Knee braces for people with IBM

For many people living with Inclusion Body Myositis (IBM), falls are an all-too-common consequence of the disease.

A study in the UK in 2014 reported that 98% of people with IBM had fallen in the previous year1. For those over 65 years of age it was 100%. Whilst the majority of these falls didn’t result in serious injury 5% of those in the study had a fall that required hospital attention. Locally a survey conducted last year by our team (publication pending) found that 73% of all myositis people had fallen in the previous year. This is much higher than the rate of falls in people without muscles disease (30%)2. It is a serious concern.

Whilst no two people with IBM have the same patterns of disease, it is known that weakness in the quadriceps muscles is the most common problem faced. The quadriceps muscle, as its name suggests, is a group of 4 muscles (Figure 1) that combine to straighten the knee and to allow it to bend slowly under load, e.g., going downstairs. Of the 4 muscles of the quadriceps, it is the 2 muscles at the side of the thigh and knee that are affected most in IBM (vastus medialis and vastus lateralis). Vastus medialis in particular operates during the last 30 degrees of extension (straightening). It is weakness in this muscle that explains why many people with IBM can’t straighten their knee fully.

Figure 1 -Quadriceps muscles

The act of walking is a subconscious activity. As humans, even if we try to concentrate on what we are doing whilst walking, our mind will wander to other things. Known as dual tasking, it is the ability to be thinking of one thing whilst doing another. We often tell patients in the Perth clinic that if they concentrate 100% of the time on their walking they will rarely fall. However, as mentioned this is very difficult to achieve. How many of us start thinking about what is for dinner as soon as we get up in the morning and take our first steps for the day!

For people with IBM, the most common mechanism of a fall, is the knee ‘giving way’. This occurs when the weight is on the leg when it is not fully straight (Figure 2).

Kee is not in full extension – may give way

Kee in full extension – won’t give way

Even with very weak muscles, if the knee if fully straightened it won’t give way (Figure 3) however if just a few degrees off from full extension, it can collapse due to the weakness in the quadriceps. For people without muscle disease if they weight bear on a knee that is not fully straight, they have enough strength to stop it from giving way. Clearly Groucho Marx didn’t have IBM!

Once the quadriceps muscle becomes very weak, it cannot fully control the knee as it goes into extension. For a number of IBMers their knee goes into extension with a considerable force that can’t be controlled due to their muscle weakness. Often when this happens the knee becomes hyperextended, i.e. it goes back further than it should. For those AFL followers this is a common complaint experienced by ruckmen when they land on one leg and the knee is forced back suddenly and without control. Some patients do not experience pain when the knee is hyperextended considerably but for others this can be a very painful experience.

For people without IBM or other forms of neuromuscular disease, the first approach is always to strengthen the quadriceps muscle via exercise. For those with IBM, whilst maintaining as much strength as possible in these muscles is vital, exercise alone will not provide the full benefits that those without muscle disease enjoy. Sadly, despite best efforts, people with IBM cannot fully reverse the weakness in their quadriceps with exercise alone.

One option worth considering is a leg brace. There are many different braces on the market but not all are suitable for people with IBM. If your Specialist suggests that you may benefit from a leg brace it is important that you seek the input of an Orthotist. Orthotists are health professionals who specialise in the prescription, construction and fitting of braces and splints.

Depending on your particular issues, there are 3 main categories of brace that may be able help people with IBM:

1. Knee extension assist

We know that getting the leg fully straight is difficult for many people with IBM. There are a number of fairly inexpensive options on the market that provide support to the knee to straighten. Simple wrap round knee braces can be fitted with strong elastic bands that will help the knee become fully straight as the leg swings through. These braces however will not stop the knee from buckling if it suddenly gives way. It is simply designed to help the knee become straight to allow you to put all your weight through it.

2. Hyperextension prevention

There are a number of devices available on the market that have locking mechanisms at the side that can be manually set. If set correctly they can prevent the knee from going into a hyperextended position. Like the extension assist braces they will not prevent the knee from giving way if the knee is not fully straightened.

