ST&G 1321 AP / AL User manual

Instructions for 1321 AP / AL
Polycentric 4 Bar Knee
ST&G USA Corp. Phone: [phone]
2691 Saturn St. Fax: [phone]
Brea, CA 92821 www.stngco.com

1. Description and purpose
Prosthetist instructions.
L1321 AP / AL knee is for lower limb prosthesis
Recommended for K1 up to K2 activity level
Weight limit for a user is up to 125kg / 275lbs
Contra-indications
Residual muscular weakness, contractures or
proprioceptive dysfunction including poor balance
Contra lateral joint instabilities or pathology
Complicated conditions involving multiple disabilities
Product Code
1321 AP / AL
Polycentric 4-Bar Knee (Aluminum)
Ensure the end user has understood any Instructions for use, especially to
the safety information.
122 Kg
275 lb

2. Construction
Principal Parts
Frame Aluminum Alloy, Brass, Stainless Steel, Steel
Knee Aluminum Alloy, Stainless Steel
Knee control Various materials principally Aluminum Alloy Stainless
Steel, Poly Urethane Bumper
Fig. 1 (a) Posterior View (b) Anterior View c) Lateral View

Exploded View
Fig. 2

The Caution symbol highlights safety information which must be
followed carefully.
Be aware of finger trap hazard at all times
Any changes in performance of the knee e.g. instability or lag in transition
from full stance flexion moment to full knee extension moment in the
knee should be immediately reported to the Clinician / Practitioner
Any excessive changes in heel height may adversely affect the stability of
the knee.
The user should be advised to contact their Clinician / Practitioner if their
condition changes.
4. Safety Information
Always use a hand rail when descending stairs and at any other time if
available.
3 Function
Pyramid and Knee Disarticulation mounting options
Tube clamp distal mount
Adjustable spring extension assist
Adjustable friction

5 Maintenance
Maintenance must be carried out by qualified personnel.
Bi-Annual inspection is recommended.
Check for visual defects that may affect proper function.
A loaner system is available should servicing be required.
The wearer should be advised:
Any changes in performance of this device must be
reported to the Clinician / Practitioner.
Changes in performance may include:
Increase in knee stiffness
Knee instability
Any unusual noises
Cleaning:
Use a damp cloth and mild soap to clean the outside surfaces.
DO NOT use aggressive cleaning agents.
If the limb/knee comes into contact with salt or chlorinated water,
it should be rinsed with fresh water and dried.
6 Limitations on use
Intended Life:
Service life of the product is covered by the warranty period (2 years)
This product is recommended for use with other ST&G Products.
Lifting Loads:
Amputee weight and activity is governed by the stated limits.
Combined weight of amputee and carrying load, should not exceed stated weight limit.
Environment:
Avoid abrasive environments such as those containing sand for example
as these may promote premature wear. Avoid contact with talcum
powder.
Operating and Storage Temperature Range:
Exclusively for use between temperatures of -10˚C to 50˚C [14˚F and 122˚F]

7. Alignment and Set-Up
Users be aware of potential finger trap hazard
Fig. 2a
Fig. 2b
Fig. 2c
Add
3mm
safety
factor

Note: 4-bar knees inherently are very stable due to the geometry built into each
design. This is commonly referred to as the Instant Knee Center (IKC). The IKC
point when doing bench alignment, will fall behind the traditional TKA line that we
will reference. (Fig. 2,3) Tg line in Fig. 3 is ideal placement, but in certain
instances, it may be necessary to accommodate placement anteriorly (up to
3mm). The Tg line is referencing a moving A/P weight bearing line, so it could be
slightly anterior or neutral.
a) With prosthesis assembled, taking into account hip flexion contractures,
abduction, Line Of Progression, and toe out (Fig.2), the TKA plumb line should
pass through the knee center (center ot proximal/anterior pivot Fig.2a, 2b) and in
front of the K point (IKC).
NOTE: Take into account shoe heel height, and add 3mm safety factor.
b) Ideally, the pylon connecting the knee and foot should end up vertical. There
may be a variance due to the foot alignment recommendations. In this case, the
maximum anterior tilt of the pylon should not to exceed 3-4 degrees, and it may
be necessary to utilize 1222T offset tube clamp adapter. In some cases, it may
be necessary to slightly adjust the Knee Angle Tilt Adjustment screw Clockwise
for a total of 1-3 degrees only. DO NOT OVERLY ADJUST THIS SETTING –
Clockwise adjustment will reduce the K point or IKC making the knee more
unstable. Some adjustment is acceptable, but take into account all aspects of
patient ability, length of limb, and foot when going to this adjustment. It is advised
to follow up in 1-2 weeks to reassess the alignment. Excessive adjustment from
factory setting will prematurely wear out the extension stop bumper. (Refer to
Section 8.2)
c) With prosthesis donned, the weight line should pass through the centerline of
the knee in the Coronal or M/L plane (Fig. 2c). Excessive outset or inset will put
undue stress on the knee joint.
d) With prosthesis donned, the weight line for Sagittal or A/P plane should have
the plumb line passing ideally through the knee center (proximal anterior pivot),
and be perpendicular to the ground. (Fig. 2a, 2b)
7.1 BENCH ALIGNMENT:
It is not recommended to have alignment posterior to the reference line, as
it could cause knee instability!

