"What's causing my hip pain?" This is one of the most common questions patients ask their doctors. Unfortunately, it's not always easy to answer. Many conditions can cause hip pain, including some you'd suspect--arthritis or a fracture--and some you wouldn't--spinal stenosis, or a previously undiagnosed congenital hip condition. Whatever the cause, chronic hip pain can force you to cut down on your activities, and leave you stiff and unable to get around as well as you once did.

Bursitis Location of Pain: Side of hip Symptoms: Pain when sitting or lying on side Treatment: Rest, heat, anti-inflammatory medication, cortisone injections, physical therapy Hip Arthritis Location of Pain: Front of hip Symptoms: Pain when walking; groin pain radiating into front of thigh Treatment: Anti-inflammatory medication, cane, behavior modification, joint replacement Spinal Stenosis Location of Pain: Low back, buttocks Symptoms: Pain on sitting/walking; pain radiating down to knee/ankle Treatment: Rest, anti-inflammatory medication, spinal injections, physical therapy, surgery

Where's Your Pain? Pain in the hip, a ball-and-socket joint, can emanate from the hip itself or from unrelated causes, including bursitis and spinal stenosis.

  The hip joint unites the femur, or thigh bone, and the pelvis. The bone ends are covered by glistening blue-white caps of "gristle" called articular cartilage. Articular cartilage is a unique material--it is more slippery than ice on ice. It is an excellent shock absorber, and contracts and expands with pressure. Articular cartilage has no nerve endings or blood supply, so it has little or no ability to reproduce itself (although researchers are currently working on changing that). The joint is held in place by a tough, flexible material called the joint capsule. On the inner capsule is the synovial lining, which produces the fluid that lubricates and nourishes the joint. Movement of the joint is dependent upon the muscles that attach around the joint.

  The hip itself is a ball-and-socket joint. Within its capsule is a very stable joint that can move in any direction. Many muscles attach around the hip, particularly around the trochanter, which is the bony protrusion you can feel at the widest part of the hip area. Around the hip there are two important nerves, the sciatic nerve and the femoral nerve. The sciatic nerve originates in the lower back and supplies sensation to almost all the major muscle groups in the lower leg. The femoral nerve supplies the muscles in the front of the thigh (quadriceps) and down to the level of the knee.

Congenital Defects of the Hip

   Congenital (present at birth) defects can affect the hip, and if not properly diagnosed and treated in childhood can lead to problems later in life.

  Congenital dislocation of the hip (CDH) involves an abnormal formation of the hip joint. The ball at the end of the femur does not fit within the socket, making the joint unstable and prone to dislocation. This condition is not always evident at birth; sometimes symptoms do not show up until the child is older. Splints are used on newborns to coax hips back into their proper position. If this does not work, open surgery may be necessary. If CDH isn't diagnosed until adulthood, it may require surgery to place the hip in its socket or to move the bone into a better position.

  A less treatable but more frequent hip condition is congenital hip dysplasia. In this case, the hip appears to be in position, but the ball is not really deeply seated in the socket. There is typically a very shallow socket, and the ball will tend to ride at the very edge of the socket.

  Left untreated, these conditions can lead to pain, abnormal gait, unequal leg length and, eventually, degenerative or arthritic changes in the hip (osteoarthritis) that may require further treatment.

Avascular Necrosis

   Another condition that affects the hip is avascular necrosis (AVN). Bone requires a constant blood supply to remain healthy; without it, bone begins to die and collapse. This is called avascular necrosis, literally bone death due to lack of blood vessels. In the hip, the head of the femur (the acetabulum, or "ball") is primarily affected. If not treated, the joint surface breaks down, leading to arthritis, pain and disability.

  The most common reason why the femoral blood supply is compromised is a hip fracture that tears the vessels supplying blood to the head of the femur. Another cause is taking steroid medications, such as prednisone and other immunosuppressant drugs. AVN is often seen in patients with chronic asthma, rheumatoid arthritis, lupus and organ transplants.

  Avascular necrosis can be diagnosed with x-rays, bone scans and other imaging methods. To prevent further bone destruction and ensure the survival of the affected hip joint, there are a variety of treatment options. Less invasive ones include reduced weight-bearing, medications and electrical stimulation to increase the growth of new bone and blood vessels. Several surgical procedures are also available. Core decompression, best used in patients with early-stage disease, removes the inner layer of bone, reducing pressure and increasing blood flow. An osteotomy can be done to reshape the bone, alleviating stress on the affected area. (This comes with a very long recovery period, however.) Bone grafts can help support the bone after core decompression by transplanting some of the patient's healthy bone into the diseased area. And when the architecture of the hip joint is completely destroyed due to avascular necrosis, total joint replacement is the treatment of choice.

