> ## Content Index > Fetch the complete content index at: https://www.medi-hi.com/llms.txt > Use this file to discover other available public pages before exploring further. # Referred Knee Pain: Why Your Lower Back May Be the Real Cause - URL: https://www.medi-hi.com/en/info/knee_joint_referred_pain_spine-en/ - Published: 2026-10-19T01:12:25.000Z - Updated: 2026-10-19T01:58:45.000Z - Author: medihi - Tags: 무릎 통증, #info, #in_루나, #in_란마, #in_의료진감수, #in_조승배, #ysmaster, #lang-en POINT ## In This Article Many people visit a clinic for knee pain only to be told that their bones and cartilage look fine. In such cases, the source of pain may not be the knee itself, but rather irritation or compression of nerves in the lumbar spine. This article explains how to distinguish a true knee joint problem from knee radicular pain caused by lumbar nerve compression, and summarizes practical criteria for evaluation, testing, and treatment. ## 1\. Can my lumbar spine be the cause even though my knee hurts? ![An illustration showing that knee pain can originate from lumbar spine nerves](https://www.medi-hi.com/content/images/2026/10/knee_joint_referred_pain_spine_01.png) Even when there is no clear abnormality in the knee itself, a lumbar spine issue can cause knee pain and numbness. This is often described as knee radicular pain, commonly occurring when nerve roots around L4–L5 (e.g., L4, L5 nerve roots) are irritated or compressed. Because nerves that start in the spine travel down into the leg, irritation at the lumbar spine can be felt as symptoms around the knee. However, nerve distribution patterns can vary from person to person. The exact source should be determined through a clinician’s physical examination and, when needed, detailed imaging. **✅Four signs that suggest the lumbar nerves may be the cause** - **Normal knee imaging:** You’re told that your knee X-ray shows no obvious bone or cartilage abnormality. - **Widespread radiating pain:** Rather than one specific spot in the knee, you may feel electric-like tingling or numbness spreading to the buttock, thigh, and calf. - **Changes with posture:** The tingling may worsen or improve when lying down, sitting, or changing positions. - **Dull or altered sensation:** Touching the skin around the knee may feel numb (as if it’s not your own skin) or burning. --- ## 2\. What’s the difference between knee osteoarthritis and lumbar radicular pain? Knee osteoarthritis typically causes an aching, sore sensation as the joint wears down, whereas lumbar radicular pain tends to cause sharp, tingling, or burning radiating pain. - **Knee osteoarthritis:** Often presents as a heavy, deep pain in the inner (medial) or front (anterior) part of the knee—especially when going up or down stairs. - **Lumbar nerve-related pain (often from a lumbar disc problem):** May continue even while standing, with a sharp, electric-like tingling that travels down the leg. **✅How to tell osteoarthritis vs. nerve pain apart** | **Category** | **Joint Wear(Knee Osteoarthritis)** | **Nerve Compression(Lumbar Neuralgia)** | | -------------------- | -------------------------------------- | ------------------------------------------------------------ | | Pain Characteristics | Aching and heavy sensation when moving | Tingling and burning sensation depending on postural changes | | Aggravating Factors | Squatting, going up and down stairs | Walking, assuming specific postures | --- ## 3\. Could it be spinal stenosis even if my back doesn’t hurt? ![A medical illustration demonstrating lumbar spinal stenosis](https://www.medi-hi.com/content/images/2026/10/knee_joint_referred_pain_spine_02.png) Yes. Even without noticeable low back pain, \*\*lumbar spinal stenosis\*\* can occur—commonly in people in their 60s and older. Because spinal stenosis narrows the pathway where nerves travel to the legs, \*\*leg or knee symptoms may be more prominent than back pain\*\*. Typical patterns include: - After walking a short distance, your legs may feel tight or intensely painful—sometimes described as feeling like they might “burst”—causing you to stop frequently. - Symptoms may temporarily improve if you squat or bend forward at the waist. - You may feel fine when resting lying down, but numbness can return once you stand and start walking again. - Pain may spread broadly and dully across both knees and the entire legs. However, the pattern of “pain with walking that improves with stopping” can overlap with vascular claudication (from narrowed leg blood vessels). A differential diagnosis is important. --- ## 4\. What is the Straight Leg Raise (SLR) test? ![A photo demonstrating a straight leg raise (SLR) test for lumbar nerve