Arthritis can absolutely cause numbness in the legs, and it does so through several distinct pathways. The most common involves degenerative arthritis of the spine physically squeezing nerve roots, but inflammatory forms like rheumatoid arthritis and ankylosing spondylitis can damage peripheral nerves through entirely different mechanisms. Even the medications used to treat arthritis occasionally contribute to the problem, which makes sorting out the true cause genuinely tricky.
How Spinal Arthritis Compresses Leg Nerves
The single most frequent way arthritis leads to leg numbness starts in the lower back, not the legs themselves. Degenerative arthritis of the facet joints, the small paired joints that run along the back of each spinal vertebra, causes those joints to enlarge over time. As the joint surfaces deteriorate, the body tries to stabilize them by growing extra bone, producing bony spurs called osteophytes. Those spurs can project into the narrow channels where spinal nerve roots exit the spine, physically trapping the nerve. Researchers studying this process documented how disc narrowing and vertebral slippage place extra stress on the facet joints, accelerating the growth of osteophytes that eventually constrict the space around the nerve root and compress it.1Journal of Neurosurgery. Lumbar nerve root compression at the intervertebral foramina caused by arthritis of the posterior facets
When this happens in the lower lumbar spine, the compressed nerves serve the legs, and the result is numbness, tingling, or pain that radiates from the low back down through the buttock and into the leg. This is what clinicians call lumbar spinal stenosis when the canal itself narrows, or foraminal stenosis when the exit holes for individual nerve roots close down. The symptoms tend to be positional: standing and walking make them worse, while sitting or leaning forward often provides relief, because bending forward slightly opens up the compressed spaces.
Studies of patients awaiting surgery for degenerative lumbar stenosis have found that leg numbness is one of the hallmark complaints, alongside pain and difficulty walking.2The Spine Journal. Objective predictors of six-minute walk distance after surgery in patients with lumbar spinal stenosis In research measuring how far these patients can walk before symptoms force them to stop, the presence and severity of leg pain after walking was the strongest factor limiting distance, even more so than the patient’s disability score.3PubMed. Predictors of objectively measured walking capacity in people with degenerative lumbar spinal stenosis
Inflammatory Arthritis and Peripheral Neuropathy
Degenerative arthritis damages nerves by mechanical compression. Inflammatory types of arthritis can damage nerves in a fundamentally different way: through the immune system itself. In rheumatoid arthritis, the chronic inflammatory process does not stay confined to the joints. Systemic inflammation, direct nerve compression from joint destruction, and even the psychological burden of chronic disease all contribute to neurological symptoms.4PubMed. Neuropsychiatric manifestations in rheumatoid arthritis Research into risk factors for peripheral neuropathy in rheumatoid arthritis patients identified elevated blood platelets, higher C-reactive protein (a marker of active inflammation), and low albumin as probable contributors, reinforcing the idea that poorly controlled inflammation itself is toxic to nerves.5PubMed. Clinical characteristics of rheumatoid arthritis patients with peripheral neuropathy and potential related risk factors
At the cellular level, the connection between joint inflammation and nerve dysfunction is becoming clearer. Pain-sensing neurons express receptors for the inflammatory cytokines that flood arthritic joints, and when those cytokines bind, the neurons become persistently oversensitized to mechanical stimuli. This process, called peripheral sensitization, helps explain why arthritic joints hurt more than the structural damage alone would predict, and why numbness and altered sensation develop even without direct physical nerve compression.6PubMed Central. Nociceptive neurons detect cytokines in arthritis
Ankylosing spondylitis presents yet another variant. While best known for stiffening the spine, it can occasionally cause polyneuropathy affecting both the arms and legs. A case report of a 45-year-old man with ankylosing spondylitis documented tingling and numbness in all four limbs; after extensive testing ruled out every other explanation, the disease itself was identified as the cause of his nerve damage.7PubMed Central. Axonal sensory-motor polyneuropathy in ankylosing spondylitis: A case report This is considered uncommon, but it illustrates how inflammatory arthritis can reach well beyond the joints.
Psoriatic arthritis adds another layer. Research comparing psoriatic arthritis patients with and without neuropathic-like pain found that those with likely neuropathic pain had higher disease activity across the board: more swollen and tender joints, more enthesitis (inflammation where tendons attach to bone), more dactylitis, greater fatigue, and higher rates of anxiety and depression.8PubMed Central. Neuropathic-like pain in psoriatic arthritis: evidence of abnormal pain processing The numbness and burning sensations in these patients seem to reflect abnormal pain processing driven by widespread inflammation rather than a pinched nerve at one specific site.
