Orthopedic surgeons have long respected the posterior cruciate ligament (PCL) for its complexity — and occasionally cursed it for the same reason. For years, PCL injuries were the quiet troublemakers of the knee: difficult to diagnose, tricky to reconstruct, and historically associated with outcomes that ranged from mediocre to disappointing.
Fast forward to today, and the story is very different.
In 2026, the Orthopaedic Research Bridging Innovation and Translation (ORBIT) Award recognized Robert F. LaPrade, M.D., Ph.D., and his research team for a body of work that fundamentally reshaped how surgeons diagnose, reconstruct, and rehabilitate PCL injuries.
Over two decades, their research transformed a ligament once considered unreliable to repair into one that can now achieve outcomes comparable to modern anterior cruciate ligament (ACL) reconstruction.
And it all started with a simple question: What if we truly understood the PCL?
The Early Days: When “Fair to Poor” Was the Norm
Twenty-four years ago, PCL reconstruction (PCLR) was often viewed with skepticism. Postoperative stretching, residual laxity, and inconsistent surgical techniques left many patients with persistent instability. Some surgeons even suggested that reconstruction might not be worth attempting at all.
For clinicians who routinely treat knee injuries, that sentiment was frustrating.
Untreated PCL tears are far from benign. They commonly occur in dashboard injuries during car crashes, falls onto a flexed knee, or episodes of hyperextension.
Left untreated, complete PCL deficiency exposes the knee to abnormal kinematics and increased contact pressures in the medial compartment and patellofemoral joint — ultimately increasing the likelihood of degenerative arthritis and even total knee arthroplasty.
The need for better solutions was clear.
Building the “Research Pyramid”
Rather than focusing solely on surgical techniques, Dr. LaPrade’s team took a comprehensive bench-to-bedside approach, building what they describe as a research pyramid.
At the base: defining the quantitative and qualitative anatomy of the PCL. In the middle: clarifying biomechanics and diagnostic methods. At the top: validating the findings through clinical outcomes studies.
This systematic approach ensured that every clinical recommendation rested on a solid scientific foundation.
Finally Pinning Down the Anatomy
For years, PCL anatomy was largely taught using illustrations and general descriptions. While helpful in textbooks, those visuals lacked the precision surgeons need in the operating room.
LaPrade’s team identified several consistent femoral landmarks corresponding to the anatomic positions of the PCL bundles: the trochlear point, the medial arch point, the posterior point.
They also described the bundle ridge, a horizontal bony ridge separating the two functional bundles of the PCL — the anterolateral and posteromedial. Remarkably, the center of the PCL consistently aligned with the center of this ridge.
Rethinking PCL Biomechanics
Historically, the anterolateral bundle was believed to be the primary stabilizer against posterior tibial translation. Consequently, many surgeons reconstructed only this bundle.
But biomechanical and robotic studies conducted by the research team told a different story.
The ALB (anterolateral bundle) and PMB (posterteromedial bundle) were not operating independently — they were codependent stabilizers. Each bundle contributed significantly to knee stability across different flexion angles.
When both bundles were reconstructed using a double-bundle PCLR technique, knee kinematics more closely resembled the native joint.
The team also identified optimal graft fixation angles: ALB fixation at 90° of knee flexion, PMB fixation in full extension.
This approach minimized graft stretching and improved postoperative stability.
Diagnosing the “Hidden” PCL Tear
Anyone who has evaluated a PCL injury knows the challenge: the ligament can look perfectly intact on standard imaging while the knee exam tells a different story.
LaPrade’s team emphasized the importance of stress radiographs and MRI to objectively identify posterior tibial translation.
Their research demonstrated that the tibia often slips backward within the medial compartment — even when the PCL appears structurally intact on imaging. These findings helped radiologists and surgeons alike move beyond simply asking whether the ligament looks normal, and instead evaluate whether it functions normally.
Rehab: When Gravity Becomes the Enemy
When a patient with a PCL tear lies on their back with the knee flexed to 90 degrees, gravity causes the tibia to sag posteriorly. This seemingly harmless position can place unwanted stress on a healing ligament or graft.
The team adjusted rehabilitation protocols to account for this phenomenon by emphasizing prone knee flexion exercises — performed while lying on the stomach. In this position, gravity actually helps maintain proper tibial alignment rather than working against it.
The Rise of the Dynamic PCL Brace
Recognizing that mechanical support could further improve healing, the researchers collaborated with industry partners to design a dynamic PCL brace.
Unlike traditional braces, this device applies pressure to the calf when the knee flexes, pushing the tibia forward and mimicking the native function of the PCL.
The result? Reduced stress on the healing ligament, less graft stretching, and in some cases, successful nonoperative healing of PCL injuries.
The Next Frontier
The research team’s next focus is evaluating earlier weightbearing after PCL reconstruction, exploring whether patients can safely begin weightbearing before the traditional six-week postoperative window.