Skip to content

Patients › Knee

Chấn thương dây chằng chéo sau

Updated Sep 2026
Illustration: knee

Trang này được dịch bằng máy và chưa được bác sĩ kiểm tra. Bản tiếng Anh là bản chính thức.

Những triệu chứng bạn đang gặp phải

Chấn thương dây chằng chéo sau xảy ra khi dây chằng nằm phía sau đầu gối bị giãn hoặc rách. Tình trạng này thường xuất hiện do va chạm vào phía trước xương chày, ví dụ như đầu gối đập vào bảng điều khiển ô tô, hoặc do ngã khi đầu gối đã gập và các ngón chân hướng xuống dưới. Các chấn thương thể thao liên quan đến dây chằng này thường do tác động trực tiếp hoặc lực từ bên ngoài gây ra, chứ không phải do các động tác xoay vặn hay giảm tốc khiến các dây chằng khác ở đầu gối bị tổn thương.

Hầu hết những người bị chấn thương này đều cảm thấy đau, sưng và cứng khớp gối. Khác với một số chấn thương dây chằng đầu gối khác, lúc bị thương bạn có thể không nghe thấy tiếng “pop” phát ra, và đầu gối cũng có thể không hề cảm thấy mất ổn định. Cơn đau thường xuất hiện ở phía trước đầu gối, quanh xương bánh chè, hoặc dọc theo mặt trong hoặc phía sau đầu gối. Cơn đau thường tăng lên khi bạn đi lên hoặc xuống dốc. Các hoạt động hàng ngày gây áp lực lên phía trước đầu gối, chẳng hạn như leo cầu thang hoặc ngồi dậy từ ghế thấp, cũng có thể gây khó chịu. Một số người nhận thấy có máu chảy vào khớp ngay sau khi bị thương, khiến đầu gối sưng lên và cảm giác căng cứng.

Trong trường hợp chấn thương đã xảy ra từ lâu hoặc ảnh hưởng đến các bộ phận khác của đầu gối, các triệu chứng có thể thay đổi. Một số người hầu như không cảm thấy gì, trong khi những người khác lại cảm thấy đầu gối bị khuỵu, đặc biệt nếu mặt ngoài đầu gối cũng bị tổn thương hoặc nếu đôi chân của bạn có xu hướng cong ra ngoài tự nhiên. Theo thời gian, khớp xương bánh chè và vùng mặt trong đầu gối có thể bị viêm khớp do hao mòn; vì vậy tình trạng đau kéo dài ở những vùng này là điều đáng chú ý.

Điều gì đang thực sự xảy ra

Bên trong đầu gối, có hai dây chằng chắc khỏe chéo qua nhau ở giữa khớp. Dây chằng nằm phía sau được gọi là dây chằng chéo sau, hay PCL. Có thể hình dung nó như một sợi dây thừng dày, có chức năng ngăn không cho xương chày trượt ngược về phía sau so với xương đùi. Dây chằng này hoạt động ở mọi góc độ của đầu gối, dù là khi duỗi thẳng hay gập lại; nó cũng giúp ổn định khớp đầu gối trước các lực tác động sang bên hoặc làm xoay khớp.

Thực ra, PCL gồm hai phần phối hợp với nhau. Một phần trở nên căng khi đầu gối gập lại, phần còn lại căng lên khi đầu gối duỗi thẳng. Khi dây chằng bị kéo giãn hoặc rách, một hoặc cả hai phần này mất khả năng hoạt động; vì vậy xương chày có thể dịch chuyển ngược về phía sau nhiều hơn mức bình thường. Tình trạng lỏng lẻo này, cùng với áp lực gia tăng lên các vùng phía trước và bên trong đầu gối, là nguyên nhân gây ra cơn đau và cứng khớp mà bạn đã đọc ở trên.

Các bác sĩ đánh giá mức độ tổn thương của dây chằng bằng cách phân loại. Mức độ nhẹ nghĩa là dây chằng bị kéo giãn nhưng vẫn còn kết nối, giống như sợi dây có vài sợi bị sờn ra. Mức độ trung bình có nghĩa là dây chằng bị rách một phần và trở nên lỏng hơn bình thường. Mức độ nặng nghĩa là dây chằng bị đứt hoàn toàn, nên không còn giữ được xương chày ở đúng vị trí nữa. Các chấn thương nhẹ và vừa thường tự lành mà không cần phẫu thuật, đặc biệt nếu các bộ phận khác của khớp đầu gối vẫn bình thường. Ngược lại, trường hợp dây chằng bị đứt hoàn toàn hoặc có tổn thương kèm theo các dây chằng khác, thậm chí cả góc ngoài của khớp, thì nhiều khả năng cần phẫu thuật hơn.

Cần lưu ý rằng dây chằng này dày và chắc khỏe hơn so với dây chằng nổi tiếng nằm phía trước đầu gối; vì vậy để gây tổn thương cho nó thường cần một lực tác động mạnh. Đây cũng là lý do khiến các chấn thương này thường đi kèm với tổn thương ở các bộ phận khác của khớp, và vì thế bác sĩ phẫu thuật sẽ kiểm tra toàn bộ khớp một cách kỹ lưỡng trước khi quyết định phương pháp điều trị phù hợp cho bạn.

Những gì chúng tôi có thể làm

Hầu hết các chấn thương nhẹ và vừa đều tự lành mà không cần phẫu thuật. Chúng tôi bắt đầu bằng việc vật lý trị liệu nhằm tăng cường sức mạnh cho cơ tứ đầu ở phía trước đùi – cơ này giữ xương chày ra phía trước và ngăn nó bị xệ về phía sau, vốn là vấn đề chính khi dây chằng này bị lỏng. Việc sử dụng nẹp đặc biệt cũng giúp giữ xương ở đúng vị trí. Đối với các chấn thương nhẹ hoặc vừa, hầu hết bệnh nhân có thể trở lại tập luyện thể thao sau 2–4 tuần. Trường hợp dây chằng bị đứt hoàn toàn mà không phẫu thuật, bệnh nhân thường phải giữ khớp gối thẳng trong nẹp hoặc bó bột trong 4 tuần, sau đó mới bắt đầu các bài tập tăng cường sức mạnh. Với việc thực hiện đều đặn các bài tập cơ tứ đầu, 80% trường hợp chấn thương này đạt kết quả tốt mà không cần phẫu thuật.