Neuropathic Pain in Hip and Knee Osteoarthritis
It is not just spinal or inflammatory arthritis that can produce nerve-related symptoms in the legs. Standard osteoarthritis of the hip and knee, the kind that develops from decades of wear, can generate neuropathic pain in a meaningful fraction of patients. A study of people with end-stage hip and knee osteoarthritis found that roughly a third of women and more than a quarter of men met screening criteria for possible or likely neuropathic pain.9Osteoarthritis and Cartilage. Neuropathic pain in end-stage hip and knee osteoarthritis: differential associations with patient-reported pain at rest and pain on activity This pain, which can include numbness, burning, and tingling, was more closely linked to pain at rest than to pain during activity, which is the opposite of what you’d expect if it were purely mechanical. For women, both rest pain and activity pain contributed to neuropathic scores, while for men, only rest pain showed a significant association.
The clinical takeaway is that if you have severe knee or hip arthritis and experience numbness or odd sensations in the affected leg even when you’re sitting still, it may not be a separate problem. The arthritis itself may have altered how your nervous system processes signals from that joint.
Nerve Entrapment Below the Spine
Not all arthritis-related nerve compression happens in the lower back. Arthritic changes in the ankle and foot can trap the nerves that run through those areas, producing numbness in the foot, toes, or lower leg. The usual culprits include osteophytes (the same bony spurs that cause trouble in the spine), tenosynovitis (inflammation of tendon sheaths), ganglion cysts, swelling, and vascular lesions, all of which have been identified as secondary causes of nerve compression in the ankle and foot region.10PubMed. Nerve Entrapment in Ankle and Foot: Ultrasound Imaging Tarsal tunnel syndrome, the lower-limb equivalent of carpal tunnel syndrome, is the classic example. The tibial nerve passes through a narrow channel behind the inner ankle bone, and arthritic swelling or bone spurs can squeeze it, causing numbness and tingling across the sole of the foot.
The diagnostic challenge with lower-limb entrapment neuropathies is that their symptoms can mimic problems originating in the spine. If you have numbness in your foot, it might be from a pinched nerve at the ankle or from a compressed nerve root in your lower back. Distinguishing between the two typically requires a careful neurological exam looking for characteristic patterns of weakness and sensory loss in specific distributions.
When Arthritis Medications Cause Numbness
Sometimes the numbness comes not from the arthritis but from the drugs prescribed to treat it. Several medications commonly used in rheumatic diseases are known to cause peripheral neuropathy as a side effect. A comprehensive review identified over 50 drugs in clinical use capable of producing sensory or mixed sensory-motor neuropathy, including antirheumatic agents such as gold compounds, indomethacin, and chloroquine.11The BMJ. Drug-induced peripheral neuropathies Gold compounds are rarely used today, but chloroquine and hydroxychloroquine remain part of the treatment landscape for various rheumatic conditions, and methotrexate, while not primarily neurotoxic, can indirectly contribute by depleting folate.
This matters because a person with rheumatoid arthritis who develops leg numbness might assume the disease is progressing when the real culprit is a medication. The standard approach is to check whether symptoms appeared or worsened after starting a new drug, and if so, to discuss the timing with a rheumatologist. Drug-induced neuropathy is usually reversible if caught early enough, but it can become permanent if the offending medication is continued for too long.
Telling Nerve Problems From Circulation Problems
Leg numbness in someone with arthritis is not always caused by nerves. Poor circulation can produce strikingly similar symptoms, and telling the two apart matters because the treatments are completely different. Both neurogenic claudication (from spinal stenosis) and vascular claudication (from narrowed arteries) cause leg discomfort with walking, and both forms can be accompanied by numbness or heaviness.
Researchers have identified several clinical patterns that help separate the two. Patients whose symptoms occur above the knees, are triggered simply by standing, improve with sitting, and are relieved by bending forward (the “shopping cart sign,” named after the posture of leaning on a cart) have a strong likelihood of neurogenic claudication from spinal stenosis. In contrast, patients whose symptoms are concentrated in the calves and are relieved by standing still, without needing to sit or bend, are more likely to have vascular claudication from arterial disease.12PubMed Central. The reliability of differentiating neurogenic claudication from vascular claudication based on symptomatic presentation
The overlap can be so close that imaging studies of both the spine and the blood vessels are sometimes needed to avoid operating on the wrong problem. Vascular claudication from blockages in the aorta and iliac arteries can present as low back, hip, and buttock pain while walking, symptoms that closely mirror those of lumbar stenosis.13PubMed Central. Differentiation of vascular claudication due to bilateral common iliac artery stenosis versus neurogenic claudication with spinal stenosis Some people have both conditions simultaneously, which makes accurate diagnosis even more critical.
