Knee Bracing

A brace is defined as an orthopaedic appliance or apparatus used to support, align, prevent, or correct deformities or to improve the function of movable parts of the body.

Classification of braces

According to the American Academy of Orthopaedic Surgeons (AAOS), knee braces fit into several categories:

1. prophylactic or protective bracing: These are braces intended to prevent or reduce the severity of knee injuries in contact sports
2. functional Bracing: braces designed to provide stability for unstable knees or following fractures
3. rehabilitative bracing: braces designed to allow protected and controlled motion during the rehabilitation of injured knees
4. patello-femoral bracing: braces designed to improve patellar tracking and relieve anterior knee pain.

Indications for bracing

Prophylactic knee braces These have protective function and are pre-emptive braces. They are primarily used for:

1. MCL protection against valgus knee stresses in previously unstable knees
2. Re-injury protection after previous MCL injury
3. Sportsmen at risk for MCL injury

Functional knee braces.

These are primarily designed for:

1. reducing translation and rotation following ACL injury
2. Additional support after ACL surgery
3. support for mild to moderate PCL or MCL instability
4. following periarticular stable fractures around the knee joint

Patello-femoral knee braces.

These are designed for :

1. patients with patellar subluxation and/or dislocation
2. Patellar tendonitis
3. chondromalacia of the patella
4. Postsurgical for patellar or quadriceps realignment surgery

Apart from specific indication there are many general indications for prescribing braces. Some of the common indications are:

1. Documented anterior or posterior cruciate ligament (ACL or PCL) tears or functional instability episodes due to cruciate ligament insufficiency when non-surgical treatment is elected
2. Grade II or III medial collateral or lateral collateral ligament sprain to support ambulation when the use of a hinged brace allows for controlled joint motion
3. Posterior cruciate or postero-lateral corner reconstruction, including reconstruction after knee dislocation
4. Recent surgery for ACL repair in the post-operative recovery phase
5. Recent surgery for meniscal cartilage repair in the post-operative recovery phase
6. Major ligament and bony reconstruction above the knee such as patella or quadriceps tendon repair, medial and lateral collateral ligament repair
7. Major fractures requiring early post-injury or post- operative motion such as patella fractures or tibial plateau fractures
8. Osteoarthritis of the knee (unicompartmental) who fulfil any of the criteria as outlined below: (1) High tibial osteotomy or total knee arthroplasty (TKA) (replacement) candidate that may elect non-surgical treatment (2)To predict the success of high tibial osteotomy (3) Severe patellofemoral arthrosis in conjunction with medial or lateral early osteoarthritis

Contra-indications for bracing

There are NO absolute contra-indications to bracing.The use of bracing to achieve rotational control in an ACL deficient knee is a relative contra-indication for bracing. Complicated multi-directional knee injuries such as postero-lateral corner injuries are best treated with surgery with more favourable outcomes. Knee disorders unrelated to the patellofemoral joint or translational instability require surgical management. Complications of Bracing

• Injuries increased by excessive preloading of MCL
• Limited speed and flexibility
• False sense of security for previously injured knee
• Brace-related contact injuries to other players
• Reported effects on translation and rotation disappear at physiologic levels of use
• Increased energy expenditure and clumsiness with decreased agility
• False sense of confidence following ACL reconstruction
• Subjective benefits frequently exceed objective findings
• Increased skin irritation and lesions
• Relatively insignificant pain relief with regular brace wear
• Less effective than conservative therapy (simple stretching and strengthening)

“The important things to consider any time you have a patient being splinted into immobility are the detrimental changes that can occur” (Edward W. Bezkor, Clinical specialist for outpatient physical therapy, NYU Medical Center) According to his research findings corroborated with research nto musculoskeletal changes after bracing reveal fibrotic changes in the tissues and fascial thickening. At the ultramicroscopic level there is the loss of sarcomeres, the contractile unit of muscle fiber most apparent when the muscle is held in a shortened range. This is accompanied by degeneration of the cartilage, because there will not be the healthy stresses placed on the cartilage and the abnormal or limited motion of synovial fluid.