Phẫu thuật được cân nhắc khi dây chằng bị đứt hoàn toàn và khớp gối vẫn đau hoặc mất ổn định, hoặc khi các dây chằng khác cũng bị tổn thương cùng lúc. Nếu có nhiều dây chằng bị đứt, chúng tôi thường khuyến nghị phẫu thuật sớm thay vì chờ đợi. Trong ca phẫu thuật, dây chằng bị đứt sẽ được thay thế bằng một mảnh mô mới gọi là “mảnh ghép”, nhờ đó xương chày lại được giữ vững ở vị trí đúng. Nếu có mảnh xương bị tách ra cùng với dây chằng, chúng tôi cũng có thể cố định lại mảnh xương đó. Chúng tôi sẽ trình bày chi tiết về quy trình phẫu thuật trên một trang riêng, và bạn cùng chúng tôi sẽ cùng quyết định xem phương pháp này có phù hợp với mình hay không.

Những điều có thể mong đợi

Đối với các chấn thương nhẹ hoặc vừa, tiên lượng thường ổn định. Nhờ các bài tập tăng cường sức mạnh và việc sử dụng nẹp hỗ trợ khi cần thiết, cơn đau và sưng thường giảm dần trong vài tuần chứ không phải vài tháng; nhiều người có thể quay lại tập luyện thể thao nhanh chóng. Kết quả lâu dài ở những trường hợp không phẫu thuật cho thấy bệnh nhân vẫn duy trì hoạt động, với sức mạnh tốt và biên độ vận động khớp gối đầy đủ. Ngay cả khi khớp gối vẫn còn hơi lỏng lẻo, điều đó cũng không nhất thiết gây ra vấn đề gì; một số người vẫn không gặp bất kỳ khó khăn chức năng nào dù có tình trạng lỏng lẻo kéo dài.

Tuy nhiên, với trường hợp đứt hoàn toàn dây chằng thì lại khác. Nếu không được điều trị, dây chằng đã đứt hoàn toàn sẽ không tự liền lại, và tình trạng lỏng lẻo khớp gối sẽ tiếp diễn. Theo thời gian, sự vận động thừa này có thể gây áp lực lên các vùng phía trước và bên trong khớp gối, dẫn đến viêm khớp do thoái hóa; vì vậy cơn đau kéo dài ở vùng này là điều đáng lưu ý. Ở trẻ em, việc trì hoãn phẫu thuật quá lâu làm tăng nguy cơ tổn thương sụn đệm ở khớp gối, từ đó dẫn đến kết quả lâu dài không tốt.

Nếu bạn thực sự cần phẫu thuật, việc hiểu rõ những gì phẫu thuật có thể và không thể khắc phục là rất quan trọng. Việc thay thế dây chằng giúp cải thiện cảm giác ở khớp gối và tăng khả năng trở lại tập luyện thể thao. Trong các ca chấn thương có nhiều dây chằng bị đứt, tất cả bệnh nhân đều có dây chằng ổn định trong lần kiểm tra gần nhất; trong đó 77% không còn tình trạng lỏng lẻo nào. Đối với trường hợp chỉ đứt một dây chằng hoàn toàn, kết quả khá tốt nhưng chưa hoàn hảo: dây chằng trở lại trạng thái ổn định hoàn toàn ở khoảng một nửa số khớp gối, trong khi một số khác vẫn còn hơi lỏng lẻo ở mức độ nhẹ hoặc vừa. Các chấn thương phức tạp liên quan đến góc ngoài khớp gối thường có kết quả kém hơn so với các chấn thương chỉ ảnh hưởng đến một dây chằng; nhìn chung kết quả phẫu thuật cũng không đạt mức tương tự như khi phẫu thuật sửa chữa dây chằng phía trước khớp gối. Trong vòng 2 năm đầu sau phẫu thuật, tỷ lệ thất bại là tương đương nhau dù chỉ sửa chữa một dây chằng hay nhiều dây chằng. Hầu hết bệnh nhân vẫn giữ được cảm giác nhận biết vị trí khớp gối trong không gian; cả điểm số đánh giá khớp gối lẫn mức độ lỏng lẻo đều có cải thiện sau phẫu thuật.

Khi nào nên gặp bác sĩ

Hãy đến gặp bác sĩ đa khoa nếu bạn bị đau đầu gối, sưng hoặc cứng khớp sau khi bị va đập vào phía trước xương chày hoặc ngã khi đầu gối đang gập; đặc biệt là khi đầu gối sưng nhanh và cảm giác căng cứng do máu tụ trong khớp. Hãy yêu cầu được chuyên gia thăm khám nếu cơn đau ở phía trước, bên trong hoặc phía sau đầu gối vẫn tiếp diễn khi bạn đi lên dốc hoặc bậc thang; hoặc nếu đầu gối bắt đầu có cảm giác lỏng lẻo hoặc bị khuỵu, điều này thường xảy ra khi các bộ phận khác của khớp gối cũng bị chấn thương. Hãy đến phòng cấp cứu ngay lập tức nếu đầu gối bị trật khớp, hoặc nếu nhiều dây chằng bị rách do ngã hoặc tai nạn; vì các mạch máu và dây thần kinh phía sau đầu gối có thể bị tổn thương và cần được kiểm tra ngay trong ngày. Nếu bạn đã từng phẫu thuật tái tạo dây chằng và hiện tại đầu gối bị nóng, đỏ, sưng và sốt, thì cũng cần được đánh giá khẩn cấp.


Evidence & references

This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.

