Yes, sciatica could be causing your knee pain!
Your knees take a hammering! They support your body weight, provide stability, and act as shock absorbers when you move. Indeed, thanks to your knees you can walk, run, jump, squat, and bend and straighten your legs.
So, when pain strikes these unsung heroes of mobility, it can literally be immobilising! And very painful… However, whilst knee pain is often associated with sports or chronic health conditions like arthritis, there are other potential causes, one of which is sciatica.
In this post, we consider whether sciatica could be causing your knee pain.
The sciatic nerve originates in your lower spine and runs through your hips and buttocks and down each leg. Sciatica refers to (painful) pinching or irritation of this nerve and is not a disorder in itself but a symptom of other underlying issues.
The pinching/irritation can happen anywhere along the nerve but is most often caused by degenerative spinal disc conditions (herniated or bulging disc) or spinal dysfunction (misaligned vertebra, spinal stenosis etc). Therefore, it’s not the first thing you think of when knee pain happens.
Sciatic pain, however, can radiate down the leg and create deferred pain in joints like your knee. So, it feels like the issue is in your knee but it actually originates further up the nerve.
Sometimes, though, the cause can be closer to the knee because the sciatic nerve branches into the tibial and common peroneal nerves just behind the knee (popliteal fossa). Some conditions, like a Baker’s cyst or a knee injury, can compress these nerves and create sciatic pain.
Sciatic pain varies in intensity and location. Some people experience a deep, throbbing pain, like an ache deep inside the knee joint.
Typically, though, sciatic pain is described as a sharp, shooting pain that starts in the lower back and radiates down one leg, often creating a burning or tingling ‘pins and needles’ sensation in the leg, knee, or foot. There may be numbness, weakness, or muscle spasms in the affected limb as well.
Sciatic pain often worsens with certain movements, like sitting for long periods, walking, or standing up from a seated position.
Because the sciatic nerve runs right down your leg, it can cause knee pain even when the underlying issue is in your lower back.
If a sciatic nerve root in the lower back becomes inflamed or compressed, the pain signals often radiate down the length of the nerve, causing discomfort down the entire leg, including knee pain. You’ll also generally have some lower back pain as well.
The hamstring muscles run down the backs of your thighs. If these muscles are tight, it not only limits your range of motion but can also strain your knee joint, and put pressure on the sciatic nerve. Again, the pain may radiate down the sciatic nerve to your knee.
Although this post is about sciatica associated knee pain, most knee pain has other causes. So, some common causes of knee pain include:
Arthritis is inflammation of one or more of your joints. Although it can affect any joint, arthritic changes are particularly common in stress-bearing joints like the knee. Both osteoarthritis and rheumatoid arthritis can affect the knee, causing pain, swelling, and stiffness.
Arthritis-related knee pain is usually localised to the knee itself and tends to worsen with activity or after long periods of inactivity.
Your thighbone (femur) and shinbone (tibia) meet at the knee. Two small C-shaped pieces of cartilage – the medial meniscus and the lateral meniscus – help keep them apart. The cartilage acts as a shock absorber, stabilises the knee, and distributes your weight evenly across the joint.
Unfortunately, these cartilages can tear (a meniscus tear), usually from an injury of some type. It may cause sudden localised pain and swelling and make it hard to bend your knee. You could also hear a clicking noise in the knee joint when you move it.
Muscle and tendon strains are injuries to muscles or tendons respectively, and not to be confused with a sprain, which is an injury to a ligament.
Tendons are the tough fibrous tissues that connect muscles to bones. Strains in muscle and tendon tissues surrounding the knee can cause localised pain and discomfort.
Strains are typically the result of overuse or an acute injury. Knee strains are typically felt in the front or back of the knee depending on the tissues affected, and can make it painful to bend or straighten your leg.
A ligament sprain is due to stretching or tearing of ligaments – the tough bands of fibrous tissue that connect the bones in your joints. In the knee, anterior cruciate ligament (ACL) and medial collateral ligament (MCL) injuries are common and can be extremely painful.
Ligament injuries are most common in sports or physical activities that involve sudden stops, changes in direction, or direct impact on the knee. The pain from a ligament sprain is often accompanied by swelling, instability, and difficulty bearing weight on the affected leg.
Tendonitis is inflammation of a tendon, often due to overuse or repetitive stress. It can cause pain that worsens with activity, particularly activities that involve jumping or running. The pain is typically felt at the front of the knee near the kneecap.
Like many injuries, managing sciatic knee pain involves a combination of strategies.
These will help reduce pain and inflammation and improve blood flow. Applying heat can help relax muscles and improve blood flow. Ice or cold packs are good for reducing swelling and to numb the area. Over-the-counter pain medication can also help reduce inflammation and pain.
Gentle movement is good for reducing sciatic pain because it helps keep the muscles around the nerve flexible. Conversely, ‘resting’ the joint can increase muscle stiffness and weakness, exacerbating the situation.
Activities like walking and swimming are also good for sciatic pain as they help strengthen the muscles supporting your spine and improve flexibility. These can help reduce pressure on the sciatic nerve and ease the pain.
If you do have sciatic-related knee pain, how long it lasts usually depends on the underlying cause. If this is ‘fixable’ – a misaligned vertebra for example can be corrected with spinal adjustments – you may notice significant improvement after 4 – 6 weeks so long as you’ve followed your treatment plan.
Unfortunately, however, if the underlying cause is a herniated or bulging disc, which is often the case, or something like spinal stenosis, the pain can become chronic and last for several months.
Common treatments for sciatic knee pain may include:
Chiropractic care can often ease sciatic pain arising from spinal issues by correcting misaligned vertebrae that may be pinching the roots of the sciatic nerve.
Specialised techniques like flexion-distraction and pelvic blocking can also help reduce pressure on herniated or bulging spinal discs, which then helps relieve pressure on the sciatic nerve roots.
Soft tissue therapy and exercises to improve mobility and alleviate discomfort in the knee are also options.
Most people with sciatica undergo physiotherapy to strengthen the muscles supporting the spine, improve flexibility, and reduce pressure on the sciatica nerve.
This approach can help alleviate knee pain by improving the underlying source of the pain, and prevent future flare-ups.
Pain medication and alternative therapies like acupuncture or chiropractic care are often recommended for pain management of sciatica and sciatic-related knee pain.
In cases where knee pain is severe and chronic, other options include surgery to remove the source of the compression on the sciatic nerve and thus reduce the associated knee pain.
If your knee pain is severe and persistent, it’s time to seek medical advice. A definitive diagnosis of sciatica can generally only be done via assessment from a healthcare professional due to the range of conditions that can cause knee pain.
If you have knee pain accompanied by pain that radiates from your lower back or down your leg, sciatica could easily be the culprit.
However, the correct treatment for sciatica-related knee pain relies on ruling out other common causes of knee pain, such as arthritis, ligament injuries, or tendonitis. This generally requires a healthcare or medical professional.