evaluation](https://www.medi-hi.com/content/images/2026/10/knee_joint_referred_pain_spine_03.gif) The Straight Leg Raise (SLR) test is performed while lying down: the leg is kept straight and lifted upward to see whether pain occurs. It is commonly used to assess pain radiating down to the knee and to evaluate possible compression of lumbar nerve roots—especially when a lumbar disc problem is suspected. - **If a lumbar disc issue is present:** Lifting the leg can tension the nerve, and the protruding disc may irritate it—causing strong tingling or numbness in the back of the thigh and behind the knee. - **If spinal stenosis is present:** Because the nerve passageway is narrowed in a different way, many people do not feel pain even when the leg is lifted high. Importantly, a negative SLR test does not rule out a lumbar spine problem. Results vary by condition, so a specialist’s overall assessment is needed, and additional tests such as MRI may be recommended. --- ## 5\. Do I have to get a nerve block injection? Nerve block injections are \*\*not required for every patient\*\*. They are considered an optional supportive treatment when pain is not well controlled with medication or physical therapy. Their role is to reduce pain so you can return to daily activities and restart rehabilitation exercises—serving as a “bridge” to recovery rather than removing the underlying cause. **✅Four things to know before nerve block treatment** - **Medication and physical therapy first:** Unless there are serious symptoms such as paralysis or bowel/bladder dysfunction, the general principle is to start with medication and physical therapy. - **A short-term aid to support rehab:** The goal is to reduce pain so you can begin rehabilitation exercises; it does not eliminate the underlying cause (such as a narrowed canal or protruding disc). - **Watch for side effects in older adults:** Long-term use of anti-inflammatory pain relievers can burden the stomach and kidneys, and steroid components in injections can raise blood sugar. - **Disclose underlying conditions and medications:** If you have hypertension or diabetes, or take blood-thinning medications such as aspirin, inform the clinician before the procedure to help reduce bleeding-related risks. --- ## 6\. Frequently Asked Questions (FAQ) #### Q. My knee X-ray looks normal, but the numbness keeps going. What other tests should I get? If there is no abnormality in the knee bones, a detailed evaluation of the lumbar spine is needed. A basic lumbar X-ray can assess spinal alignment, and a lumbar MRI or electromyography (EMG) can help determine whether a nerve is being compressed. #### Q. When I walk for a long time, my knee feels like it’s going to burst and becomes very numb, but squatting makes it better. Is that a spine problem? Pain that improves when you squat or bend forward while walking is a typical feature of spinal stenosis. However, similar symptoms can also occur with vascular disease, so a differential diagnosis is necessary. #### Q. During my appointment, what should I make sure to ask my doctor? It’s helpful to confirm whether your knee numbness is due to joint wear (such as osteoarthritis) or lumbar nerve compression. You may also want to ask whether the prescribed anti-inflammatory pain relievers could burden your stomach or kidneys. #### Q. If I get a nerve block injection, does that mean the condition is completely cured? This injection does not remove narrowed bone structures or a protruding disc; it reduces pain by calming inflammation around the nerve. It’s important to continue walking-based rehabilitation when pain improves. [ RECOMMENDED READ Knee Test Guidelines: Order of X-ray, MRI, & Ultrasound with Insurance Rules Do you need an MRI right away for knee pain? Learn the right testing order of X-rays, MRIs, and ultrasounds to avoid unnecessary costs. ➔ ](https://www.medi-hi.com/en/info/knee%5Fjoint%5Fimaging%5Fpriority-en/) This health content has been reviewed by medical professionals, compiled from authoritative domestic and international sources, and is regularly updated in accordance with the latest clinical guidelines. Last Reviewed: Oct 19, 2026 Last Updated: Oct 19, 2026 ### Sources - Korean Society of Spine Surgery, Non-surgical Treatment Guidelines for Chronic Low Back Pain, 2016\. - Health Insurance Review & Assessment Service (HIRA), Coverage Criteria Notice for Image-Guided Nerve Root Block and Epidural Injections, 2023. - Cochrane Database of Systematic Reviews, Epidural corticosteroid injections for lumbosacral radicular pain, 2021. ※ The copyright for all content on this blog belongs to medihi. Unauthorized copying, distribution, or derivative use is strictly prohibited, and violations may result in legal action without prior notice.