Hip Pain

Picture of the anatomy of the hip

Facts You Should Know About Hip Pain

1. The hip is a ball and socket joint that attaches the leg to the torso of the body. In the hip joint, the head of the femur (thighbone) swivels within the acetabulum, the socket, made up of pelvic bones. While many causes of hip pain can arise from the joint itself, there are numerous structures surrounding the hip that can also be the source of pain. Trauma is often the cause of hip pain, but any source of inflammation may cause pain in the hip area. Pain is one of the symptoms of inflammation, along with swelling, warmth, and redness; together these are signals and symptoms that a problem may exist.
2. Seek medical care if you are concerned that a bone is broken, if you're experiencing fever and swelling, or you have a loss of bladder or bowel function.
3. Hip pain treatment depends upon your underlying illnesses and diagnosis.

Pain may arise from structures that are within the hip joint or from structures surrounding the hip.

The hip joint is a potential space. This means that normally there is a minimal amount of fluid inside the joint to allow the femoral head to glide in the socket of the acetabulum. Any illness or injury that causes inflammation will cause this space to fill with fluid or blood, stretching the hip capsule lining and resulting in pain.

Articular cartilage lines the femoral head and the acetabulum, allowing the bones to move within the joint with less friction. Also, the socket area of the acetabulum is covered with tough cartilage called the labrum. Just like any other joint cartilage, these areas can wear away or tear and become the source of pain. There are thick bands of tissue that surround the hip joint, forming a capsule. These help maintain the hip joint stability, especially with movement, keeping the femoral head firmly in the acetabulum.

Movement at the hip joint is possible because of the muscles and tendons that surround the hip and that attach across the hip joint, allowing the leg to move in different directions. Aside from controlling movement, these muscles also act together to maintain joint stability. There are large bursas (fluid-filled sacs) that surround areas of the hip and allow the muscles and tendons to glide more easily over bony prominences. Any of these structures can become inflamed.

Pain can be referred from other structures outside the hip joint, meaning that while the hip hurts, the problem may potentially originate elsewhere. Inflammation of the sciatic nerve as it arises from the spinal cord in the back can cause hip pain, especially if the L1 or L2 nerve roots are involved. Other types of nerve inflammation may manifest as hip pain, including pain arising in the lateral femoral cutaneous nerve of the thigh, which is often inflamed in pregnancy. Pain from an inguinal or femoral hernia or a sports hernia (athletic pubalgia) may also cause pain that is felt in the hip.

Hip pain is a nonspecific complaint that requires the health care professional to find the underlying cause of the many potential injuries or illnesses. The approach to the diagnosis of hip pain requires an open mind because the source of trauma or the cause of the illness may not be readily apparent.

Hip Fracture

Falls are the most common reason that elderly people break a hip. The fracture is due to a combination of two effects of aging, osteoporosis (thinning of bones), and a loss of balance. These two risk factors are the potential cause of many falls. Occasionally, the bone may spontaneously break due to osteoporosis and become the cause of the fall.

Bones may also weaken because of other diseases that have affected the hipbones. A pathologic hip fracture describes this situation, and osteoporosis is but one cause. Other potential causes of bone weakening are cancer within the bones, benign tumors and cysts, Paget's disease, and inherited diseases of bone.

When health care professionals talk about a hip fracture, they really mean a fracture of the proximal or upper part of the femur. Fractures of the acetabulum are less common and usually are due to major trauma like a motor-vehicle collision or a fall down a flight of stairs.

The precise location of the fracture is important because it guides the decision of the orthopedic surgeon as to which type of operation is needed to repair the injury.

Aside from a fall, any trauma can potentially cause a hip fracture. Depending upon the mechanism of injury, the femur may not break; rather, a portion of the pelvis (often the pubic ramus) may be fractured. The initial pain may be in the hip area, but examination and X-rays may reveal a source different than the hip joint as a cause of hip pain. Trauma can also cause a hip dislocation in which the femoral head loses its relationship with the acetabulum. This usually is associated with an acetabular (pelvic bone) fracture; however, in patients with hip replacements, the artificial hip may dislocate spontaneously.

