Popliteus tendinitis, also known as popliteus tendonitis or tenosynovitis, is a rare cause of pain at the back and outside of the knee. It’s poorly understood and often misdiagnosed as another problem, such as a ligament or cartilage injury. So what is the popliteus tendon, and how do we detect popliteus tendinitis?
What is the popliteus tendon?
The popliteus tendon starts on the outside of the knee, attaching to the thigh bone (femur) and the lateral meniscus. It then passes down and forms a muscle across the back of the knee, inserting into the tibia (the leg bone). Its main action is to rotate the leg — the popliteus rotates the thigh outwards and “unlocks” the knee when running.
Popliteus tendinitis symptoms
People usually damage the popliteus tendon after a knee twist or overuse. The tendon can also be injured after a total knee replacement.
People with popliteus tendinopathy experience pain at the back or outside of the knee when walking, climbing stairs, or running. Sometimes, moving the knee causes a popping sensation, and it is tender to the touch on the back and outside. A specific test — the “Garrick” test — reproduces the pain.
Popliteus tendinitis on MRI
We order tests to confirm the diagnosis. MRI is the most useful imaging modality, showing tendon swelling, tenosynovitis, or tearing. It also rules out other causes of pain at the back of the knee, such as a cartilage or meniscal tear. Ultrasound can also show changes in the popliteus tendon, although they are more subtle.
Treatment of popliteus tendinitis
For popliteus tendinopathy, we start with simple treatments. First, reduce or stop running. Anti-inflammatory measures such as ice and ibuprofen tablets also help.
Exercise therapy is essential to restore knee function. We start by strengthening the buttock muscles, such as the gluteus medius, then focus on strengthening knee rotation with resistance bands. Forward, backwards, and sidestepping on a step improve the functional stability of the popliteus.
In difficult cases, an ultrasound-guided cortisone injection into the popliteus tendon sheath can reduce pain while running and help rehabilitation. We use ultrasound to place the cortisone into the sheath while avoiding the tendon itself.
We reserve surgery for cases involving instability of the popliteus tendon or a tear of other structures such as the lateral collateral ligament.
Frequently asked questions about popliteus tendinopathy
What is the Garrick test?
It’s a specific clinical test for the popliteus tendon. With the knee positioned to expose the tendon (a figure-of-four position), the doctor presses over the tendon at the outside of the knee. Reproducing the pain supports the diagnosis of popliteus tendinitis.
How do you tell popliteus tendinitis from other causes of outer knee pain?
Several conditions cause pain at the back and outside of the knee — ITB syndrome, biceps femoris tendinopathy, and lateral meniscal or ligament problems. Because popliteus tendinitis is rare and easily missed, a careful examination and MRI are used to distinguish it from other causes. See our guide to posterolateral knee pain for the full picture.
How long does popliteus tendinitis take to heal?
Most cases settle over several weeks to a few months with relative rest and a progressive rehabilitation programme. Because it’s often misdiagnosed, getting the right diagnosis early tends to shorten recovery.
Can you run with popliteus tendonitis?
Not at full load while it’s painful — we reduce or stop running during a flare and switch to non-impact cross-training, then build back gradually once the pain settles and strength returns.
Does popliteus tendinitis need surgery?
Rarely. Almost all cases respond to rest, rehabilitation, and sometimes a guided injection. Surgery is reserved for tendon instability or an associated tear of other structures, such as the lateral collateral ligament.
Final word from Sport Doctor London about popliteus tendonitis
Consider popliteus tendinitis if you have pain at the outside or back of the knee. Remember that a twisting injury can damage the tendon along with other vital structures at the back of the knee — so an accurate diagnosis is essential.
If you have persistent pain in the back or outside the knee, Dr Masci can assess you in London, including in-clinic ultrasound. Contact the team here or call +44 (0) 203 488 0350.
I spin regularly. I had pain in my knee and stupidity I continued exercising. I now have pain behind knee which really hurts when I try to bend the knee of lift leg up.