context: BACKGROUND: Research into the optimal treatment of @entity82 has been limited by the lack of an established classification system for the disease. The purposes of this study were to develop a radiographic classification for @entity82 of the proximal femur and to test this classification's intra- and interobserver reliability as well as the effectiveness of our treatments. METHODS: We retrospectively reviewed radiographs and computed tomography (CT) of 227 femurs from 206 @entity1 with @entity82 . The radiographs were evaluated in the coronal plane for neck-shaft angle, @entity85 in the proximal femoral shaft, and distal juxtaarticular @entity85 . CT was evaluated in the axial plane for destruction of cortex. Reduction of bone strength was defined as the thickness of the remaining cortex less than 50  % of the original on axial CT. Two senior orthopedists evaluated each radiograph and CT twice at 8-week intervals. Intra- and interobserver reliability testing was performed using the kappa statistic. Treatments were assessed through mid-term follow-up. RESULTS: The 227 femurs were classified into five reproducible types: type 1 (33  %), normal bone strength without @entity85 (30  %), decreased bone strength without @entity85 ; type 3 (12  %), isolated @entity3192 with neck-shaft angle <120  ; type 4 (11  %), isolated @entity85 in the proximal femoral shaft; and type 5 (14  %), @entity3192 with @entity85 in the proximal femoral shaft. Intra- and interobserver kappa values were excellent, ranging from 0.85 to 0.88. Good clinical outcomes were achieved. CONCLUSIONS: This radiographic classification of @entity82 is reproducible and useful for describing and assessing this disease. The treatments based on this classification were effective.
  