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Rebound PCL Course

Rebound® PCL Course

This text-based course is ABC approved for 1.5 CEUs upon successful completion of the online quiz (click button at the bottom of the page) and patient profiler. This may also qualify you for a live course to learn about custom measuring using Össur’s SmartMeasure App, Rebound PCL fitting best practices, and product adjustments. This follow-up course is approved for an additional 1.5 CEUs.

Learning Objectives

After completing the course, learners will demonstrate knowledge regarding PCL injuries, treatment, rehabilitation protocols, and benefits of using the Rebound PCL knee brace by successfully completing the quiz at 80% or better.

Learners will demonstrate proper patient profiling for this brace by successfully completing the patient profiler.


The Rebound PCL is designed to apply a physiologically-correct dynamic force, optimum for rehabilitation of posterior cruciate ligament (PCL) ruptures, whether during functional (non-surgical) treatment or post-surgical reconstruction.

The dynamic load of the Rebound PCL on the tibia is generated by applying an anterior-directed dynamic force on the calf area and opposing counter forces on the anterior aspect of the leg.

Anatomical Considerations

Ligament Anatomy

The two bundles of the PCL complement each other in movement. The posteromedial bundle is stretched in knee extension, and the stronger anterolateral bundle shows higher tension while the knee is in flexion. The anterolateral bundle is the main stabilizer of posterior translation. The Posterior medial bundle also helps to stabilize external rotation. Due to this, the PCL can stabilize the knee with regard to posterior tibial shifting in both extension and knee flexion.

Figure 3.

Figure 3. The relative position and orientation of the subject's knee are reproduced by the knee model during flexion from 0 degrees to 90 degrees (top). The relative motion of the insertion areas of the PCL of the same subject during flexion (bottom). Note the elongation and twisting motion of the PCL with increasing flexion. See below in mm.

Knee Flex (deg) PCL (mm) tolerance (mm)
0 28.70 1.50
30 30.70 1.00
60 33.20 2.40
90 32.90 2.40

Diagnosis of PCL tears

The diagnosis of PCL tears has been traditionally much more difficult than that of ACL tear diagnosis. There are many factors that play into this. The special tests utilized for diagnosis of a PCL tear can oftentimes give the practitioner a false positive or a false negative, especially if they are not experienced in dealing with PCL injuries. The special test used is known as the Posterior Drawer test. This test is conducted by the practitioner by applying a posterior force on the anterior tibia as the knee is in a flexed position. As you may guess, in this position the knee ligaments have to battle gravity to maintain an anatomically neutral position.

As the practitioner is applying this posterior force to the tibia, if the PCL is not fully intact, the leg will be sitting in a slightly posterior position. By applying this test, we are looking for perceived ligament laxity. If gravity is pulling down on the leg, the appearance of laxity may not present. Here is where we have had some misdiagnoses of the injuries in the past. Of course, the use of MRI is considered the gold standard and often used to confirm the findings of a positive test. The awareness of PCL injuries is much higher these days, and the diagnosis of these injuries is on the rise due to this awareness and the innovation of other special tests.

Healing Potential

The PCL, compared to the ACL, has the intrinsic ability to heal and regain continuity after an injury. The PCL is covered by a synovial membrane and has a rich blood supply compared to the ACL, which is important for the treatment of an injured PCL. That supply comes from the medial genicular artery off the large popliteal artery.

Historical treatment of PCL injuries

Often, treatment of PCL injuries in the past has been dependent on the physician and the setting in which they are practicing. It has been historically found that an orthopedic surgeon dealing primarily with athletes has had a relatively low incidence of dealing with PCL trauma, as compared to ACL damage. Conversely, a trauma surgeon practicing in an emergency room may see a higher incidence of PCL trauma, due to the number of high-velocity injuries. Some may say that, in both of these scenarios, we will see an increase in the number of PCL tear diagnoses increasing, as the diagnostics today are much more advanced and continue to improve.

In many settings, it has been reported that the PCL has been diagnosed with a greater amount of partial tears and isolated grade I - II sprains, as compared to the ACL. These partial tears of the PCL have a greater potential of a good outcome, both operative and non-operative. This is believed to be due to the increased vascularity the PCL poses. It is important to maintain the proper positioning of the PCL, in these healing phases, to insure a proper healing of the PCL. This will maintain the correct anatomical length of the PCL and maintain ideal joint laxity in the future.

