Zimmer Biomet Headless Compressionand Twist-Off Screws User manual

Headless Compression
and Twist-O Screws
Surgical Technique

1 | Headless Compression and Twist-O Screws Surgical Technique
Table of Contents
Headless Compression Screw.......................................................................... 2
Incision....................................................................................................................... 3
Lateral Release ........................................................................................................... 3
Unicortical Applications ........................................................................................... 4
Osteotomy ................................................................................................................. 4
K-Wire Placement....................................................................................................... 5
Screw Measurement................................................................................................... 6
Insertion..................................................................................................................... 7
Drilling (Optional)....................................................................................................... 7
Screw Removal ........................................................................................................... 7
Bicortical Osteotomy................................................................................................ 8
K-Wire Placement....................................................................................................... 8
Drilling (Optional)....................................................................................................... 8
Insertion..................................................................................................................... 9
Screw Removal ........................................................................................................... 9
Twist-O Screw .................................................................................................. 10
Surgical Approach .................................................................................................... 11
Osteotomy ............................................................................................................... 11
Insertion................................................................................................................... 12
Final Step ................................................................................................................. 14
Ordering Information ....................................................................................... 15
Indications and Contraindications................................................................ 17

2 | Headless Compression and Twist-O Screws Surgical Technique
2.5 mm
10-40 mm (2 mm increments)
3.0 mm
10-40 mm (2 mm increments)
Tapered Threads
0.9 mm Cobalt Chrome K-Wire
T7 Hexalobe Drive
Four Cutting Edges
TiMAX®Titanium
1.8 mm minor diameter
designed for increased
strength over prior screw1
Headless Compression Screws

3 | Headless Compression and Twist-O Screws Surgical Technique
Figure 1
The following surgical technique describes the use of
a Headless Compression Screw for a distal Chevron
osteotomy of the first metatarsal or various types of
osteotomies (Figure 1).
Incision
A 7 cm incision is centered over the dorsal aspect of
the first metatarsophalangeal joint, just medial and
parallel to the EHL tendon. The incision is carried
down to the subcutaneous tissues (Figure 2). Retract
the soft tissues carefully being certain to protect the
neurovascular bundle in the skin flap.
Lateral Release
If necessary, a standard lateral release is performed
through the same incision. This includes the release
of the adductor tendon and the fibular sesamoidal
ligament.
Figure 2
Headless Compression Screw Technique

4 | Headless Compression and Twist-O Screws Surgical Technique
Osteotomy
A linear capsulotomy is then used to expose the
joint. The hypertrophic medial eminence on the 1st
metatarsal head is then osteotomized (Figure 3).
Insert a 0.9 mm k-wire perpendicular into the center
of the first metatarsal head (Figure 3a).
A medially based long arm Chevron type osteotomy
is then created from medial to lateral. Remove
the k-wire. The capital fragment is then mobilized
and transposed laterally to correct the 1st IMA and
impacted on the 1st metatarsal shaft (Figure 3b).
Figure 3 Figure 3b
Figure 3a
Headless Compression Screw Technique – Unicortical Applications

5 | Headless Compression and Twist-O Screws Surgical Technique
K-Wire Placement
The osteotomy is then stabilized in a uni-cortical
application, such as a distal Chevron osteotomy, by
advancing the 0.9 mm K-Wire across the osteotomy
site until the tip is visible. Retract the wire slightly, so
the tip is below the articular cartilage (Figure 4). Verify
k-wire position via fluoroscopy.
Note: It is recommended to subtract 3-4 mm from
the depth gauge measurement to avoid penetrating
the articular cartilage with the distal tip of the
screw. For example, if the measurement is 20 mm
then select the 16 mm screw.
Tip: When using a screw longer than 28 mm for
oblique applications, it may be beneficial to use a 0.9
mm x 105 mm k-wire.
Tip: For hammertoe applications, a sterile double
tipped 0.9 mm x 152 mm k-wire is available for order.
Figure 4
Headless Compression Screw Technique – Unicortical Applications
0.9 x 70 mm K-wire Cobalt Chrome
0.9 x 105 mm Sterile K-wire Cobalt Chrome
0.9 x 152 mm Trocar Sterile K-wire Stainless Steel
K-Wire Options

