[Imaging of chronic hip pain in adults].

Adult hip pathologies are mainly represented by the degenerative disease, so called "osteoarthrosis, or more precisely coxarthrosis". The means of imaging are exposed, according to their specific value: X Rays (measurement of the characteristic angles of the adult hip), Arthrography, CT Scanner, Arthro-CT Scanner, MRI, Bone Scintigraphy, Ultrasonography. Clinical findings differentiate a mechanical syndrome and an inflammatory syndrome. The coxarthrosis is the most frequent, under two forms: primary (idiopathic) coxarthrosis and secondary coxarthrosis. Primary (idiopathic) coxarthrosis has a localised narrowing of the joint space, osteophyte formation, subchondral sclerosis, cyst formation. The destruction progresses slowly, in 10 to 15 years leading to a complete destruction. Bilaterality is frequent. it is treated with total hip prosthesis. There is a rapid form (1 to 2 years) (Postel's Disease). Secondary coxarthrosis occurs after architectural vice, chondral diseases, lack of balance between the size of the head and the acetabulum as in the case of previous fracture or dislocation, avascular bone necrosis of the head of the femur, Paget's disease. Calcium pyrophosphate Deposition disease (CPPD) involves mostly aged women, and also leads to cox-arthrosis. Avascular bone necrosis of the head of the femur involves young adults. Bilateral involvement are frequent. MRI is the most sensitive and the most specific means of early diagnosis, The area of bone necrosis appears as well defined modifications of the upper head of the femur, precisely surrounded by a low signal intensity line on both Ti and T2 weighted imaging. MRI shows articular effusion, bone marrow edema. Scintigraphy gives early findings which are a characteristic, but non specific, hot spot. CT scanner is used for hip destruction evaluation. o Algodystrophy: transient osteoporosis of the hip has a cyclic course, lasting 3 to 9 months. MRI shows an inflammatory pattern in the area of the process(dark in Ti and white in T2, with positive Gadolinium response). Scintigraphy is positive. Staphylococcus location in the hip can be acute or chronic. MRI shows joint effusion, cystic formation and subchondral non specific modifications. Tuberculosis of the hip joint is relatively rare. Greater trochanteric tuberculous involvement is possible under special contexts. Chronic Inflammatory diseases are represented by Rheumatoid Arthritis, Spondylarthritis and other chronic inflammatory diseases. Synovial tumors such as Pigmented Villo Nodular Synovitis, Primary Osteochondromatosis, synovial sarcoma have special presentations. The subchondral bone can be involved by amorphous depositions such as in tophaceous gout, different varieties of lipidosis, amyloidosis, reticulo histiocytosis. Pen arthropathies are enthesopathies in the anterior rectus tendon, calcifying tendonitis (not to be confused with calcifying soft tissue tumor/chondrosarcoma). The pelvis bone and the femur are involved by primary and secondary tumors or by insufficiency fractures which can mislead to hip pathologies.