4-motion® Knee Joint

With the development of the 4-motion® knee joint, we are following the consistent path of reconstructing the anatomical planes of movement in the knee joint. On average, the joint plane drops about 3° medially and about 3-7° posteriorly. The reconstruction of this anatomical specification brings about numerous changes in the prosthesis design and advantages in the context of prosthesis implantation. Femorally, the posterior offset can be reconstructed, since the operation-related external rotation of the femoral component is no longer necessary with this anatomical design. The condylar radii of the medial and lateral side have different radii of curvature according to the anatomical specifications. The need for ligamentary releases is significantly reduced by the anatomically variable position that can be set between 87° and 90°.

The “image to instrument” procedure used for the implantation of the 4-motion® knee joint allows customised knee endoprosthetic treatment.

Advantages

This concept combines various functions and offers many advantages for both surgeons and patients:

3-dimensional reconstruction of the operated knee
Interactive 3D web planning, preoperative optimisation of components placement
Precise positioning of the implant
No need to open the medullary canal
Reduction of surgical steps and operation time
Verringerung des Zeitaufwands und der Kosten für Wasch-, Montage,- und Sterilisationsverfahren

The instruments manufactured on this basis are precisely adapted to the individual surface contour and anatomy of the respective knee joint.

Product features

Femoral component

Anatomical joint line and reconstruction of the dorsal offset
Q angle of 9°
widened patella inlet
Different radii of curvature medial and lateral
10 sizes allow fine tuning

Tibial component PSA (Patient Specific Alignment)

Round keel allows free placement in MPTA angle from 87° to 90°
Homogeneous force application independent of the selected MPTA angle
asymmetrical support
Anatomical reconstruction of dorsal slope in the range of 3° – 6
10 sizes – fine tuning
Material Ti6Al4V – no allergy variant necessary for this tibia

Inlays

XLPE with vitamin E (VEX)
Standard PE

Allergy variant

TiNbN version for allergic sensitive patients
Not required for PSA Tibia

Videos about the 4-motion knee

Prof. Dr. med. H. Schroeder-Boersch
Why provide TKA patients with individual care?

M. Frank

Implementation of personalized alignment with the 4-motion® knee

Articles on the subject of knees

eIFU from August 2025: Instructions for use digitally and always up-to-date

Instead of the previous printed instructions for use in the inner carton, the information is available digitally at any time as an electronic instruction manual (eIFU)....
4-motion® knee system: Anatomical flexibility – also conventionally instrumented in the future

The anatomical and patient-specific alignment should also be possible with conventional, available instruments in the first half of 2025....