Pseudoarthrosis

The balance between these tissue varieties is controlled by the action of chemical mediators which issue instructions for the amount of bone and soft tissue to be formed as an appropriate healing response. This delicate balance can easily be disturbed inadvertently and may cause the undesirable end-result of an interfacial soft tissue embedment of the implant or, in the case of fracture healing, formation of a pseudoarthrosis. The discussion in this section will focus on various modes of implant fixation, such as cementation, ingrowth and osseointegration (Figure 3.1). 

Congenital pseudoarthrosis of the clavicle may he mistaken for a fracture. This condition is almost always right sided and rarely hilateral. It usually presents with a painless, palpable prominence in the mid-portion of the clavicle. Approximately half of all patients present in the first 2 weeks of life, the others during childhood. The differential diagnosis includes cleidocranial dysostosis or a birth injury. Radiographically there is a defect in the middle segment of the clavicle, and the ends of the bones are... 

Fig. 7.5. Typical appearances of congenital pseudoarthrosis of the right clavicle in a 5-week-old infant...

When indicated surgical treatment requires excision of the pseudoarthrosis, grafting and plate fixation. 

Even during World War I, Lobmayer claimed that the Turkish soldiers suffered severely from scurvy and that in those who developed the disease both skin and flesh wounds and fractures healed poorly. In many cases the fractures showed not the slightest sign of the formation of a callus, even after several months. In confirmation of the fact that it was lack of the antiscorbutic substance which was directly responsible for this failure of fractures to unite, he quoted two cases who suffered from pseudoarthrosis of the humerus and who recovered rapidly and completely as soon as they were put on a diet which was rich in antiscorbutic material. 

The scaphoid is the most common site of occult fractures in the wrist area, with up to 20-25% of cases unnoticed at the initial evaluation (Waizenegger et al. 1994). When the diagnosis is delayed, scaphoid fi actures have high rates of complications such as pseudoarthrosis, avascular necrosis of the proximal pole of the bone and secondary radiocarpal osteoarthritis with chronic pain and impaired function. A variety of diagnostic modalities, such as additional radiographic views, bone scan, CT and MR imaging, have been advocated for early detection of scaphoid fractures. The choice between an addi-... 

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