Donjoy Armor Professional Knee Brace with Fourcepoint
Donjoy Armor Professional Knee Brace with FourcepointDonjoy Armor Professional Knee Brace with FourcepointDonjoy Armor Professional Knee Brace with Fourcepoint
Donjoy Armor Professional Knee Brace with FourcepointDonjoy Armor Professional Knee Brace with Fourcepoint
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Donjoy Armor Professional Knee Brace with Fourcepoint

  (24 Reviews)
  • The ultimate ACL knee brace providing support to the knee joint
  • Ideal knee brace for skiing, high impact and contact sports
  • For severe ACL instabilities, reconstruction and deficiencies
  • Fourcepoint hinge provides added ACL support to improve your gait
£299.99(Inc. 20% VAT)List Price:  £499.99
(£249.99 Exc. VAT)

IMPORTANT: Please note that we recommend reading our guide to choosing the right size before placing your order.

Additional Accessories

To enhance comfort and versatility, you can select accessories for your Donjoy Armor with the drop-down menus below:

Donjoy Armor Knee Brace with Fourcepoint

After injury or surgical reconstruction of your ACL, a strong and reliable brace is needed to provide stability and prevent hyperextension. The Donjoy Armor Professional Knee Brace with Fourcepoint is the ultimate ACL knee brace, and is ideal for protecting and providing stability to the knee during skiing, as well as high impact and contact sports.

What's the Donjoy Armor Designed For?

The Donjoy Armor is the best brace to use for active people suffering from ACL instability or injury. This ACL knee support is particularly suited to treatment and protection of:

  • Moderate to severe ACL instability
  • Recovery from ACL reconstruction and surgery
  • MCL or LCL instability
  • Meniscus injury
  • Hyperextension prevention

What's Included?

The Donjoy Armor with Fourcepoint is supplied with everything needed to start receiving the best ACL support right away. It includes:

  • 1 x Donjoy Armor Knee Brace with Fourcepoint
  • 2 x Anti-migration condyle pad
  • 1 x Mesh carry bag
  • 1 x Instruction booklet and fitting tips
  • 1 x Warranty card

How Does the Donjoy Armor with Fourcepoint Support the ACL?

The strongest and most supportive ACL brace around, the Donjoy Armor with Fourcepoint is a hinged knee brace using the Donjoy Fourcepoint hinge technology. The spring-loaded Fourcepoint hinges keep the hamstring in constant tension, and takes pressure off the ACL using a "Four Points of Leverage" system. As the hamstring is attached to the tibia (or shin bone), the hamstring tension pulls the tibia back keeping it stable and almost entirely eliminating the chance of an ACL injury.

Which Sports Is This Knee Support Designed For?

The Donjoy Fourcepoint Knee Brace is designed to provide maximum protection to the knee for high impact and contact sports. Among others, this knee brace is suitable for:

  • Skiing and snowboarding
  • Motocross
  • Football
  • Hockey
  • Volleyball
  • Baseball and softball
  • Extreme and contact sports
  • Watersports (including salt water)

How Does the Fourcepoint Hinge Improve ACL Support?

While the Donjoy Armor is available without Fourcepoint technology, it's the Fourcepoint hinge that really puts this brace at the top of the class in terms of ACL support. The brace works by limiting the time your knee is in an "at risk" position, increasing the posterior load applied by the brace on the tibia when you reach a certain level of knee flexion. This dampens knee extension and reduces shear forces on the knee, all while improving your natural gait by applying increasing resistance until you reach a firm point during your natural movement.

The Fourcepoint hinge limits the time your knee is in an "at risk" position

Sizing Information

The Donjoy Armor with Fourcepoint Knee Brace is available in seven sizes and is suitable for men and women. To determine which size is right for you, you must measure the circumference of your thigh, knee and calf, and then refer to the table below.

The thigh measurement is taken around the thigh 15cm (6") above the knee cap. The knee cap measurement is taken directly around the centre of the knee cap. The calf measurement is taken around the calf 15cm (6") below the knee cap.

