An inability to extend the knee can be indicative of which condition?

An inability to extend the knee is commonly associated with a patellar tendon tear. This tendon plays a crucial role in connecting the kneecap (patella) to the tibia and is essential for knee extension. When the patellar tendon is torn, it disrupts the mechanism that allows for the extension of the leg, leading to significant functional limitations. Patients with this condition often experience acute pain, swelling, and a noticeable inability to complete movements that require knee extension, such as standing up or walking.

In contrast, while other knee injuries can cause pain and functional limitations, they might not specifically result in an inability to extend the knee. For instance, a meniscal tear can cause pain, swelling, or locking sensations, but it may still allow for some degree of knee movement, including extension. A quadriceps strain primarily affects the muscle that helps in knee extension but may not completely inhibit the ability to extend the knee. A fractured patella can lead to pain and swelling which may impact movement, but complete inability to extend is most characteristic of a tear in the patellar tendon.