Pain Behind the Knee? Here’s What’s Going On
On this page:
- Hamstring or calf muscle or tendon injuries
- Popliteus and plantaris muscle injuries
- Tibial or other nerve problems
- Meniscus tears
- Baker’s cyst
I talk a lot about knee pain and what to do and what not to do about it. This time, I want to pinpoint a precise location: the back of the knee. What does it mean, and what exactly could be causing your back of knee pain? Let’s first address this by looking at what structures live behind the knee.
What Causes Pain Behind the Knee?
There are many structures behind the knee or that affect the back of the knee, including the following:
- Hamstring muscles and calf muscles and tendons
- Popliteus and plantaris muscles
- Tibial and other nerves
Let’s look at the problems that could lead to back of knee pain.
1. Hamstring and Calf Muscle and Tendon Injuries
The hamstrings muscles are a group of large muscles that run the length of the upper legs, ending at the knee. The calf muscles are the beefy muscles that run behind the lower legs, starting at the knee.
There are tendons in the hamstrings and calf muscles that connect these muscles to the bone just behind the knee. So your back of knee pain could be caused by an injury or problem in these muscles or tendons. An additional sign of this problem might be chronically tight hamstrings or calf muscles that you constantly feel like you need to stretch or roll out (1).
And even further up the line, if you have hamstrings or calf muscles that won’t let go and are always tight, it could be your back, not your hamstrings or your knee, that’s the true cause of the problem (2). How does that work? Check out the video which explains the connection.
2. Popliteus and Plantaris Muscle Injuries
The back of the knee is also where deeper muscles, like the popliteus and plantaris, live (3). The popliteus muscle crosses from the inside bottom back of the knee to the outside top of the knee. The plantaris muscle bridges directly behind the knee and terminates at its tendon, which stretches all the way down to the Achilles tendon at the back of the heel.
If there is a problem with either of these, you will feel back of knee pain and tightness deeper into the knee when you massage or put pressure there. With the popliteus muscle, you might also experience the knee locking up, and addressing this muscle could be the “key” to unlocking the knee as well as eliminating your back of knee pain.
3. Tibial or Other Nerve Problems
The tibial and other nerves also run behind the knee. The tibial nerve branches off the sciatic nerve, which starts in the lower back, and travels all the way down to the foot. An issue in this nerve locally or even at the spinal level could cause pain at the back of your knee (4).
The spinal nerves that connect to the muscles may be an issue if you have any sort of low-back problem, even if your back isn’t acutely bothering you right now. If it is a nerve issue, you might have numbness, tingling, burning, or electrical sensations in the leg or foot.
4. Meniscus Tears
The meniscus, or joint spacer, also lives behind the knee, so a tear in the meniscus could cause pain in this area. Be very careful, though, with a diagnosis of a meniscus tear because most middle-aged or older patients have meniscus tears—they’re as natural as wrinkles—without any pain (5).
Just because your knee hurts and a doctor says you have a meniscus tear on your MRI, doesn’t mean that this is the cause of your pain! In addition, meniscus surgery has been shown in multiple high-level studies to be no better than sham surgery or placebo, so don’t get your meniscus operated on.
5. Baker’s Cyst
A Baker’s cyst can also cause back of knee pain. This is really just a blowout of the synovial lining, or the back wall, of the knee joint. If you have a Baker’s cyst, you’ll feel fluid at the back of your knee, and it will get bigger with more activity and smaller with less activity.
The upshot? The knee is a very complex joint with a multitude of structures that can become injured and cause back of knee pain. The key is to first get a thorough exam and a solid diagnosis on the true cause of the problem.
Cutting out pieces of a meniscus, for example, isn’t going to address knee pain if the problem is centered in the lower back. And whether it’s the meniscus, hamstrings, spine, or anything else, from there we can seek regenerative-medicine solutions, not surgery, to treat the problem and eliminate your pain.
(1) Kumar D, Subburaj K, Lin W, et al. Quadriceps and hamstrings morphology is related to walking mechanics and knee cartilage MRI relaxation times in young adults. J Orthop Sports Phys Ther. 2013;43(12):881-890. doi:10.2519/jospt.2013.4486
(2) Miller, J, Rockey, AM, Doberstein, S. Foam Rollers Show No Increase in the Flexibility of the Hamstring Muscle Group. 2006.
(3) Spina AA. The plantaris muscle: anatomy, injury, imaging, and treatment. J Can Chiropr Assoc. 2007;51(3):158-165.
(4) Collados-Maestre I, Lizaur-Utrilla A, Martinez-Mendez D, Marco-Gomez L, Lopez-Prats FA. Concomitant low back pain impairs outcomes after primary total knee arthroplasty in patients over 65 years: a prospective, matched cohort study. Arch Orthop Trauma Surg. 2016;136(12):1767-1771. doi:10.1007/s00402-016-2576-8
(5) Risberg MA. Degenerative meniscus tears should be looked upon as wrinkles with age–and should be treated accordingly. Br J Sports Med. 2014;48(9):741. doi:10.1136/bjsports-2014-093568
(6) Sihvonen R, Paavola M, Malmivaara A, et al. Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. N Engl J Med. 2013;369(26):2515-2524. doi:10.1056/NEJMoa1305189