Donjoy Thigh Measurement Sizing Image

Size Thigh Circumference (cm/inches) Knee Centre Circumference (cm/inches) Calf Circumference (cm/inches)
Extra Small

33 - 39cm

13 - 15.5"

30 - 33cm

12 - 13"

25 - 30cm

10 - 12"


39 - 47cm

15.5 - 18.5"

33 - 35cm

13 - 14"

30 - 35cm

12 - 14"


47 - 53cm

18.5 - 21"

35 - 38cm

14 - 15"

35 - 40cm

14 - 16"


53 - 60cm

21 - 23.5"

38 - 43cm

15 - 17"

40 - 45cm

16 - 18"

Extra Large

60 - 67cm

23.5 - 26.5"

43 - 48cm

17 - 19"

45 - 50cm

18 - 20"


67 - 75cm

26.5 - 29.5"

48 - 53cm

19 - 21"

50 - 55cm

20 - 22"


75 - 83cm

29.5 - 32"

53 - 58cm

21 - 23"

55 - 60cm

22 - 24"

What If My Measurements Fall Under Different Sizes?

If your measurements fall under different sizes (for example: Medium for Thigh Circumference and Large for Knee Centre), we recommend you choose your size based on your Thigh Circumference measurement.

What If I Need More Help with Sizing My Brace?

For extra information and directions on how to size and apply your knee brace, read our sizing guide blog.

How Durable Is the Donjoy Armor?

Constructed from light aircraft grade aluminium, the Donjoy Armour with Fourcepoint Knee Brace is exceptionally strong and lightweight and enables you to continue with any sporting activity. As this is the standard short calf version, the knee injury brace doesn't interfere with either a ski or motocross boot and remains clear from the top of your boot. This makes the support more versatile, allowing it to be used without restriction across a number of sports.

What Is the Four Points of Leverage System?

As is mentioned above, the Donjoy Armor uses a "Four Points of Leverage System" to increase the posterior load on your tibia, thereby reducing the load on your ACL. These leverage points are labelled in the diagram below.

The Donjoy Armor Brace provides ACL relief and knee support with a Four Points of Leverage design

Can the Fourcepoint Hinge Be Adjusted?

Yes, the Fourcepoint Hinge allows you to set your flexion levels based on your stage of recovery. This adjustment changes the angle where the Fourcepoint's tension stops, allowing you to choose between 25°, 35° (default setting), 45°, 55° or 65°. This allows you to choose the perfect level of movement for you, and lets you add progressively more range of motion as you recover. The level you choose should be based on your doctor's advice and your own personal comfort.

Will the Donjoy Armor Fit Into Ski Boots?

Yes, this is the short calf version of the Donjoy Armor, meaning the calf portion is shortened to allow it to fit into ski boots, snowboard boots, skates, and other specialist footwear that requires space on the calf. Designed primarily for skiing and high-impact sports, the Donjoy Armor is definitely the best Donjoy knee brace for skiing.

Will This Knee Brace Stay Put?

To ensure it's always providing support to your ACL, this knee brace is designed to stay put no matter your level of activity. It does this with the anti-migration supra condyle pads, each of which holds your knee in place in the centre of the brace to ensure it doesn't slip. The images below show the inside of the brace with, and then without, the condyle pads fitted.

Donjoy armor brace with condyle pad attachedDonjoy armor brace without condyle pad attached

Are Spare Parts Available?

Yes, spare pads are available if the initial pads supplied with your Donjoy Armor Knee Brace begin to wear away. You can purchase these separately as the Pack of 5 Knee Pads for Donjoy Armor Professional Knee Brace with Fourcepoint.

Is This Knee Brace Heavy?

While incredibly strong, this knee brace remains light enough to avoid hindering athletic performance or weighing you down. Weighing in at just 612g (1.35lbs) the Donjoy Fourcepoint Knee Brace made with 6061 T6 aircraft aluminium, meaning it provides maximum strength with minimal weight.

Why Does the Donjoy Armor Offer Adjustable Tension?

The Donjoy Armor is designed to react during leg extension and offer an increasing resistance in the last 35° of extension at factory setting. It does this in order to reduce extension shock and increase posterior tibial loads, thereby reducing the strain placed on your ACL.

Are Comfort Liners Available?

