Static vs dinamic short nail in pertrochanteric fractures: experience of two center in Northern Italy.

BACKGROUND: Lateral fractures of proximal femur are the most frequent to treat for the traumatologist surgeon. Intramedullary nailing is the gold standard treatment of this type of fracture. The aim of the study is to analyze the results obtained with the Elos Intrauma nail by the experience of two Departments of Orthopedics and Traumatology ("Guglielmo da Saliceto" Hospital in Piacenza and the Maggiore hospital in Bologna).
METHODS: We performed a retrospective cohort study of 400 patients with lateral femoral neck fracture surgically treated with Elos Intrauma standard nail. The examined period is from 1st Jannuary 2018 to 31st Dicember 2020.  In all patients we implanted Elos® - Intrauma nail, a titanium cervical diaphyseal nail, according to the standard technique.
RESULTS: We evaluate at a minumum of three months of follow up 286/400 patients. Average follow up was 3.94 months, minimum 3 months and maximum 24 months. We obtain the 96.85 % of fracture healing, recording 33 complications (11.54%). The incidence of surgical revision was 2.8% (8 cases). No mechanical complications was found in stable fractures treated with short nail and without distal locking.
CONCLUSIONS: With the use of Elos nail we obtained 95% of radiographic healings within three months with a complication rate comparable to literature report. Distal locking is absolutely recommended in complex fractures, it may be superfluous after careful evaluation of the fracture pattern and morphological characteristics of the femur to be treated; future in-depth studies may narrow the criteria to choose distal locking or non locking.

Introduction

Although the current SARS Covid 19 pandemic has decreased the number of fractures overall (1,2), lateral fractures of proximal femur remain by far the most frequent to treat for the traumatologist surgeon. Intramedullary nailing is the gold standard treatment of this type of fracture (3); cervical-diaphyseal nails allowed to reach excellent clinical results and a rapid recovery in elderly patients who usually fracture the proximal femur.

The socio-economic impact of proximal femur fractures (PFF) in terms of public health is significant. It has been shown that the incidence and costs of PFF for elderly in Italy are comparable to myocardial infarction (4) with additional social costs, resulting from emergence of new comorbidities, sarcopenia, disability and mortality. Moreover pertrocantheric fractures are expected to double in the next few decades to the aging of the population (5).

The choice of a stable and reliable synthesis tool is essential to allow an early mobilization and rehabilitation of patients, usually elderly, who risk potentially fatal complications related to prolonged bed rest (3).

Many types of cervical diaphyseal nails are produced with different materials (6) and with different designs and also developed during time (7); in this work we will analyze the results obtained with the Elos Intrauma nail by the experience of two Departments of Orthopedics and Traumatology (“Guglielmo da Saliceto” Hospital in Piacenza and the Maggiore hospital in Bologna).

Materials and methods

We performed a retrospective cohort study of 400 patients with lateral femoral neck fracture surgically treated with Elos Intrauma standard nail at the Orthopedic and Traumatology Unit of the Ospedale Maggiore “C.A. Pizzardi “ in Bologna and Ospedale “Guglielmo da Saliceto” of Piacenza during the period from 1st Jannuary 2018 to 31st Dicember 2020.

The patients distribution of two hospitals is shown in tables 1 and 2.

Table 1.

Ospedale Maggiore Bologna starting cohort

	Patients	Mean age	Fracture AO type		Distal Locking
			A1	A2	No	Static
Males	62	80.16	42	20	1	61
Females	215	84.09	97	118	0	215
tot	277	83.21	139	138	1	276

Table 2.

Ospedale Piacenza starting cohort

	Patients	Mean age	Fracture AO type		Distal Locking
			A1	A2	No	Static
Males	29	82.51	20	9	20	9
Females	94	83.65	57	37	57	37
tot	123	83.39	77	46	77	46

Our population consists of 400 patients with an average age of 83.27, IQR 89-79 and range 42-101: 309 females (mean age 83.96 range 42-101) and 91 males (mean age 80.91 range 52-97), 216 fracture type A1 according to AO-OTA Classification and 184 type A2, follow up average 3.94 months (range 0-24 months).