Picture of the Location of Most Hip Fractures

Contusions (Bruises)

Contusions (bruises), sprains, and strains may occur because of trauma, and even though there is no broken bone, these injuries can still be very painful. Sprains are due to ligament injuries, while strains occur because of damage and inflammation to muscles and tendons (tendinitis: tendon + itis = inflammation). Because of the amount of force required to walk or jump, the hip joint is required to support many times the weight of the body. The muscles, tendons, bursas, and ligaments are designed to shield the joint from these forces. When these structures are inflamed, the hip cannot function and pain will occur.

Overuse Injuries

Hip pain may also arise from overuse injuries in which muscles, tendons, and ligaments can become inflamed. These injuries may be due to routine daily activities that may cause undue stress on the hip joint or because of one specific strenuous event. Overuse may also cause gradual wearing away of the cartilage in the hip joint, causing arthritis (arth = joint + itis = inflammation).

Other structures should be mentioned as a cause of hip pain because they become inflamed.

• Hip tendonitis is a common cause of pain, especially with the involvement of the hip flexor tendons.
• The iliotibial band stretches from the crest of the pelvis down the outside part of the thigh to the knee. This band of tissue may become inflamed and cause hip pain, knee pain, or both. This is a type of overuse injury that has a gradual onset associated with tightness of the muscle groups that surround the knee and hip.
• Piriformis syndrome, in which the piriformis muscle irritates the sciatic nerve in the buttock, can also cause significant posterior hip pain. This pain often occurs when sitting, squatting, straining to have a bowel movement, or when trying to get out of bed. Because the sciatic nerve may be irritated, pain may radiate down the leg.

Bursa Inflammation (Hip Bursitis)

The trochanteric bursa is a sac on the outside part of the hip that serves to protect muscles and tendons as they cross the greater trochanter (bony prominence on the femur). Trochanteric bursitis describes the inflammation of this bursa. The bursa may become inflamed for a variety of reasons, often due to minor trauma or overuse.

A variety of illnesses may cause hip pain. Anything that causes systemic inflammation in the body may also affect the hip joint. The synovium is a lining tissue that covers those parts of the hip joint not covered by cartilage. Synovitis (syno = synovium + itis = inflammation), or inflammation of this lining tissue, causes fluid to leak into the joint, resulting in swelling and pain.

Arthritis

• Osteoarthritis is the most common cause of hip pain in those over the age of 50 and often is the cause of hip pain that occurs at night. However, other types of arthritis can be present. These may include
  • rheumatoid arthritis,
  • ankylosing spondylitis,
  • arthritis associated with inflammatory bowel disease (Crohn's disease or ulcerative colitis).
• Some systemic diseases are associated with hip pain, including sickle cell disease, in which a joint may swell during a sickle crisis either with or without an underlying infection. The hip joint is not the only joint that may be involved.
• Viral or bacterial infections may cause hip inflammation. Examples include Lyme disease, Reiter's syndrome, and infections caused by food poisoning.
• Avascular necrosis (a = none + vascular [blood] necrosis [death]) of the femoral head may occur in people who have taken corticosteroid medications like prednisone for a prolonged period. In this condition, also called osteonecrosis (osteo = bone), the femoral head loses its blood supply, becomes weakened, and causes hip pain.
• Legg-Calvé-Perthes disease (or just Perthes disease) describes avascular necrosis of the femoral head in children and is idiopathic, meaning the cause is unknown. It usually affects males between the ages of 4 and 8.
• Fibromyalgia is a systemic pain syndrome associated with pain and stiffness that can cause significant discomfort throughout the body and may manifest as hip pain. There may be associated sleep disorders, muscle cramps and spasms, tenderness of a variety of muscle groups in the whole body, and fatigue.

