Inside the Joint
Each hip is a ball-and-socket joint. The ball is the top of your thighbone (femoral head). The socket (acetabulum) is in your pelvic bone. Smooth, slippery tissue called cartilage lets the ball and socket glide against each other when you move. A thin lining (synovium) tops the cartilage and makes a bit of synovial fluid, which further eases rubbing. Tendons, ligaments, and muscles complete the joint.
It's the "wear and tear" type of arthritis that many people get in middle age. Cartilage on the ball end of the thighbone and in the hip socket slowly breaks down and causes grinding between bones. You'll have stiffness, and you might feel pain in your crotch and at the front of your thigh that radiates to your knee and behind. It's often worse after a hard workout or when you don’t move for a while.
With RA, your immune system attacks parts of your body, which can include the synovium. This normally thin lining starts to thicken and swell and to make chemicals that damage or destroy the cartilage that covers the bone. Doctors don't know why this happens. When one hip is affected, the other often gets it too. The joint may hurt and swell, and you might notice heat and red skin around it.
Too much sitting and too little exercise, among other things, might irritate and inflame the sciatic nerve, the largest in the human body. It runs from the bottom of your spine through your hips and down the back of your leg, which is where you'll feel the pain when it's pinched. It will radiate from the hip and might be mild, sharp, tingly, numb, or even like an electric shock.
It's a break in the top part of your thighbone. If you're young and healthy, it takes a lot of power, like a serious car wreck, to do it. But if you're over 65, especially if you're a woman, or you have brittle bones (osteoporosis), even a minor fall can cause it. Your groin and the top, outer part of your thigh will likely hurt, especially when you try to flex the joint. In a complete break, one leg may look shorter than the other.
It happens when the ball on top your thighbone is knocked out of its pelvic socket. It usually takes a lot of force, as when you fall from a ladder or crash a car. All that power often causes other injuries like tissue tears, bone fractures, and could even damage nerves, cartilage, and blood vessels. Get to a hospital. It's very painful, and you won’t be able to move your leg much, if at all, until your doctor starts to treat it.
Here, the socket of your hip isn't deep enough for the ball to fit firmly inside. The looseness can vary from just a little jiggly, to fairly easy to push out (dislocate), to complete dislocation. Babies may be born with it, or they may get it in their first year. Female, firstborn, and breech birth (feet-first) babies get it more often. You could also cause it if you wrap (swaddle) your baby's legs too tightly.
It's when fluid-filled sacs, or "bursae," that ease friction between muscle, tendons, and bones get irritated and swollen. It can happen on the outside bony part of your hip (trochanteric bursitis), where it causes sharp, intense pain that dulls and spreads out over time. Less often, it happens on the inside (hip bursitis), where it causes pain in the groin. Either may worsen when you walk, squat, or climb stairs.
You can damage the cartilage at the bony edge of your hip socket that helps keep the joint together. You could injure it suddenly in a twisting fall or an accident, or you might simply wear it away with the same motion over time. You might feel clicking sensations and have pain in your groin or hip. You're more likely to get it if you play ice hockey, soccer, football, or golf.
It's when you overstretch or tear any of the muscles and tendons that help your hip joint move. (It's a "sprain" when it happens to a ligament.) It could affect lots of muscles like your hip flexors, glutes, abductors, adductors, quadriceps, and hamstrings. The area might swell, weaken, and hurt, especially when you use it. Rest, ice, and over-the-counter pain relievers are often enough to get you healthy again.
RICE: Rest, Ice, Compress, Elevate
It's a good first step for any hip pain. Rest, but don't stop all movements (that could make things worse), just the ones that hurt. Ice for 20 minutes at a time, and use a cloth so you won't damage your skin. Compress the painful area with an elastic bandage, but not too much. Loosen it up if you see skin turning blue. Elevate the injured part on a pillow or stool to stop blood from pooling there.
Nonsteroidal anti-inflammatory drugs, or NSAIDs, are often used to lessen pain and inflammation for arthritis and other painful hip problems. Most are pills, but creams and gels are also available. Your doctor can help you treat more serious pain and underlying conditions with corticosteroids, pain relievers, and drugs to treat autoimmune and inflammatory diseases.
When to Go to the Doctor
If home care doesn't curb your pain, make an appointment with your doctor. Ask someone to drive you to the emergency room if an injury caused your hip pain and your hip doesn't look normal, or you can't move your leg or put weight on it. You should also go to the ER if you have intense pain, sudden swelling, or any sign of infection like fever, chills, and red skin.
Your doctor will want to know about your symptoms and health history. Be sure you mention any falls or injuries you've had, and any other joints that bother you. Your doctor will also examine your hip and might check to see how well it moves (range of motion). You may also get blood tests or imaging, like an X-ray or MRI.
Some of the same things that help treat hip pain can make it less likely for you to get it in the first place. For example, if you're overweight, losing even a few pounds may ease stress on the joint. Exercise (ask your doctor about the right amount) can also help. Take it easy. Start with a warmup and stretch, stop when something hurts, wear the right shoes, and seek soft surfaces like hiking trails, not hard ones like asphalt and concrete.