Osteoporosis is generally a progressive and painless condition. But one type of osteoporosis is both painful and reversible. Because it isn't permanent and is usually most obvious in the hip joint, this condition is called transient osteoporosis of the hip.  Women in the late stages of pregnancy (after the sixth month) and middle-aged men (between 40 and 70 years old) are most at risk of developing this condition.

Causes
As yet, there is no clear explanation for what causes this condition. Although it is most common in the hip joint, multiple joints may be affected.

Symptoms
Symptoms of this condition include a sudden onset of pain, typically in the front of the thigh, the side of the hip, the buttocks or the groin; limited motion and pain that intensifies with weight bearing or turning movements; and a change in gait as the patient tries to protect the joint and ease the pain. There may be a gradual increase in pain over a period of weeks or month that may be so intense that it is disabling.

Diagnosis
A diagnosis of transient osteoporosis of the hip is usually made by eliminating other possible causes of hip pain, such as a muscle injury or stress fracture. Your doctor will ask you whether you can remember any injury to the joint. You may also be asked to do certain range-of-motion tests to replicate the pain. Because X-rays may not show bone loss until the condition is well-advanced, your physician may request an MRI (magnetic resonance image) or bone scan to confirm the diagnosis. If you are pregnant, your physician may elect to delay any imaging studies until the last stages of your pregnancy, or even until after the delivery.

Treatment
This condition generally resolves by itself over 6 to 12 months. Treatment focuses on preventing any damage while bones are weakened by osteoporosis. If you are pregnant, this condition increases your risk of a hip fracture.

Interim treatment measures may include use of a mild pain reliever and assistive devices such as crutches, a cane, or other walking aids that help relieve the stress of weight bearing on the joint. To help maintain strength and flexibility in the muscles, your physician may also recommend a series of flexibility and range-of-motion exercises that you can do as the pain subsides. Aquatic exercises may be helpful not only because they ease movement, but also because they relieve weight bearing.