Osteonecrosis



Osteonecrosis


Thomas P. Sculco

Paul Lombardi



An evaluation of hip pain begins with considering the multiple structure/function relationships that comprise the joint itself and the surrounding soft tissue structures. The hip joint comprises the proximal femur and acetabulum, articular surfaces, and synovium. The periarticular soft tissues comprise bursae (e.g., greater trochanteric, iliopsoas, and ischial), tendons (e.g., hip abductor, adductor, internal–external rotators, extensors, flexors, and hamstrings), and acetabular labrum which is the soft tissue rim surrounding the acetabulum.

The clinician should also consider other structural abnormalities, such as inguinal and femoral herniae, and the possibility that the complaint of pain in the hip is actually referred from another location, for example, lower back, knee, and even visceral organs such as the gastrointestinal tract, prostate, ovary, and aorta.


CLINICAL MANIFESTATIONS

The most important initial step while obtaining the patient’s clinical history is to ask the patient to point to the area of “hip pain.” Most will point to their back or their lateral thigh, not their groin. In general, hip pain is groin pain. Patients with true hip pain usually complain of limitation of hip motion, a painful limp, and pain in the groin on movement. Pain occurs less often at rest and rarely at night. Care while obtaining the patient’s clinical history may reveal childhood hip disorders, such as Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, developmental dysplasia of the hip, and septic arthritis. Concomitant disorders such as osteoarthritis, rheumatoid arthritis (RA), psoriatic arthritis or ankylosing spondylitis, malignancy, or low back pain may provide insight into the etiology of the hip pain. A history of alcohol or steroid use is pertinent in patients suspected of having osteonecrosis. Response to prior therapies, including physical therapy, anti-inflammatory medications, modification of activity, night pain, or use of assistive devices helps one to assess the severity of the pain. Accompanying fever, chills, weight loss, or fatigue, or a history of recent infection are important symptoms that could reflect an infected hip or metastatic lesion.


I. DURATION AND LOCATION OF PAIN



  • Pain of short duration is usually post-traumatic or inflammatory.


  • Pain that is chronic and progressive may indicate mechanical joint incongruity related to an underlying arthritis. The pain of osteoarthritis is usually alleviated by rest.
    Constant hip pain, especially if severe and unresponsive to simple pain medications, is characteristic of an inflammatory/septic or neoplastic process. Synovitis due to RA or psoriatic arthritis tends to be worse in the morning; however, it may not go away completely during the day. It rarely causes night pain unless there is an associated infection or it has led to severe secondary osteoarthritis.


  • Groin pain that radiates to the buttock indicates hip joint dysfunction. Pain that is confined purely to the buttock or back, without affect on the groin, usually has its origin as a back pain. When patients say their hip hurts, they mostly point to the buttock. Lateral hip pain with radiation to the lateral thigh may be related to greater trochanteric bursitis or abductor tendinitis. Discomfort over the anterior superior iliac spine extending down the anterior thigh is associated with meralgia paresthetica (inflammation of the lateral femoral cutaneous nerve). Medial groin pain can be due to adductor tendinitis, sometimes associated with overuse or yoga positions, or a pubic ramus fracture. Hip pain can also be referred to the knee through the obturator nerve.


  • Buttock pain may be related to ischial tuberosity bursitis or spinal disorders, such as spinal stenosis, ruptured intervertebral disc, and instability.


II. RELATION OF PAIN TO ACTIVITY



  • Pain from the hip joint and surrounding soft tissues is usually aggravated by weight bearing and relieved by rest.


  • Patients will usually describe a specific position of the limb which exacerbates or relieves their symptoms.


III. DECREASED FUNCTION

Patients complain of a progressive decrease in the maximum distance they are able to walk and tolerance to exercise. Ability to perform activities of daily living is decreased. These decreases can be quantified with functional assessment scores such as Western Ontario McMaster Arthritis index (WOMAC), the Harris Hip Score, and Short Form-36 health survey questionnaire (SF-36) (see Chapter 9). A persistently severe hip pain that limits function and awakens a patient at night should stimulate consideration of an infection, a fracture, metastatic lesion, or very severe osteoarthritis.


PHYSICAL EXAMINATION


I. GAIT

The patient is observed while entering the examination room, and the presence of a limp or an expression of pain is noted.



  • Abductor lurch (Trendelenburg’s gait). The patient shifts the center of gravity away from the affected limb during the stance phase of gait to unload the weakened abductors and to avoid pain.


  • Coxalgic gait. The patient quickly unloads the painful leg while bearing weight. Decreased stance phase of gait and stride length on the affected side will be seen.


  • Stiff hip gait. The patient will walk by rotating the pelvis and swinging the legs in a circular fashion.


II. PATIENT IN STANDING POSITION



  • Measure unequal leg lengths by balancing the pelvis with calibrated blocks, if necessary. Note for fixed pelvic obliquity if present.


  • Evaluate the spine for scoliosis or kyphosis.


  • Trendelenburg’s sign. While bearing weight with the leg on the affected side, the opposite side of the patient’s pelvis will droop because the hip abductor, which normally elevates the pelvis, is weakened. This may take 30 to 45 seconds to become apparent.


III. PATIENT IN SUPINE POSITION

Jul 29, 2016 | Posted by in RHEUMATOLOGY | Comments Off on Osteonecrosis

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