What is Hip Pain?
The hip joint is a large weight bearing joint that attaches the leg bone (femur) to the pelvis. It is an extremely important joint, as it allows the body to walk, run, and sit. The hip is a very strong structure, but still can be damaged. Sports-related injuries, motor vehicle accidents (MVA), and falls in the elderly are subject to the most crucial hip injuries. However, severe chronic hip pain is often due to arthritis.
In 2007 the Centers for Disease Control (CDC) published an article that stated, “Arthritis continues to burden the U.S. population as the leading cause of physical disability and affects women disproportionately: women with arthritis report greater prevalence of activity and work limitations, psychological distress, and severe joint pain than their male counterparts” (Theiss 2007).
Hip Pain Anatomy
The hip joint is a ball and socket joint, where the femur (large thigh bone) connects to the pelvis. The top of the femur is a round ball, which fits into the socket (acetabulum) formed by the pelvic bone. The ball is allowed to glide and rotate within the acetabulum because a group of ligaments and muscles support the joint and inhibit over extension or malrotation from occurring. Also, within the joint is a synovial lining, which provides lubricating fluid to decrease friction, produced when the joint is in motion.
Hip Pain Pathology
Hip dislocations and femur fractures are often acute injuries and can be acutely treated. There are other conditions that can produce chronic progressive hip pain.
Diseases, besides trauma, that can cause chronic hip pain:
Osteoarthritis (OA)- also known as degenerative arthritis or degenerative joint disease. OA is the most common cause of arthritis in the United States. It is most common in women, people over the age of 55, obese people, and those with a history of previous joint trauma or disease.OA results from repetitive wear and tear of the joint. OA can cause a chronic, non-inflammatory arthritis of any moveable joint. The most common joints involved in OA are the DIP joints (small joints closest to your fingernails) of the fingers and the knees. Typically the joint involvement is one-sided and asymmetric. Patients typically experience crepitus, which is a crackling or popping sound and sensation. This is created when the cartilage has broken down and two rough edges are coming into contact with each other. This can also cause a decrease in range of motion, pain that worsens with activity, and improves with rest. There is typically no localized swelling or redness seen with this cause of arthritis.
Rheumatoid Arthritis (RA)- Unlike OA, RA is a chronic, systemic, destructive, inflammatory arthritis. It is commonly seen in younger aged women 35-50, although can be seen in anyone. Infections by viruses, and bacteria and genetic factors (HLA-DR4) are thought to possibly trigger the destructive inflammation.RA is characterized by symmetric involvement of the large and small joints. The originating cause is by a nonspecific inflammation which then produces T-cell activation (cell of your immune system) and a pannus (flap of tissue) is formed. The pannus erodes into the surrounding cartilage, tendons, and even bones.
Avascular Femoral Head Necrosis- Results from incomplete blood supply to the bone. The bone then typically develops necrosis or destruction of normal tissue. A fracture of the femoral neck or dislocation of the femoral head may damage the blood vessels that supply the femoral head. Other causes can be from arthritis syndromes, local or systemic steroids, infection, radiation, or unknown causes. When there is necrosis in the femoral head, the bone typically cannot support the body weight and the femoral head can eventually collapse and fracture causing pain and further complications.
Labral Tears- The hip socket or acetabulum is lined by cartilage. This cartilage is called your labrum and allows for smooth movements of the femur ball in your hip joint. A labral tear can result from injury or wear and tear arthritis. Labral tears can often be painful and those affected often complain of a “catching” or “locking” sensation with certain movements. Treatment often involves medications, injections, physical therapy, and sometimes surgery.
Lumbar Radiculitis- Spinal nerve in the low back can become irritated and aggravated by various conditions. If a nerve root becomes irritated it can cause painful radiation into the lower extremity. The pain is called referred because it is felt in the hip, but the pathology is in the low back. Typically radiculitis can be diagnosed with a physical exam and relevant spinal imaging.
Diagnosing patients with hip pain is never straight forward and is often difficult, as many of the symptoms are similar for different etiologies. The first step in evaluating a patient with hip pain is a comprehensive history and physical exam. Several aspects will be covered in the history and some of the most common questions asked are:
Where is the pain located?
How long has the pain been there?
What were you doing when you first noticed the pain?
Is there anything you can do that alleviates the pain?
Are you currently taking any medications for the pain? Do they work?
Is there any family history of arthritis or other autoimmune disease?
After conducting a full history and physical exam your physician may want additional studies, including radiological films and blood work. Imaging techniques are useful because your physician is often able to see pathology inside the affected joint.
Common imaging techniques to evaluate arthritis include:
X-Ray – a diagnostic test which uses an electromagnetic energy ray to produce images of internal tissues. Bones are well visualized.
CT Scan – a diagnostic test that combines x-rays with computer technology to produce cross sectional views of the body. This is helpful because it helps to visualize detailed images of the body, including the bones, muscles, and organs.
MRI Scan – a diagnostic image that uses large magnets and a computer to produce detailed images of the structures within the body. This is even more detailed than the CT Scan and X-Ray.
Common laboratory tests that your physician may want to check are complete blood count (CBC), complement, antinuclear antibody (ANA), creatinine, erythrocyte sedimentation rate, rheumatoid factor, urinalysis, and a white blood cell count (WBC). Another aspect that may potentially need to be evaluated is the consistency of the fluid accumulation in the joint.
Your physician may want to perform an arthrocentesis to look at the components of the fluid in the joint. This is especially crucial when gouty arthritis or a septic arthritis is suspected. Another method in evaluating the joint is performed by an orthopaedic surgeon and is called an arthroscope. This procedure involves placing a small, optic tube (arthroscope) into the joint through. Images of the joint are projected onto a screen and viewed by you and your physician. Your physician and pain specialist will decide which items are necessary to diagnose your arthritis.
Hip Pain Treatment
There are many surgical and interventional options for severe causes of arthritis and joint pain. The most common and recommended methods to treating arthritis are conservative alternative therapy provided by a pain specialist. Staying active and physical therapy as well as NSAIDs and Acetaminophen (Tylenol), have also proven to be beneficial. Physical therapy has been noted to significantly improve the postural stability in hip OA patients (Giemza 2007). Also, intra-articular joint injections are rapidly gaining popularity and use in the treatment for arthritis because of their success, minimally invasive nature, and long-acting effects.
A joint injection may be considered for patients with symptoms suggesting arthritis. The injection can help relieve pain by reducing the inflammation and numbing the joint and can also help diagnose the source of pain. The most important and greatest success achieved with the use of joint injections is the rapid relief of symptoms that allows you to experience enough relief to become active again. With this you regain the ability to resume your normal daily activities that was not achieved with oral medications and physical therapy.
There are many more treatments dependant on the cause of your specific pain. Each person suffering from pain is an individual and needs an individualized pain plan.
Arthritis burden and impact are greater among U.S. women than men: intervention opportunities. J Womens Health (Larchmt). 2007 May;16(4):441-53 Theis KA, Helmick CG, Hootman JM.
The effect of physiotherapy training program on postural stability in men with hip osteoarthritis. Giemza C, Ostrowska B, Matczak-Giemza M. Aging Male. 2007 Jun;10(2):67-70