3. Stance control knee brace

It is this type of brace that has greatest application for people with IBM.

An ideal brace is one that will lock the knee when in the stance phase of walking but unlock to allow the leg to move freely during the swing phase of walking. These braces tend to work better in people with single limb weakness but sadly in IBM both legs are often impacted. Anecdotally we hear reports from patients who have had falls whilst wearing their leg brace. Often this has occurred when the wearer puts weight onto the leg when the knee isn’t fully locked and just as occurs when not wearing a brace, the leg ‘gives way’.

The Holy Grail has always been a brace that will lock if the leg gives way suddenly. In essence, a brace that will act like a normal healthy muscle does.

The team in WA have been looking into what is on the market and are having discussions with engineers locally and in Adelaide for a device that may be able to achieve this. Don’t hold your breath, however, as this may take a while.

In looking at what is currently available, there are new devices currently on the market that ticks all the boxes for people with severe leg weakness. There is a catch however…

One device known as a C Brace does not come cheap. Don’t expect any change from $100,000 dollars for one brace.

The brace has a computerised knee device that not only senses movement but has the ability to react to any movement such as giving way suddenly. To our knowledge there have been no studies looking at the benefits of the C Brace in people with IBM but if those 6 numbers and the Powerball come up soon then this may be worth exploring.

The C Brace
The Keeogo brace

The Keeogo brace is another new entry to the market which like the C Brace provides options for people with significant leg weakness and tendencies to frequent falls. It has the advantage in that it has been developed for people with weakness in both legs. Although still expensive the keeogo has been quoted at $70K

There are thankfully other devices on the market that have the potential to help people with IBM. Whilst significantly cheaper they still fall within the $10-15K range. Remember that for most IBMers the cost needs to be doubled. Below are examples of the most commonly prescribed stance control braces on the market

Freewalk Ankle Foot Knee Orthosis

As you can see there is no one size fits all device for people with IBM. That is why it is important that you consult with an orthotist before outlaying money to ensure that you purchase a device that works for you.

For those on NDIS there is the option to explore funding via this source. Likewise for those on a My Aged Care package but remember this source tends to be less generous than the NDIS.

Funding via the public health system varies from State to State so it would be worth exploring whether the cost of a custom-made brace will be covered.  

Summary of brace types

Brace type



Knee extension assist

  • Helpful when unable to straighten then knee whilst walking
  • Relatively inexpensive May be able to buy ‘off the shelf’
  • Does not lock the knee once in extension
  • Will not stop knee from giving way

Hyperextension Control

  • Can reduce pain and injury caused by knee hyperextension
  • Does not lock the knee once in extension
  • Will not stop the knee from giving way More expensive (usually custom made)

Stance control knee brace

  • 1 small study3 has demonstrated benefits but mainly in people with reasonable strength
  • Will lock the knee once fully straight the unlock when you want to start walking
  • May not be effective if quadriceps are quite weak.
  • Expensive for the basic model
  • VERY expensive for the more advanced models
  • The less expensive devices will not prevent falls if all the weight is on the leg and the brace is not locked

Ian Cooper
Myositis Discovery Programme 
Murdoch University

Kelly Beer
Research Nurse
Myositis Discovery Programme
Murdoch University

Jens Baufeldt
X-Tremity Prosthetics and Orthotics 


  1. Hiscock A, Dewar L, Parton M, Machado P, Hanna M, Ramdharry G. Frequency and circumstances of falls in people with inclusion body myositis: a questionnaire survey to explore falls management and physiotherapy provision. Physiotherapy. 2014;100(1):61-65. doi:10.1016/j.physio.2013.06.002
  2. Australian Institute of Health and Welfare https://www.aihw.gov.au/reports/injury/falls
  3. Bernhardt K, Oh T, Kaufman K. Stance control orthosis trial in patients with inclusion body myositis. Prosthet Orthot Int. 2011;35(1):39-44. doi:10.1177/0309364610389352

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