Anatomy & Pathophysiology

Bony Anatomy & Ligament Structure

  • The PCL is stronger than the ACL [6].
  • The PCL has a broader femoral attachment than the ACL [6].
  • The PCL is an intrasynovial but extraarticular structure [7].
  • The PCL has an extrasynovial location, which provides better healing potential [6].
  • The PCL is composed of two major parts: a large anterolateral bundle (ALB) and a smaller posteromedial bundle (PMB) [7].
  • The ALB forms the bulk of the ligament [7].
  • The PMB runs obliquely to the back of the tibia [7].
  • The PCL cross-sectional area increases from tibia to femur [7].
  • The PCL is approximately 50% larger than the ACL at the femur [7].
  • The PCL is approximately 20% larger than the ACL at the tibia [7].
  • The meniscofemoral ligaments average approximately 22% of the entire cross-sectional area of the PCL [7].
  • The PCL insertion sites are 300% to 500% larger than the cross section of the midsubstance [7].
  • The femoral insertion of the PCL extends more than 20 mm from anterior to posterior [6].
  • The ALB is more vertical than the PMB and inserts on the anterior roof of the intercondylar notch [6].
  • The PMB is more oblique and inserts posteriorly on the lateral wall of the medial femoral condyle [6].
  • The PCL and meniscofemoral ligaments cover almost all of the medial aspect of the intercondylar notch anterior to the medial intercondylar ridge [6].
  • The anterior margin of the PCL is 2 mm from the articular cartilage [6].
  • The bundle centers of the PCL are an average of 12 mm apart on the femur [6].
  • The tibial insertion of the PCL is narrower than the femoral insertion [6].
  • The tibial insertion is located in the posterior intercondylar fossa of the proximal tibia [6].
  • The PCL tibial footprint extends from the medial meniscus root and the edge of the lateral plateau articular cartilage to a point 1 to 1.5 cm below the joint line [6].
  • The most posterior distal fibers of the PCL consist of the thicker PMB [6].
  • The PMB blends with the periosteum and posterior capsule to insert distal to the osseous ridge cradling the anterior proximal fibers of the ALB [6].
  • The centers of the PCL bundles on the tibia are an average of 9 mm apart [6].
  • The tibial attachment is in a depression 1.0 to 1.5 cm behind and below the intraarticular portion of the tibia [7].
  • The tibial attachment slips usually blend with the posterior horn of the lateral meniscus, the meniscofemoral ligaments of Humphrey and Wrisberg [7].
  • The center of the femoral insertion of the ALB is 7.4 mm from the trochlear point [7].
  • The center of the femoral insertion of the ALB is 11.0 mm from the medial arch point [7].
  • The center of the femoral insertion of the ALB is 7.9 mm from the distal articular cartilage [7].
  • The center of the tibial attachment site is 6.1 mm from the shiny white fibers of the posterior medial meniscus root [7].
  • The center of the tibial attachment site is 4.9 mm from the bundle ridge [7].
  • The center of the tibial attachment site is 10.7 mm from the “champagne glass” drop-off [7].
  • The bundle ridge is horizontal and separates the ALB from the PMB [7].
  • The ALB is bordered medially and posteriorly by the PMB [7].
  • At its femoral insertion, the PMB is bordered by the medial intercondylar ridge proximally, the ALB anteriorly, and the anterior meniscofemoral ligament distally [7].
  • The center of the PMB femoral attachment is 11.1 mm from the medial arch point [7].
  • The center of the PMB femoral attachment is 10.8 mm from the posterior point of the articular cartilage margin [7].
  • The tibial attachment of the PMB is more compact than the ALB [7].
  • The PMB fans out in its attachment border along the posteromedial aspect of the ALB [7].
  • The thickest portion of the PMB, including the functional center of the bundle, is located posteromedial to the ALB [7].
  • The functional center of the PMB is 3.1 mm lateral from the medial groove of the medial tibial plateau articular surface [7].
  • The functional center of the PMB is 4.4 mm anterior to the champagne glass drop-off [7].
  • The PCL originates on the posteromedial aspect of the intercondylar notch and inserts into the posterior sulcus of the tibia between the medial and lateral joint surfaces [9].

Biomechanics & Function

  • The primary function of the PCL is to resist posterior displacement of the tibia in all knee flexion angles [6].
  • The PCL is a secondary varus, valgus, and rotational stabilizer [6].
  • The PCL facilitates internal rotation of the tibia at higher flexion angles [6].
  • The ALB carries more load in flexion [6].
  • The PMB carries more load in extension [6].
  • The anterolateral fibers are taut in flexion [9].
  • The posteromedial fibers are taut in extension [9].
  • With flexion, there is tightening of the bulk of the ligament (ALB) but less tension on the small band (PMB) [7].
  • The PCL is associated with the meniscofemoral ligaments of Humphrey (anterior) and Wrisberg (posterior) [6].
  • The PCL is the primary restraint to posterior tibial translation in the intact knee [1].

Mechanism of Injury

  • A direct blow to the proximal aspect of the tibia is the most common cause of PCL injury [1].
  • In athletes, the mechanism of injury is usually a fall onto the flexed knee with the foot plantarflexed [1].
  • This athletic mechanism places a posterior force on the tibia and subsequently causes rupture of the PCL [1].
  • In high-energy trauma such as motor vehicle accidents, the PCL is often injured with other capsuloligamentous structures [1].
  • The most common mechanisms of injury are a direct blow to the anterior tibia with the knee flexed or a fall into the ground with the foot plantar flexed [3].
  • The “dashboard” injury involves the anterior tibia sustaining a posteriorly directed force from the dashboard with the knee in 90 degrees of flexion [3].
  • Sports injuries to the PCL result from an outside force or blow, in contrast to the typical deceleration twisting mechanism of ACL injuries [3].
  • The most common mechanism for isolated PCL injury in the athlete is a partial tear associated with hyperflexion of the knee [3].
  • Significant multiligamentous knee injuries with PCL tears can occur after a varus or valgus stress is applied to the hyperextended knee [3].
  • PCL injury usually occurs from a motor vehicle accident (dashboard injury) or during athletic activities [9].
  • In athletic injuries, the typical mechanism is a fall onto a flexed knee while the foot is in a plantar flexed position [9].
  • A direct blow to the anterior aspect of the tibia while the knee is flexed may result in a tear of the PCL [9].
  • PCL injuries are associated with more severe traumas that cause a knee dislocation or a multi-ligamentous injury including a posterolateral corner injury [9].

Associated Injuries & Pathology

  • Injuries to the PCL may be isolated or combined with other capsuloligamentous injuries in the knee [1].
  • When three or more ligamentous structures are injured, the injury should be viewed as a dislocated knee and the vascular status of the injured limb should be assessed [1].
  • Injury to the posterolateral structures has been reported to occur in up to 60% of PCL injuries [3].
  • Concomitant injuries are common with PCL injury, including posterolateral corner and meniscus injuries [3].
  • The natural history of certain PCL injuries, especially combined ones, will progress to instability, pain, and osteoarthritis of the knee [1].
  • This progression to osteoarthritis is especially noted in the patellofemoral and medial tibiofemoral compartments [1].
  • Patients with significant varus alignment or injury to the lateral structures of the knee will often complain of feelings of instability and giving way [3].
  • In contrast to an ACL tear, it is rare for patients with PCL injuries to report hearing a “pop” or report any feelings of subjective instability [3].
  • Patients with PCL injuries more commonly complain of knee pain, swelling, and stiffness [3].
  • The presentation of a subacute or chronically injured PCL can range from asymptomatic to significant instability and pain [3].
  • Specific cues to PCL injury on initial inspection include abrasions or ecchymosis around the proximal anterior tibia and ecchymosis in the popliteal fossa [3].
  • Subtle posterior subluxation on the lateral radiograph may indicate PCL injury [3].
  • In the chronic setting of PCL injury, radiographs are useful to assess for patellofemoral and medial compartment degenerative changes [3].

