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THE ROLE OF KNEE BRACES

Introduction
Types of knee brace
Just some of the controversies around functional bracing
So do knee braces work?
Choosing and fitting a knee brace
Useful weblinks 
References

Introduction

The knee joint is the commonest single area to sustain an injury if you're an alpine skier, telemark skier or a skiboarder. Whilst the majority of these injuries are relatively minor and will recover quickly without any functional deficit, this may not be the case if you are unfortunate enough to sustain a more serious knee injury. Injuries like a tibial plateau fracture, or complete ruptures of the anterior cruciate, medial or lateral collateral ligaments, with or without damage to the knee cartilage may require a surgical operation followed by intensive rehabilitation in order to regain enough function to consider a return to the slopes.

Paramount in the mind of an individual who returns to the slopes having sustained a serious knee injury is to prevent it ever happening again. There are many ways to help reduce the risks of a further injury - most (if not all) of them are outlined somewhere or other on this website - this page focuses specifically on the role of knee braces following a knee injury.

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Types of knee brace

If you've already looked into knee braces - done a Google search maybe - you''ll see that this is a huge topic! There are a lot of different braces out there, ranging in price from less than £20 up to several hundred pounds. It can all be a bit confusing. So lets start by describing the main kinds of brace available to you. These are:

1. Prophylactic braces
   
   As the name implies, these braces are used as primary prevention - to stop an injury occurring in the first instance. These braces are usually hinged (either on one side or both sides) and their aim is to prevent excessive movement in the knee joint when an abnormal force is applied to it. These movements may be front to back, side to side or rotational in nature. 
   

2. Rehabilitation braces
   
   These braces are used under the supervision of an orthopaedic surgeon (+/- a physiotherapist) to control the amount of movement the knee joint is allowed to make, usually after an operation. The idea is that this protects the healing ligament(s) and promotes recovery.
   

3. Functional braces
   
   Functional bracing is mainly used to protect the anterior cruciate ligament (ACL) - either after surgery for those who have had a ligament reconstruction performed, or after injury in those who decide against surgery or who are still waiting for their operation. They aim to reduce rotational and front to back movements, the forces that are associated with injury to the ACL. Functional braces can be bought "off the shelf" or may be custom-fitted. Custom braces are not surprisingly the more expensive option as they are tailored to the individual's specific needs. They are usually the brace of choice for those who wish to ski/board again with any degree of intensity (by which I'm talking average intermediate level and above). They normally also offer a higher level of user comfort.
   
   Functional braces may be of a "hinge and shell" or a "hinge and strap" design. The first kind of brace incorporates moulded shells of plastic and foam connected by a hinge system whereas the latter uses leg and thigh straps for attachment. Most ski physicians would recommend a "hinge and shell" brace as these seem to offer superior support, comfort and durability. 
   
   The rest of this page will focus on these functional braces, as they are of the most interest to injured skiers and boarders.
   

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Just some of the controversies around functional bracing....!

• Braces from difference manufacturers vary considerably in the movement restrictions that they apply
• Laboratory studies using models and physical studies using patients performing controlled movements show that functional knee braces do limit rotation and translation. The problem is that this effect may disappear in the "real world", when an individual actually begins to use his or her brace.
• Some studies have shown no difference in efficacy between custom and off-the-shelf braces.
• Wearing a functional brace may interfere with the joint position sense ('proprioception') of the affected knee joint.
• Wearing a functional brace might lead to increased muscle fatigue in the leg with the brace on.

So do braces work?

This has always been the million dollar question!! Thankfully, we are now in a better position to answer it. A study published in the American Journal of Sports Medicine in October 2006 looked at 820 skiers who had undergone ACL reconstruction at least 2 years before the study started. Of these, 257 skiers used a functional knee brace and 563 did not. The skiers who wore the braces were assessed at the start as having generally 'weaker' knees - i.e. their ligaments were more lax on clinical testing. Neverthless, the study showed that those skiers who did not wear a brace were 2.74 times more likely to sustain a subsequent knee injury from skiing than those who did. The authors (who incidentally were from the world renowned Steadman Hawkins Research Foundation in Vail, USA) concluded "Because of the increased risk of subsequent knee injury in nonbraced skiers, the authors recommend functional bracing for skiers with anterior cruciate ligament reconstruction. Whether the protective effect of functional bracing can be extrapolated to other high-demand patients is yet to be determined."

