Bracing and Support

Reaction Brace

The main properties of the Elastomeric Knee Brace are:
• Pain Control
• Shock Attenuation
• Acceleration.

The REACTION knee brace was developed by Dr. Nordt. The objective of the device was to control contact stresses within the knee. The brace achieves this in two ways; 1) it absorbs and disperses energy that enters the knee, much the same as muscles do upon foot impact, and 2) control and stabilize subtle laxity within the joint. This stabilization function is based upon the principle that a joint will always take the “path of least resistance.” The form-fit of the REACTION elastomeric web helps to maintain the knee joint in a neutral position whereby the contact stresses are distributed more uniformly, minimizing peak loading of a given area. Peak loading is particularly detrimental to articular cartilage surfaces.
In studies of small series of patients, the Reaction Brace has been shown to significantly diminish shear stress at the knee. The Reaction has the advantage of being light weight and comfortable. It can be worn for activities of daily living as well as sporting activities. Its fit and tensionability gives the device a broad range of potential users. The older patient who needs stabilization and kinetic assist will find the brace user-friendly and effective. The younger, athletic individual will find the REACTION to be responsive and comfortable. The REACTION has been successful in controlling pain even in the heavier hard-to-fit patients.

As compared to the conventional knee sleeve, the REACTION has superior functional properties and comfort. The REACTION brace is tensionable, that is, it can be released for resting activities and re-tensioned according to the user’s desired activity level and functional demands. The Reaction affords some of the characteristics of a rigid brace without the bulk. The REACTION tends to have minimal migration, seen in many other brace designs.

Knee Sleeve

The most cost efficient and least cumbersome brace available for someone with cartilage injuries or arthritic knees is a basic knee sleeve. These can be purchased over the counter (OTC) and are usually made of neoprene, cotton, or a drytex material. Indications for this brace include edema, pain, and very mild instabilities.

These signs/symptoms may be caused by meniscal tears as well as uni or multi-compartmental osteoarthritis. Contraindications include circulatory conditions, moderate to severe instabilities, neoprene allergies etc. In their study Brouwer et al found decreased pain and increased function with a group of participants wearing knee sleeves vs the control group. Knee sleeves can also be used to help with joint position sense. Chuang et al found that knee sleeves are effective in assisting with proprioception and balance in patients with knee OA. They tested both static and dynamic balance of 50 subjects with knee OA and found statistical significance in both groups. Balance scores improved by 28% in the static testing and by 8% in the dynamic testing. These braces are a good option for the patient with knee OA who has trouble with balance and frequent falls but doesn’t have any true ligamentous instability.

Patellar Tracking Brace

These braces are also referred to as lateral J braces, patella stabilizers, patellofemoral braces etc. They are designed to prevent lateral patellar maltracking. Maltracking is usually caused by tight lateral structures (i.e. retinaculum and IT Band), and weak quadriceps muscles (i.e. vastus medialis oblique.) For the patient with chondromalacia patella or later stages of patellofemoral arthritis they can help prevent the grinding of the patella over the trochlea. Similar to the function of knee sleeves this brace also provides compression. In a study of the effects of patellofemoral bracing while ascending and descending stairs researchers found a 56 percent reduction in pain. However there was not a significant difference in patella joint stress. The researchers attributed the decrease in pain to the brace putting pressure on the patella and setting it deeper in the trochlea. They believe this increased contact of the patella and femur actually helped dissipate the forces. (3)

Hinged Knee Brace

These braces are helpful for patients whose cartilage injury or arthritis has caused instability within the knee. These braces can help prevent the sensation of “buckling” or giving way that patients describe in their knee with ambulation. Stability is provided via bilateral plastic or metal stays. The longer stays (lever arms,) provide greater stability.

The knee is usually encompassed by a neoprene, cotton, or drytex material and 2-4 straps which secure it to the leg and prevent brace migration. This brace may not be the best option for someone with an exceptionally large thigh and small calf. In these cases where the calf is too small to suspend the orthosis a custom fabricated brace should be considered.

A study was performed on twelve participants with medial compartment OA comparing a hinged knee brace and an unloader brace. The hinged knee brace did not affect pain levels but did increase confidence in participants with walking. Researchers suggested this may be a placebo effect of the brace. They found unloader braces were more supportive in the coronal plane. (4)

Unloader Brace

Also referred to as off-loaders, unloader braces are useful for treatment of uni-compartmental knee arthritis or joint space narrowing. These braces function to take pressure off of the affected compartment and open up the joint space on that side. They do this by using three points of pressure to transfer the load to the contralateral compartment. They are usually constructed out of poly carbon fiber, magnesium, graphite, or titanium. These braces are a great option for patients wishing to delay a knee replacement. In particular the younger patient in the early stages of OA may benefit from this brace. Having a total knee arthroplasty at such a young age would most predispose the patient to need a revision in the future. They are also helpful for those patients who are not candidates for surgery due to age, heart conditions etc. These braces are contraindicated for patients who are known to be non-compliant as they are very expensive. They are also a challenge for the patient who is morbidly obese, has a large thigh and small calf, or severe calf atrophy. The most commonly noted drawbacks to these braces are: brace migration, tibial pressure, and poor outcomes for those with high BMIs.

For patients with a lot of adipose tissue on the thigh, a severe valgus knee, or someone whose only symptom is pain a single upright brace may be a better option versus the traditional double upright brace. This brace does not have a medial hinge or stays on the medial side and therefore is contra-indicated for instabilities.

The effectiveness of unloader braces is very controversial. Part of the problem is that there are very few published studies and the studies out there are lacking randomized trials. Many studies show little to no statistical significance between braced and non-braced knees. However one study worth noting found positive results with valgus bracing. Nadaud et al used five subjects and five different valgus braces and found significant condylar separation during gait in all but one participant. The maximum separation was found during heel strike with an average of 0.7 to 1.3mm of separation. Interestingly enough the best results were found with the Bledsoe and Donjoy braces. Other studies report positive subjective feedback from participants. Divine and Hewett report the following positive findings from their study: decreased pain, decreased use of pain medication, increased ability to tolerate ADLs, and increased condylar separation (on average between 1.2mm and 2.2 degrees.) Likewise Schmalz et al reported a ten percent reduction of varus moment at the knee when wearing an unloader brace due to a valgus moment produced by brace. They also reported a more symmetrical gait pattern when subjects wore the brace. Lastly Barnes et al reported decreased night pain, stiffness, and swelling with brace use.