Classification

  • PCL injuries occur in isolation or in combination with other injuries [1].
  • The grades of PCL injuries are based on physical examination and MRI findings [1].
  • A partial PCL injury is characterized by posterior tibial translation of less than 10 mm on the posterior drawer test with the knee in neutral rotation [1].
  • A partial PCL injury is characterized by the presence of an end point on the posterior drawer test [1].
  • A complete isolated PCL injury is characterized by posterior tibial translation of 8–10 mm on the posterior drawer test with the knee in neutral rotation [1].
  • In a complete isolated PCL injury, posterior tibial translation is diminished with the knee in internal rotation [1].
  • A combined PCL and capsuloligamentous injury is characterized by posterior tibial translation greater than 10 mm on the posterior drawer test with the knee in neutral rotation [1].
  • In a combined PCL and capsuloligamentous injury, the PCL is injured in conjunction with other structures such as the ACL, posterolateral corner, or medial side [1].
  • A grade I PCL injury is defined by a step-off of less than 1 cm between the tibial plateau and femoral condyle at 90° of flexion, with the tibial plateau remaining anterior to the femoral condyle [1].
  • A grade II PCL injury is defined by the tibial plateau being flush with the femoral condyle at 90° of flexion [1].
  • A grade III PCL injury is defined by the tibial plateau being posterior to the femoral condyle at 90° of flexion [1].
  • A grade I PCL injury on the posterior drawer test is defined by 3 to 5 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • A grade II PCL injury on the posterior drawer test is defined by 6 to 10 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • A grade III PCL injury on the posterior drawer test is defined by greater than 10 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • The degree of posterior tibial translation may decrease with internal tibial rotation in partial tears [1].
  • A combined PCL and capsuloligamentous injury is indicated by more than 15 mm of posterior translation with the knee at 90° and in neutral rotation [1].
  • A combined PCL and capsuloligamentous injury is indicated by more than 10 mm of posterior translation with the knee in internal rotation [1].

Clinical Presentation

History and Mechanism of Injury

  • In athletes, the mechanism of injury is usually a fall onto the flexed knee with the foot plantarflexed, which places a posterior force on the tibia [1].
  • The "dashboard" injury involves a posteriorly directed force to the anterior tibia with the knee in 90 degrees of flexion [3].
  • Sports injuries to the PCL result from an outside force or blow, contrasting with the typical deceleration twisting mechanism of ACL injuries [3].
  • Significant multiligamentous knee injuries with PCL tears can occur after varus or valgus stress is applied to the hyperextended knee [3].
  • It is rare for patients with PCL injuries to report hearing a “pop” or report feelings of subjective instability [3].
  • Patients with PCL injuries commonly complain of knee pain, swelling, and stiffness [3].
  • Patients with significant varus alignment or injury to the lateral structures of the knee often complain of feelings of instability and giving way [3].
  • An isolated PCL injury may be less obvious than a combined injury because instability is often subtle or even asymptomatic [1].

Physical Examination

  • The posterior drawer test is the primary dynamic test to diagnose a PCL injury [1].
  • The posterior drawer test is performed with the knee flexed to 90 degrees and a posteriorly directed force applied to the anterior tibia [3].
  • In a grade I PCL injury, the step-off between the tibial plateau and femoral condyle is < 1 cm but the tibial plateau remains anterior to the femoral condyle [1].
  • In a grade II PCL injury, the tibial plateau is flush with the femoral condyle [1].
  • In a grade III PCL injury, the tibial plateau is posterior to the femoral condyle [1].
  • A grade I injury on posterior drawer test is defined as 3 to 5 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • A grade II injury on posterior drawer test is defined as 6 to 10 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • A grade III injury on posterior drawer test is defined as >10 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • The quadriceps-active test is positive when the tibia translates anteriorly at 90° of flexion with resisted knee extension [1].
  • The posterior sag or Godfrey test involves flexing the knee and hip and noting the posterior pull of gravity creating posterior “sag” of the tibia on the femur [3].
  • An adjunct to the posterior sag test involves watching for a reduction of subluxation with active quadriceps contraction [3].
  • The reverse pivot shift test is performed by placing a valgus stress on the knee with the foot externally rotated and extending from 90 degrees of flexion [3].
  • A palpable reduction of the posterolateral tibial plateau is noted between 20 and 30 degrees of flexion during the reverse pivot shift test [3].
  • Evaluation of ACL laxity in the presence of an acute PCL injury is challenging due to the lack of a stable reference point for Lachman or anterior drawer tests [3].

Imaging

  • Plain radiographs are important initially to rule out fractures and avulsions [1].
  • Plain radiographs are essential to evaluate for bony injuries, dislocation, or evidence of other associated injuries given the magnitude of forces required to injure the PCL [3].
  • Stress posterior drawer radiographs and contralateral comparisons may increase the sensitivity for detecting PCL injuries with plain radiographs [3].
  • MRI has been shown to have a very high sensitivity and specificity in diagnosing a PCL injury [1].
  • MRI has been reported to be 96–100% sensitive at diagnosing PCL tears [3].
  • MRI helps determine the site and degree of injury by assessing the continuity of the PCL [1].
  • MRI may indicate the presence of other meniscal, chondral, or ligamentous injuries which may influence treatment strategies [1].
  • MRI is valuable in detecting associated injuries, particularly posterolateral corner injuries that can be missed on initial clinical examination [3].
  • In multiligamentous knee injuries, MRI can be used to assess the ACL as clinical examination of the ACL is challenging in the setting of a complete PCL tear [3].

Investigations

History and Mechanism

  • The history of injury helps differentiate between high- and low-energy traumas [1].
  • Concurrent injuries such as knee dislocation, neurovascular injury, and additional ligamentous or skeletal injuries assist in the evaluation [1].
  • Patients with PCL injuries rarely report hearing a "pop" or feelings of subjective instability, unlike ACL tears [3].
  • Sports injuries to the PCL result from an outside force or blow, contrasting with the deceleration twisting mechanism of ACL injuries [3].

