Popliteus Tendonitis
Popliteus tendonitis is a condition where the popliteus tendon, a small tendon at the back and outer side of the knee, becomes irritated or inflamed. This causes focal posterolateral knee pain, which means the pain is felt in a very specific spot at the back and outside of the knee (Figure 1). The popliteus muscle helps control knee rotation and stability, especially when walking downhill or going downstairs. Popliteus tendonitis usually happens due to overuse or strain, often from activities like running, hiking, or playing sports that involve sudden changes in direction. Athletes, especially runners and soccer players, are the most likely to develop this type of tendonitis.
How is Popliteus Tendonitis Diagnosed?
To diagnose popliteus tendonitis, a doctor will start by asking about symptoms and how the pain began. During the physical exam, the doctor will press on the back and outer side of the knee to check for tenderness and may ask the patient to move their leg in certain ways to see if it causes pain. Because the pain can be similar to other knee problems, the doctor may order imaging tests like an MRI to look closely at the tendon and rule out other conditions, such as a meniscus tear, ligament injury, or knee arthritis. X-rays may also be used to make sure there’s no bone problem.
Treatment of Popliteus Tendonitis
Most people with popliteus tendonitis can recover with conservative (non-surgical) treatment. This begins with rest, avoiding activities that cause pain, and applying ice to reduce swelling. Anti-inflammatory medications can also help with pain and inflammation. Once the pain improves, a physical therapy program is important to stretch and strengthen the muscles around the knee and hip, and to improve movement patterns. Proper warm-ups, stretching, and body mechanics are key to preventing the problem from coming back.
When Surgery Is Needed
Surgery is rarely ever needed for popliteus tendonitis. It is usually only considered if the pain continues for many months despite physical therapy and other treatments. In very rare cases, surgery might be used to remove damaged tissue or release pressure on the tendon. This is typically only done in severe or chronic cases that interfere with daily life or athletic performance.
What to Expect Long-Term
The long-term outlook for popliteus tendonitis is generally very good. Most people recover fully with proper treatment and can return to their normal activities, including sports. Recovery usually takes a few weeks to a few months, depending on how severe the condition is and how quickly treatment begins. Keeping the muscles around the knee strong and flexible, along with good stretching habits and body mechanics, helps prevent the problem from coming back.
Edited by Amari Eubanks and Stephen Pinney MD, August 18th 2025.