The document describes a new surgical technique called biplane double-supported screw fixation (BDSF) for treating femoral neck fractures in patients with osteoporosis. BDSF involves placing two screws in different coronal planes to provide stronger fixation than conventional methods. It establishes two supporting points - the femoral calcar and proximal diaphysis cortex - to better distribute loads. Early results found BDSF achieved bone union in 97.6% of patients and had a lower failure rate compared to conventional fixation. The technique provides improved stability and is particularly suitable for unstable fractures in osteoporotic bone.

1. BIPLANE DOUBLE-SUPPORTED
SCREW FIXATION (F-TECHNIQUE):
A METHOD
OF SCREW FIXATION AT OSTEOPOROTIC FRACTURES
OF THE FEMORAL NECK
DR RAVINDRA CHAURASIA
DNB orthopedics
MAX HOSPITAL VAISHALI

2. INTRODUCTION
• The femur neck fracture is one of the most common
traumatic injury in the elderly.
• Osteosynthesis is associated with poor results in 21–46%.
• Osteosynthesis failure can be due to insufficient
reduction, unstable fixation or poor-quality osteoporotic
bone.

3. CONVENTIONAL FIXATION
• Multiple cannulated cancellous screw have a
compression effect at the fracture site. It also avoids
re displacement and rotation.
• Three cancellous screws, placed parallel to each other
and parallel to the femoral neck axis, (complication 20
to 48%) (Asnis 1994, Lu-Yao 1994, Tidermark 2003, Blomfeldt 2005, Rogmark 2006,
Gjertsen 2010.

4. NUMBER OF SCREWS
• Cannulated cancellous screws are thick in diameter.
• Diameter of the neck of the femur and the width of the
lateral cortex is relatively smaller in Indian patients.
• Therefore it is not always possible to fix femoral neck
fractures with three cannulated cancellous screws.
• Springer et al suggested that the fourth screw adds little
in additional fixation.

5. • Peripheral placement of screws in the femoral neck
(rather than central placement) to improve the strength of
fixation.
• Mizrahi et al specifically recommended an inverted
triangle configuration as it was stronger construct.
• The apex-proximal configuration was found to slip in the
cancellous bone because insufficient cortical purchase.

6. The starting position is above the
level of the lesser trochanter, and
the apex-proximal configuration
of the screws can be seen.
(B) A subtrochanteric femur
fracture resulted after a fall from
the standing position
Subtrochanteric femur fractures after screw fixation have
been documented in all age groups.

7. • A triangular screw configuration with its apex distal
would withstand greater forces than an apex-proximal
configuration.
• A larger stress riser is created when two screws are
placed distally (because of the
larger cortical defect), and
fracture will occur at lower
loads in this area.

8. FAILURE OF CONVENTIONAL FIXATION
• Lack of stability of the construction regarding
varus stress
• Lack of sliding phenomenon.
• Inability to move the entry point of the screws
distally into the solid diaphyseal cortex

9. • This may be attributed to several factors e.g. the entry
points below the level of the lesser trochanter, screws
placed too close together, and violation of the lateral cortex
with multiple guide-wire .
• This leads to the development of a stress riser along the
lateral aspect of the proximal femur.

10. BIPLANE DOUBLE-SUPPORTED SCREW
FIXATION
• BDSF implements two calcar buttressed
screws, oriented in different coronal
inclinations and intended to provide sufficient
stability during various physical activities.

11. • It provides strongest possible posterior cortical support
for the fixation construct.
• Biomechanically, the most effective component is the
distal screw placed at steeper angle and supported on a
large area.

12. The distal screw (red) is placed in the dorsal oblique plane, whereas the middle (blue) and
proximal screw (grey) are oriented in the anterior oblique plane. The distal and the middle
screws are calcar-buttressed with coronal inclinations of 150°–165° and 130°–140°,
respectively.

13. • It establish two supporting points. The solid cortex of
the calcar acts as a medial supporting point for the
screws. This supporting point works under pressure.
• The entry points of the distal and the middle screws
in the solid cortex of the proximal diaphysis, acts as a
lateral supporting point for the two screws.

14. BDSF ADVANTAGES
1) Provide antero-posterior bending stability of the neck.
2) Due to the biplane placement, enough space for a third
screw is provided.
3) due to the increase in the distance between the two
supporting points, the weight borne by the bone is
reduced.
4) The entry points of the screws are positioned wide apart
from each other so the tensile forces spread over a
greater surface of the lateral cortex and thus the risk of a
subtrochanter fracture decreases significantly.
5) The screw, placed at a highly increased angle, works in a
direction close to the direction of the loading force.