Physical Examination

  • The physical examination is specific for PCL injury and is classified based on the degree of injury [1].
  • At 90° of flexion, there is normally a 1-cm step-off between the tibial plateau and femoral condyle [1].
  • In a grade I injury, the step-off is < 1 cm but the tibial plateau remains anterior to the femoral condyle [1].
  • In a grade II injury, the tibial plateau is flush with the femoral condyle [1].
  • In a grade III injury, the tibial plateau is posterior to the femoral condyle [1].
  • The posterior drawer test is the primary dynamic test to diagnose PCL injury [1].
  • Grade I PCL injury on posterior drawer test is defined as 3 to 5 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • Grade II PCL injury on posterior drawer test is defined as 6 to 10 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • Grade III PCL injury on posterior drawer test is defined as >10 mm of increased posterior tibial translation compared with the uninvolved knee at 90° of flexion [1].
  • The Lachman test for ACL injury, varus and valgus laxity testing, and assessment of external and internal tibial rotation differences are critical in differentiating between isolated and combined injuries [1].
  • An adjunct to the posterior sag test involves watching for a reduction of this subluxation with active quadriceps contraction [3].
  • The reverse pivot shift is performed by placing a valgus stress on the knee with the foot externally rotated and extending from 90 degrees of flexion, noting a palpable reduction of the posterolateral tibial plateau between 20 and 30 degrees of flexion [3].
  • The accuracy, sensitivity, and specificity of clinical examination findings for PCL injury are greater than 90% [14].
  • In a simplified grading system, a grade A injury presents with a slight loss of anterior tibial offset at 90° of flexion [14].
  • In a simplified grading system, a grade B injury presents with the tibia flush with the femoral condyles at 90° of flexion [14].
  • In a simplified grading system, a grade C injury presents with tibial displacement posterior to the femoral condyles at 90° of flexion [14].
  • Grades A, B, and C injuries correlate with grades I, II, and III injuries when considering treatment options and outcomes [14].

Imaging

  • Radiographs can reveal PCL tibial avulsion injury, capsular avulsion, or associated fracture as well as posterior resting position and subluxation of the tibia [14].
  • Stress radiographs can be used to assess PCL disruption [14].
  • MRI complements the history and physical examination and helps determine the site and degree of injury by assessing the continuity of the PCL [1].
  • MRI is extremely valuable in its ability to detect associated injuries, particularly posterolateral corner injuries which can often be missed on initial clinical examination [3].
  • MRI is used to determine the location and severity of PCL disruption and shows concomitant meniscal, osteochondral, chondral, and ligament injuries [14].
  • If grade III posterior tibial laxity is present and radiographs show more than 10 mm of posterior subluxation, a combined PCL and posterolateral corner injury should be suspected [14].

Treatment

Nonsurgical

  • Nonsurgical treatment is reserved for isolated partial PCL injuries with <10 mm of increased posterior tibial translation [1].
  • Conservative management for PCL injuries focuses on quadriceps strengthening to prevent posterior tibial sag [17].
  • Return to sports is usually achieved in 2 to 4 weeks for grade I–II PCL injuries [17].
  • Treatment for grade III PCL injuries includes relative immobilization in extension for 4 weeks [17].
  • Special braces have been designed to prevent posterior sag in PCL injuries [17].
  • Chronic PCL deficiency can lead to increased contact pressures in the patellofemoral and medial compartment of the knee [17].
  • Nonsurgical treatment is recommended for patients with an isolated grade I or II PCL injury [19].
  • The nonsurgical program for isolated grade I or II PCL injuries includes extension bracing treatment, protected weight bearing, and quadriceps strengthening rehabilitation [19].
  • Two natural history studies of nonsurgically treated isolated grade I or II PCL injuries found good subjective and objective outcomes with no functional deterioration [19].
  • Two natural history studies of nonsurgically treated isolated grade I or II PCL injuries found 97% quadriceps and 93% hamstring strength [19].
  • A 7-year follow-up study reported that 92% of patients with grade I or II PCL injuries had a good to excellent result after nonsurgical management based on the Tegner Activity Level Scale and Lysholm-II Knee Questionnaire scores [19].
  • Shelbourne and Muthukaruppan reported good clinical outcomes when partial PCL injuries with 1+ to 2+ posterior laxity were treated conservatively initially [18].
  • Conservative treatment for partial PCL injuries consists of knee extension and a protective rehabilitation program with no active hamstring strengthening [18].
  • Long-term results for conservatively treated isolated PCL injuries did not correlate with the initial degree of instability [18].
  • Subjective scores for conservatively treated isolated PCL injuries did not deteriorate with time [18].

Surgical Indications

  • Surgical treatment is indicated in patients with symptomatic isolated PCL tears [17].
  • Surgical treatment is indicated in patients with PCL avulsion fractures [17].
  • Surgical treatment is indicated in the setting of a multiligament injured knee [17].
  • Surgical treatment is recommended for a chronic grade III PCL lesion if the patient is symptomatic [19].
  • PCL injuries with 3+ laxity (≥ 8 mm on stress radiographs) are reconstructed [18].
  • Symptomatic PCL injuries are reconstructed [18].