Fabrication / Materials

Knee braces may be custom made or available off-the-shelf in a variety of sizes. Knee braces may be intended for rehabilitation, to reduce pain, or to prevent injury in either stable or unstable knees. Knee braces typically consist of 3 components: a superstructure (usually a rigid shell), a hinge, and a strap system. The superstructure extends proximally and distally to a hinge centered around the knee axis of motion. The strapping system secures the brace to the limb.

Benefits and Limitations of bracing

Since the widespread use of prophylactic braces, several international studies have been carried out to establish if bracing reliably and predictably prevent knee injuries. In most studies there has been serious deficiencies with inadequate control groups, subjective biases, variable rules of different sport, alternative treatment options and regional variations and preferences for ACL / MCL injuries and poor and biased methods of data collection. Thus the outcomes do not lend well to adequate comparison among most studies of prophylactic knee braces. Though some research has shown that that prophylactic knee braces significantly reduce MCL injuries, others have shown very little or no benefit at all even with regular use. As with many types of athletic braces, reported subjective benefits often exalted by inventors or manufacturing companies often exceed objective findings. Patients have also noted significant differences in proprioception between the braced and unbraced extremity. At best, prophylactic knee braces may offer some resistance to lateral knee impact and provide some protection against rotational stresses. It is eminently possible that with ill-fitting or ill-prescribed braces may generate increased forces that compound the original insults to the joint.

Current articles regarding the benefits or otherwise of bracing

1. In vitro assessment of prophylactic knee brace function. France EP, Paulos LE. Clin Sports Med. 1990 Oct;9(4):823-41. Department of Bioengineering, University of Utah, Salt Lake City.

In an attempt to evaluate the effectiveness of prophylactic knee bracing and to determine the influence of brace design and material characteristics on the protection of knee ligaments, a series of biomechanical studies were completed. The first series of tests were preliminary parametric tests of brace function utilising cadaver limbs to understand the failure biomechanics of the medial restraints during low- and high-rate valgus-producing knee trauma. Static and dynamic mechanical properties of the braces were also studied. Finally, a limited series of brace/cadaver knee low-rate loading response tests were performed. The majority of prophylactic knee braces tested proved to be biomechanically inadequate for protecting the MCl from a direct lateral impact. A few, however, appear to protect the ACL preferentially. In the case of a controlled, direct lateral blow, all but a few braces tested provided some beneficial protection to the MCL and ACL, but performed well below the standard 1.5 ISF level. Therefore, based on the biomechanical research, it is our opinion that the concept of prophylactic lateral knee bracing can be effective. We recommend that prophylactic braces not be abandoned, but rather improved, biomechanically validated, and further evaluated through well-controlled prospective clinical studies.

2. Use of knee braces in sport. Current recommendations. Albright JP, Saterbak A, Stokes J. Sports Med. 1995 Nov;20(5):281-301.

