Man is hiking with orthosis m4s OA comfort

M.4®s OA comfort

4-point knee brace for varus or valgus pressure relief and stabilisation

  • Pain reduction and recovery of mobility
  • Light weight frame and hinge construction
  • Reliable relief of the affected compartment

 Medical specifications

Knee brace for varus / valgus pressure relief

M.4s OA comfort is a varus / valgus offloading brace. The product is exclusively to be used for the orthotic fitting of the knee and only on intact skin.


Product benefits

  • Relief of the lateral or medial compartment using the 3-point principle

  • Pain relief by reducing weight-bearing on the affected side of the joint

  • Optimal stabilisation using 4-point principle

  • Safe collateral stabilisation by riged Frame

  • Extension and flexion limitation protects against damaging joint movements and relieves injured structures

How does it work?/Mode of action

This orthosis is intended to help you to reduce stress on your knee. The orthosis is used in both postoperative therapy and in conservative (non-operative treatment). It protects the leg from swerving outwards. Stress is reduced on the painful areas of the knee join and the orthesis brings a perceptible reduction in pain. Some patients only improve gradually.

Donning/fitting instructions

Open all the belts and pull the numbered end from the belt eyelets. Tip: To prevent the belt from getting stuck, it is advisable to close the  the hook and loop fastener in the attachment.
Sit on the edge of a chair and spread the orthosis over the affected leg. Slightly bend your leg. Place the brace in such a position that the wedges visible from the front are at the level of the upper edge of the kneecap. Please take care that the orthosis is not the wrong way round on your knee.
Now close the lowest belt on the front side and the top belt at the back. Press the joints gently backwards.
Now close the lower belt at the back of the thigh. Check that the belt is fitting properly. The lateral joints should be positioned slightly backwards (more exactly: behind the lateral middle line of the knee).
Now close the front upper lower leg belt, followed by the back lower leg belt and finally the front thigh belt and then the front thigh belt.
Take a few steps or bend your knee a few times to check the fit. If necessary, the belt can be readjusted in the same sequence to guarantee a good fit.
If you suffer excessive pain or discomfort during wear, please take off the product immediately and contact your doctor or specialized shop.

Wearing directions

Setting the flexion and extension limits (only to be done by an othropaedic technician):
The orthosis is equipped with a 0° extension wedge. It includes additional wedges. The extension and flexion limits should only be limited in accordance with the instructions from the responsible doctor. To avoid hyperextension, extension wedges must be used. The wedges exactly specify the radius of motion of the orthosis. The situation in soft tissue may cause compression, making it necessary to use a larger wedge to restrict the movement of the knee to within the desired radius.
Select the required wedge. Extension wedges are marked with an E and flexion wedges with an F. Insert the wedge into the joint and lock it by clamping it with help of the frame ends. The wedge then slides automatically into the correct position and does not rotate. Tighten the wedge using the screw. It is sufficient to do this by hand. No great force is necessary.

Setting the varus-valgus decompression:
Tip: Get the responsible technician to give you a thorough explanation about how to adjust the M.4s OA. This well help you to master the handling rapidly and to benefit from optimal support from the orthosis.
Sit down and adjust the varus-valgus adjustable joints to the neutral position, using an Allen key. You have reached the neutral position when the padding of the orthosis joint is covering the surface, but producing little or no pressure.
Stand up and set the tension to a quarter cycle (on both adjusting screws). This is a good initial setting for the first time you wear the orthosis. If you want, you can adjust the orthosis to the breadth of your knee with the various joint pads enclosed. Take care that thebrace is sitting properly. For conservative therapy (without an operation), it should not be worn for more than two hours per day in the beginning. You can then wear it for longer periods, depending on how well you tolerate it. It is most important to wear the orthosis for activities that normally cause pain. By using the Allen key, the decompression can gradually be adjusted over time, or during the course of a day.
For postoperative therapy, the orthosis must always be worn when there is stress. Please ask your doctor for instructions.

Extreme settings have no therapeutic value, they only cause additional discomfort.
What can I do if...
... the brace slips?
Make sure that the back thigh strap (#5) is above the belly of the calf muscle.
Take the covers off the knee pads and wear the pads directly on your skin. Watch out carefully for skin reactions. Skin irritation may occur in people with very sensitive skin.
Do not wear the brace over clothes.
... the pads have worn down?
Replacement pads can be obtained from medi UK Ltd.. Your orthotist will be pleased to help.


Standard colours

Material components

Avional, velours, polyester and PU-foam

Washing instructions

The brace cannot be worn in saltwater. If the brace is worn in chlorinated water, it should be rinsed out thoroughly with clean water afterwards. Soap residues, lotions and ointments can cause skin irritation and material wear.
Wash the paddings and covers by hand, preferably using medi clean washing agent.

Do not bleach.
Leave to dry naturally.
Do not iron.
Do not dry clean.

With normal use, the hinge mechanism should not require any maintenance, but it can be lubricated with Teflon spray. Check regularly that the joint screws are secure, tighten them if necessary.






Medical specifications


  • Serious medial or lateral gonarthrosis (at least grade III) in connection with compley ligament instability
  • Cartilage surgery/chondroplasty/ meniscus refixation/changeover osteotomy with necessary postoperative relief of the medial or lateral compartment
  • Stress fracture


  • Combined medial and lateral osteoarthritis

Further information

File download


M.4®s OA / M.4®s OA comfort – instructions for patients

The new medi OA-range – Patient specific osteoarthristis therapy

What is osteoarthritis (OA)?

Similar products

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