15. INDICATION
• Patient in which primary arthroplasty is contraindicated
Fractures of the Garden types from I to IV.
• Implants: 7.3-mm self-tapping cannulated screws.

16. REDUCTION
• Closed reduction (mild traction, slight abduction and
internal rotation of the limb).
• criteria for acceptable reposition: no varus, and valgus
alignment of 0°–15° on AP view, maximum
displacement of 2 mm, up to 20° ventral and 10° dorsal
angular displacement on lateral view.
• Open reduction, through Watson–Jones approach

17. TECHINIQUE
• A straight lateral incision is performed, starting at the
level of the lower border of the greater trochanter,
with a distal length of 6–10 cm. Following a direct
lateral transmuscular approach, a stripping of the
periosteum of the lateral diaphysis over a distance of
6–7 cm is performed.

18. PLACEMENT AND POSITIONING OF GUIDING WIRES
• First: 5–7 cm distally from the lower border of the
greater trochanter, inclined at an angle of 150°–165°
and directed posteriorly, so that after it touches onto
the “calcar” tangentially on AP view, the wire goes
into the dorsal third of femoral head.

19. • The second guiding wire is placed is at 2–4 cm
proximally from the distal wire, inclined at an angle of
130°–140°, directed anteriorly so that it goes in frontal
one-third of the femoral head (on lateral view) and into
the distal one-third of the femoral head (on AP view).

20. • Third : 1.5–2.0 cm proximally from the middle wire
and parallel to it. It goes into the front one-third of the
femoral head (on lateral view) and into the proximal
one-third of the femoral head (on AP view).

21. INSERTION OF SCREWS
• Measurement of the screw lengths and drilling with a 5-
mm cannulated reamer.
• The middle and proximal screws are placed first because
they are perpendicular to the fracture surface.
• Before placing the middle and distal screws, overdrill their
holes in the lateral cortex using a 7-mm cannulated
reamer.
• Then foot traction is released, impaction of the fracture
with an additional tightening up of the screws.
• Finally, the distal screw is placed.
• All three screws are inserted subchondrally (less than 5
mm), and no screw is placed in the central zone of the
femoral neck on lateral view.

22. AFTER-TREATMENT
• FWB Mobilization can be done after surgery without
limitations in the range of motion.
• In younger patients(< 55 years) PWB (30 kg) during the
first 8 weeks. (enough frictional stability at the fracture
site can not be achieved by intraoperative impaction
because of their dense bone).

23. Comparision b/w conventional and BDSF
The load acting at point A is pressure in a distal direction and denoted as A = FL/a
The load acting at point B is pressure in a proximal direction and denoted as B = A - F.
Static models of the implant. a A beam on elastic foundation; b A simple beam with an
overhanging end.
F load, L = length of beam; a distance between points A and B

24. CONVENTIONAL METHODS
• The screws are often located in the soft cancellous bone
near the axis of the femoral neck, without any cortical
support.
• Due to the lack of two solid supporting points, the
implant works like a beam on an elastic foundation.
• The elastic foundation is realized by the cancellous bone.

26. RESULTS
• 42 males and 165 females, aged 75.7 ± 10.3 (range 49–
99)
• The average follow-up period was 29.6 months,
• Five complications were developed within less than 12
months.
• Radiographical results
• The bone union was seen in 97.6%
• One case with pseudoarthrosis and 1 nonunion with
AVN (Garden IV fracture).
• Fixation failure occurred in 5 patients.

28. CONCLUSION
• Femoral neck fracture stability can be substantially
increased applying BDSF due to better cortical screw
support and screw orientation.
• The more unstable fracture, the better BDSF stability
is in comparison to CFIX.

29. REFERENCE
• Filipov O. Biplane double-supported screw fixation (F-technique): a
method of screw fixation at osteoporotic fractures of the femoral
neck. Eur J Orthop Surg Traumatol 2011;21:539–43.
• Thiele OC, Eckhardt C, Linke B, Schneider E, Lill CA. Factors affecting
the stability of screws in human cortical osteoporotic bone. A
cadaver study. J Bone Joint Surg (Br) 2007;89-B(5):701–5.
• Lindequist S, Waldemark T, Eriksson SA, Samnegard E. Screw
positions in femoral neck fractures. Comparison of two different
screw positions in cadavers. Acta Orthop Scand 1993;64:67–70
• von Bahr V, Syk B, Walheim G. Osteosynthesis of femoral neck
fracture using screws. Acta Chir Scand 1974;140:277–82.
• Gurusamy K, Parker MJ, Rowlands TK. The complications of
displaced intracapsular fractures of the hip: the effect of screw
positioning and angulation on fracture healing. J Bone Joint Surg
(Br) 2005;87(5):632–4.

30. Thank you