Primary XXXX of the hip: extracapsular patterns of spread.

@entity11665 @entity1 @entity5
OBJECTIVE: To identify patterns of extracapsular extension of @entity11665 of the hip. DESIGN AND @entity1 : Seven cases of @entity11665 of the hip were retrospectively reviewed. Imaging performed included conventional radiography ( n=7), arthrography ( n=1), CT ( n=3) and MR imaging ( n=3). Disease extent on imaging was assessed for each @entity1 and the presence of intra-articular effusion, capsular abnormality and osteochondral bodies recorded. The presence and distribution of extra-articular spread was also assessed and correlated with the surgical findings. In all cases diagnosis was confirmed by biopsy, with all @entity1 undergoing @entity5 resection with or without synovectomy. RESULTS: In five cases (5/7) disease extended beyond the hip capsule, while the remaining two cases (2/7) were confined to the hip joint. These findings were confirmed at surgery. Two distinct patterns of extracapsular spread were identified. The first pattern, noted in three cases, involved @entity5 extension along iliopsoas. The second pattern, noted in five cases, involved @entity5 extension along the obturator externus fat plane. In three cases both patterns were present. CONCLUSIONS: Extra-articular spread of @entity11665 is common. Patterns of extra-articular spread may be predictable based on involvement of recognized periarticular bursae of the hip joint. Bursal patterns of extra-articular spread include extension into the iliopsoas bursa as well as communication along the obturator externus bursa of the hip.
