Does Arthritis in Knee Cause Hip Pain?

Arthritis in the knee can absolutely contribute to hip pain, and it does so more often than most people realize. The connection runs through altered walking mechanics, muscle wasting that extends well above the knee, and postural shifts that change how force travels through the pelvis. In a large cohort of people with early knee or hip osteoarthritis, roughly 42% reported pain in both joints at the same time, hinting that these two problems rarely stay neatly separated.

How a Bad Knee Changes the Way You Load Your Hip

When your knee hurts, you change the way you walk, whether you notice it or not. You may shorten your stride, shift weight to the opposite leg, or rotate your foot outward. These adjustments are unconscious, and they ripple up and down the entire lower limb. Research comparing people with knee osteoarthritis to healthy controls found that the range of motion at both the hip and ankle was significantly smaller in the osteoarthritis group, and those reductions tracked closely with how limited the knee itself was.

The forces involved also shift in measurable ways. In people with knee osteoarthritis, the sideways bending moment at the hip was smaller than in controls, while the same moment at the ankle was larger. The knee’s own sideways loading correlated with hip loading, suggesting these joints don’t operate in isolation during walking.

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A separate biomechanics study took this further by looking at stair climbing, which demands more from both joints than flat walking. People with knee osteoarthritis loaded their same-side hip significantly more during stair ambulation compared to healthy controls, and the excess loading also showed up in the opposite hip and knee.

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That finding matters because stairs are unavoidable for many people, and the extra hip stress they create during a task you repeat multiple times a day can accumulate into genuine discomfort.

A scoping review covering a decade of research confirmed a consistent pattern: people with knee osteoarthritis tend to develop weakness in the hip abductor muscles (the muscles on the outer side of the hip that stabilize your pelvis when you stand on one leg). As knee arthritis worsens, the hip increasingly drifts into an abducted position during walking, a compensatory posture that protects the knee but places abnormal demand on hip structures.

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Muscle Wasting That Reaches the Hip

Pain does more than make you limp. Persistent knee pain appears to trigger selective muscle loss on the affected side, and the damage doesn’t stop at the thigh. An AI-assisted cross-sectional study found significant volume reductions in three quadriceps components on the painful side, which was expected, but it also found meaningful atrophy in the gluteus maximus, the large hip muscle that powers walking, climbing, and standing up from a chair.

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The researchers described this as “pain-induced selective muscle sarcopenia,” distinguishing it from the generalized muscle loss that comes with aging. In other words, the knee pain itself appears to act as an accelerant for muscle breakdown in specific muscles. A weaker gluteus maximus means less hip stability, which means more stress on hip joint surfaces and surrounding soft tissues, which can eventually translate into hip pain, even if the hip joint itself started out healthy.

How Posture and Pelvic Tilt Play a Role

Knee arthritis often limits how fully you can straighten the joint, creating what clinicians call a flexion contracture. Even a modest inability to fully extend the knee has cascading effects on posture. A gait study simulating knee flexion contracture found that when the knee stays slightly bent, the pelvis tilts backward while standing. During walking, the trunk and pelvis both tilt forward more than normal to compensate.

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These postural changes push the hip joint into positions it wasn’t designed to sustain for prolonged periods. A forward-tilted pelvis loads the front of the hip differently, and the muscles around the hip have to work harder to maintain balance. Over months and years, this altered posture can contribute to hip discomfort, bursitis, or muscle fatigue even in someone whose hip cartilage looks fine on an X-ray. This is one reason people with longstanding knee problems sometimes develop hip or lower-back pain seemingly out of nowhere.

When the Pain Goes the Other Direction

The knee-to-hip pain pathway gets an interesting twist when you learn that hip problems can also masquerade as knee pain. The hip joint and the knee share nerve supply through branches of the femoral and obturator nerves, which means a problem originating in the hip can produce pain that the brain perceives as coming from the knee.

