Yes, prednisone can cause knee pain through several different mechanisms, some minor and some serious. The most concerning is a condition called osteonecrosis, where bone tissue dies due to reduced blood supply. But knee pain can also develop from steroid withdrawal, muscle weakening, or increased infection risk. The cause depends largely on how much prednisone you’ve taken, for how long, and whether you’re currently tapering off.
Osteonecrosis: The Most Serious Risk
The most significant way prednisone causes knee pain is through osteonecrosis, sometimes called avascular necrosis. This happens when corticosteroids disrupt blood flow to bone tissue, causing bone cells to die. Without adequate blood supply, the bone weakens, develops tiny fractures beneath the cartilage surface, and can eventually collapse. The knee is one of the joints most commonly affected, along with the hip, shoulder, and ankle.
The biological process involves multiple overlapping problems. Prednisone promotes fat buildup in blood vessels, triggers abnormal clotting, and suppresses the growth of new capillaries. It also causes blood vessel constriction by interfering with nitric oxide production. At the cellular level, corticosteroids directly kill bone-building cells. Studies in mice show a threefold increase in bone cell death in steroid-treated animals, with apoptosis (programmed cell death) affecting roughly 28% of bone cells in certain regions.
The pain from osteonecrosis typically starts as a dull, aching sensation in the knee. In one published case, a 29-year-old man developed bilateral knee pain after about a year of daily steroid use, with the pain persisting for two years before he sought treatment. The onset is often gradual, which can make it easy to dismiss early on.
How Much Prednisone Raises the Risk
Dose matters enormously. A large meta-analysis found that for every 10 mg/day increase in oral steroid dose during the first six months of therapy, the risk of osteonecrosis rises by about 4.6%. Among patients who developed osteonecrosis, 100% had been taking more than 20 mg/day during their highest month, and 93% had exceeded 40 mg/day.
Cumulative dose is equally important. Roughly 1,000 mg of oral prednisone given within a short window places patients at increased risk. One study found that a cumulative dose greater than 5,000 mg during the first three months was a critical threshold. Another calculated that a 9-gram cumulative dose given in a single month carried a 22% incidence of osteonecrosis. For patients on long-term therapy, fractures occur in 30 to 50% and osteonecrosis develops in 9 to 40%.
If you’re on a low dose (under 10 mg/day) for a short course, osteonecrosis is unlikely. The risk climbs sharply with higher doses sustained over weeks or months, and with repeated courses that stack cumulative exposure.
Knee Pain During Tapering or After Stopping
Many people notice knee pain not while taking prednisone, but while reducing the dose or after stopping entirely. This is part of steroid withdrawal syndrome, which can include joint pain, fatigue, fever, nausea, weakness, and low blood pressure. The joint pain can feel similar to an arthritis flare, which makes it confusing if you were prescribed prednisone for an inflammatory condition in the first place.
Several explanations exist for why this happens. One theory is that your body develops an increased tissue demand for steroids during treatment, and when the supply drops, tissues react with pain and inflammation. Another points to a rebound surge in prostaglandins, inflammatory molecules that prednisone had been suppressing. A third involves changes in immune signaling molecules like interleukin and tumor necrosis factor after the steroid is withdrawn. In practice, all three likely contribute.
This type of knee pain is typically temporary and improves as your body readjusts to producing its own cortisol. Tapering gradually rather than stopping abruptly reduces the severity.
Muscle Weakness Around the Knee
Prednisone can cause a condition called corticosteroid-induced myopathy, a gradual weakening and shrinking of muscles, particularly in the hips and thighs. The muscles surrounding your knee play a critical role in stabilizing the joint. When those muscles weaken, the knee absorbs more mechanical stress with every step, which can produce pain even without direct bone damage.
This type of myopathy develops slowly with long-term use. People typically notice difficulty rising from a chair, trouble climbing stairs, or a general sense that their legs feel weak. The muscle wasting itself is usually painless, but the resulting instability and altered movement patterns can make the knee ache, especially during activity. Because the onset is gradual, many people attribute the symptoms to aging or deconditioning rather than their medication.
Increased Infection Risk in the Joint
Prednisone suppresses the immune system, which raises the risk of infections throughout the body, including in joints. Septic arthritis, a bacterial infection inside the joint, is more likely in people who are immunosuppressed. Additional risk factors include age over 60, uncontrolled diabetes, elevated body weight, recent surgery, and recent skin infections. While septic arthritis remains uncommon overall, the combination of prednisone use with other risk factors can push the likelihood higher, with some estimates reaching 0.5% in high-risk groups.
Septic arthritis in the knee causes rapid-onset pain, swelling, warmth, and often fever. It feels very different from the slow, dull ache of osteonecrosis. If your knee becomes suddenly hot, swollen, and painful while you’re on prednisone, that warrants urgent medical evaluation because joint infections can cause permanent damage if not treated quickly.
Telling Prednisone Side Effects From a Flare
If you’re taking prednisone for an inflammatory condition like rheumatoid arthritis or lupus, it can be genuinely difficult to tell whether new knee pain is a medication side effect or your underlying disease flaring. A few patterns can help you sort this out.
Osteonecrosis pain tends to be persistent and worsens with weight-bearing. It often affects both knees or multiple joints simultaneously, and it doesn’t respond well to anti-inflammatory measures. A disease flare, by contrast, usually comes with other familiar symptoms of your condition and may respond to adjustments in your treatment. Withdrawal-related joint pain correlates clearly with recent dose changes.
Standard X-rays can miss early osteonecrosis because significant bone damage needs to occur before it shows up on plain films. MRI is far more sensitive for detecting early bone changes and is the preferred imaging tool when steroid-related bone damage is suspected. If you’ve been on moderate to high doses of prednisone and develop new or worsening knee pain, imaging can clarify whether bone damage is developing before it progresses to joint collapse.
What Influences Your Personal Risk
Not everyone on prednisone develops knee problems. Your risk depends on a combination of factors: total cumulative dose, peak daily dose, duration of therapy, and individual susceptibility. People with lupus appear particularly vulnerable to osteonecrosis, though the disease itself may contribute independently. Alcohol use, smoking, and pre-existing blood clotting disorders also raise the risk.
Short courses of prednisone (a few days to two weeks at moderate doses) rarely cause the bone or muscle complications described above, though withdrawal-related joint aches can occur even after brief courses. The serious structural damage to bone and muscle is primarily associated with sustained use at higher doses over weeks to months. If you’re on a longer course and notice new knee pain that wasn’t there before, bringing it up promptly allows for early detection, which is when interventions are most effective at preventing permanent joint damage.