Surgical Techniques

  • Primary repair or open reduction and internal fixation is performed for PCL avulsion injuries [17].
  • Reconstruction is performed for PCL injuries other than avulsion injuries [17].
  • Options for PCL reconstruction include tibial inlay versus transtibial, single-bundle versus double-bundle, and autograft versus allograft [17].
  • The tibial inlay technique theoretically reduces the “killer turn” between the posterior border of the tibial plateau and the graft [17].
  • The reduction of the “killer turn” by the tibial inlay technique may decrease failure rates [17].
  • Double-bundle PCL reconstruction is theoretically stronger than single-bundle reconstruction [17].
  • Double-bundle PCL reconstruction may be beneficial in the revision setting or with multiple ligament reconstruction [17].
  • There has been no evidence to suggest one PCL reconstruction technique is superior over another [17].
  • The results of PCL reconstruction are less favorable than primary repair of avulsion fractures as residual posterior laxity often exists [17].
  • An osteotomy should be considered in the setting of malalignment for PCL injuries [17].
  • A high tibial osteotomy can treat varus malalignment as well as increase tibial slope to help reduce posterior tibial sag [17].
  • Avulsion of the PCL usually occurs at the femoral attachment and can be repaired using suture anchors or femoral bone tunnels [19].
  • Large osseous avulsion fragments from the tibial attachment can be repaired with open reduction and screw-and-washer fixation [19].
  • The tibial inlay technique is usually performed through an open posterior approach [19].
  • In the tibial inlay technique, the bone block is recessed and fixed with an interference screw at the posterior tibia, ensuring to avoid graft protrusion [19].
  • Advantages of the tibial inlay technique include osseous graft healing, avoidance of so-called killer turn stresses, decreased graft wear, and improved graft biomechanics [19].
  • An arthroscopic inlay technique using suture button fixation over the tibial-side bone block has been described as combining the advantages of arthroscopic and inlay techniques [19].
  • In the transtibial technique, the tibial tunnel is reamed from anterior to posterior through the tibia under direct arthroscopic and fluoroscopic visualization [19].
  • The tibial footprint for the transtibial technique is approximately 7 mm anterior to the posterior tibial cortex as seen on a perfect lateral image [19].
  • Cadaver biomechanical data revealed no difference between transtibial and tibial inlay techniques when grafts were appropriately pretensioned before insertion [19].
  • Multiple studies report no difference in functional, radiographic, or clinical outcomes between transtibial and tibial inlay techniques [19].
  • Multiple studies report no difference in functional, radiographic, or clinical outcomes between arthroscopic and open PCL reconstruction techniques [19].
  • Biomechanical comparison studies concluded that double-bundle PCL reconstruction is preferable for decreasing posterior tibial translation and improving rotational restraint [19].
  • Biomechanical advantages of double-bundle PCL reconstruction were not correlated with superior clinical outcomes [19].
  • Isolated single-bundle PCL reconstruction yields good long-term results without functional differences in comparison with double-bundle reconstruction [19].
  • Double-bundle reconstructions have gained favor with many surgeons, but anatomic single-bundle techniques have good results similar to those for transtibial and inlay techniques [18].
  • The two-tunnel technique has been shown in clinical studies to have increased stability and to better fill the large PCL footprint [18].
  • The single-tunnel technique is used mostly for reconstruction of multiple knee ligaments in knee dislocations [18].
  • The two-tunnel technique is used primarily in isolated PCL reconstruction [18].
  • An Achilles tendon allograft is the preferred graft source for PCL reconstruction in the described protocol [18].
  • Comparable results have been reported with allografts and autografts for PCL reconstruction [18].
  • An all-arthroscopic inlay procedure using a retrocutting reamer and a closed-ended tibial tunnel with suture fixation anteriorly produces a shorter, stiffer graft construct [18].
  • The all-arthroscopic inlay procedure removes the “killer curve” that sometimes occurs in the transtibial technique, although a killer curve still remains on the femoral side [18].
  • Comparative studies show that anatomic single-tunnel and inlay procedures produce equal function and stability [18].
  • Double-bundle PCL techniques have been shown to be slightly better than single-bundle techniques with 2.5 mm of posterior displacement compared with 3.2 mm [18].
  • Double-bundle PCL techniques have been shown to have better IKDC scores in most studies [18].
  • The most important factors for long-term success in PCL reconstruction are correction of associated instabilities and meniscal preservation [18].
  • Slow, protected rehabilitation increases the likelihood of knee stability and should emphasize early maintenance of knee extension, delayed weight bearing, and delayed return to sports [18].
  • LaPrade et al. showed that a decreased posterior tibial slope puts athletes at some increased risk of PCL injuries [18].
  • With double-bundle PCL reconstruction, there is no increased failure rate based on tibial slope [18].

Postoperative Rehabilitation

  • Postoperative rehabilitation for PCL surgery consists of early immobilization in extension and protection against gravity [17].
  • Early range of motion should be performed in the prone position [17].
  • The focus of postoperative rehabilitation is on quadriceps strengthening [17].
  • Resisted hamstring strengthening should be avoided early in rehabilitation because the posterior pull increases stress on the graft [17].

Complications

  • Posterior laxity increases over time after PCL reconstruction [2].
  • Tibial slope strongly influences knee stability after posterior cruciate ligament reconstruction [2].
  • Consequences of tibial tunnel reaming on the meniscal roots during cruciate ligament reconstruction were evaluated in a cadaveric model for the posterior cruciate ligament [2].
  • Septic arthritis after arthroscopic posterior cruciate ligament and multi-ligament reconstructions is rare [4].
  • Septic arthritis after arthroscopic posterior cruciate ligament and multi-ligament reconstructions can be successfully treated with arthroscopic irrigation and debridement [4].

References

[1] Aaos Comprehensive Orthopaedic Review 3. Ligamentous Injuries of the Knee > II. Posterior Cruciate Ligament Injuries.

[2] Campbell S Operative Orthopaedics 4 Volume Set. ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION WITH BONE-PATELLAR TENDON-BONE GRAFT > POSTERIOR CRUCIATE LIGAMENT.

[3] A Lange Medical Book Current Diagnosis Treatment In Orthopedics Fifth Edition. 3Sports Medicine > 4. Posterior Cruciate Ligament Injuries.

[4] Campbell S Operative Orthopaedics 4 Volume Set. ANTERIOR CRUCIATE AND ANTROLATERAL LIGAMENT RECONSTRUCTION (BOX 51.8) > POSTERIOR CRUCIATE LIGAMENT.

[6] Orthopaedic Knowledge Update Sports Medicine 6. Cruciate Ligament Injuries > Posterior Cruciate Ligament Injury > Anatomy and Biomechanics.

[7] Campbell S Operative Orthopaedics 4 Volume Set. ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION WITH BONE-PATELLAR TENDON-BONE GRAFT > POSTERIOR CRUCIATE LIGAMENT ANATOMY.

[9] Tachdjian S Pediatric Orthopaedics From The Texas Scottish Rite Hospital For Children E Book. Plate 35.2 Scapulocostal Stabilization for Scapular Winging (Ketenjian Technique) > Pediatric Posterior Cruciate Ligament Injuries.

[14] Orthopaedic Knowledge Update Sports Medicine 6. Cruciate Ligament Injuries > Posterior Cruciate Ligament Injury > Diagnosis.

[17] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Soft-­Tissue Injuries About the Knee > Posterior Cruciate Ligament > Treatment.

[18] Campbell S Operative Orthopaedics 4 Volume Set. ANTERIOR CRUCIATE AND ANTROLATERAL LIGAMENT RECONSTRUCTION (BOX 51.8) > POSTERIOR CRUCIATE LIGAMENT RECONSTRUCTION.

[19] Orthopaedic Knowledge Update Sports Medicine 6. Cruciate Ligament Injuries > Posterior Cruciate Ligament Injury > Treatment and Outcomes.