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Animal research has identified a specific mechanism for this: some nerve cells in the spinal cord send branching fibers to both the hip joint and the skin around the knee. When the hip joint is inflamed, those shared neurons can fire signals that the brain interprets as knee pain.

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This two-way neural crosstalk creates a real diagnostic puzzle. A study of 1,000 patients presenting with knee pain found that about 14% actually had referred pain originating from the hip, with a higher rate in women than in men.

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The practical takeaway is important: if you’ve been treating knee arthritis but also have nagging hip pain, the relationship could be biomechanical (your knee changing how you walk), but it could also be neurological (your hip referring pain to the knee, and the “knee arthritis” was never the full story). A thorough clinical exam that includes the hip is essential whenever knee pain doesn’t respond as expected to treatment.

How Common Is It to Have Both Knee and Hip Pain?

Extremely common, as it turns out. In a large cohort study tracking people with early knee or hip osteoarthritis over 10 years, about 83% reported knee pain, 59% reported hip pain, and 42% reported pain in both at the start of the study.

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That 42% overlap is striking, especially in a cohort where people were recruited early in their disease course. It suggests the knee-hip connection starts well before arthritis becomes advanced.

A population-based survey of older adults found that roughly one in five reported hip pain and about a third reported knee pain, with around 11% reporting both. Fewer than half of all symptomatic people had pain confined to just one joint.

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The gap between the two studies (42% vs 11% overlap) reflects different populations: one was a clinical cohort already diagnosed with osteoarthritis, while the other was a general community sample. But both make the same point: pain rarely stays in one joint.

Why Women May Be More Affected

Sex differences show up repeatedly in osteoarthritis research. Women are more likely to develop osteoarthritis, and when they do, the disease tends to be more severe in the knee.

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But the sex differences extend beyond simple prevalence. A study examining systemic inflammation and painful joint burden found that women with osteoarthritis reported pain in more joints than men (an average of about 3.7 joints vs. 2.5) and were more likely to have pain in four or more joints. Increasing levels of the inflammatory marker CRP were associated with a greater number of painful joints in women but not in men.

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This matters for the knee-to-hip question because it suggests that in women, arthritis may be more of a whole-body inflammatory process rather than a purely local mechanical problem. If systemic inflammation drives joint pain across multiple sites, controlling that inflammation (through weight management, anti-inflammatory medication, or exercise) could help prevent knee arthritis from dragging the hip down with it. The diagnostic challenge mentioned earlier, where hip problems refer pain to the knee, was also more common in women, which adds another layer of complexity.

Why Strengthening the Hip Helps the Knee

If the hip and knee are mechanically linked, it stands to reason that strengthening one could protect the other. That logic has been tested directly, and the results are encouraging. A systematic review of studies on hip muscle strengthening for knee osteoarthritis found clear benefits across the board: reduced knee pain, better physical function, and stronger hip muscles.

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An eight-week clinical trial of hip abductor strengthening in people with medial knee osteoarthritis found that the exercise group had reduced knee pain and improved ability to perform a sit-to-stand task compared to a control group.

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A randomized controlled trial comparing standard knee exercises to knee exercises plus hip abductor strengthening found that both groups improved over 10 weeks, but the group doing hip exercises improved faster, reaching meaningful pain relief roughly two weeks sooner and better symptom control about four weeks sooner.

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The logic is straightforward: stronger hip abductors stabilize the pelvis during walking, which reduces the sideways forces that drive knee osteoarthritis progression. As a bonus, those same muscles protect the hip from the compensatory overloading described earlier. Hip strengthening for knee arthritis is one of those interventions that addresses both the original problem and its downstream consequences at the same time.

What Knee Braces Do to the Hip

Unloader knee braces, designed to take pressure off the damaged compartment of the knee, are a common conservative treatment for medial knee osteoarthritis. They work well for the knee, but their effects don’t stop there. A biomechanics study found that wearing an unloader brace reduced the hip adduction angle on the braced side by about 2.6 degrees during the first half of the walking stance phase and lowered the hip’s sideways bending moment. The brace also altered forces at the opposite hip and the opposite knee.

