Prophylactic+Knee+Braces


 * __History and Costs__**

Epidemiological studies have shown that knee injuries are the most common disabling injuries in sports today. The use of prophylactic knee braces in sports has increased in an attempt to reduce the incidence and/or severity of injuries in the knee joint. Knee injuries are estimated to cost almost 2 billion dollars per year. An estimated cost for an ACL surgery and rehabilitation in the US is up to $25,000 per athlete (Didn’t consider the costs of Non-surgical option). ACL injuries while playing soccer had 51% higher radiographic changes related to OA 12– 14 years post-injury. This will increase the risk for having more surgeries down the road.

 The first to report the use of a prophylactic knee brace was an athletic trainer for the Oakland raiders. The Quarterback at this time was Ken Stabler who had a MCL sprain. He used a dual-hinged brace for 9 games without reinjuring the MCL. It then was tested on 9 players after that for 1 to 9 games depending on how long the athlete needed it. These athletes did not reinjure their knees as well. Even though this report did not show sufficient efficacy, the popularity of prophylactic knee braces exploded. While positive aspects were shown, negative aspects started to emerge about the braces soon thereafter.

 __ **Review of the knee structures** __ Mechanism of Injury [4] ** Types of Braces
 * Four main ligaments in the knee to help stabilize it.
 *  Medial collateral ligament (MCL) and the lateral collateral ligaments (LCL).
 * Stabilize the side-to-side (Valgus and Varus) movement.
 *  Anterior cruciate ligament (ACL).
 * It helps prevent tibia from rotating and sliding forward during sports activities.
 *  Posterior cruciate ligament (PCL)
 * Prevents opposite action of the ACL, which is sliding the tibia posteriorly (Knee, 2008).
 *  Meniscus
 *  Consist of two parts the lateral and medial meniscus.
 *  Shock absorption as well as lubrication
 * ACL: Hyperextension with anterior translationPCL: hyperflexion with posterior translation
 * Non-contact
 * Hyperextension
 * Sudden deceleration
 * Contact
 * Excessive twisting of the knee or valgus stress on the knee
 * MCL: Valgus stress
 * LCL: Varus stress
 * ACL + medial meniscus: hyperextension with rotation
 * <span style="font-family: Arial,Helvetica,sans-serif;">ACL+ medial meniscus + MCL: extension, valgus with rotation
 * <span style="font-family: Arial,Helvetica,sans-serif;">Meniscus:
 * <span style="font-family: Arial,Helvetica,sans-serif;">Traumatic / sports (non-contact)Degeneration
 * Compression and rotation at the knee
 * Flexion + rotation or extension + rotation during Weight bearing activities
 * Sudden acceleration or deceleration combined with a change of direction
 * <span style="font-family: Arial,Helvetica,sans-serif;">decreased healing
 * <span style="font-family: Arial,Helvetica,sans-serif;">stiffness and decreased compliance
 * <span style="font-family: Arial,Helvetica,sans-serif;">increased age
 * **//SIGN/SYMPTOM//** || **//GRADE I//** || **//GRADE II//** || **//GRADE III//** ||
 * Ligament || No tear || Partial tear || Complete tear ||
 * Loss of functional ability || Minimal || Some || Great ||
 * Pain || Minimal || Moderate || Severe ||
 * Swelling || Minimal || Moderate || Severe ||
 * Ecchymosis || Usually not || Frequently || Yes ||

** __Prophylactic Knee Braces__ ** are used to protect the MCL against valgus stress and always support the cruciate ligaments during rotational stress. They are also used to protect against re-injury protection after a previous MCL injury or with athletes who are at high risk for an MCL injury. Football players (offensive/defensive linemen and quarterbacks) are among the athletes who wear prophylactic knee braces most often. It has been reported that prophylactic knee braces reduce the frequency and severity of MCL injuries, increase support of the cruciate ligaments, and enhance proprioception. However, there is a lack of evidence that supports prophylactic knee braces actually prevent ligamentous knee injuries. <span style="font-family: Arial,Helvetica,sans-serif;">** __Functional Knee Braces__ ** are used to reduce knee instability when returning from an ACL injury. They help protect an ACL graft after surgical intervention by reducing translation and rotation of the femur or tibia. Also, they can be used when mild to moderate PCL or MCL instability is present and help by preventing additional knee injuries. Functional knee braces are usually worn by athletes who cut and change direction often. Decreased pain, enhanced performance, increased confidence, increased proprioception, and prevention of hyperextension of the knee has been reported by those wearing functional knee braces. <span style="font-family: Arial,Helvetica,sans-serif;"> __Patellofemoral Knee Braces__ ** aid in correct alignment of the patellofemoral joint and help prevent lateral subluxation/dislocation of the patella by a medially directed force. The correction of patellar tracking and prevention of subluxation/dislocation both reduce pain. These knee braces are also indicated with patellar tendonitis, condromalacia of the patella, and postsurgical effusion control but are not indicated when instability is present due to lack of strength.Those wearing patellofemoral knee braces have reported improved patellar tracking during knee flexion and extension, decreased pain, improved performance, and an increase in confidence during activity.