Creative Commons BY-NC 4.0

CC Creative Commons licence
BY Attribution — you must credit the source
NC NonCommercial — not for commercial use

Attribution-NonCommercial 4.0 International


Creative Commons Corporation ("Creative Commons") is not a law firm and does not provide legal services or legal advice. Distribution of Creative Commons public licenses does not create a lawyer-client or other relationship. Creative Commons makes its licenses and related information available on an "as-is" basis. Creative Commons gives no warranties regarding its licenses, any material licensed under their terms and conditions, or any related information. Creative Commons disclaims all liability for damages resulting from their use to the fullest extent possible.

Using Creative Commons Public Licenses

Creative Commons public licenses provide a standard set of terms and conditions that creators and other rights holders may use to share original works of authorship and other material subject to copyright and certain other rights specified in the public license below. The following considerations are for informational purposes only, are not exhaustive, and do not form part of our licenses.

Considerations for licensors: Our public licenses are intended for use by those authorized to give the public permission to use material in ways otherwise restricted by copyright and certain other rights. Our licenses are irrevocable. Licensors should read and understand the terms and conditions of the license they choose before applying it. Licensors should also secure all rights necessary before applying our licenses so that the public can reuse the material as expected. Licensors should clearly mark any material not subject to the license. This includes other CC- licensed material, or material used under an exception or limitation to copyright. More considerations for licensors: wiki.creativecommons.org/Considerations_for_licensors

Considerations for the public: By using one of our public licenses, a licensor grants the public permission to use the licensed material under specified terms and conditions. If the licensor's permission is not necessary for any reason--for example, because of any applicable exception or limitation to copyright--then that use is not regulated by the license. Our licenses grant only permissions under copyright and certain other rights that a licensor has authority to grant. Use of the licensed material may still be restricted for other reasons, including because others have copyright or other rights in the material. A licensor may make special requests, such as asking that all changes be marked or described. Although not required by our licenses, you are encouraged to respect those requests where reasonable. More considerations for the public: wiki.creativecommons.org/Considerations_for_licensees


Creative Commons Attribution-NonCommercial 4.0 International Public License

By exercising the Licensed Rights (defined below), You accept and agree to be bound by the terms and conditions of this Creative Commons Attribution-NonCommercial 4.0 International Public License ("Public License"). To the extent this Public License may be interpreted as a contract, You are granted the Licensed Rights in consideration of Your acceptance of these terms and conditions, and the Licensor grants You such rights in consideration of benefits the Licensor receives from making the Licensed Material available under these terms and conditions.

Section 1 -- Definitions.

a. Adapted Material means material subject to Copyright and Similar Rights that is derived from or based upon the Licensed Material and in which the Licensed Material is translated, altered, arranged, transformed, or otherwise modified in a manner requiring permission under the Copyright and Similar Rights held by the Licensor. For purposes of this Public License, where the Licensed Material is a musical work, performance, or sound recording, Adapted Material is always produced where the Licensed Material is synched in timed relation with a moving image.

b. Adapter's License means the license You apply to Your Copyright and Similar Rights in Your contributions to Adapted Material in accordance with the terms and conditions of this Public License.

c. Copyright and Similar Rights means copyright and/or similar rights closely related to copyright including, without limitation, performance, broadcast, sound recording, and Sui Generis Database Rights, without regard to how the rights are labeled or categorized. For purposes of this Public License, the rights specified in Section 2(b)(1)-(2) are not Copyright and Similar Rights.

d. Effective Technological Measures means those measures that, in the absence of proper authority, may not be circumvented under laws fulfilling obligations under Article 11 of the WIPO Copyright Treaty adopted on December 20, 1996, and/or similar international agreements.

e. Exceptions and Limitations means fair use, fair dealing, and/or any other exception or limitation to Copyright and Similar Rights that applies to Your use of the Licensed Material.

f. Licensed Material means the artistic or literary work, database, or other material to which the Licensor applied this Public License.

g. Licensed Rights means the rights granted to You subject to the terms and conditions of this Public License, which are limited to all Copyright and Similar Rights that apply to Your use of the Licensed Material and that the Licensor has authority to license.

h. Licensor means the individual(s) or entity(ies) granting rights under this Public License.

i. NonCommercial means not primarily intended for or directed towards commercial advantage or monetary compensation. For purposes of this Public License, the exchange of the Licensed Material for other material subject to Copyright and Similar Rights by digital file-sharing or similar means is NonCommercial provided there is no payment of monetary compensation in connection with the exchange.

j. Share means to provide material to the public by any means or process that requires permission under the Licensed Rights, such as reproduction, public display, public performance, distribution, dissemination, communication, or importation, and to make material available to the public including in ways that members of the public may access the material from a place and at a time individually chosen by them.

k. Sui Generis Database Rights means rights other than copyright resulting from Directive 96/9/EC of the European Parliament and of the Council of 11 March 1996 on the legal protection of databases, as amended and/or succeeded, as well as other essentially equivalent rights anywhere in the world.

l. You means the individual or entity exercising the Licensed Rights under this Public License. Your has a corresponding meaning.

Section 2 -- Scope.

a. License grant.

1. Subject to the terms and conditions of this Public License, the Licensor hereby grants You a worldwide, royalty-free, non-sublicensable, non-exclusive, irrevocable license to exercise the Licensed Rights in the Licensed Material to:

a. reproduce and Share the Licensed Material, in whole or in part, for NonCommercial purposes only; and

b. produce, reproduce, and Share Adapted Material for NonCommercial purposes only.

2. Exceptions and Limitations. For the avoidance of doubt, where Exceptions and Limitations apply to Your use, this Public License does not apply, and You do not need to comply with its terms and conditions.

3. Term. The term of this Public License is specified in Section 6(a).

4. Media and formats; technical modifications allowed. The Licensor authorizes You to exercise the Licensed Rights in all media and formats whether now known or hereafter created, and to make technical modifications necessary to do so. The Licensor waives and/or agrees not to assert any right or authority to forbid You from making technical modifications necessary to exercise the Licensed Rights, including technical modifications necessary to circumvent Effective Technological Measures. For purposes of this Public License, simply making modifications authorized by this Section 2(a) (4) never produces Adapted Material.

5. Downstream recipients.

a. Offer from the Licensor -- Licensed Material. Every recipient of the Licensed Material automatically receives an offer from the Licensor to exercise the Licensed Rights under the terms and conditions of this Public License.

b. No downstream restrictions. You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, the Licensed Material if doing so restricts exercise of the Licensed Rights by any recipient of the Licensed Material.

