Synthes DHS User manual

Original Instruments and Implants of the
Association for the Study of Internal Fixation –
AO/ASIF
DHS/DCS Standard System
Surgical Technique

SYNTHES 1
Implants 2
Indications/Contraindications 4
DHS®Plate 6
DHS®Trochanter Stabilizing Plate 11
DCS®Plate 95° 12
Assembling the insertion instruments 17
Implant removal 18
Bibliography 19
DHS/DCS Standard System
Table of contents
Image intensifier control
Warning
This description is not sufficient for immediate application
of the instrumentation. Instruction by a surgeon experienced
in handling this instrumentation is highly recommended.

2
DHS/DCS Standard System
Implants
DHS Trochanter Stabilizing Plates (281.869/870)
The DHS trochanter stabilizing plates offer anchoring
options for the fixation of fragments of the greater trochanter
(a), an aperture for an anti-rotation screw (b), an oval
aperture for the DHS/DCS screw (c) and holes for fixation to
the DHS plate (d). The scooped section can be adapted
to the anatomical contours of the greater trochanter using
bending irons or flat-nosed pliers.
–for use with DHS plates
–Steel
–Short: 138 mm
–Long: 148 mm
b
a
a
a
a
c
d
d
d
d
d
d
c
b
DHS®Plates 130°–150° (281.040–560)
–Steel
–Fixation with cortex screws 4.5 mm
–Lengths: 43–270 mm (2–16 holes)
–Thickness: 5.8 mm
–Width: 19 mm
–Hole spacing: 16 mm
–Barrel lengths: 25–38 mm
Anti-rotation screw
The anti-rotation screw can be used on its own, with the
DHS plate, or the DHS plate and the DHS trochanter
stabilizing plate. The screw effectively prevents rotation of
the head-neck fragment of the femur around the DHS
screw.
–Cancellous bone screw 6.5 mm, steel (214.814–910)
–Cannulated screw 7.0 or 7.3 mm, steel

SYNTHES 3
DHS Locking Device (280.960)
The DHS locking device is used together with the
DHS for temporary locking of the sliding mechanism of
the DHS/DCS screw.
–Steel
–Inner hexagon for DHS Torque-indicating Screwdriver
338.560
–Length: 35 mm
DCS Plates (281.900–990)
–Steel
–Fixation with cortex screws 4.5 mm
–Lengths: 114–370 mm (6–22 holes)
–Thickness: 5.4 mm
–Width: 16 mm
–Hole spacing: 16 mm
–Barrel length: 25 mm
DHS/DCS Screws (280.000–950)
–Steel
–Lengths: 50–145 mm
–Thread diameter: 12.5 mm
–Thread length: 22 mm
–Shaft diameter: 8.0 mm
DHS/DCS Compression Screw (280.990)
The compression screw is used together with the DHS
and DCS plates.
It is used in pertrochanteric fractures to compress
the femoral fragments on the proximal and distal sides of
the fracture.
The DHS/DCS compression screw must be used if a DCS
plate is applied to the distal femur.
–Steel
–Inner hexagon for Hexagonal Screwdriver 314.120 and
314.270
–Length: 36 mm

4
Indications for DHS plates
–Pertrochanteric and intertrochanteric fractures of type
31-A in the AO/ASIF classification.
For highly unstable types of fracture, additional implants
such as the DHS trochanter stabilizing plate or DHS locking
device may be required.
–Femoral neck fractures 31-B2/B3, in conjunction with
the use of an anti-rotation screw.
Indications for DHS trochanter stabilizing plates
–Group 31-A2 and A3 fractures, particularly multifragment
fractures.
The DHS Trochanter Stabilizing Plates (281.869 and
281.870) are viewed as an extension of the DHS plate for
stabilizing the greater trochanter and for accepting
an anti-rotation screw.
Where telescoping is present in the fracture zone, the
combination of a DHS plate and a DHS trochanter stabilizing
plate prevents the tendency of the trochanter fragments
to move laterally with consequent medialization of the shaft
in relation to the head-neck fragment. Additionally,
a rotationally unstable head-neck fragment can be stabilized
by inserting an anti-rotation screw cranially and parallel
to the DHS/DCS screw.
DHS trochanter stabilizing plates can also be used to
secure splintered greater trochanter fragments and stabilize
them by using screws or cerclage wires in the scooped
section of the DHS trochanter stabilizing plate.
DHS/DCS Standard System
Indications/Contraindications