** Obtaining and Fitting of Braces **
<span style="font-family: Arial,sans-serif;">After the right brace is selected, obtaining a brace can be done in a number of ways. One way can be ordering from a manufacturer catalog or a manufacturer website. Another way is from a medical supply store, which will carry prefabricated braces. Proper fitting and application of the brace is important for the brace to be effective. The brace will lose its effects if it is too loose and migrates or if it is too tight. The size of the brace is determined through girth measurements of the thigh, knee, and lower leg. There are custom and prefabricated braces with the custom braces being more expensive.

__**<span style="font-family: Arial,sans-serif;">Prophylactic Knee Brace **__ <span style="font-family: Arial,sans-serif;"> The hinge of a prophylactic knee brace should line up with the femoral condyles and the bars in line with the femur and tibia. The longer the brace is the more protection for the MCL. The brace should be examined every day to check for position and to make sure the brace is not broken.

__**<span style="font-family: Arial,sans-serif;">Functional Knee Brace **__ <span style="font-family: Arial,sans-serif;"> Measurements are taken 6 inches above the mid patella. Brace can be set to limit extension. Any exposed metal from the brace should be covered to limit injuries to others. Prefabricated may be better for patients with edema changes because it is easy to switch the braces. [6] Inspect the brace often to make sure fit is appropriate.

__**<span style="font-family: Arial,sans-serif;">Patellofemoral Brace **__ <span style="font-family: Arial,sans-serif;"> Elastic material plus buttresses or straps to stabilize patella make up a patellofemoral brace. The buttresses are usually placed lateral to the patella to prevent lateral deviations. To find the circumference needed for a brace, measure the leg 3 in above and 3 in below mid patella or around the joint line. [6] Then position buttresses where needed and fasten the strap with moderate tension. Check regularly for position and strap strength. <span style="font-family: Arial,sans-serif;"> [] <span style="font-family: Arial,sans-serif;"> [] <span style="font-family: Arial,sans-serif;"> [] <span style="font-family: Arial,sans-serif;"> http://www.youtube.com/watch?v=ZRB7S2Pj2-A

**Advantages and Disadvantages of Knee Braces**
The advantages and disadvantages of knee brace use vary widely in the literature. For every piece of literature found that shows benefits to the use of a knee brace, there is seemingly another just as easily found piece of literature that provides reasoning against the use of a knee brace (particularly with high-school and collegiate athletes).

Some research points to no change in outcomes(no significant advantage or disadvantage) with knee brace use in athletes. Deppen et al found no significant difference in the occurrence of knee injuries among high school football players who did and did not wear a prophylactic knee brace during the game, and also found that when an injury did occur, there was no difference in the severity of injury between the braced and non-braced test groups.

Other findings suggest that there may be some positive attributes from prophylactic knee brace use. Some studies suggest that the use of prophylactic knee braces may be able to provide some improvements in coordination and maximal force production by enhancing proprioception of the knee joint itself. There have also been studies showing that the use of prophylactic knee bracing can help to increase the inherent stability of the knee joint and may play an important role in guarding against injuries resulting from impact in sports. Soheil et al found that prophylactic knee braces provided a moderate (deemed by the authors to be 20-30%) reduction in MCL sprains due to excessive valgus forces from a contact injury. The authors went on to suggest that the very best possible protection for the knee from MCL sprains/injuries would come from a custom metal, dual-upright brace, but went on to say that this would not be a practical solution to decreasing the occurrence of MCL sprains due to the weight and other negative performance attributes associated with this type of brace. [9]

Similar to studies done with prophylactic knee braces, there seems to be some potential advantages to Functional Knee Braces (FKB) as well. Some results suggest that FKB's may help to disperse forces from both GRF and forces from direct impact, as well as help to add further stability to the knee joint. A recent AAOS position paper on the use of knee braces showed that an average of 20-30% increase in ligament protection can be seen with FKB wear. The same paper also showed a similar (20-30%) level of increase in protection against lateral blows to the knee joint that were strong enough to cause gaping of the medial joint line of the knee. [11]

Not all findings have been positive regarding knee brace wear, however. Even with the positive findings they proposed for knee brace use, Deppen et al had notable concerns with potential increases in knee injury occurrences due to improper brace wear, and even went on to state that they could not recommend advocating for the use of prophylactic knee brace use in high school football players after taking into consideration the cost of the braces as well as the negative findings encountered in the study. [7] Other findings have shown that subjects who were not used to wearing a knee brace demonstrated decreases in sport-specific parameters, such as sprinting speeds, which subsequently led to decreases in athletic performance. [8]A high level of non-compliance with brace wear has been seen in individuals who have not experienced an injury (so they're wearing the brace as a preventative measure) for the very reasons stated above -- because they feared that the use of the brace may lead to impaired performance ability. [10] Needless to say, significant problems and potential injury could arise from the implementation of knee braces as a preemptive endeavor to minimize potential injuries if the individual wearing the brace was fearful or not comfortable with their use.