Treatment Options and Why Timing Matters
For arthritis-related leg numbness caused by nerve compression in the spine, treatment ranges from conservative management to injections to surgery, depending on severity. Epidural steroid injections are widely used and do help some patients with radicular pain, though the benefit is often limited in duration. Steroids appear to speed recovery and help people reduce pain medication and increase activity while the body’s natural healing takes its course, rather than providing a permanent fix.14PubMed. Epidural steroid therapy for back and leg pain: mechanisms of action and efficacy
More targeted approaches are being explored. One study compared an anti-inflammatory biologic (tocilizumab, which blocks a specific inflammatory signal called interleukin-6) delivered epidurally against a standard steroid injection. The biologic was more effective for leg pain, back pain, and leg numbness across multiple follow-up time points.15PubMed Central. Efficacy of epidural administration of anti-interleukin-6 receptor antibody onto spinal nerve for treatment of sciatica This remains experimental, but it reflects a shift toward targeting the specific inflammatory pathways that sustain nerve irritation rather than broadly suppressing inflammation with steroids.
When conservative measures fail, decompression surgery to physically relieve pressure on the nerve is the main surgical option. A study following over 300 patients after decompression surgery for lumbar degenerative conditions found that numbness scores improved steadily over the first six months, though the improvement in numbness was slower than the improvement in pain.16PubMed Central. Predictive factors for residual leg numbness after decompression surgery for lumbar degenerative diseases Pain relief tends to come relatively quickly after surgery; numbness takes longer to resolve and sometimes does not resolve completely.
Timing turns out to be one of the strongest predictors of a good surgical outcome. Research has shown that patients with lumbar spinal stenosis who had persistent leg numbness for more than three months before surgery had significantly poorer outcomes at two years compared to those who were operated on sooner.17PubMed Central. Poorer surgical outcomes at 2 years postoperatively in patients with lumbar spinal stenosis with long-term preoperative leg numbness: a single-center retrospective study In another study, roughly 30% of patients had residual leg numbness two years after surgery, and the strongest predictor of that residual numbness was having resting numbness before the operation, meaning the numbness was present even when not standing or walking.18PubMed Central. Predictors of residual symptoms in lower extremities after decompression surgery on lumbar spinal stenosis The practical implication is clear: if conservative treatment is not working and numbness is persistent, delaying surgery in the hope that things will improve on their own can backfire. Nerves that have been compressed for a long time are harder to rehabilitate than nerves caught early.
Cauda Equina Syndrome in Ankylosing Spondylitis
One rare but serious complication deserves separate mention because it constitutes a medical emergency. Cauda equina syndrome occurs when the bundle of nerve roots at the base of the spinal cord is severely compressed, causing sudden-onset numbness in both legs, loss of bladder or bowel control, and sometimes weakness or even paralysis below the waist. It has been documented as a neurologic complication of longstanding ankylosing spondylitis, though it remains uncommon.19The Journal of Rheumatology. Cauda Equina Syndrome in Ankylosing Spondylitis: Challenges in Diagnosis, Management, and Pathogenesis
What makes this worth knowing is the time pressure. Unlike the gradual numbness from spinal stenosis, cauda equina syndrome demands emergency surgery, usually within hours, to prevent permanent damage. The red flags are numbness that involves the groin or inner thighs (so-called “saddle anesthesia”), sudden difficulty urinating or having bowel movements, and rapidly worsening weakness in both legs. Anyone with long-standing ankylosing spondylitis who develops these symptoms should go to an emergency room immediately rather than scheduling a routine appointment.
The broader pattern across all of these conditions is that the type of arthritis, the location, and the mechanism of nerve involvement determine both the urgency and the treatment approach. Numbness from degenerative spinal stenosis tends to come on gradually and may respond to conservative treatment for months or even years. Numbness from inflammatory arthritis damaging peripheral nerves may improve with better disease control. Numbness from a trapped nerve at the ankle may resolve once the swelling is managed or the bony spur is removed. And numbness that is actually from compromised blood flow needs an entirely different specialist. Sorting out which pathway is responsible is the essential first step, and it often requires more than one type of test to get there.