SYNTHES 5
Indications for DCS plates
–Proximal femur: very proximally located, purely sub-
trochanteric fractures of types 32-A 1.1, A 2.1, A 3.1;
32-B 1.1, B 2.1, B.3.1.
–Fractures of type 33-A (extra-articular, supracondylar fractures
of the distal femur)
–Fractures of type 33-C1/C2/C3 (fully articular fractures
of the distal femur)
Contraindications for DCS plates
–Pertrochanteric fractures or trochanteric fractures extending
to the subtrochanter.
Indications for the DHS locking device
The locking device is used if there is a risk of severe
shortening of the femoral neck due to telescoping of
the head fragment.
–Group A 2 and A 3 fractures in young patients, particularly
fractures with a comminuted zone.
A 2.2 With several intermediate fragments
A 2.3 Fracture extending more than 1 cm below the
lesser trochanter
A 3.3 Multifragment fractures
Contraindication for locking device
–Osteoporotic bone

6
1
Position patient
Place the patient in a supine position on the operating table.
2
Reduce fracture
If possible reduce the fracture while closed under the
image intensifier.
If an operating table without extension is used, reduce
the fracture by flexion, lengthwise traction, abduction and
internal rotation. Fix the fracture temporarily with Kirschner
wires. Position the Kirschner wires so that they do not
hamper insertion of the DHS/DCS screw and DHS plate.
3
Access
The proximal femur is approached laterally. Make a
15–20 cm straight incision starting two fingerwidths proximal
to the greater trochanter.
Split the iliotibial tract lengthwise. Detach the M. vastus
lateralis dorsally from the intermuscular membrane, retract
ventrally and, if necessary, make a slight notch in the
muscle in the region of the innominate tubercle. Expose the
proximal femoral shaft without retracting the periosteum.
4
Determine antetorsion
To determine the antetorsion of the femoral neck using the
DHS Angled Guide (358.005–040) and the DHS/DCS T-Handle
(338.080), place a Kirschner wire ventrally over the femoral
neck and tap the tip slightly into the femoral head.
DHS/DCS Standard System
DHS plate

SYNTHES 7
5
Determine entry point for the DHS/DCS screw and
insert guide wire
Implants with CCD angles from 130° to 150° are available.
Depending on the angle of the implant, the entry point
for the DHS/DCS screw is approx. 2.5 – 6.0 cm distal to the
innominate tubercle.
Locate the DHS angled guide and drill the outer cortex
using the Drill Bit 2.0 mm (310.190). Insert the DHS/DCS
Guide Wire with Threaded Tip 2.5 mm (338.000) until
the tip reaches the subchondral part of the femur head.
The guide wire runs approximately 6 mm proximal to
Adams’ arc in the dorsocaudal quadrant of the femoral head.
The thread on the tip of the guide wire stops the wire
from being pulled out. Check the position of the guide wire
under the image intensifier in the a.p. view and the
Lauenstein position. If an extension table is used, record
an axial view.
Note: Leave the guide wire in the femur until the plate is
fitted (step 9, page 9). If the guide wire is not correctly
positioned it must be reinserted. Once the DHS/DCS screw is
inserted in an incorrect position, no subsequent correction
is possible.
6
Measure the length of the guide wire
Slide the DHS/DCS Direct Measuring Device (338.050)
over the guide wire and measure the length of the guide wire
in the bone (e.g. 120 mm).
Remove the antetorsion Kirschner wire.
ventral
caudal
cranial
dorsal

8
7
Reaming
Assemble the DHS triple reamer: Slide the DHS Reamer
(338.110 or 338.440) over the Drill Bit 8.0 mm (338.100)
until it clicks into place at the selected mark (in this
example at 110 mm). The reaming depth can be adjusted
in 5 mm increments. Secure the reamer by tightening
the Knurled Nut (338.120).
Adjust the reaming depth on the DHS Triple Reamer
(338.130). The appropriate reaming depth is 10 mm less than
the measured length of the guide wire (in this example
120 mm – 10 mm = 110 mm).
Ream the screw channel until the tip of the reamer is 10 mm
in the subchondral part of the femoral head.
The length of the appropriate DHS/DCS screw is identical
to the reaming depth (in this example 110 mm).
Notes: While reaming, ensure that the guide wire
does not bend. Bending the guide wire can result in incorrect
placement of the DHS plate and DHS/DCS screw.
If the guide wire is pulled out during reaming it must be
replaced. Push the short DHS Centering Sleeve (338.180) into
the drill hole and insert a DHS/DCS screw with the shaft
foremost into the centering sleeve. The guide wire can now
easily be reinserted back in its original position.
Remove the DHS triple reamer.
Option
In case of hard bone, tap the thread using the DHS/DCS
Tap (388.170) and the short DHS/DCS Centering Sleeve
388.180). Tap the thread until the selected depth in the small
window of the centering sleeve reaches the lateral cortex
(in this example 100 mm).
Note: The DHS/DCS tap may not be used in osteoporotic
bone.

