Hip vs Knee Arthritis in Women: How to Tell Which Joint Is the Problem

Point to where it hurts: true hip osteoarthritis is usually felt in the groin or front of the thigh, while knee osteoarthritis is felt over or around the kneecap, but the two trade signals so often that a knee that hurts can be a hip in disguise.

For two years I called my problem a “knee”, because that is where it ached when I climbed stairs. It took a clinician pressing on the front of my thigh and rotating my hip to show me how much of my own map was guessed. The body is not tidy about pain: the leg is one chain, and a worn joint at the top can shout from the bottom. Telling hip and knee arthritis apart is less about a clever test and more about giving a clinician the few details that actually point at the right joint.

Why this gets confused in the first place

Hip and knee osteoarthritis (OA) are easy to mix up because they are the same disease in two stations of the same limb. OA is a degenerative disease of the whole joint, in which cartilage thins and roughens and the bone, ligaments, and joint lining are all involved, with low-grade inflammation in the mix ¹. That same process can be running in your hip and your knee at once, and the leg transmits load from one to the other with every step. OA overall affects roughly 595 million people worldwide, about 7.6% of the global population, and the knee is the large joint most often disabled by it ².

The women’s angle matters here too. Both hip and knee OA are more common and often more severe in women, particularly after about age 50, and they share the familiar risk factors: age, female sex, excess body weight, prior joint injury, family history, and joint malalignment ². So the question is rarely “is it arthritis”, it is “which joint, or both”.

Location: the single most useful clue

Where you feel the pain separates the two more reliably than how it feels. True hip OA is typically felt in the groin or the front of the thigh, sometimes the buttock, and many people instinctively cup the side of the hip in a C-shape with the thumb and fingers when describing it. Knee OA, by contrast, is felt over the kneecap, along the joint line at the sides of the knee, or deep inside the joint.

The trap is referred pain. A worn hip very commonly sends pain downward along the front of the thigh to the knee, so the knee can ache while the real trouble sits in the hip. This is why a knee that hurts, but shows little when the knee itself is examined, earns a hip check. The reverse is much rarer: knee OA does not usually masquerade as groin pain. So groin pain is a strong vote for the hip, while knee pain alone leaves the hip still in the running.

How each joint moves when it is worn

The movements that set off the pain are the next clue, because the hip and knee are stressed by different actions. Hip OA tends to stiffen rotation and deep flexion: turning to look behind you, putting on socks and shoes, crossing your legs, and getting in and out of a low car seat. A common early sign is a quiet loss of the ability to rotate the hip inward, long before pain dominates.

Knee OA flares with a different set: going up and especially down stairs, kneeling, squatting, and standing up after sitting for a while. Stiffness after rest that eases as you move, sometimes called the “gel” feeling, shows up in both joints, so it does not separate them. Tracking which specific movements reliably trigger your pain, and noting it before an appointment, often points at the joint before any imaging is ordered.

What a clinician actually does to tell them apart

Diagnosis of OA is mainly clinical: history plus examination, with X-ray used to confirm and grade what the examination already suspects ³. A clinician will move each joint deliberately, because hip rotation and knee bending load different structures, and the joint that reproduces your pain on movement is the prime suspect. They will also watch you walk, since a hip and a knee produce different limps, and check whether pressing along the knee joint line hurts, a finding that points back at the knee rather than a referred hip.

X-rays of the suspected joint then confirm the picture and grade the wear, commonly on the Kellgren-Lawrence scale of 0 to 4. One caution to carry into the room: symptoms and imaging often do not match closely, so a clinician treats the joint that is causing trouble, not simply the one that looks worst on film ³. If the examination says hip and the knee X-ray looks mild, the hip is still the likely culprit.

When it is both, and why the order matters

Having one arthritic joint does not protect the other, and with shared age, weight, and genetic risk, both hips and knees can be affected together. A limp from a painful hip also changes how you load the knee on the same or opposite leg, and a stiff knee can throw extra work onto the hip, so one joint quietly recruits the next. If both hurt, say so plainly, because clinicians often plan the sequence of treatment around the joint limiting you most.

This is also where the two paths diverge in care, even though the first-line plan rhymes. For both joints, international guidance puts non-surgical care first: exercise and physiotherapy, weight management, and education or self-management are the core, well-supported steps, and weight is the largest modifiable factor, with a loss of about 5 to 10% of body weight improving symptoms for many people ⁴. The exercises differ by joint, but the principle is identical, and getting the diagnosis right is what lets you target the work. If the knee turns out to be the joint, the companion overview of knee osteoarthritis in women walks through diagnosis, staging, and the conservative steps in order, and alternatives before knee surgery covers what actually helps before a replacement is on the table.

What I should have done sooner is stop diagnosing myself by where it ached and instead bring a clinician the useful details: exactly where the pain sits, which movements trigger it, and whether anything radiates. Those three answers do more to point at the right joint than any guess about which one feels worse.

This article is general information, not medical advice. For diagnosis and decisions about your own joints, see a qualified clinician.