While the Donjoy Armor is anatomically designed for maximum comfort, intense activity may cause it to catch the skin at certain areas. To avoid this, a Donjoy Armor Black Lycra Undergarment is available to protect the skin and make wearing your brace more comfortable. This liner can be added to your order using the drop-down menu near the top of the page.

How Can I Cushion the Brace for Contact Sports?

Since the Donjoy Armor with Fourcepoint is made with aircraft-grade aluminium, we recommend covering it to avoid injuries to your opponents. For the purpose we would recommend the Donjoy Armor Sports Cover, which is a padded cover designed to cushion your brace without affecting use. You can add it to your order using the drop-down menu near the top of the page.

How Long After Surgery Can I Wear the Donjoy Armor Brace?

Unfortunately, everyone's recovery and condition is different, so there's no concrete time frame as to when you should start wearing the Donjoy Armor Brace. We would recommend that you consult your doctor, and come up with a plan that includes the introduction of your Donjoy Armor Knee Brace at a certain point in your recovery.

Is the Donjoy Armor with Fourcepoint Suitable for Salt Water Sports?

Yes, the Donjoy Armor is an excellent option for ACL support during water sports such as wakeboarding and water skiing. If you intend to use your Donjoy Armor in salt water, we would recommend rinsing it with clean water after each use to maximise longevity.

Is this Brace Suitable for PCL Injuries?

No, this brace is NOT suitable for PCL lesions and injuries, as this brace is only designed for ACL injuries. The Fourcepoint hinge provides resistance that will increase force on the PCL, making it entirely unsuitable for recovery from PCL injuries. If you have a PCL injury or have a combination of knee injuries or problems and require a combined instability knee brace (CI), please see the Donjoy Armor Professional Knee Brace without Fourcepoint.

See For Yourself!

For a quick overview of the Donjoy Armor Knee Brace and to see it in action for yourself, take a look at the short video below.

Key Features

  • The ultimate knee support for supporting and protecting the ACL
  • Provides support with an enhanced "Four Points of Leverage" system
  • Resistance threshold is adjustable based on your stage of recovery
  • Ideal for providing support during recovery from knee injury
  • Gradual soft stop the extension for comfortable movement
  • Helps prevent hyperextension of the knee
  • Suitable for both men and women
  • Short calf design to fit into ski boots and skates
  • Made with a mouldable, medial swooping frame for custom fit
  • Includes a 1 year warranty on frame and hinge
  • Includes a 6 month warranty on soft goods

To find out more information about the Donjoy Armor Professional Knee Brace with Fourcepoint or injuries that the support can help with, check out the following links:

Delivery - Free UK Mainland Delivery

This item is usually dispatched by 24 hour courier.

This item is usually dispatched the same day for next working day delivery when ordered before 2.00pm, Monday to Friday.

Please call our Health and Care Customer Care Team on 020 7720 2266 if you have any questions about the delivery of this item.

Customer Reviews
Average Rating (24 Reviews):  
Write a review and share your opinions!

helps with the acl but fit isnt 100% for me
Tuesday, 8 June 2021  | 

I'm different sizes in the 3 dimensions so cant be helped unfortunately but is still perfectly wearable.

Its only minor but really annoying, the covers for the condyle pads regularly get stuck to the velcro and come off!

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Wednesday, 18 December 2019  | 

have recently used the brace for a week in the Alps & although took it easy to start with was skiing most things on & off piste by the end. big improvement as last time was occasionally hyperextending & falling over.

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A relief
Monday, 16 December 2019  | 

I was worried after tearing my ACL last year that I wouldn’t be able to ski; wearing the brace I am confident, and according to my friends, skiing as I normally do. It is a bit bulky under salopettes, and a bit uncomfortable without the ‘undergarment’ sleeve, but worth it. I love skiing!!

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Donjoy Armor Professional Knee Brace
Wednesday, 17 April 2019  | 

First class service

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Donjoy Kneebrace
Friday, 22 February 2019  | 

I snapped my acl 20 years ago and had an operation to mend torn cartilage six months ago. This brace has revolutionised my ability to ski aggressively again. You barely know it’s on but it totally stops any hyperextending of the knee and allows me to ski moguls and powder again.

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Read all 24 customer reviews...