SYNTHES 9
8
Insert the DHS/DCS screw
Slide the insertion instruments (see page 17 for assembly)
over the guide wire and advance the long Centering Sleeve
(388.190) into the drilled hole. Insert the DHS/DCS screw
(in this example 110 mm) until the zero mark reaches
the lateral cortex. Continue inserting the screw for a further
5 mm if the bone is osteoporotic.
The handle of the DHS/DCS Wrench (338.060) must
remain parallel to the femoral axis since only in this screw
position can the DHS plate be positioned correctly
over the flat-sided shaft of the DHS/DCS screw against
the femoral shaft.
Note: Do not use the DHS/DCS wrench to reduce the
fracture as this only allows limited transmission of forces.
Remove the DHS/DCS wrench and the long centering sleeve.
9
Position DHS plate
Position the DHS plate over the short Connecting Screw
(338.200) against the femoral shaft. Loosen the connecting
screw and remove the Guide Shaft (338.210).
Set the power tool to reverse operation to remove the guide
wire. Dispose of the guide wire.
10
Tap DHS plate
Tap the DHS plate into the predrilled channel using
the DHS/DCS Impactor (388.140). Compress the fracture by
gentle hammer taps against the impactor.
Option
Where a Trochanter Stabilizing Plate (281.869 or 281.870)
is indicated, perform steps 11b–13b on page 11.
DHS/DCS Standard System
DHS plate

10
11a
Fix DHS plate
Using the DCP Hip Drill Guide 4.5 (322.430) and the
Drill Bit 3.2 mm (310.310), drill neutral holes through
the plate holes.
Fix the DHS plate using cortex screws 4.5 mm of
the appropriate length.
Option
The fracture fragments can also be compressed with
the DHS/DCS Compression Screw (280.990). First fix the
plate to the femoral shaft with screws. Insert and
tighten the compression screw.
Particularly if the bone is osteoporotic, insert the
compression screw carefully and ensure that the thread is
not stripped.
The compression screw can then be removed.
12a
Insert DHS locking device (Option)
The DHS Locking Device (280.960) is used to temporarily
block the sliding mechanism.
In order to fully countersink the DHS locking device in
the DHS plate barrel, the selected DHS/DCS screw must be
10 mm shorter (step 8, page 9) than the reaming depth
(in this example 100 mm). The DHS/DCS screw must
then be inserted 10 mm deeper, i.e. until the «10» mark
on the DHS/DCS wrench reaches the lateral cortex.
Tighten and secure the DHS locking device using the DHS
Torque-indicating Screwdriver (338.560). To ensure that
an optimal locking force is achieved, the locking device must
be tightened to a torque of 4 Nm.
DHS/DCS Standard System
DHS plate

SYNTHES 11
DHS/DCS Standard System
DHS trochanter stabilizing plate
11b
Position DHS trochanter stabilizing plate on DHS plate
Insert the DHS/DCS screw and DHS plate as described in
steps 1 to 10. If an anti-rotation screw is to be used,
the DHS/DCS screw must be inserted in a slightly more caudal
direction than for the standard technique.
Fix the DHS plate by inserting a cortex screw 4.5 mm
through the second proximal plate hole and insert a new
guide wire.
Locate the DHS trochanter stabilizing plate flush against the
DHS plate.
Note: The scooped section of the DHS trochanter
stabilizing plate can be shaped beforehand using parallel
flat-nosed pliers or a bending iron.
12b
Fix plates
Fix the DHS trochanter stabilizing plate and the DHS
plate using cortex screws 4.5 mm of the appropriate
length.
Depending on the indication, individual fracture
fragments of the greater trochanter can be fixed against the
scooped section of the DHS trochanter stabilizing plate
using screws 4.0 mm or cerclage wires.
13b
Insert anti-rotation screw (option)
An anti-rotation screw can be inserted cranially and parallel
to the DHS/DCS screw.
Cancellous bone screws 6.5 mm (with the Drill Sleeve
System 338.730 and 338.740), cannulated screws 7.0 mm
(with the Drill Sleeve System 338.720 and 338.740) and
cannulated screws 7.3 mm (with the Drill Sleeve System
338.731 and 338.740) can be used.
Position the DHS Parallel Drill Guide (338.750) over the
guide wire (aperture with the 0 mark). Insert the appropriate
drill sleeve system in the 12 mark of the guide. For the
cancellous bone screws 6.5 mm tap a threaded hole. For
cannulated screws 7.0 mm and 7.3 mm, insert a
guide wire.
Insert the screw according to the usual insertion technique.
Remove the guide wire.

