Conservative Treatment of the Posterior Cruciate Ligament (PCL) Rupture

Posterior cruciate ligament (PCL) rupture has naturally healing potential, in 72–86% of the ruptured PCL looks good continuity by MRI studies after 6 months. In our clinical experience, in the case of chronic posterior cruciate ligament injury, it is very rare that there is no continuity of the injured PCL, and almost 95% or more of them have good continuity in elongated posterior cruciate ligament. It is thought that a ruptured isolated PCL naturally heals over time, due to the fact that PCL is well-covered by synovial tissue and its blood supply is better than ACL’s. The isolate PCL rupture is considered to be within 5–6%. In the PCL partially ruptured case, less than 1.5 ~ 2.0° clinically, we can treat it with immobilization, such as a long leg cast or cylinder cast in full extension of the knee for 6 weeks, and then, for 6 more weeks, take a PCL brace . The ruptured PCL will be healed and reduce posterior instability and improve stability by active conservative treatment (cast immobilization) and taking PCL brace, which prevents posterior sagging pad with a spring (Fig. 9.3). The active conservative treatment is done in an isolated PCL ruptured case, which is grade 2 posterior instability; it improves somewhat posterior instability, but in most cases, some instability remains, so surgical treatment can yield better results for young and active patients. Therefore, we recommend active conservative treatment for the isolated PCL injury of grade 1–1.5, which means an incomplete PCL injury, less than grade 2. The active conservative treatment, such as cylinder cast or long leg cast immobilization of the PCL injury, is a good indication, one of the treatment method, especially when the growth plate open in young children with an acute PCL injury.