The Treatment of Intertrochanteric Fractures of the Femur with Endovis Nail

Abstract

Dear Editor,further to the stimulating discussion between the Authors and some readers, we feel that some details about the paper we authored [1] should be clarified.For instance, we called the analyzed system Endovis while the exact name is Endovis Bio Advanced (Endovis BA). Both devices are pertrochanteric intramedullary nails, both are manufactured by Citieffe s.r.l., but Endovis BA represents the evolution of Endovis nail (which has been no more on the market since 2008). The underlying concept design is the same for both nails; in fact, they are both equipped with two parallel cephalic screws and they both allow for distal locking. The two parallel cephalic screws are designed to control and reduce undesired side-effects such as rotational instability and femoral head "cut-off" [2]. Both are available in two different versions (Standard and Medium, Endovis BA is completed by a Long version), and have cervical-diaphyseal angulation to naturally fit the procurved femoral anatomy. Both have a distal diapason profile in order to decrease stiffness difference between the nail and the hosting bone and, consequently, avoid excessive contact stress generation.The main differences between the two systems are represented by [3], [4]: • Material -Endovis BA is made of titanium, whereas Endovis was made of stainless steel. • Cephalic screws -in Endovis BA they have the same diameter, whereas in Endovis they had two different diameters. • Dimensions -Endovis BA is about 15% smaller.Nevertheless, it must be stressed that, with Endovis BA the same key features that proved successful with Endovis were emphasized and improved with the state-of-the-art production technologies and materials. Overall, Endovis BA evolved toward higher patient tolerability while maintaining safety and improving effectiveness [5].The study we documented in the referred paper [1] was performed using Endovis BA nail (in the period 2007-2009). Hopefully, on the basis of the additional information provided here (which is not anyhow influencing the study's results), perspective readers will be able to adapt the issues faced in the discussion and conclusion sections to Endovis BA rather than to Endovis.

Clinical Outcome of Peritrochanteric Fractures Treatment with an Antegrade Trochanteric Static Lag Screw Nail (Inter TAN)

“…Over compression femoral neck shortening can lead to limb length discrepancy and is a wellknown clinical finding after fixation with SHS and IMN, particularly in geriatric patients [10,12,17]. The peritrochanteric fracture should be reduced as accurately as possible and the implant should be placed centrally within the femoral head, according to maintain Tip Apex Index (TAD) between 20-25 mm [15,[18][19][20]. The single lag screw when is rotationally unstable within the bone, results in loosening of the bone-screw interface, with the screw cutting out [21].…”