6. No endorsement. Nothing in this Public License constitutes or may be construed as permission to assert or imply that You are, or that Your use of the Licensed Material is, connected with, or sponsored, endorsed, or granted official status by, the Licensor or others designated to receive attribution as provided in Section 3(a)(1)(A)(i).

b. Other rights.

1. Moral rights, such as the right of integrity, are not licensed under this Public License, nor are publicity, privacy, and/or other similar personality rights; however, to the extent possible, the Licensor waives and/or agrees not to assert any such rights held by the Licensor to the limited extent necessary to allow You to exercise the Licensed Rights, but not otherwise.

2. Patent and trademark rights are not licensed under this Public License.

3. To the extent possible, the Licensor waives any right to collect royalties from You for the exercise of the Licensed Rights, whether directly or through a collecting society under any voluntary or waivable statutory or compulsory licensing scheme. In all other cases the Licensor expressly reserves any right to collect such royalties, including when the Licensed Material is used other than for NonCommercial purposes.

Section 3 -- License Conditions.

Your exercise of the Licensed Rights is expressly made subject to the following conditions.

a. Attribution.

1. If You Share the Licensed Material (including in modified form), You must:

a. retain the following if it is supplied by the Licensor with the Licensed Material:

i. identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any reasonable manner requested by the Licensor (including by pseudonym if designated);

ii. a copyright notice;

iii. a notice that refers to this Public License;

iv. a notice that refers to the disclaimer of warranties;

v. a URI or hyperlink to the Licensed Material to the extent reasonably practicable;

b. indicate if You modified the Licensed Material and retain an indication of any previous modifications; and

c. indicate the Licensed Material is licensed under this Public License, and include the text of, or the URI or hyperlink to, this Public License.

2. You may satisfy the conditions in Section 3(a)(1) in any reasonable manner based on the medium, means, and context in which You Share the Licensed Material. For example, it may be reasonable to satisfy the conditions by providing a URI or hyperlink to a resource that includes the required information.

3. If requested by the Licensor, You must remove any of the information required by Section 3(a)(1)(A) to the extent reasonably practicable.

4. If You Share Adapted Material You produce, the Adapter's License You apply must not prevent recipients of the Adapted Material from complying with this Public License.

Section 4 -- Sui Generis Database Rights.

Where the Licensed Rights include Sui Generis Database Rights that apply to Your use of the Licensed Material:

a. for the avoidance of doubt, Section 2(a)(1) grants You the right to extract, reuse, reproduce, and Share all or a substantial portion of the contents of the database for NonCommercial purposes only;

b. if You include all or a substantial portion of the database contents in a database in which You have Sui Generis Database Rights, then the database in which You have Sui Generis Database Rights (but not its individual contents) is Adapted Material; and

c. You must comply with the conditions in Section 3(a) if You Share all or a substantial portion of the contents of the database.

For the avoidance of doubt, this Section 4 supplements and does not replace Your obligations under this Public License where the Licensed Rights include other Copyright and Similar Rights.

Section 5 -- Disclaimer of Warranties and Limitation of Liability.

a. UNLESS OTHERWISE SEPARATELY UNDERTAKEN BY THE LICENSOR, TO THE EXTENT POSSIBLE, THE LICENSOR OFFERS THE LICENSED MATERIAL AS-IS AND AS-AVAILABLE, AND MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND CONCERNING THE LICENSED MATERIAL, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHER. THIS INCLUDES, WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT, ABSENCE OF LATENT OR OTHER DEFECTS, ACCURACY, OR THE PRESENCE OR ABSENCE OF ERRORS, WHETHER OR NOT KNOWN OR DISCOVERABLE. WHERE DISCLAIMERS OF WARRANTIES ARE NOT ALLOWED IN FULL OR IN PART, THIS DISCLAIMER MAY NOT APPLY TO YOU.

b. TO THE EXTENT POSSIBLE, IN NO EVENT WILL THE LICENSOR BE LIABLE TO YOU ON ANY LEGAL THEORY (INCLUDING, WITHOUT LIMITATION, NEGLIGENCE) OR OTHERWISE FOR ANY DIRECT, SPECIAL, INDIRECT, INCIDENTAL, CONSEQUENTIAL, PUNITIVE, EXEMPLARY, OR OTHER LOSSES, COSTS, EXPENSES, OR DAMAGES ARISING OUT OF THIS PUBLIC LICENSE OR USE OF THE LICENSED MATERIAL, EVEN IF THE LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSSES, COSTS, EXPENSES, OR DAMAGES. WHERE A LIMITATION OF LIABILITY IS NOT ALLOWED IN FULL OR IN PART, THIS LIMITATION MAY NOT APPLY TO YOU.

c. The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.

Section 6 -- Term and Termination.

a. This Public License applies for the term of the Copyright and Similar Rights licensed here. However, if You fail to comply with this Public License, then Your rights under this Public License terminate automatically.

b. Where Your right to use the Licensed Material has terminated under Section 6(a), it reinstates:

1. automatically as of the date the violation is cured, provided it is cured within 30 days of Your discovery of the violation; or

2. upon express reinstatement by the Licensor.

For the avoidance of doubt, this Section 6(b) does not affect any right the Licensor may have to seek remedies for Your violations of this Public License.

c. For the avoidance of doubt, the Licensor may also offer the Licensed Material under separate terms or conditions or stop distributing the Licensed Material at any time; however, doing so will not terminate this Public License.

d. Sections 1, 5, 6, 7, and 8 survive termination of this Public License.

Section 7 -- Other Terms and Conditions.

a. The Licensor shall not be bound by any additional or different terms or conditions communicated by You unless expressly agreed.

b. Any arrangements, understandings, or agreements regarding the Licensed Material not stated herein are separate from and independent of the terms and conditions of this Public License.

Section 8 -- Interpretation.

a. For the avoidance of doubt, this Public License does not, and shall not be interpreted to, reduce, limit, restrict, or impose conditions on any use of the Licensed Material that could lawfully be made without permission under this Public License.

b. To the extent possible, if any provision of this Public License is deemed unenforceable, it shall be automatically reformed to the minimum extent necessary to make it enforceable. If the provision cannot be reformed, it shall be severed from this Public License without affecting the enforceability of the remaining terms and conditions.

c. No term or condition of this Public License will be waived and no failure to comply consented to unless expressly agreed to by the Licensor.

d. Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.


Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” The text of the Creative Commons public licenses is dedicated to the public domain under the CC0 Public Domain Dedication. Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at creativecommons.org/policies, Creative Commons does not authorize the use of the trademark "Creative Commons" or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.

Creative Commons may be contacted at creativecommons.org.