tissue damage and deperiostation. In these conditions, the local vascularization is greatly impaired, and the risk of local complications is higher.

Furthermore, immediate restoration of weight bearing is not entirely possible, and considering the mean age of the patients, this is of vital importance.

Intramedullary implants existed since the development of the Y-profile Küntscher nail and due to the implant position in the medullary canal, they all share a less bending force compared to extramedullary implants. Also, the surgical technique required for their implantation minimizes the soft tissue damage [16].

The most common intramedullary implants are the gamma nail and the proximal femoral nail (PFN). Since 1994, extensive clinical and experimental investigations conducted in Germany have led to the development of an intramedullary gliding nail (GN). This system has the biomechanical advantages of an intramedullary locked implant, and because of the double-T angle blade profile, the gliding screw system creates an increased resistance [17] (**Figure 6**).

**Figure 5.** *(A) Extramedullary DHS system and (B) intramedullary GN system.*

*Recent Advances in Biomechanics*

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**Figure 4.**

*Load-deformation diagrams corresponding to the four types of metallic implants loaded in external rotation:* 

variable speeds (0.01–800 mm/min) and an accuracy of minimum 0.2%. The compression forces were measured using the force cell of the machine (0.01% precision), and the deformations were measured with a resolution of 0.1 microns. For the testing trials, we used the Nexygen and Ondio producer provided software. All of the constructs were submitted to torsion essays in external and internal rotation

According to the measured values, the authors obtained load-deformation diagrams corresponding to the four types of implants and two types of torsion

The load-deformation diagrams were compared and statistically analyzed for

The shorter LCP proved to be the most rigid implant for each type of loading essay, the mean values of the loading being the highest in the entire group. This construct with a short angular stable plate and a small working length is unfortunately

The intramedullary locked nail showed to be the most elastic implant of all types

The classic DCP demonstrated, surprisingly, in all types of torsional loading, a mechanical behavior close to the AxSOS angular stable plate; this result is related to the fact that by using longer plates with few screws placed far from fracture site

a stiff device that concentrates stress at the bone-screw interface.

of loading but, at the same time, the less rigid implant in torsion.

*(a) locked nail; (B) DCP; (C) AxSOS plate; and (D) LCP.*

as to obtain the same amount of torque [11].

*(A) Locked plate; (B and C) locked nail; and (D) DCP-buttress plate.*

loading (**Figure 4**).

**Figure 3.**

each type of implant.

**Figure 6.**

*(A) Axial view of the double-T blade profile inside the femoral head (sawbone); (B) lateral view of the GN in three sizes; and (C) 3D view of the gliding nail.*

The double-T profile has a higher stiffness due to its rotational stability and due to its reduced risk of damage in osteoporotic bone. The nail curvature of 6° in frontal plane and straight in sagittal plane allows the entry point on the tip of the trochanter (thus having a lower risk of circulatory disorders to the femoral head than opening the piriformis fossa) (**Figure 7**).

Another important characteristic is the dynamic impaction possibility in the femoral neck direction with dynamic stability in the femoral shaft direction (**Figure 8**).

The first study from 1996 [18], which compared the gliding nail system with the gamma nail, showed better intraoperative and postoperative results for the GN. The rate of intraoperative complications for the GN was 2.7%, while for the gamma nail, it was between 17.2 and 42.2%. The difference in outcome is highlighted by the longterm results, where the gliding nail had only 3.9% rate of complications, while the gamma nail had 6–13.8% [18].

Following the promising results, a biomechanical study from 1998 showed the importance of the blade geometry for the stability of fixation in proximal femoral fractures. The alternating load examinations on Sawbone femoral heads revealed no instability of the implant after 100,000 cycles at a load of 2000 N. The displacement of the double-T blade after 1000 cycles at 1500 N was 1–4 mm, while for the 10 mm, screw of the gamma nail was 4–8 mm [19].

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*Clinical and Experimental Biomechanical Studies Regarding Innovative Implants in Traumatology*

In 1998, Friedl et al. published a study on 186 patients with pertrochanteric fractures treated with gliding nail; the authors revealed a very good outcome with low complication rate, especially for intraoperative complications (1.1%) and late

*(A) Garden IV femoral neck fracture and (B and C) closed reduction and osteosynthesis with gliding nail.*

The superiority of the gliding nail system over the DHS or gamma nail was highlighted by the authors in a series of clinical and biomechanical studies.

**5. Locked intramedullary XS nail for ankle and pilon fractures:** 

The most recent study published in 2009 carried out over a period of 5 years and studied 501 patients with trochanteric and subtrochanteric fractures operated only with the GN system and immediate weight bearing. The results revealed that local complications of these difficult fractures like cutout or severe impaction can be

Fractures around the ankle are very frequent injuries, and the aim of the treatment is reconstruction of the anatomy with stable and minimally invasive osteosynthesis techniques [22, 23] while avoiding further trauma of soft tissue in a local region with anatomical peculiarities: the skin is thin, with limited mobility, with almost nonexistent skin excess, a very poorly represented subcutaneous soft tissue,

Plate osteosynthesis is the "gold standard" procedure for distal fibula, pilon, and lower leg fractures, but Zaghloul et al. reported a rate of 21.5% complications, with

The severe wound complications associated with an extramedullary implant due to the compromised blood supply (arterial occlusion diseases, diabetes, and postthrombotic sequels) and the thin soft tissue envelope require removal of the plate (with secondary stability impairment) and additional challenging reconstructive technical solutions including split-thickness skin grafts and local or locoregional flaps [27–29]. With regard to the use of split-thickness skin grafts, they are often impossible to use in the case of soft part defects in the ankle, due to bone or tendinous exposure. Lately, a solution worthy of consideration is the use of negative pressure therapy, so that a good, vascularized bed can be created, which will allow

Intramedullary implants had biomechanical advantages over plates by reduc-

limitations of simple wires, intramedullary pins, and distally locked flexible nails,

ing the lever arm and increasing the stability of the construct [27, 30]. The

*DOI: http://dx.doi.org/10.5772/intechopen.91728*

local complications (4.9%) [20].

**Figure 8.**

and poor blood supply [24, 25].

avoided by using the gliding nail system [21].

**design, biomechanics, and clinical results**

2% infections and 10.8% operative revisions [26].

the use of a split-thickness skin graft (**Figure 9**).

*Clinical and Experimental Biomechanical Studies Regarding Innovative Implants in Traumatology DOI: http://dx.doi.org/10.5772/intechopen.91728*

**Figure 8.** *(A) Garden IV femoral neck fracture and (B and C) closed reduction and osteosynthesis with gliding nail.*

In 1998, Friedl et al. published a study on 186 patients with pertrochanteric fractures treated with gliding nail; the authors revealed a very good outcome with low complication rate, especially for intraoperative complications (1.1%) and late local complications (4.9%) [20].

The superiority of the gliding nail system over the DHS or gamma nail was highlighted by the authors in a series of clinical and biomechanical studies.

The most recent study published in 2009 carried out over a period of 5 years and studied 501 patients with trochanteric and subtrochanteric fractures operated only with the GN system and immediate weight bearing. The results revealed that local complications of these difficult fractures like cutout or severe impaction can be avoided by using the gliding nail system [21].
