Biplane double-supported screw fixation (F-technique): a method of screw fixation at osteoporotic fractures of the femoral neck

Abstract

The present work introduces a method of screw fixation of femoral neck fractures in the presence of osteoporosis, according to an original concept of the establishment of two supporting points for the implants and their biplane positioning in the femoral neck and head. The provision of two steady supporting points for the implants and the highly increased (obtuse) angle at which they are positioned allow the body weight to be transferred successfully from the head fragment onto the diaphysis, thanks to the strength of the screws, with the patient’s bone quality being of least importance. The position of the screws allows them to slide under stress with a minimal risk of displacement. The method was developed in search of a solution for those patients for whom primary arthroplasty is contraindicated. The method has been analysed in relation to biomechanics and statics. For the first time, a new function is applied to a screw fixation—the implant is presented as a simple beam with an overhanging end.

The Method of Biplane Double-Supported Screw Fixation (Bdsf) at Femoral Neck Fractures - Principle and Clinical Outcomes

“…From a series of 178 operated patients, 88 were studied [7]. Out of the 88 studied patients, 27(30.68%) are male and 61(69.31%) female; the average age is 76.9 (with the youngest patient aged 38 and the oldest aged 99).…”

“…Biplane Double-supported Screw fixation (BDSF) -operative technique [7] Approach. A straight lateral incision, starting at the level of the lower border of the greater trochanter, with distal length of 6 to 10 cm.…”

“…The traditional screw fixation methods, however, do not meet the above-named requirement. Present-day popular traditional methods of femoral neck fixation, which are performed by three cancellous screws, placed parallel to each other and parallel to the femoral neck axis, are associated with poor outcomes in 20 to 48% (Asnis 1994 The new method of Biplane double-supported screw fixation (BDSF) increases the fixation strength by its innovative concept of biplane positioning of the three screws, which makes it possible for the screws to be placed at an increased angle, so they to lean on two solid supporting points [7] (Fig.2). The BDSF-method has two calcar-buttressed implants.…”

“…(7):539-543). [7] In the sagital plane (in lateral view) the distal screw is touched on the posterior cortex of the femoral neck, thus ensuring a posterior supporting point, which works under pressure in posterior direction, in the process of anteroposterior bending of the neck (when rising from a chair).…”

Biomechanics of the Fractured Femoral Neck - The New BDSF-Method of Positioning the Implant as a Simple Beam with an Overhanging End

“…The screws are often located near the axis of the femoral neck in the soft cancellous bone, without any cortical support. According to my previous investigations [12], with conventional methods, due to the lack of two solid supporting points, the implant acts statically like a beam on an elastic foundation. The elastic foundation is implemented by the soft cancellous bone (Fig.2).…”