Referred Hip Pain

Hip pain may not originate in the hip itself but may be felt there due to issues in adjacent structures.

• A hernia or defect of the abdominal wall may cause pain in the front part of the hip. A hernia occurs when there is a weakness or tear in an area where muscles of the abdominal wall come together. They are named according to their location; inguinal (groin) hernias are the most common. Femoral hernias that arise from a canal near the hip joint are another type of hernia that might also cause hip pain. A sports hernia (athletic pubalgia) is a strain or tear of any soft tissue (muscle, tendon, ligament) in the lower abdomen or groin area and can also cause pain that is difficult to isolate in the hip.
• Peripheral nerves can become inflamed, causing hip pain. Meralgia paresthetica occurs when the lateral femoral cutaneous nerve of the thigh becomes irritated. This condition is common in pregnancy, in people wearing tight clothes, or in people with diabetes.
• Sciatica, or inflammation of nerve roots from the spinal cord, may also appear with hip pain and pain that runs down the leg. There are a variety of reasons for the sciatic nerve to become inflamed, including spinal stenosis due to osteoarthritis of the lumbar spine, ruptured or bulging disks in the vertebral column of the back, and spasms of the muscles that support the low back. Piriformis syndrome describes sciatic nerve inflammation that causes buttock and posterior hip pain due to sciatic nerve irritation because of inflammation of the piriformis muscle in the buttock area.

Special Considerations for Children

Children who complain of leg or hip pain should be taken seriously and the pain not be ignored. If the pain is persistent, if a limp is present, or if the child has a fever, a health care professional should be contacted.

Potential concerns in children with hip pain include

• a slipped capital femoral epiphysis, a condition in which the bone growth plate of the femoral head shifts out of place,
• Legg-Calvé-Perthes disease, or avascular necrosis of the femoral head,
• juvenile rheumatoid arthritis, or Still's disease.

If a fever is present, septic arthritis or an infection of the hip joint may be present. This may be due to a virus or bacteria. Symptoms include fever, pain, limping, and sometimes refusal to walk. Viral infections are the most common cause of synovitis in infants and resolve without treatment. If the health care professional is concerned that the cause of synovitis may be a bacterial infection, urgent orthopedic consultation and evaluation may be needed in this situation.

Hip pain is often difficult to describe, and patients may complain that the hip just hurts. The location, description, intensity of pain, what makes it better, and what makes it worse depend upon what structure is involved and the exact cause of the inflammation and injury.

Pain from the hip joint may be felt anteriorly (in front of the hip) as groin pain, laterally over the greater trochanter (the outer aspect of the hip), or posteriorly in the buttock. Sometimes the patient may complain of knee pain that has been referred from the hip. This is especially true in children.

Trauma to the hip: With a fall, direct blow, twist, or stretch, the pain is felt almost immediately.

Overuse injury: The onset of pain may be delayed by minutes or hours as inflamed muscles surrounding the hip joint go into spasm or joint surfaces become inflamed, causing fluid accumulation. Overuse injuries may also cause cartilage, labrum, or capsule damage, resulting in inflammation, pain, and limping. Hip labrum tears may also cause clicking, catching, or a locking sensation in the hip, in addition to pain and decreased range of motion.

Pain: Most often, pain is felt in the front of the hip, but the joint is three-dimensional. Pain may be also felt along the outside part of the hip or even in the buttock area.

Limp: Limping is the body's way of compensating for pain by trying to minimize the amount of weight the hip has to support while walking. Limping is never normal. Limping produces abnormal stresses on other joints, including the back, knees, and ankles, and if the limp persists, these areas may also become inflamed and cause further symptoms.

