Sudden Hip Pain Without an Injury: What Causes It?

Why can hip pain start suddenly without an injury?

Many hip problems build quietly for months and then cross a threshold. A tendon that has been slowly wearing, a joint with early arthritis or a labrum that has been rubbing against an irregular bone shape can all become painful after one ordinary day. A long walk, a new exercise class, a weekend of yard work or a long car ride is often enough.

So when people say there was no injury, it usually means there was no single dramatic moment. That is useful information for our team, because it points away from sudden trauma and toward the overuse and wear patterns below.

What are the common causes of sudden hip pain?

These explain most cases of hip pain that seem to come out of nowhere. MedlinePlus lists each of them among the usual causes of hip pain.

• Tendon or bursa flare on the outer hip: pain over the bony point, worse lying on that side or climbing stairs
• Arthritis flare: deep groin or thigh pain and stiffness, often worse after sitting
• Labral tear or impingement: deep groin pain with pivoting, sitting or deep bending, sometimes with catching
• Referred pain from the lower back: buttock pain that may travel down the leg, sometimes with tingling
• Muscle strain: front or inner thigh pain after a burst of unfamiliar activity

How does a flare differ from a new problem?

Outer hip tendon and bursa pain often flares after a change in routine, such as more walking, a new class or long hours on your feet. MedlinePlus notes that bursitis tends to hurt when getting up from a chair, walking, climbing stairs and driving. The sore spot is usually on the outside of the hip and tender to press.

Arthritis flares feel different. MedlinePlus explains that arthritis pain is often felt in the front of the thigh or the groin. People describe a deep ache with stiffness, especially when they first stand up, and a flare can follow a busy day or a long stretch of sitting. Arthritis develops slowly, yet a hip with early wear can feel fine for years and then become painful quite quickly.

Pain from the lower back is one of the most commonly missed explanations. MedlinePlus notes that pain felt in the hip may reflect a problem in the back rather than the hip itself. That is why Dr. Stride examines the spine at every hip visit. Back-related pain often comes with tingling, numbness or pain that travels below the knee.

Which rare causes should not be missed?

A small number of sudden hip pain cases have causes that need prompt diagnosis. They are uncommon, and they are the reason pain that does not fit a normal pattern deserves imaging.

Clues that make our team look harder include pain that is constant instead of tied to movement, pain that gets worse week after week, pain that wakes you regardless of position, and pain that comes with fever, night sweats or weight loss you cannot explain. None of these proves something serious is present. Each one simply moves imaging higher on the list.

• Stress fracture: an ache that builds with activity in runners, walkers who suddenly increased mileage, or people with weak bones
• Osteonecrosis (avascular necrosis): loss of blood supply to the ball of the hip, causing a deep groin ache
• Joint infection (septic arthritis): fast-onset severe pain with fever and a hot, swollen joint
• Tumor or cancer spread to bone: constant deep pain unrelated to activity, often worse at night

Who is more likely to have one of the rarer causes?

Risk factors help our team decide how quickly to image the hip. AAOS OrthoInfo lists heavy alcohol use, long-term corticosteroid medicines, prior hip injury and conditions such as sickle cell disease and lupus as risk factors for osteonecrosis, which is most common between ages 40 and 65. MedlinePlus advises contacting a provider for sudden hip pain if you have sickle cell disease or use long-term steroids.

Stress fractures follow a jump in activity. AAOS OrthoInfo notes that they often appear three to four weeks after starting a new routine or season, and that people with osteoporosis can develop them even with everyday activities. For cancer, AAOS OrthoInfo advises that anyone with a history of cancer who develops new bone pain, especially pain not tied to activity, should tell their doctor right away.

When does sudden hip pain need same-day care?

Go to an emergency room or call 911 if sudden hip pain comes with fever or chills, a hot and swollen joint, an inability to put weight on the leg or move the hip, or numbness in the groin with bladder or bowel changes. MedlinePlus explains that septic arthritis symptoms usually come on quickly with fever and intense pain that worsens with movement, and that prompt antibiotics matter for recovery.

Pain that is severe but without those signs should be checked within a few days, especially if you have risk factors for the rarer causes. Pain that lasts more than a week despite rest also deserves an exam.

How does our team find the cause?

A visit at Dr. Stride Hip & Joint starts with your history, including medicines, activity changes and past cancer or steroid use, followed by a careful exam of the hip, tendons and back. Standing X-rays are usually the first test. AAOS OrthoInfo notes that MRI can detect early bone changes, such as osteonecrosis or a stress injury, that do not yet show on X-rays.

Most people leave with a clear explanation and a plan built around non-surgical care. If hip pain arrived out of nowhere and is not settling, the Saturday Hip Pain Clinic in Memorial City is set up for new hip pain, and new patients are usually seen within the week.

Questions patients ask