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These changes are small in isolation, but they demonstrate the mechanical interconnection between the knee and hip in real time. Changing how the knee bears weight immediately changes hip mechanics. For someone wearing a brace daily, those altered hip mechanics add up to a meaningful shift in how the hip joint is loaded over weeks and months. This is generally a positive shift since the brace reduces the compensatory patterns that stress the hip, but it also means that any brace fitting should consider the whole lower limb, not just the knee.

Getting the Diagnosis Right

One of the most underappreciated aspects of the knee-hip connection is how easily it leads to misdiagnosis. If you go to a doctor with knee pain and they find arthritis on an X-ray, the case seems closed. But arthritis on imaging doesn’t always explain the pain, and pain doesn’t always come from where you feel it. The study that found 14% of knee-pain patients actually had referred pain from the hip underscores how often the hip gets overlooked.

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This works both ways. If you have knee arthritis and develop new hip pain, it could be the biomechanical cascade described above, but it could also be the hip developing its own arthritis independently. The two joints share many of the same risk factors: age, excess body weight, prior injury, genetic predisposition. Having arthritis in one joint doesn’t cause arthritis in the other through some direct biological pathway, but the mechanical stresses and muscle changes make it more likely, and the shared risk factors mean you were probably predisposed to both.

The difference matters for treatment. If your hip pain is primarily a compensation problem from altered knee mechanics, strengthening exercises, gait retraining, and proper bracing can make a real difference. If the hip has developed its own structural arthritis, those interventions still help but may not be sufficient on their own. A clinical examination that includes internal rotation of the hip, an assessment of gait, and possibly imaging of the hip is worthwhile for anyone whose knee arthritis treatment isn’t fully controlling their symptoms.

Practical Steps When Knee Arthritis and Hip Pain Overlap

If you’re dealing with knee arthritis and have started noticing hip discomfort, a few things are worth doing sooner rather than later:

• Ask for a hip exam: If your provider has focused exclusively on the knee, request that they assess the hip’s range of motion and strength. Internal rotation of the hip is one of the first movements to become limited or painful when the hip joint is involved.
• Add hip exercises: Evidence supports hip abductor and gluteus maximus strengthening as beneficial for both knee pain and hip stability. These are typically simple exercises such as side-lying leg raises, clamshells, and bridges that can be done at home.
• Watch your gait: If you’re limping or favoring one side, consider a few sessions with a physical therapist who can identify compensatory patterns and help correct them before they create new problems.
• Reconsider footwear and bracing: Shoes with good support and properly fitted knee braces can reduce the compensatory forces that travel up to the hip. A brace that unloads the knee has measurable effects on hip mechanics.
• Address weight if relevant: Every extra pound of body weight translates to multiple additional pounds of force across the knee and hip during walking. Even modest weight loss reduces loading at both joints.

The broader point is that treating a knee in isolation, without considering how the rest of the lower limb is adapting, misses a large part of the picture. The hip and knee are partners in every step you take, and a problem in one reliably affects the other.

The Question of Timing

One aspect that research hasn’t fully nailed down is how long knee arthritis typically takes to produce hip symptoms. The biomechanical changes are measurable even in mild knee osteoarthritis, and muscle wasting in the gluteus maximus appears to track with knee pain severity rather than disease duration alone.

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That suggests pain intensity matters more than how many years you’ve had the diagnosis. Someone with moderate knee pain who walks a lot may develop hip problems faster than someone with mild pain who is more sedentary, though sedentary behavior brings its own muscle-wasting risks.

The 10-year cohort data showing that 42% of early-osteoarthritis patients already had both knee and hip pain at baseline suggests the overlap starts early.

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Waiting until hip pain becomes severe before addressing the knee-hip connection misses the window where exercise and gait correction are most effective. The evidence points toward acting early, when compensatory patterns are still new enough to be reversed with consistent effort.