Objective To improve the recognition of synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome by investigating its clinical features and imaging manifestations. Methods The data of 14 patients with SAPHO syndrome (8 males, 6 females, age range: 18-61 years) between January 2014 and January 2017 were retrospectively analyzed. The clinical features, the results of laboratory (erythrocyte sedimentation rate (ESR), C reaction protein (CRP), complement component 3 (C3) and component 4 (C4), human leukocyte antigen (HLA)-B27) tests, pathology and imaging examinations (CT and whole-body bone im-aging) were collected. Results SAPHO syndrome was mainly characterized by skin damage and bone joint damage. The main manifestations of skin lesions were pustules, desquamation and erythema. Those of bone and joint injury were sternocostoclavicular hyperostosis, stiff spinal hyperostosis, peripheral arthritis, and sacroiliitis. There were 5 with fasting ESR, 5 with abnormal CRP, 3 with abnormal C3, and 1 with abnormal C4 among 14 patients. HLA-B27 was negative in all patients. Whole-body bone imaging revealed that 14 pa-tients had abnormal radioactivity, mainly involving the anterior chest wall, spine, pelvis and long bone. Chest CT manifestations of the patients were the destruction of joint bone, the fusion of the hypertrophy and the narrowing of the joint space. Symmetric lesions accounted for the majority. Pathology examination showed non-specific inflammation in 9 patients. Conclusions SAPHO syndrome is a disease characterized by skin, bone and joint abnormalities. Whole-body bone imaging can find systemic bone damage in early stage, and CT can detect bone changes and soft tissue lesions.

Objective:To establish a model of patellar dislocation by femoral osteotomy or surgical release of medial retinaculum in immature rabbits, and observe morphological and trabecular microarchitectural changes in the trochlea.Methods:Forty rabbits at 3 months of age were included. All right knees underwent surgery, 20 knees were treated with femoral osteotomy and internal rotation of distal femur to increase femoral anteversion angle (Osteotomy group, OS group), and another 20 knees were treated with surgical release of medial retinaculum and overlap suture of lateral retinaculum (Soft tissue group, ST group). All left knees were acting as internal controls. Micro-CT scans for distal femur were acquired after 4 months post surgery. the height of Medial, central, and lateral trochlear, sulcus angle, and lateral and medial trochlear slope were measured to describe the trochlear morphology, and bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular spacing (Tb.Sp), and bone mineral density (BMD) were calculated to evaluate the microarchitectural structure. All parameters were compared between groups.Results:In OS group, one rabbit sustained a hip dislocation without patellar dislocation. Three knees developed complete patellar dislocation in daily flexion position, and the remaining 16 patellae were dislocated when the knee was placed in the maximal extension position. In ST group, 15 knees were complete patellar dislocation in daily flexion position, and 5 knees were without dislocation. A local boss was formed proximal to the entrance of the groove and the articular cartilage was smooth, and no obvious osteoarthritis was observed in OS group. In ST group no boss was formed, while obvious cartilage degeneration and defect was seen. Compared to the control group, the central trochlear height and sulcus angle were greater in both groups, but without significant difference between the two groups. The Tb.Th was increased in both medial and lateral condyle, and Tb.N was decreased in medial condyle compared with its control knees in OS group. The BV/TV, Tb.Th, Tb.N and BMD were decreased and Tb.Sp was increased in both medial and lateral condyle compared with its control knees in ST group. Compared to the OS group, the BV/TV, Tb.Th, Tb.N and BMD were smaller and Tb.Sp was greater in both medial and lateral condyle in ST group, with significant differences.Conclusion:The model of patellar dislocation could be successfully achieved by femoral rotational osteotomy to increase femoral anteversion or surgical release of medial retinaculum and overlap suture of lateral retinaculum, and subsequent morphological and trabecular microarchitectural changes in the trochlea are different. Different bony and soft tissue factors should be addressed for different patients with patellar dislocation in clinical practice.