Fracture: With a hip fracture, there is an acute onset of constant pain after the injury that usually is made worse with almost any movement. The muscles that attach to the hip cause the fracture to displace, or move, and the leg may appear shortened and rotated outward. If no displacement occurs, the leg may appear normal but there is pain with any range of motion of the hip joint and with attempts at weight bearing. Pelvic fractures may have pain similar to a hip fracture, but the leg appears normal.

Sciatica pain: Pain from the sciatic nerve tends to start in the lower back and radiate to the buttocks and to the front or side of the hip. It may be described in different ways because of nerve inflammation. Some typical descriptive terms used for the pain of sciatica include sharp, stabbing, or burning. The pain of sciatica may be made worse by straightening the knee, which stretches the sciatic nerve and may make it difficult to stand from a sitting position, or walk with a full stride. There may be associated numbness and tingling in the leg or foot. Physical examination may be able to map out which nerve root from the spine is involved.

Loss of bowel and bladder function associated with the pain may signal a neurosurgical emergency and the presence of cauda equina syndrome. If not recognized and treated with immediate surgery, there is a risk of permanent damage to the spinal cord.

Arthritis: If arthritis narrows the hip joint and impinges the femoral head's gliding motion within the acetabulum or if there is a tear in cartilage or labrum, the patient may describe a click, catch, or feeling that range of motion is somehow impeded. Usually, there is pain almost immediately that does not get better as the activity continues.

Pain from arthritis tends to be worse after a period of inactivity and gets better as the joint "warms up" with use. Hip arthritis often causes pain at night. However, as activity increases, the pain will return.

Bone cancer: Cancer that arises primarily in bone or is metastatic, having spread from another site in the body, can cause intense, constant pain. It is often not related to activity and not made better with rest. Its location and radiation (where the pain spreads) may depend upon the location of cancer within the hip or pelvis and what neighboring structures are involved or irritated.

People often decide to seek care after an injury based on their ability to stand, bear weight, and walk. If there is a concern that a bone is broken, seek medical care in an urgent manner. Since patients with a broken hip tend to have significant pain even with minimal movement, it may be wise to call emergency medical services (usually by calling 911) for help in lifting and transporting the victim.

If the pain is more gradual in onset and does not respond to rest, ice, and over-the-counter pain medications, it is reasonable to seek help. This is especially true if the hip pain begins to limit daily activities, the hip's range of motion, or causes limping.

If hip pain is associated with fever and swelling, an infection may be the cause. In this case, seek medical care urgently.

If there is a loss of bowel or bladder function, this may signal that the pain is coming from the back and a true emergency called cauda equina syndrome may exist. Medical care should be accessed emergently.

Limping is not normal in infants and children. If the pain and limp are associated with a fever, emergency care should be accessed because of the risk of having a joint space infection. Even if no obvious injury has occurred, it is wise to be evaluated within a day or two if the pain and limp have not resolved.

History

Making the diagnosis of the cause of hip pain begins with the health care professional talking with the patient, their family, or caregivers and taking a careful history of the what, where, and when of the pain as well as reviewing any other underlying complaints. By factoring in the past medical history of the patient, the health care professional can make a differential diagnosis or list of what potential causes might be considered. The physical examination helps refine that list, and tests may be done to confirm a specific diagnosis.

Sometimes the diagnosis is evident. The patient fell, hurt their hip, can't bear weight, and X-rays show a fractured hip. Sometimes the diagnosis requires more searching and may take time and repeat visits to find the source of the hip pain.

The history may involve many questions regarding everything from the onset of the hip pain to what makes it better or worse. The goal is for the health care professional to understand the frequency, duration, and context of the pain in relation to the daily activities of the patient.

Aside from the history of the pain, other information looking for a systemic illness may be helpful in finding the cause of the pain. Has there been an injury? Has there been a history of fever or chills? Weight loss? Abdominal pain? Diarrhea? Do other joints hurt or swell? While the questions may seem unrelated to the hip, it is necessary for the health care professional to consider all possibilities. A review of past medical history, including medications, may give direction to assessing the situation.

