Subchondral insufficiency fracture (SIF) of the femoral head is one of the predominant etiologies of rapidly progressive osteoarthritis of the hip (RPOH). SIF is a rare disease that causes acute pain in the hip joint. It is most frequently found in elderly women with osteoporosis. It is often underdiagnosed or misdiagnosed as osteonecrosis of the femoral head. SIF is currently a well-established cause of RPOH; however, the deeper etiology of SIF is not clear. Good clinical outcomes have been reported for hip preservation therapy and hip replacement. SIF is not obvious radiologically in the early stage, and a T1-weighted magnetic resonance imaging shows a discontinuous low-intensity band under the articular cartilage convex to the articular surface as its characteristic manifestation. Some patients will lose the opportunity to preserve the hip joint due to symptoms such as progressive joint space narrowing and subchondral collapse within a very short period. Patients with progressive hip space narrowing and subchondral collapse on X-ray should be converted to total hip arthroplasty. Based on the characteristics of the disease, surgeons need to master the clinical and radiological characteristics of SIF and strive for early diagnosis and treatment.

No abstract

No abstract

No abstract

As the sandwich structure materials extensively used in the engineering field, the existing sandwich structure materials can not meet the requirements of engineering design gradually. New sandwich structural materials with efficient, energy-saving and easy processing need to be developed urgently. Relying on the mature research results now on honeycomb sandwich structure, the class-honeycomb sandwich structure is put forward for the first time, meanwhile, innovate configuration in the structure. Based on this, the paper analyzes the mechanics properties of the structure and the results showed that the new class-honeycomb sandwich structures mechanics properties have improved greatly compared with the original hexagonal honeycomb sandwich structure. And also simulation analysis was carried out on the cores structure. The validity of the equivalent elastic constant is confirmed through the theoretical analysis and simulation analysis. For this reason, it has great theoretical significance and engineering application value.