Other studies suggest that there is potential for prophylactic knee brace use to increase the risk and incidence of knee injuries due to alteration of muscle firing and activation, and that there may be a possible increase in muscular fatigue while wearing the brace during exercise due to reduced perfusion of the surrounding musculature from the compression of the brace itself and a subsequent increase in the rate of oxygen consumption. [9] There has even been some evidence showing a significant increase in blood lactate levels in individuals wearing the knee brace during exercise when compared to those who were not wearing a brace. [9]

**__Quick Summary of Advantages and Disadvantages of Knee Brace Use__:** **Advantages** Some notable __positive__ attributes advocating knee brace use that have been found within the literature include the following factors/elements: -potential reduction in MCL sprains from valgus forces resulting from an impact [9] -potential improvements in coordination and maximal force exertion [8] -use of FKB may help disperse GRF and forces due to impact and may help to increase overall stability around the knee joint [10] -up to 20-30% increase in knee ligament protection with FKB wear [11] -up to 20-30% greater protection level against lateral knee blows significant enough to cause medial knee joint gapping [11]

**Disadvantages** Both potential and confirmed __negative__ attributes associated with knee brace use include the following factors/elements: -potential for increased knee injury occurrence due to improper brace wear [7] -potential increase in muscular fatigue while wearing the brace [9] -moderate to significant reduction in maximal knee extension velocity while wearing a knee brace [9] -significantly higher production and accumulation of blood lactate in surrounding knee musculature while wearing brace during exercise as compared to exercise performed without a brace [9] -potential for increased rate of oxygen consumption in individuals wearing a knee brace during exercise [9] -decrease in maximal performance potential in new brace users [8]

**__Closing Remarks on Advantages and Disadvantages of Knee Brace Wear__**

Although some advantages and disadvantages have been shown within the literature regarding knee brace use, the results vary widely and depend largely on numerous different factors, including brace type, individual type (i.e. body type, type of performance, and performance and fitness level of the individual), brace fit and wear, as well as user experience with the brace. [8]

** Discussion/Overview **
Several studies have shown that the use of prophylactic knee braces decreased the incidence of knee injury compared with the control groups of players or subjects that did not wear prophylactic knee braces. Three of these studies, Teitz et al., Sitler et al., and Hansen et al., indicated that 42, 32, and 17 players, respectively, would need to be braced for 1 season to prevent 1 knee injury. Unfortunately, the conclusions from these studies have been confounded by other studies that demonstrated the opposite; prophylactic knee bracing has a harmful effect on knee injuries. These confound studies indicated that if 63, 32, 26, and 32 players were braced for 1 season, 1 knee injury would occur.

The related studies have significant flaws and many threats to internal and external validity. Throughout the studies, there has been no consistency regarding the braces used, positions played, or the injuries reported which causes us to question the external validity and just how we can generalize the results to athletes.

Some authors reported the use of more than one type of brace and included different ligamentous and meniscal injuries when assessing the efficacy of a brace which is designed to prevent collateral ligament knee injuries. By including these types of injuries, the injury rate could have been inflated and by default, not a true representation of how efficacious prophylactic knee braces truly are. [14]

Sitler et al. and Albright et al. stated that the statistically significant lower knee injury rates pertained only to players playing in a defensive or in a “non-skilled” position on the football field. On the other hand, some studies did not evaluate the effect of defensive players and solely looked at offensive lineman or reduced risks in other sports for that matter.

There has also not been consistent inclusion or exclusion criteria. Most of the studies were nonrandomized and did not account for the fact that some subjects in the intervention group had previously injured their knee so they are more susceptible to re-injury. If these athletes were injured, injury rates would increase in the intervention group and may offer an explanation why there were more injuries in the braced group compared to the non braced group.

Although it is unclear whether prophylactic knee braces decrease the risk of injury or not, we cannot disregard the possibility that prophylactic knee bracing may increase the risk of injury. These knee braces have been proven to alter muscle activation, speed, strength, agility, and endurance and have also been said to cause the athlete to become weak and more dependent upon the brace which may be a factor in increasing injury risks. [2]

We can say, however, that due to the Big Ten Football Study made by Anderson et al, the position played (linebacker, linemen, skill) the string (player, nonplayer), and the type of session (games, practices) have a greater impact on the occurrence of knee injury than does the knee brace. [16]

With this said, several publications suggest that a functional knee brace, instead of a prophylactic knee brace, may offer stability to an ACL-deficient knee joint but research is inconclusive regarding the use of prophylactic knee braces in non-injured athletes as previously stated. The AAOS has stated some studies have found prophylactic knee braces can provide at least 20% to 30% greater resistance to a valgus force which reduces the incidence of MCL injuries, but contradicting studies have shown that the incidence of MCL injury was increased while using a prophylactic knee brace. [2] Stephens et al also found that there is an accommodation phase to non injured athletes with knee braces and that once they are “used” to wearing the brace, there is not statistically significant differences between the braced and non-braced conditions.

With the previously mentioned evidence and the inconsistent findings within the literature, we hold the current evidence regarding the efficacy of prophylactic knee bracing in reducing knee injuries inconclusive. Further studies are needed to determine the true efficacy of prophylactic knee braces on ligamentous knee injuries.