So, we now have evidence that if you have undergone ACL surgery, then wearing a functional brace may reduce the risks of subsequent knee injury. Whether a functional brace would help those with any other previous knee injury or surgery is not proven. Nevertheless, I think most ski physicians would support the use of a properly-fitted functional knee brace in these circumstances on the basis that there is no real evidence to suggest that they might do harm, but there is plenty of anecdotal evidence to support their use. As ever, further studies are needed.

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Choosing and fitting a knee brace

As I've already mentioned, there is a large choice of knee braces out there. Deciding which one to go for will be an individual decision, although you will often be given guidance from your orthopaedic surgeon, physiotherapist or attending physician. Well known knee brace brands (links below) include DJ Orthopaedics, Technology in Motion/ Ossur (previously known as Innovation Sports) and OrthoTec. Most of these companies offer a comprehensive fitting service although there is usually an additional fee payable for this. As an example, click here for details of Technology in Motion's fitting service. 

Useful Weblinks 

DJ Orthopaedic knee braces
Off the shelf knee braces from Ossur
CTi knee braces
About.com article on knee braces written by orthopaedic surgeon J Cluett, MD.

References

1. Chew KT, Lew HL, Date E, Fredericson M. Current evidence and clinical applications of therapeutic knee braces. Am J Phys Med Rehabil. 2007 Aug;86(8):678-86.
2. Sterett WI. Briggs KK. Farley T. Steadman JR. Effect of functional bracing on knee injury in skiers with anterior cruciate ligament reconstruction: a prospective cohort study. American Journal of Sports Medicine. 34(10):1581-5, 2006 Oct.
3. Hagner, W. Knee Braces - an evaluation of treatment effectiveness after reconstruction of anterior crucial ligament. Ortop Traumatol Rehabil. 2006 Dec 29;8(6):699-703
4. Wright RW, Fetzer GB. Bracing after ACL reconstruction: a systematic review. Clin Orthop Relat Res. 2007 Feb;455:162-8. Review
5. Wetherbee E, Pellecchia GL. Is there evidence that bracing could provide adequate stability for a 47-year-old man with a deficient anterior cruciate ligament to resume downhill skiing? Phys Ther. 2004 Mar;84(3):274-82. Review.
6. Liu S.H., Mirzian R. Current review: Functional knee bracing. Clin Orthop. 1995, 317, 273-281.
7. Beynnon B.D., Pope M.H., Wertheimer C.M. et al. The effect of functional knee-braces on strain on the anterior cruciate ligament in vivo. J Bone Joint Surg. 1992, 74-A (9), 1298-1312.
8. Wojtys E.M., Looubert P.V., Samson S.Y. et al. Use of a knee-brace for control of tibial translation and rotation. A comparison, in cadavera, of available models. J Bone Joint Surg. 1990, 72-A (9), 1323-1329.
9. Lunsford T.R., Lunsford B.R., Greenfield J. et al. Response of eight knee orthoses to valgus, varus and axial rotation loads. Journal of Prosthetics and Orthotics. 1990, 2 (4), 274-228.
10. Liu S.H., Lunsford T., Gude S. et al. Comparison of functional knee braces for control of anterior tibial displacement. Clin Orthop. 1994, 303, 203-210.
11. Beynnon B.D., Johnson R.J. et al. The effect of functional knee bracing on the anterior cruciate ligament in the weightbearing and non-weightbearing knee. Am. Orthop, Society for Sports Med. 1997, 25 (3), 353-359.
12. Albright J.P., Powell J.W., Smith et al. Medial collateral ligament knee sprains in college football. Soc. for Sports Med. 1994, 22 (1), 12-18.
13. Risberg M.A., Beynnon B.D., Peura G.D. Proprioception after anterior cruciate ligament reconstruction with and without bracing. Knee Surg., Sports Traumatol., Arthrosc. 1999, 7 (5), 303-309.
14. Styf J.R., Lundin O., Gersguni D.H. Effects of a functional knee brace on leg muscle function. Am. Orthop. Soc for Sports Med. 1994, 22 (6), 830-834.
15. Styf J. The effects of functional knee bracing on musicle functional performance. Sports Medicine. 1999, 28 (2), 77-81.
16. Kartus J., Stener S., Kohler K et al. Is bracing after anterior cruciate ligament reconstruction necessary? Knee Surg., sports Traumatol., Arthrosc. 1997, 5, 157-161.
17. Butler P.B., Evans G.A., rose G.K. et al. A review of selected knee orthoses. British J Rheumatol. 1983, 22, 109-120.