12
The following surgical technique is illustrated using the
example of a fracture of the distal femur.
The DCS plate 95° can also be used on the proximal
femur using the same technique. To determine the entry
point on the proximal femur see step 4, page 13.
1
Position patient
Place the patient in a supine position on a normal
radiolucent operating table such that the knee can be flexed
through 90°.
2
Access
Access is via a 15–20 cm incision along the connecting
line between the greater trochanter, the lateral femoral
condyle and the tibial tuberosity.
3
Reduce articular fracture component
Temporary fixation with Kirschner wires, which are
subsequently replaced by lag screws. The position of these
screws must not hamper the insertion of the DCS/DCS
screw.
DHS/DCS Standard System
DCS plate 95°

SYNTHES 13
4
Determine entry point for the DHS/DCS screw and
insert guide wire
The entry point for the DHS/DCS screw is on the femoral
shaft axis approx. 2 cm from the knee joint.
Using two Kirschner wires determine the correct alignment
of the DHS/DCS screw.
–The first Kirschner wire in the frontal plane (a) marks
the orientation of the knee joint cavity at the level of the
condyles.
–Insert the second Kirschner wire (b) ventrally over the
lateral and medial condyles to demonstrate the incline of
the femoropatellar joint surface.
–Insert the DHS/DCS Guide Wire 2.5 mm (338.000) (c)
at the predetermined entry point such that it runs parallel
both to the first Kirschner wire (a) in a.p. view and to
the second, ventrally located wire (b) in the axial view. Insert
the guide wire until the medial cortex is reached.
Remove the Kirschner wires.
Determine entry point in the proximal femur
Using the Condylar Plate Guide (333.200), determine the
correct alignment of the DHS/DCS guide wire.
The entry point is located at the transition from the ventral
third to the mid-third of the greater trochanter, since the
guide wire in the femoral neck – in relation to the Lauenstein
projection – must be inserted in the centre.
Determine the 95° alignment to the axis of the femoral
shaft using the DCS Angled Guide (338.420) or the Condylar
Plate Guide (333.200).
5
Measure the length of the guide wire
Slide the DHS/DCS Direct Measuring Device (388.050)
over the guide wire and determine the length (in this example
80 mm).
a
b
c
2/31/3
2 cm
a
b
c

14
6
Reaming
Adjust the reaming depth on the DCS Triple Reamer
(338.460). The appropriate reaming depth is 10 mm shorter
than the measured length of the guide wire (i.e. 80 mm –
10 mm = 70 mm).
Assemble the DCS triple reamer: Slide the DCS Reamer
(338.470) over the Drill Bit 8.0 mm (338.100) until it clicks
into place at the selected mark (in this example at 70 mm).
Secure the reamer by tightening the Knurled Nut (338.120).
Ream down to the stop.
The appropriate DHS/DCS screw is 5 mm shorter than the
reaming depth (in this example the DHS/DCS screw is 65 mm
long).
Remove the DCS triple reamer.
Note: Check that “DCS“ is marked on the reamer to avoid
any mix-up with the DHS triple reamer.
Option
If the bone is hard, tap the thread using the DHS/DCS
Tap (338.170) and the short DHS/DCS Centering Sleeve
(338.180). Tap the thread until the selected depth
in the small window of the centering sleeve reaches the
lateral cortex (in this example 70 mm).
Note: The tap may not be used in osteoporotic bone.
7
Insert the DHS/DCS screw
Slide the insertion instruments (see page 17 for assembly)
over the guide wire and advance the long Centering
Sleeve (338.190) into the drilled hole. Insert the DHS/DCS
screw until the 5 mm mark reaches the lateral cortex. In case
of osteoporotic bone continue inserting the screw for a
further 5 mm.
The handle of the DHS/DCS wrench must remain parallel
to the femoral axis since only in this screw position
can the DCS plate be positioned correctly over the flat-sided
shaft of the DHS/DCS screw against the femoral shaft.
Note: Do not use the DHS/DCS wrench to reduce the
fracture as this only allows limited transmission of forces.
Remove the DHS/DCS wrench and long centering sleeve.
DHS/DCS Standard System
DCS plate 95°°

