Assessment of the Hip Joint (Causes of Hip Pain)

Problems inside the joint usually create symptoms in front of the hip in the groin region, sometimes radiating down the inside of the thigh even as far as the knee. Pain in the back of the hip is more commonly associated with problems of the lumbar spine or sacroiliac joint. Tenderness along the outside of the hip is commonly bursitis or tendinitis but may be indicative of more severe tendon damage. These problems are indicated when pain is produced when pushing over the area. In contrast, hip joint symptoms are deep-seated, and it is hard to push on a spot that creates the type of symptoms that occur with activities.

Pain and symptoms from joint problems that are potentially amenable to arthroscopy tend to have a “mechanical” character; they are somewhat intermittent and can be described as catching or sharp and stabbing in nature. Simply aching, or aching that is independent of activity is sometimes associated with more of an arthritic process or condition that may be less correctable.

Hip joint problems tend to be aggravated by torsional maneuvers more than straight plane activities. For example, turning, twisting and changing direction may be more troublesome than walking, or even jogging, straight ahead. Stairs or inclines typically cause more difficulty than level surfaces. Activities such as entering and exiting an automobile may exacerbate symptoms and be particularly noticeable. Even just rising from a seated position will sometimes result in a painful, catching type sensation. Hip pain often becomes a problem with intercourse. With more advanced problems and loss of rotational motion in the hip, people start to have difficulty getting shoes and socks on and off.

These are just a few of the characteristic symptoms that might indicate a problem emanating from inside the joint. Also, with long-standing joint trouble, secondary problems can develop as the body compensates for the hip. These may include muscle soreness, bursitis, tendinitis, or even back symptoms. These may obscure the hip as the principal underlying problem. An experienced examiner can usually tell whether the hip is involved, but determining the exact nature of the underlying disorder can be more of a challenge.

Arthritis

Approximately 70 million Americans suffer from arthritis and about 300,000 total hip replacement procedures are performed each year for this condition. Arthritis is characterized by breakdown of the articular cartilage, with resultant pain and stiffness. The two most common types are osteoarthritis and rheumatoid arthritis.

Osteoarthritis is simply accelerated wear and tear of the joint. A previous injury may leave the joint damaged and susceptible to progressive breakdown. Variations in how the joint is shaped may lead to abnormal joint mechanics and accelerated wear. This is especially attributed to “dysplasia,” a condition where the socket is abnormally shallow; and “femoroacetabular impingement” (FAI), a condition where abnormal bony build-up around the acetabulum or femoral head may result in accelerated cartilage breakdown.

Arthritis of the hip is often a great imitator as far as how it behaves. Typically, we expect arthritis to come on gradually over time and be associated with advancing age. However, the onset of symptoms may sometimes be surprisingly sudden and people may experience intermittent episodes of spontaneous remission. It can also strike young adults, even without a family history of disease, and may be isolated to a single joint.

Rheumatoid arthritis is the most common of a large group of inflammatory arthritides. This is characterized by a poorly controlled proliferation of the synovium, resulting in erosion of the articular surface, and is generally considered one of the most devastating of all non-lethal diseases. Chemotherapy agents are often used to try to arrest the synovial proliferation but, even if the synovium is brought into control, the resultant articular damage may continue to cause problems. Arthroscopic excision of the diseased synovium can be effective for cases that are unresponsive to pharmacologic management. Arthroscopy cannot reverse the articular damage that has occurred, but debridement of the fragments and associated diseased tissue can sometimes help reduce discomfort.

In general, arthroscopy in the presence of arthritis is sometimes considered, especially for younger patients, if the x-rays do not show the joint to be too badly worn. Preserving the natural joint as long as possible is preferable, even though arthritis may continue to advance and the patient may eventually require a total hip replacement. While an artificial hip is superior to a painful, worn-out joint, it is not a normal hip and carries with it numerous concerns including the seriousness of the procedure, life-long precautions that are necessary with an artificial joint, and the possibility of the artificial joint becoming painful and requiring revision.

Arthroscopy is an attractive consideration as a procedure that could potentially preserve the natural joint, and it does not burn any bridges with regard to future options. Realistically, however, successful outcomes, in the presence of significant arthritis, have been reported only in upwards of 50% of cases with two-year follow-up and in only slightly greater than one third of these cases after five years. Arthroscopic debridement for arthritis may not be a panacea, allowing patients to resume a fully active lifestyle, but may simply be an alternative that reduces discomfort and preserves the natural joint for a while before contemplating a replacement. An added benefit of postponing a hip replacement is that the technology and materials for these artificial joints continue to improve.

We are gaining an understanding of conditions that predispose people to developing various types of arthritis. Thus, we are making significant strides in joint preserving strategies that may improve the long term outlook for some of these diseases.

Femoroacetabular Impingement

Femoroacetabular Impingement (FAI) is a condition of abnormal bony overgrowth around the ball and socket hip joint. Most commonly, this is a consequence of the way the hip forms during the childhood growing years. The abnormality can be quite variable but generally consists of overgrowth around the socket (acetabulum) resulting in pincer-type impingement or an out-of-round femoral head causing cam-type impingement, and these may occur in combination.

FAI is much like the front end of a car being out of alignment that can lead to uneven wear inside the joint over time. Tearing of the labrum and articular cartilage starts to occur that then leads to painful symptoms. This can develop as early as the teenage years or may not start to develop for decades. FAI is often characterized by restricted internal rotation of the hip (rotating the leg inward) and generally poor hip flexibility. When pain starts to occur, that is more of a warning sign that joint damage is developing.

Several scenarios can lead to pincer impingement. There may be bony overgrowth off the front of the acetabulum that crushes the labrum against the femur when the hip is flexed. Alternatively, the whole socket may be tilted forward too far (retroversion) or some people simply have a very deeply situated socket, referred to as profunda or protrusio. Although the labrum breaks down first, eventually the articular cartilage also starts to deteriorate.

Cam impingement refers to the femoral head being out of round. Most commonly, this is a consequence of a growth disturbance in the way the growth plate develops around the femoral head, but it can sometimes occur from an acute growth plate injury (slipped capital femoral epiphysis). The loss of sphericity of the femoral head results in abnormal shear forces on the articular cartilage as the misshapen ball rotates inside the acetabulum.

FAI first results in painful symptoms associated with tearing of the labrum and breakdown of the articular cartilage, and it eventually leads to frank osteoarthritis that starts to become evident on x-ray and can lead to the need for an artificial hip joint at a young adult age.

FAI also leads to other compensatory problems. The body tries to adjust for the limited hip flexibility which puts more stress on other structures and makes them more vulnerable to injury. Lower abdominal and groin symptoms, referred to as athletic pubalgia or sometimes sports hernias, are common, especially in athletes. Limited hip flexibility puts more stress on the lumbar spine and can trigger back problems. Hamstring injuries, bursitis and any number of surrounding hip troubles can also occur. These secondary problems may obscure the existence of the underlying FAI disorder and may defy treatment until the FAI is corrected.