6 | Headless Compression and Twist-O Screws Surgical Technique
Figure 5
Screw Measurement
The length of the screws is measured using the depth
gauge. Slide the depth gauge over the 0.9 mm k-wire
down to bone ensuring the depth gauge is sitting flush
against bone.
Note: The depth gauge is only compatible with the
0.9 mm x 70 mm and 0.9 mm x 105 mm k-wires.
The depth gauge displays the measurement from the
distal tip of the depth gauge to the tip of the k-wire.
Important: The screw length may vary depending
upon the level of obliquity applied to the k-wire
during insertion. To determine the screw length, and
with the obliquity of the k-wire in mind, record the
measurement. Using the K-Wire Obliquity Chart
below, subtract the corresponding milimeters from
the recorded measurement (Figure 5).
It is recommended that each screw length be verified
o the screw caddy measurement slot before the
screw is implanted.
90° degrees 45° degrees 22.5° degrees
K-Wire Obliquity
90 degrees Subtract 0 mm from measurement
45 degrees Subtract 2 mm from measurement
22.5 degrees Subtract 5-6 mm from measurement
Headless Compression Screw Technique – Unicortical Applications

7 | Headless Compression and Twist-O Screws Surgical Technique
Insertion
Load the screw onto the T7 Cannulated Driver and
Mini Rachet Handle. Place screw over the 0.9 mm
k-wire down to surface of bone. Advance the screw
into bone by turning the T7 Cannulated Driver
clockwise (Figure 6). Continue advancing until
the head of the screw is at or just below the near
cortex. After compression is achieved, remove the T7
Cannulated Driver and 0.9 mm k-wire. Verify screw
position with fluoroscopy (Figure 7).
Drilling (Optional)
Note: The Zimmer Biomet Headless Compression
screws are designed to be self-drilling and self-
tapping, and may be inserted under power.
If the bone is deemed to be too hard prior to screw
insertion, or an oblique approach is required, use a
Head Relief Drill to prepare the near cortex. For the
2.5 mm screw use the 2.5 mm Head Relief Drill, and
for the 3.0 mm screw, use the 3.0 mm Head Relief Drill
(Figure 8).
Screw Removal
For screw removal, insert the T7 Solid Driver into the
head of the screw, and turn the Driver counterclockwise
until the screw is removed.
Figure 8Figure 6
Figure 7
2.5 mm Head Relief Drill AO
110 02774 6
3.0 mm Head Relief Drill AO
110 027747
Headless Compression Screw Technique – Unicortical Applications

8 | Headless Compression and Twist-O Screws Surgical Technique
Drilling (Optional)
Note: The Zimmer Biomet Headless Compression
screws are designed to be self-drilling and self-
tapping, and may be inserted under power.
If the bone is deemed to be too hard, or an oblique
approach is required, use a Head Relief Drill to prepare
the near cortex.
Tip: For the 2.5 mm screw use the 2.5 mm Head Relief
Drill, and for the 3.0 mm screw, use the 3.0 mm Head
Relief Drill (Figure 10).
Headless Compression Screw Technique – Bicortical Applications
Figure 9
K-Wire Placement
For bi-cortical applications, such as the Scarf-Z or
Ludlo osteotomy, insert the k-wire until the tip
begins to exit the outer wall of the far cortex (Figure 9).
Screw measurement subtraction is not necessary for
bi-cortical fixation.
0.9 x 70 mm K-wire Cobalt Chrome
0.9 x 105 mm Sterile K-wire Cobalt Chrome
0.9 x 152 mm Trocar Sterile K-wire Stainless Steel
K-Wire Options
Figure 10