Using a 6mm hex wrench turn screw:
- clockwise to increase extension assist
-anti-clockwise to reduce the extension assist
After inserting pylon, apply thread locker to
the pinch bolt and torque with 5mm hex
wrench to 12Nm
Using a 5mm hex wrench turn the screw:
- clockwise to reduce geometric stability of
the knee (high front/low rear) –will make
knee easier to flex
-anti-clockwise to increase geometric
stability of the knee (low front/high rear) –
will make knee more difficult to flex
Using a 3mm hex wrench to turn both
screws on base of linkage:
- clockwise to increase friction
-anti-clockwise to decrease friction.
Turn screws equally so friction is
distributed evenly. On linkage
bearing.
Level or slight up-sloping tilt of 1-2
degrees (clockwise adjustment) is
most common. Adjustment from
factory setting will cause decrease
in bumper life span due to
excessive compression forces.
8.3 Knee Friction Adjustment
8.2 Knee Head Level Adjustment
8 Knee Adjustment
8.1 Knee Extension Assist Adjustment

8.3 Pyramid Head Position Adjusting
Loosen bolt pyramid bolt
with an 8mm hex wrench
Note: Mark/indicate pyramid orientation.
Loosen screw with a
2.5mm hex wrench.
Rotate to desired orientation
Tighten bolt with 8mm hex
wrench.
Remove pyramid bolt, apply thread locker, and torque bolt to 18Nm.
Tighten set screw to help prevent rotation.

Use a small screw driver to pick out
the rubber bumpers on the back of
knee head. Apply glue to new ones
and insert back into knee head.
Use a small screw driver to pick
out the extension stop rubber
bumper on knee level adjusting
screw. Insert new one into slot.
9 Maintenance of Knee Unit
9.1 Servicing Extension and Flexion Stop Bumpers

10 Technical Specification
Operating & Storage Temperature Range: -10˚C to 50˚C ( 14˚F to 122˚F)
Weight: 766 g (1lb 11oz)
Recommended Activity: K2
Maximum User Weight: 125kg (275lbs)
Maximum flexion angle: 135 degrees
Proximal Alignment attachment: Male Pyramid
Lotus Adapter
Distal Alignment attachment: Tube Clamp
Tube clamp torque setting: 12Nm
Pyramid Center Bolt: 18Nm
Build Height: Pyramid / Lotus 108 mm / 114.3
Materials: Aluminum Alloy, Stainless Steel, Steel, Rubber
Maximum flexion angle: 135 degrees
Build Height:
Pyramid = 108mm
Lotus = 114.3mm

CE Conformity
This product meets the requirements of 93/42/EEC guidelines for medical products.
This product has been classified as a class I product according to the classification
criteria outlined in appendix IX of the guidelines. Please keep this manual in safe place
for future use.
10 Warranty
Warranted for 2 years from the date of invoice by ST&G.
The user should be aware that changes or modifications not approved will void the
warranty.
11 Liability
The manufacturer recommends using the device only under the specified conditions
and for the intended purposes. The device must be maintained according to the
instructions for use supplied with the device. The manufacturer is not liable for
damage caused by the component combinations that were not authorized by the
manufacturer.

ST&G USA Corporation
www.stngco.com e-mail: [email protected]
2691 Saturn Street, Brea, CA 92821, USA
Tel: [phone] Fax: [phone]
1321IFU Rev. B (01-19-18)