[The coxopathies of Paget's disease. Radio-clinical and anatomopathological study].

A systematic study was carried out on 105 patients with Paget's disease (60 men and 45 women, average age 62 years) involving the acetabulum and/or the femoral head in the juxta-articular zone. In two-thirds of the patients only the pelvis (in particular the acetabulum) was affected, in a quarter both the pelvis and the femoral head were affected, and in one case in ten only the femoral head. 1. 18 coincidental coxopathies should first be excluded (12 coxarthrosis, 2 coxitis, etx.). The occurrence of 17 percent of coxopathies not caused by Paget's disease is normal in older patients (Vignon and Jacquet; Sebban, Lequesne et al.). 2. In 105 cases, there were only 50 coxopathies really due to Paget's disease, of which almost half remained painless. 3. This proportion did not vary with age. On the other hand, coxopathy was more frequent in patients with bipolar, pelvifemoral Paget's disease and above all in Paget's disease with acetabular protrusio. 4. The radiographic appearance is slightly different from that of coxarthrosis; the reduction in joint space is more often internal or supero-internal (50 percent of cases); osteophytosis is usually moderate (22 percent of cases), or absent (48 percent). The geodes are rarely visible : 6 percent of cases. 5. The acquired bone deformations in patients with Paget's disease are classical. In 105 cases, the authors noted 14 acetabular protrusions, all with coxopathies, and 10 coxa vara, 5 of which had coxapathies. Anatomo-pathological studies did not reveal anything in particular about the bone : superimposition of the Paget's disease lesions and of the lesions usually found in cases of coxopathy due to overload, with a dense pressure cone. With reference to cartilage, the lesions of Paget's coxopathies presented several specific characteristics compared with those of common arthrosis : (1) the presence of particularly numerous cupshaped defects on the remaining cartilage; (2) a very basophilic, intra- and extra-cytoplasmic substance impregnated the chondroplasts of the bottom layer, nine times out of twenty-six, an anomaly not observed in cases of arthrosis; (3) pseudo-angiomatous vascular outgrowths from the bone, flush with the articular surface of the acetabulum are a source of bleeding during surgery.