Insufficiency Fractures

Postactinic radiogenic colitis is characterized by concentric edematous thickening of the intestinal wall with preservation of the layered structure and may be associated with additional edematous thickening and infiltration of the perirectal fat. Radiation-induced stricture of the ureter or insufficiency fracture of the... 

Children with a neuromuscular disease are susceptible to insufficiency fractures of the distal femoral metaphysis due to their osteopenia. These fractures may require a manipulation and can usually be treated non-weightbearing in a long-leg cast. 

Fig. 21.5. Osteopetrosis. Osteosclerosis, modelling deformities (Erlenmeyer flask deformity distal femur) and an undisplaced insufficiency fracture of the proximal tibial diaphysis...

Fig. 21.6. Pyknodysostosis. Osteosclerosis with a chronic insufficiency fracture of the tibial diaphysis...

The spectrum of metabolic bone diseases will result in a generalized weakness of bone thereby predisposing to pathological fracture formation. In rickets, due to a dietary deficiency of vitamin D, this can manifest as insufficiency fractures in the pelvis and long bones of the lower limb (Fig. 21.14). Advances in the management of chronic renal failure... 

Fig. 21.14a,b. Rickets. Insufficiency fracture of the distal femoral diaphysis. The immature callus formation on the CT was originally misinterpreted as due to an osteosarcoma... 

Fig. 21.24. Insufficiency fracture of the distal femoral metaphysis in a child treated for a sarcoma of the proximal femur. The osteopenia is due to a combination of disuse, immobilization and chemotherapy...

Fig. 35.4. a T1-weighted image postcontrast with fat saturation shows bilateral diffuse enhancement within the sacral wings. Since the patient preciously had a carcinoma of the uterus and because of increased uptake in the bone scan, bony metastases were suspected, b CT shows serpiginous sclerosis within the sacrum parallel to the sacroiliac joint typical for sacral insufficiency fractures. The patient had previously received radiation therapy of the pelvis, which is known to result in local osteoporosis with weakening of the bone. The patient was followed-up, and bisphosphonates were administered... 

Stress fractures result from repetitive stress forces transferred to bone they can be divided in fatigue fractures and insufficiency fractures. Fatigue fractures occur when normal bone undergoes repetitive overuse stressing distal to the fracture site. Insufficiency fractures involve weakened bones that are more vulnerable to normal stresses these fractures are observed in aged women with osteoporosis and involve, in most cases, the calcaneus and the metatarsals. On the other hand, fatigue fractures typically involve the lower extremities... 

Insufficiency fractures occur when a weak bone fails as a result of repetitive loading. This condition typically involve postmenopausal women after... 

Steric Factors. Initially, most of the coUisions of fluorine molecules with saturated or aromatic hydrocarbons occur at a hydrogen site or at a TT-bond (unsaturated) site. When coUision occurs at the TT-bond, the double bond disappears but the single bond remains because the energy released in initiation (eq. 4) is insufficient to fracture the carbon—carbon single bond. Once carbon—fluorine bonds have begun to form on the carbon skeleton of either an unsaturated or alkane system, the carbon skeleton is somewhat stericaUy protected by the sheath of fluorine atoms. Figure 2, which shows the crowded hehcal arrangement of fluorine around the carbon backbone of polytetrafluoroethylene (PTFE), is an example of an extreme case of steric protection of carbon—carbon bonds (29). 

At still higher true stress, do/de, the rate of work-hardening decreases further, becoming insufficient to maintain stability - the extra stress in the neck can no longer be accommodated by the work-hardening produced by making the neck, and the neck grows faster and faster, until final fracture takes place. 

Without Vascular Insufficiency Adult (greater 50 years) Postoperative (e.g., hip fractures), soft-tissue infections 5. aureus Nafci 11 i n or cefazolin... 

Hydroxyapatite (HAP), with basically the same crystal structure as Ca-deficient, carbonate-containing hydroxyapatite, is compatible with and reactive in a live human body. However, sintered HAP prepared by treating fine HAP particles under elevated temperature and pressure has insufficient mechanical properties, in particular fracture toughness, which greatly limits its commercial applicability. It is rarely implanted alone. On the other hand, zirconia, particularly partially stabilized zirconia (PSZ),... 

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