Physical Examination

The physical examination for hip pain most often will focus on the hip, leg, and back, however, the rest of the body will not be ignored; a health care professional will look for associated findings that may help explain the patient's complaints.

Physical exam may include the following:

• Observation of the hip
  • Watching how the hip and leg are positioned
    • at rest, in bed, or on a chair,
    • while standing to see whether weight is evenly distributed on both legs, and
    • while walking (gait evaluation) to look for a limp or other abnormality.
  • Palpation (or feeling) of the hip and surrounding structures
    • Assessing areas of pain, tenderness, and swelling
    • Range of motion of the hip
    • Power of the muscles that move the hip
    • Testing blood flow by feeling for pulses
    • Evaluation of sensation, by testing for pain, touch, and vibration

Imaging

Many times plain X-rays of the hip and pelvis are done to look at the bones and the joint spaces. In a fall, this may diagnose an acute fracture, but occasionally, the break cannot be seen with routine films. The bone fracture may be occult (hidden) and if the suspicion of fracture is high, computerized tomography (CT) or magnetic resonance (MRI) imaging may be considered to confirm or disprove that a fracture is present, even in the presence of normal plain X-rays.

Narrowed joint spaces and arthritis can be seen on plain X-rays and help confirm the diagnosis of osteoarthritis and degenerative joint disease.

When looking for cartilage or labrum tears in the hip, an arthrogram may be done, in which a radiologist injects contrast dye into the hip joint using a long thin needle. Usually, MRI images are taken to look at the joint surfaces outlined by the dye. With the test, a local anesthetic is injected prior to the dye. It is helpful to know if the anesthetic resolves the pain, because if so, it may confirm that the source of the pain is from within the joint.

A bone scan may be performed to look for inflammation. A radioactive dye is injected intravenously, and the whole body is scanned. The radiologist looks for abnormal accumulations of the dye that may help establish a diagnosis. This might be helpful in determining whether it is a single hip joint that is involved or whether multiple parts of the body are also inflamed.

Blood Tests

If the health care professional is concerned that a systemic (body-wide) illness is the cause of hip pain (like rheumatoid arthritis), blood tests may be ordered. Some markers for inflammation include elevation of the white blood cell count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). These are nonspecific tests but can help direct further testing based on the clinical situation. A white blood cell count may also be helpful as a screening test for infection and inflammation.

The treatment of hip pain depends upon the diagnosis and any underlying illness that may be present.

As we age, the body tends to tolerate falling less easily. Falls often can cause contusions (or bruising) and inflammation of the tissues that are damaged. This pain may not be felt immediately, and the injured area may begin to stiffen and get sore over a few hours. If the patient can stand and walk relatively easily with minimal limp, then it is reasonable to rest and ice the injured areas and begin activity as tolerated.

Just because a patient can move the hip joint does not mean that there is not a broken bone present. In some hip fractures, the bones may be impacted and allow some movement or even weight-bearing for a short period of time.

Over-the-counter pain medications (acetaminophen [Tylenol], ibuprofen [Advil, Motrin], naproxen [Aleve]) may be taken for pain control. It is important to remember that while over-the-counter medications do not require a prescription, they may have side effects or interactions with prescription medications. Especially in older people, it is wise to ask a health care professional or pharmacist for advice and direction.

Crutches, a cane, or a walker may be useful in the short term, but these need to be fitted to the patient's height, and some people may need training to use them properly. Usually, the pain and stiffness will resolve over a few days. If the pain persists or starts to worsen instead of getting better, a medical evaluation may be helpful.

Hip pain and soreness that develop because of overuse but without any specific injury may be cared for at home with rest and gradual return to full activity. While rest is important, it is also important to maintain range of motion, meaning that an exercise program may be suggested with attempts to stretch the leg, hip, and back and keep the whole body moving.

Care for hip pain that exists because of an underlying medical condition should be coordinated with the health care professional. Often, the hip pain will be episodic, depending upon the control of the medical condition.

