Popliteus Tendinopathy: Pain at the Outer Back of the Knee

What is the popliteus?

The popliteus is a small muscle at the back of the knee. Its tendon runs diagonally upwards and outwards, passing inside the joint capsule to attach on the outer side of the thigh bone, close to the lateral collateral ligament. It helps "unlock" the knee as it starts to bend from straight, and it resists the shin bone sliding forwards and rotating outwards, especially when you are walking or running downhill.

Because it works hardest when the body is slowing down on a slope, repeated downhill loading can overwork the tendon and make it painful.

Symptoms, in patients' own words

• "It hurts on the outside of my knee, towards the back"
• "It's fine on the flat but painful running downhill"
• "Going down stairs is worse than going up"
• "It aches when I squat or crouch deeply"
• "It starts a few kilometres into a run and gets worse"

The pain is usually well localised and there is rarely much swelling. Locking, giving way or major swelling suggest a different or additional problem, such as a meniscus or ligament injury.

Causes and who gets it

Popliteus tendinopathy is most common in runners and hikers, particularly after a sudden increase in hill or downhill training, and in people who run on cambered roads or tracks. It is also seen in football, basketball and padel players, whose sports involve braking and twisting. Feet that roll inwards (overpronation), weak hip and thigh muscles, and tired legs at the end of a long session add to the load on the tendon.

In Qatar, runners often move from treadmills to outdoor routes and trails when the weather cools, or join hiking trips abroad, and a quick change in terrain can trigger symptoms.

How it is diagnosed

The diagnosis is mainly clinical. Dr. Gelber feels for tenderness at the tendon's attachment on the outer thigh bone and along its course, and uses tests that load the tendon by resisting rotation of the shin with the knee bent. The examination also checks the iliotibial band, lateral collateral ligament, lateral meniscus and the posterolateral corner, as these produce pain in the same region.

An MRI is not always needed, but it helps when symptoms persist, follow an injury, or when a meniscus tear or ligament damage is suspected. Ultrasound can also show the tendon.

Treatment

• Relative rest: reduce downhill running, stairs and deep squats while continuing activities that do not hurt, such as cycling or swimming
• Ice and short-term pain relief if suitable for you
• Physiotherapy with progressive strengthening of the hamstrings, quadriceps, calves and hip muscles, including controlled loading of the popliteus itself
• Running technique and training changes, such as shorter steps downhill, flatter routes and a gradual return to hills
• Footwear review, and insoles for some patients with marked overpronation

Most people improve over several weeks. In stubborn cases, an image-guided injection is occasionally used to settle pain so that rehabilitation can continue. Surgery is rarely needed for tendinopathy alone; it is reserved for associated structural damage such as a torn tendon, a meniscus tear or posterolateral corner injury.

Returning to running and sport

Return is gradual. Start on flat ground at an easy pace, then add short gentle slopes before longer descents. Mild discomfort that settles by the next day is usually acceptable; pain that builds during a run or lingers is a sign to slow the progression. In the hot months, training indoors or at cooler hours makes consistent, sensible build-up easier.

When to see a knee specialist in Doha

Book an assessment if outer-knee pain lasts more than a few weeks despite rest, stops you running, or began with a twist, fall or tackle. See a doctor promptly if the knee swells quickly, locks, gives way, or you cannot bear weight. At Aman Hospital, Dr. Gelber examines the whole outer and back corner of the knee to separate tendon pain from ligament or meniscus injury, and plans treatment around your training.