Arthritis and the Hip

   Of the more than 100 forms of arthritis, two are most common in the hip: osteoarthritis (OA) and rheumatoid arthritis (RA).

  OA is the most common arthritic condition affecting the hip. It is characterized by loss of cartilage space and pain in the groin or buttocks, sometimes radiating down the front of the thigh to the knee. There is limited motion and increased pain when walking. Later in the disease process, motion is even more limited and there is pain at rest. Osteoarthritis of the hip can usually be handled with exercise, less-strenuous activity, anti-inflammatory medication and support from a cane or walker. Adult arthritic hips that do not respond to treatment require total hip replacement.

  Rheumatoid arthritis (RA) affects multiple systems in the body and is associated with acute inflammation and severe pain, frequently resting pain at night. Often there is an acute episode of pain, swelling and limitation of motion involving many joints, followed by cyclic flare-ups. The disease process damages joint cartilage, resulting in secondary changes later in life. Patients who are unable to successfully manage their disease process working with a rheumatologist and using conservative means such as medication may also need joint replacement surgery.

   With RA, initial treatment is the key to long-term success. Rest, directed exercise, proper diet and medication can be used to suppress the disease process before damage occurs to the hip and other joint surfaces. However, most patients will experience continued deterioration and need surgery at some point later in life.

Hip Fractures

   Through the teen and young adult years, hip trauma, whether from an accident or sports injury, can result in a fracture. Later in life, osteoporosis is also a common cause of hip fracture. If the fracture is repaired and put in perfect anatomical position, the hip can heal without problem. But if there is any damage to the joint surface itself, patients will later develop arthritic changes.

   Proper treatment for a hip fracture usually is an open reduction and pinning of the hip, unless the joint is so unstable or the fracture is so displaced that a total hip replacement may be the better alternative. Fractures can lead to later arthritic changes in the hip that may require further reconstructive surgery, even though the fracture itself healed properly.

Other Causes of Hip Pain

   Two non-arthritis-related conditions are also major causes of hip pain. Certainly the most common disorder around the hip joint is bursitis. Numerous large muscles that control the motion of the entire leg attach to the bone around the outside of the hip joint. The muscles attach to the crest or top of the pelvis, travel down the side of the leg and form a tendon; this tendon then attaches the muscle to the hip joint. As the muscle contracts, it will pull on the tendon, and thus move the hip joint. If this were to occur without some protection for the tendon, the tendon would rub directly on bone and over a period of time would fray and rupture. The body protects the tendon with a bursa, a sac filled with a gel-like, fluid material that lies between the tendon and the bone and acts as a buffer for the tendon to work across. Unfortunately, the bursa may become inflamed and swell, causing even more pressure and pain. Most forms of hip bursitis can be treated effectively with behavior modification and anti-inflammatory medications. Sometimes directed exercise or an injection of steroids is recommended. Rarely, the bursa must be removed.

  The second most common non-arthritis hip condition is actually a spine disorder. In adult patients, this may be a ruptured disk in the spine or degenerative arthritis of the spine. Older adults will often have spinal stenosis. In these patients the cartilage disks, or spacers between the vertebrae, will lose a large portion of their water content and begin to degenerate and flatten. The bone will form spurs, causing pressure on the nerves that exit at each disk level and then exit out of the pelvis into the buttock. Patients will experience chronic back pain, muscle spasms in the lower back and pain in the buttocks. In more advanced stages, the pain will travel down the back of the leg to the knee, ankle or foot, either in front or in back of the calf (sciatica). Because the sciatic and femoral nerves may be affected, pain from spinal stenosis may sometimes feel like hip pain.

  A comprehensive treatment plan includes strengthening and flexibility exercises, use of heat and cold, joint protection including weight control, anti-inflammatory medication, analgesics and muscle relaxants. If symptoms persist, a series of epidural blocks can decrease the amount of swelling in the nerves and relieve pain. Occasionally, surgery will be necessary. Spinal surgery has improved markedly over the past decade and gives significant relief of nerve compression.

   The bottom line is that you don't have to live with hip pain that drives you crazy and limits your activities. It can be successfully treated and you can regain better long-term function once the correct diagnosis is obtained.

About the author:
Dennis Armstrong, M.D. graduated from the Wayne State School of Medicine and completed his orthopaedic residency at Henry Ford Hospital in Detroit, Michigan. Dr. Armstrong is board certified in orthopaedic surgery and specializes in arthritis reconstructive surgery. He has been involved in several clinical investigative studies researching the surgery and care of those undergoing total joint replacement, and has authored numerous papers and provided multiple presentations on his clinical research.

© Copyright 2005. Arthritis Education by Professionals, Inc.