If the hip pain is associated with activity like aggressive walking or running, resting from that activity may be helpful. Finding another non-weight-bearing exercise, like cycling or swimming, may allow the patient to maintain aerobic fitness and hip range of motion. It is important to listen to one's body, and if pain persists, medical care should be accessed.

The cause of the hip pain will direct the treatment provided.

Aside from medications, therapy will be directed to maintain the strength and range of motion of the hip. As with any illness or injury, the goal is to return the patient to their normal level of function. A team approach involving the health care professional, physical therapist, or chiropractic care provider may be considered.

Discomfort often may be managed with over-the-counter pain medications. Acetaminophen, ibuprofen, and naproxen all may be used. Even though these drugs do not require a prescription, each has its own potential for side effects if underlying medical conditions are present. It is worthwhile asking for help from a pharmacist or advising a health care professional that one is taking a new nonprescription medication. For example, acetaminophen (Tylenol) should be avoided in people with liver disease, while nonsteroidal anti-inflammatory medications like aspirin, ibuprofen, and naproxen should be taken with care by people taking blood thinners or who have peptic ulcer disease.

Prescription medication use will depend upon the reason for the hip pain. Most often, the medications are directed at treatment of the underlying illness or injury causing the pain. For example, methotrexate and sulfasalazine are two first-line medications often prescribed for the treatment of rheumatoid arthritis.

Hip fractures commonly require surgery to fix the fracture. The type of surgery depends upon the location of the fracture within the hip joint. The underlying health of the patient needs to be assessed, and the risks of general anesthesia need to be considered. Surgery often occurs soon after the injury, if the patient's condition allows, to allow quicker return of activity. Patients who are immobilized and lie in bed for prolonged periods of time are at risk for developing blood clots in their legs (deep vein thrombosis) and breakdown of their skin, or bedsores.

Hip replacement is perhaps the most common joint replacement surgery. It is considered in patients with progressive arthritis that affects the patient's ability to do daily activities. Hip resurfacing is an alternative to hip replacement. The choice of procedure is a joint decision made by the orthopedic surgeon and patient to be able to return the patient to the level of activity that they would like to achieve.

Hip arthroscopy has become more widely available to evaluate and treat hip joint damage, including labrum and cartilage tears, loose bodies within the joint, and early arthritis.

The goal of hip pain therapy is to treat the underlying cause and return the patient to full function. Follow-up care will depend upon the illness or injury and the particular medical treatment or surgery that is required to reach that goal.

The body is a machine that needs to be well looked after over a lifetime. By maintaining a normal body mass index (BMI) and avoiding obesity, providing a good diet to build strong bones, and by exercising routinely to preserve normal range of motion of the hip, osteoarthritis of the hips and back pain may be avoided or minimized.

Medications that prevent osteoporosis in women should be considered to minimize the risk of hip and back fractures in at-risk women. These include calcium, vitamin D, and bisphosphonates (Actonel, Boniva, Fosamax). Bone mineral density screening is recommended by the U.S. Preventive Services Task Force and the American Congress of Obstetricians and Gynecologists beginning at age 65 for all women, or for younger women with risk factors for bone thinning or fractures.

For older individuals, it is important to minimize the risk of falling and breaking a hip or sustaining other injuries related to a fall. Preventive measures include wearing well-fitting shoes with a good tread, using a cane or walker for stability if needed, and making certain that walking areas in the home are free of clutter. The use of area rugs and mats should be avoided.

For individuals of all ages, it is important to maintain good strength, flexibility, and posture throughout life to allow the hip to move and function normally.

The most common causes of hip pain involve the aging process of the joint, causing arthritis and the loss of calcium content in the bone and predisposing one to fracture. As people improve their diet and increase their exercise programs to maintain healthy bodies (including healthy bones and joints), the goal is to allow people to be as active as possible as late in life as possible.