We are not aware of any cases in which the tibial component has fractured. There have been a few cases in which there have been fractures of the femoral component. These have almost all occurred when the femoral component has been used with the fixed bearing Vanguard M tibia. The fractures tend to occur just posterior to the 6 mm peg and are probably the result of inadequate posterior support.
Fourteen instances of fracture of an OUKA bearing have been reported in the literature (Berger et al, 2005; Tibrewal et al, 2014). We have also been told about a few other fractures. Fracture usually, but not always occurs with the thinnest (3.5 mm) bearings and is associated with impingement, resulting in increased wear. Treatment is by replacement with a new bearing usually one size bigger, and addressing the impingement.
The cause of bearing fracture is discussed in detail in Chapter 2. From a surgical point of view, the common factor was wear caused by impingement. The surgeon should ensure that impingement does not occur.