Following a PCL injury, regardless of whether surgery is called for or not, it is important to maintain a correct anatomical load on the PCL as it heals. This will eliminate the chances of the PCL healing in an elongated position, causing a posterior sag sign, and could potentially lead to the early onset of osteoarthritis in the knee. Looking at the knee, as it is flexed from 0° to 5° of flexion, the force on the PCL is decreased. As the knee continues to flex up to 105° of flexion, the forces increase in a nonlinear nature. Moving up to 120° of flexion, the force decreases in a nonlinear manner.

In a study published by Dr. LaPrade of the Steadman Philippon Research Institute in Vail, CO; he looked at the bracing options for patients suffering a PCL trauma at the time and found that “A properly designed PCL brace should apply correct anatomic joint forces that vary with the knee flexion angle and also provide adjustability to satisfy the demands of various activities. “ In this study, it is suggested that a brace should apply a force that varies with the knee flexion angle and mimic anatomical forces applied by a healthy PCL. There is now a brace that fits these requirements, the Rebound PCL brace by Össur.

Better Outcomes both Surgical and Non-surgical

As mentioned earlier, the PCL has a greater vascularity than that of the ACL. Because of this, it has a greater ability to regenerate on its own. This is a possible reason a physician may find it more beneficial for the patient not to perform reconstructive surgery. There are many factors that can lead the physician to determine the appropriate procedure. If the determination is to allow the PCL to heal on its own, it is very important to ensure that the ligament heals in the appropriate position. This is where the Rebound PCL Brace can be most beneficial. It is designed to keep the PCL in an anatomically-correct position throughout the healing phase to insure a good outcome for the patient. We will discuss the specifics of how this happens in later sections.

If it is deemed necessary for surgery to be performed, the post-operative considerations are just as important as those of the surgical ones. Following a reconstructive procedure, it is equally important to keep the PCL and surrounding structures in an anatomically-correct position to allow them to maintain the same stability of the knee, following surgery, as they had prior to the injury itself.

By providing the correct anatomical positioning of the knee joint, the forces imparted on the ligaments will allow them to heal at the optimum length, thus reducing the laxity of those stabilizing structures. This is with consideration of the early onset of osteoarthritis development of patients following reconstructive ligament surgery.

The rehabilitation process is as critical for a positive outcome as that of the surgery itself. Dr. LaPrade and his colleagues took a look at rehabilitation protocols and found the following:

“A review of peer-reviewed PCL rehabilitation protocols revealed that the treatment of PCL injuries depends on the timing and degree of the injury. Rehabilitation should focus on progressive weight bearing, preventing posterior tibial subluxation and strengthening of the quadriceps muscles. General principles of proper PCL rehabilitation, whether non-operative or postoperative, should include early immobilization (when necessary), prone passive range of motion to prevent placing undue stress on grafts or healing tissue, and progression of rehabilitation based on biomechanical, clinical, and basic science research.”

This illustrates where the Rebound PCL fits into the healing phase of the PCL by limiting the undue stress on the ligament as it heals.

What is the Rebound PCL?

Now let’s take a closer look and examine the brace and give you a better understanding of how it reduces the stress on the PCL. The Rebound PCL brace is designed to apply an anatomically-appropriate dynamic force to the posterior tibia, which reduces stress on a damaged PCL, allowing it to heal properly.

This is accomplished by utilization of a three-point force system applied by the Dynamic Tension System (DTS). This Dynamic Tension System delivers variable force to tibia throughout knee range of motion. As we looked at the varying length and tension of the PCL in earlier graphs, this concept is crucial to a properly healing PCL.

Benefits of Dynamic Loading

By applying a dynamic force to the posterior tibia, it is working against the tension of the hamstrings and that of gravity in order to keep the PCL in its anatomically-correct position. It is known that the PCL is under a greater amount of tension as the knee moves into greater flexion. The PCL continues to lengthen as the knee is flexed up to 105 degrees of flexion. The dynamic nature of the force delivered by the Rebound PCL is allowing the posterior cruciate ligament to function normally. It is merely removing the stress imparted by gravity and surrounding structures as it moves through the healing phases. The anterior force is applied at a level that will not impede on proper healing of other potentially-damaged structures, meaning that if the ACL is damaged, the force applied will not put it in a compromised position that may impair proper healing. This can be said for any structure in the knee that may be healing along with the PCL. The dynamic force is designed to keep all the structures of the knee in anatomically-correct positions.