In all patients we implanted Elos®-Intrauma nail which is a titanium cervical diaphyseal nail with a proximal end of trapezoidal section and a maximum side of 15 mm, distal diameter 10 mm, a lateral bending of 5 degrees and a flat lateral wall, it allows the implantation of a cephalic screw with a fixed angle of 127 degrees and a possible second screw antirotational, short straight nails are 180 or 240 mm and available longer nail sizes from 300 to 460mm with the possibility of a dedicated distal hole centering guide up to 300mm. It presents an expanded side wall of cefalic screw hole to increase mechanical resistance in this critical area, a canulated screw pre-assembled proximally to lock cephalic screw.

In both study centers nails were set up according to the standard technique, as described by the producer (Intrauma S.p.A. - Via Genova, 19, 10098 Rivoli (TO) Italy), with patient positioned on orthopaedic bed and with leg traction, reaming only the proximal part of intramedullary canal with a dedicated tool; cephalic screw was positioned after insertion of the guide wire, and a second optional antirational screw could be placed (no definitive second screw was implanted in our series).

About distal locking screw, it was placed in a static configuration in all 184 A2 fractures and in 138/139 A1 fractures treated in Bologna while no screw in all A1 fractures treated in Piacenza (77 cases). Fig. 2

Figure 2.

Male 85 years old, 31A1 fracture AO classification, healing at 6 months

Proximal femur fracture treated with Elos nail

All patients were subjected to early progressive loading within the first week, depending on the general subjective clinical conditions. Clinical and radiographic controls were scheduled at 1-2-3-6-12 months.

We considered as inclusion criteria of our study:

- Elos nail short implant without second proximal antirotational screw

- Lateral proximal femur fractures type A1 and A2 according to the AO classification, not A3 where we usually use intermediate or long nails which would also be excluded from the study

- minimum follow-up of 3 months to be able to give credible judgment on the patient’s clinic and radiographic recovery.

Considering these criteria the definitive cohort resulted of 286 patients, 62 males and 224 females, mean age 82.41 (min 42 – max 99), IQR 88-78 (table 3).

Table 3.

Definitive cohort

	Patients	Mean age	Fracture AO type		Distal Locking
			A1	A2	No	Static
Males	62	79.12 (52-97)	41	21	10	52
Females	224	83.32 (42-99)	104	120	32	192
Tot	286	82.41	145	141	42	244

Results

We evaluate at a minumum of three months of follow up 286/400 patients (71.5 %); 62/91 males (68.13%), 224/309 females (72.49%), 145/216 patients with A1 fractures (67.13%), 141/184 patients with A2 fractures (76.63%), 42/78 patients without distal locking screw (53.85%) and 244/322 with a distal static screw (75.78%). Average follow up was 3.94 months, minimum 3 months and maximum 24 months.

We obtain with Elos nail 96.85 % (277/286) of fracture healing; we recorded 33 complications (11.54%) in our series (see table 4).

Table 4.

Complications

Complications	Total	Bologna	Piacenza	Treatment
cut out	3	2	1	3 revision with endoprosthesis
refractures at distal screw level	2	0	2	2 revision with long nail
non union	4	3	1	3 no treatment (1 bad general condition, 2 no walking patient) 1 endprosthesis
superficial infection	3	2	1	antibiotic therapy
deep vein thrombosis	4	2	2	blood thinning therapy
ictus cerebri	2	1	1
lateral screw protrusion for fracture compaction	6	4	2	5 no treatment, 1 screw replacement
coxarthrosis	3	2	1	2 no treatment, 1 hip arthroplatsy
malunion	3	2	1	no treatment (hypometry)
knee arthrosis	3	1	2	2 no treatment, 1 knee prosthesis

The incidence of surgical revision was 2.8% (8 cases), and could have doubled (another 8 cases) but the comorbidities or poor general conditions of elderly patients advised against a further surgical approach.

The most frequent revision surgery was nail removal and prosthetic replacement in 5 cases (Fig. 3), 2 cases of new synthesis with long nail for peri-implant fracture, one case of procident cephalic screw replacement for impingment on the fascia lata.

Figure 3.

Cut out and revision with Dual Mobility Cup and locked Stem

The Bologna group believes in distal static fixation even in stable fractures (A1) to control proximal rotation and fracture shortening, and to prevent axial and rotational instability.

On the other hand, none of the A1 pertrochanteric fractures treated in Piacenza were blocked distally to avoid the distal nail jamming which could compromise dynamic compression at the fracture site during loading, inducing nonunion of fracture or leading to breakage of the osteosynthesis device.