This article provides a review of the progress that has been made on the biomechanical, functional performance and epidemiological investigations into the effectiveness of prophylactic knee braces (PKBs) since the position statement against their use was issued in 1987 by the American Academy of Orthopaedics and a review of this subject was last published in Sports Medicine in 1989 by Montgomery and Korziris. The evolution of the salient design features of three surrogate knee models are reviewed along with the results of PKB effectiveness and safety factor testing. While still too limited in scope to be totally realistic, major advances have been made in the sophistication of the present biomechanics laboratory testing conditions. The on-the-field functional performance effects of wearing a knee brace are not always manifest in all individuals. The efficacy of PKBs remains in question but recent studies have taught us enough to put their use into perspective. While they may play some role, PKBs probably represent the least important factor in influencing the likelihood that a medial collateral ligament (MCL) sprain will occur. On the other hand, there is no evidence that such braces put added valgus pressure on some knees, or that wearing a brace is associated with an increased frequency or severity of knee or ankle injury. All else being equal, from the biomechanical studies, we know that whilst some braces are better than others, currently available PKBs can provide 20 to 30% greater resistance to a lateral blow, with the possibility that the anterior cruciate ligament (ACL) is given even greater protection than the MCL. This appears to be true when the lateral blow is of sufficient magnitude to cause significant medial joint line opening, but is not as great at the very lowest levels of impact. Regardless of the material they are made of, the most effective PKBs are those sufficiently stiff to prevent an external blow at the joint line from causing brace hinge contact with the knee tissues. Based on the superior results of the custom-fit functional braces, the most important future design feature appears to be the sizing and fitting of the thigh and tibial cuffs. On the negative side, the presence of a brace may slow an athlete’s straight-ahead sprint speed and cause early fatigue to its wearer. This effect appears to vary from one brace to another according to its weight, design features, and pressure from the leg and thigh straps. However, it appears that knee braces do have the potential to restrict performance of the athlete for high-speed running but the effect is related to several factors. The weight of the brace resultant friction of the hinges, completeness of fit, and tightness of straps appear to be important. The most measurable effects include: increased muscular relaxation pressures; increased energy expenditure; and a related increase in blood lactate levels, maximal torque output, oxygen consumption and heart rate. On the other hand, experienced brace wearers and larger, stronger individuals displayed fewer, or no effects of donning a brace. Improvements in the protectiveness of the PKB are likely to accompany improvements in the ability to contour the braces to fit each individual’s leg in the equipment room without the added expense of the cast-moulding process. Further improvement may be realised by friction-free polycentric joints, as well as an attachment system that minimises thigh and calf soft tissue compression perhaps by incorporating the braces into the trousers of the uniform to provide suspension from the waist.

3. Efficacy of knee braces and foot orthoses in conservative management of knee osteoarthritis: a systematic review. Raja K, Dewan N. Am J Phys Med Rehabil. 2011 Mar; 90(3):247-62. Manipal University, Manipal, Karnataka, India.

A systematic analysis was conducted on the effectiveness of knee braces and foot orthoses in conservative management of knee osteoarthritis. The methodologic quality of the randomised clinical trials, controlled clinical trials, and observational studies were systematically reviewed using the Structured Effectiveness Quality Evaluation Scale. Twenty-five studies met the inclusion criteria. The orthoses used in the studies included Generation II osteoarthritis knee brace, valgus knee braces, functional off-loading knee braces, knee sleeves, lateral-wedged insoles with subtalar strapping, medial-wedged insoles, and specialised footwear. Results suggest that knee braces and foot orthoses are effective in decreasing pain, joint stiffness, and drug dosage. They also improve proprioception, balance, Kellgren/Lawrence grading, and physical function scores in subjects with varus and valgus knee osteoarthritis. Knee braces and foot orthoses could be cautiously considered as conservative management for relief of pain and stiffness and improving physical function for persons with knee osteoarthritis. The conclusions of this review are limited by methodologic considerations like poor quality of trials and heterogeneity of interventions.

References

1. American Academy of Pediatrics Committee on Sports Medicine. Knee brace use by athletes. Pediatrics. 1990;85:228.
2. France EP, Cawley PW, Paulos LE. Choosing functional knee braces. Clin Sports Med. 1990;9:743–50.
3. American Academy of Orthopaedic Surgeons. The use of knee braces. Document number 1124. Retrieved November 24, 1999, from the World Wide Web: www.AAOS.org/wordhtml/papers/position/kneebr.htm.
4. Kramer JF, Dubowitz T, Fowler P, Schachter C, Birmingham T. Functional knee braces and dynamic performance: a review. Clin J Sports Med. 1997;7:32–9.
5. Beynnon BD, Pope MH, Wertheimer CM, Johnson RJ, Fleming BC, Nichols CE, et al. The effect of functional knee-braces on strain on the anterior cruciate ligament in vivo. J Bone Joint Surg [Am]. 1992;74:1298–312.
6. Saliba E, Foreman S, Abadie RT. Protective equipment considerations. In: Zachazewski JE, Magee DJ, Quillen WS, eds. Athletic injuries and rehabilitation: Philadelphia: Saunders, 1996: 924–32.
7. Liu SH, Lunsford T, Gude S, Vangsness CT Jr. Comparison of functional knee braces for control of anterior tibial displacement. Clin Orthop. 1994;303:203–10.

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