The dynamic force is delivered by the Dynamic Tensioning System. This system is a spooled wire cable integrated with the hinges of the brace to deliver the dynamic force throughout the range of motion. To set this system in the initial fitting of the brace, there are three sheer knobs that allow the clinician to wind the cable to the appropriate tension for the patient. The sheer knobs give the clinician options based on patient comfort and tolerance to the corrective force. Recommended is the 10lb knob, this is the knob that was found best utilized to deliver an appropriate force to achieve desired outcomes. The 7lb and 4lb knob is available patients of smaller stature or a sensitivity on the shin from the dynamic force on the tibia. These knobs are one time use only and have a breakaway component that prevents the clinician from over tightening the Dynamic Tension System. Multiple sheer knobs of each setting are included with each brace.

Looking at the two images below, you can see the natural force curve of the healthy PCL and, in the second image, the dynamic force delivered by the Rebound PCL Brace, along with a static force brace. Note how closely the Rebound PCL Brace follows the force curve of the PCL, where the static brace’s force only influences the PCL at the beginning of the flexion. This could allow for external forces on the PCL to allow it to heal in a lax position, leading to instability and potential of early onset osteoarthritis.

In another study done by LaPrade, Quantification of functional brace forces for posterior cruciate ligament injuries on the knee joint: an in vivo investigation, the results found:

“During unloaded flexion at the lowest force level setting, the force applied by the DF brace increased as a function of flexion angle (slope = 0.7 N/°; p 0.001) compared to the SF brace effect. Force applied by the SF brace did not significantly change as a function of flexion angle (slope = 0.0 N/°; n.s.). y 45° of flexion, the average force applied by the DF brace (48.1 N) was significantly larger (p 0.001) than the average force applied by the SF brace (25.0 N). The difference in force continued to increase as flexion angle increased. During stair descent, average force (mean ± standard deviation) at toe off was significantly higher (p = 0.013) fo the DF brace (78.7 ± 21.6 N) than the SF brace (37.3 ± 7.2 N). Similar trends were observed for squatting and for the higher force level settings. The Rebound PCL brace applies significantly larger forces at higher knee flexion angles, where the posterior cruciate ligament (PCL) is maximally loaded in vivo, compared to a static PCL brace.”

The conclusion found in this study suggests that “The DF brace applied forces to the posterior proximal tibia that dynamically increased with increased flexion angle. Additionally, the DF brace applied significantly larger forces at higher flexion angles compared to the SF brace where the PCL is known to experience larger in situ forces.”

Clinical studies need to be done to determine if the DF brace will improve long-term results following PCL trauma.

Who Benefits from the Rebound PCL?

It can conservatively be said that any individual experiencing a PCL injury can benefit from this type of bracing. The available data finds the dynamic forces imparted on the tibia to maintain anatomical positioning of the PCL and surrounding structures can be beneficial to good outcome healing of the knee as a whole. This can be said for patients who require surgery or those who are being treated in a conservative manner without the use surgery. The Rebound PCL Brace can be used with patients following isolated PCL trauma or those experiencing combined ligament or structural trauma as found in motor vehicle accidents.

Reimbursement and Billing

This brace, due to its innovative nature, has an L2999 code, which is a miscellaneous code. Össur has an entire team: Össur R&R, who are able to walk the practitioner through the reimbursement process. There are other tools to assist the clinician with proper reimbursement, including a Reimbursement Guide that gives you a step-by-step guide to a successful claim. Generally speaking, this brace reimburses greater than that of a traditional ligament brace. Subscribe to Össur R&R.


The PCL is a complex ligament in and of itself. It has the ability to regenerate itself due to an increased vascularization. This is a reason surgery may not be indicated. Regardless if surgery is needed or not, it is very important to keep the PCL in an anatomically-correct position to allow it to heal at the proper length. This is important to maintain proper overall knee stability and reduce the chances of developing osteoarthritis in the future. The innovative nature of the Rebound PCL will allow your patient to enter the rehabilitation process with little concern of the PCL healing in an elongated position.

Take the Quiz

To finish the online course, and earn 1 CEU, please click the button below to take the Course Quiz.


Pierce CM, O’Brien L, Griffin LW, LaPrade RF. (2013) Posterior cruciate ligament tears: Functional and postoperative rehabilitation. Retrieved from

Jansson KS, Costello KE, O’Brien L, Wijdicks CA, LaPrade RF. (2012, May 24). A historical perspective of PCL bracing. Retrieved from

LaPrade RF, Smith SD, Wilson KJ, Wijdicks CA. (2014, August 22). Quantification of functional brace forces for posterior cruciate ligament injuries on the knee joint: an in vivo investigation. Retrieved from