SYNTHES 15
8
Position DCS plate
Position the DCS plate over the connecting screw against
the femoral shaft. Loosen the connecting screw and remove
the Guide Shaft (338.210).
Set the drill to reverse operation to remove the guide wire.
Dispose of the guide wire.
9
Tap DCS plate
Tap the DCS plate into the predrilled channel using
the DHS/DCS Impactor (388.140). Compress the fracture
by gentle hammer taps against the impactor.
10
Achieve compression using cancellous bone screws
6.5 mm
Secure the two joint fragments of the Y-fracture by
interfragmental fixation using two cancellous bone screws
6.5 mm through the two distal plate holes (use the
DCP Hip Drill Guide 4.5 [322.430], the Drill Bit 3.2 mm
[310.310] and the Tap [311.660] according to the
standard technique).

16
11
Insert compression screw
In Y-fractures, compression must be achieved using the
DHS/DCS Compression Screw (280.990).
First fix the plate to the femoral shaft with screws. Insert and
tighten the compression screw.
Particularly if the bone is osteoporotic, insert the compression
screw carefully and ensure that the DHS/DCS screw thread
is not stripped.
12
Reduce metaphyseal fracture component
Reducing the shaft fragment against the DCS plate can
achieve an anatomically correct reduction in respect
of varus/valgus deviations. The length and rotation must be
adapted by comparing the contralateral side.
13
Fix DCS plate
Using the DCP Hip Drill Guide 4.5 (322.430) and the Drill Bit
3.2 mm (310.310), drill neutral holes through the plate
holes. Fix the DCS plate using cortex screws 4.5 mm of the
appropriate length.
Note: With simple fractures, before fixing the plate, axial
compression can be generated between the distal joint block
and the shaft fragment using the Tension Device (321.120).
DHS/DCS Standard System
DCS plate 95°

SYNTHES 17
DHS/DCS Standard System
Assembling the insertion instruments
338.060
338.190
338.210
338.200
Insert the short Connecting Screw (338.200) in the Guide
Shaft (338.210) and screw into the inner thread of the
DHS/DCS screw. The cam and slot must interlock correctly
and firmly.
Slide the long Centering Sleeve (338.190) over the DHS/DCS
Wrench (338.060). Insert the whole assembly into the
DHS/DCS wrench.

18
First remove the DHS or DCS plate. Advance the
DHS/DCS Wrench (338.060) over the DHS/DCS screw.
The outer thread of the long Connecting Screw (338.220)
must be securely held by the inner thread of the
DHS/DCS screw. Undo the DHS/DCS screw while exerting
axial traction.
DHS/DCS Standard System
Implant removal

SYNTHES 19
DHS/DCS Standard System
Bibliography
Babst R, Renner N, Biedermann M, Rosso R, Heberer M,
Harder F, Regazzoni P (1998) Clinical results using the
trochanter stabilizing plate (TSP): the modular extension of
the dynamic hip screw (DHS) for internal fixation of
selected unstable intertrochanteric fractures. J Orthop
Trauma 12: 392–9
Euler E, Betz A, Schweiberer L (1992) The Treatment of
Trochanteric and Femoral Neck Fractures Using the Dynamic
Hip Screw (DHS®). Orthopaedics and Traumatology 1:
246–258 (no. 4)
Gruss M, Traut R (1992) Die Versorgung instabiler
pertrochantärer und per- bis subtrochantärer Oberschenkel-
brüche mit der dynamischen Hüftschraube (DHS®).
Akt Traumatologie 22:144–148
Regazzoni P (1993) Method of Treatment of Proximal
Femoral Fractures: Choice of the Implant. Proximal Femoral
Fractures, Operative Technique and Complications,
Marti R and Dunki Jacobs P, Volume 2, 389–408, Medical
Press Ltd., London
Rüedi T, Murphy W (Ed.) (2000) AO Principles of Fracture
Management. Thieme, Stuttgart