We didn’t found any mechanical complications in stable fractures (ie 31 A1 according to AO classification) (8) treated with short nail and without distal locking all healed but in the same fracture type distally locked, we noted 2 cases of peri-implant fracture both at distal locking screw level (Fig. 4).

Figure 4.

Stable fracture treated with short nail and distal locking; refracture at distal screw level, revision with long nail.

Discussion

Carrying out studies on the treatment of pertrochanteric fractures can certainly be difficult as it concerns the elderly population, already fragile and with multiple comorbidities (9,10,11); frequently the patients do not show up even at early checks in fact the literature reports about 30% mortality one year after surgery (12). In addition checks during 2020, included in our series, were even more difficult for ongoing Covid 19 pandemic, which mowed down elderly population and limited outpatient re-evaluations to strictly necessary.

For reasons just mentioned, it is extremely difficult to obtain medium or long follow ups in this type of patients / fractures. We considered a minimum time of three months to be able to evaluate fractures healing which has been reported, in some literature, an average time of 70 days (13).

Certainly a limitation of our study is that we limited to consider outcomes as the fracture healing and the onset of complications; we did not consider clinical criteria or functional rating scales. We chose this approach to evaluate the validity and reliability of internal fixation rather than the functional results in patients who are often compromised before surgery and who often worsen for trauma sequelae and for factors related to surgery, but not related to osteosynthesis quality and tool choice.

The different view between the two groups in the execution or not of the distal locking of the nail to treat the A1 fracture allowed us to evaluate the literature and compare our data.

It is necessary to note that the technical sheets and relative surgical techniques of the most commonly used cervical diaphyseal nails always include distal locking, allowing static or dynamic assembly position but do not indicate the option to not implant the screw. However, there are numerous litterature works that propose to avoid distal locking, especially in stable pertrochanteric fractures (14,15,16,17).

Rosenblum et al. (18) found that the use of distal locking screw does not change femoral stress load for stable intertrochanteric fractures, and the tension of the proximal femoral bone does not change. Other authors as well reported various complications in the use of distal locking of intramedullary nails, including fascia lata irritation, additional operative time, intraoperative bleeding, radiation exposure, superficial femoral artery tear, implant loosening, and secondary femoral fractures. (13,14,15,16,18)

Our numbers are too small to express a static significance but in our serie there were no cut outs (although present in 3 cases but in more complex A2 type fractures) or mechanical complications related A1 pertrochanteric fractures treated without distal screw. However, we reported two cases of peri-nail fractures at the level of locking screw occurred a few months after surgery. Leed’s group refered thigh pain, erosion of the femoral cortex, and femoral fracture as consequences of the stress load at the distal screw (19).

A recent metaanalysis of Li YH et al demonstrate that distal unlocking of stable intertrochanteric fractures can shorten the operation time, reduce intraoperative bleeding, and reduce the blood transfusion rate; furthermore the use of locked or unlocked intramedullary nailing does not affect long-term outcomes regarding complications and function. (20)

More complex fractures deserve a different approach, especially in case of medial support deficit (for example with dislocation of the lesser trochanter) and in case of a large femoral medullary canal, in these cases biomechanical studies show a risk of varus deviation of the nail and fracture so high to make distal locking necessary. (21) Furthermore, the cephalic screw is rotationally unstable within the bone; especially the flexion-extension of the limb causes the loosening of the bone-screw interface, with the screw secondarily “cutting” (21).

The Elos nail has a particular shape, designed with a trapezoidal proximal end which may prevent uncontrolled shortening during fracture healing and limit varus collapse. Furthermore proximal trapezoidal geometry improves rotational stability by allowing a press-fit into the femoral metaphysis where more material is placed laterally. This combined with a press-fit insertion and medialization of the nail at the time of lag screw compression seems to minimize the rate of implant fatigue and/or failure (22). These design features guarantee an advantage for the possible complications previously explained.

Conclusions

The Elos nail we implanted brought us well over 95% of radiographic healings within three months with a complication rate comparable to literature report. The characteristics of the nail in particular the proximal trapezoidal section can give a biomechanical advantage. Distal locking (23,24) is absolutely recommended in complex fractures, it may be superfluous after careful evaluation of the fracture pattern and morphological characteristics of the femur to be treated; future in-depth studies may narrow the criteria to choose distal locking or non locking.