Can an untreated PCL tear cause arthritis later?

Why load changes after a PCL tear

When the PCL is lax, the tibia sits slightly further back, particularly when the knee is bent. This increases pressure behind the kneecap and in the inner compartment of the knee. Over many years, that extra load can contribute to cartilage wear. The effect is usually gradual and varies a lot between people.

Who is at higher risk

• Complete tears with a large amount of backward movement
• PCL tears combined with injury to the posterolateral corner or other ligaments that were not treated
• Knees that also lost part of the meniscus
• Bow-legged alignment, which already loads the inner knee
• Weak quadriceps, which leaves the shin less supported
• Heavy manual work or sports with frequent deep squatting and kneeling

Protecting the knee

Quadriceps strength is the single most useful long-term measure, because this muscle holds the shin forward. Staying at a healthy weight reduces joint load, and low-impact exercise such as cycling and swimming keeps the knee strong with less stress. Treating a meniscus tear or other ligament injury appropriately also matters.

For knees with persistent instability and early symptoms, PCL reconstruction may be considered to restore more normal mechanics, although no operation fully removes the long-term risk.

When to have an old injury reviewed

Book an assessment if an old PCL injury now causes aching at the front or inner side of the knee, swelling after activity, or new unsteadiness. Dr. Gelber examines the ligament and alignment, and imaging such as standing X-rays and MRI shows whether the cartilage is changing.